[PATCH v3 0/3] Add ANX7814 I2C bridge driver

[PATCH v3 0/3] Add ANX7814 I2C bridge driver

[Enric Balletbo i Serra]

Hi all,

This is the third version of the patch, thanks to all that did some comments.
Since I got some reviews and acks I'm wondering if would be possible to land
these patches. Otherwise all reviews are welcome.

I'm not sure if there is a drm bridge maintainer, I think Thierry Reding
maintained this in the past but I'm not sure he's still maintaining the bridge
drivers, so who is the most suitable person to pick up the patches if they are
ok? Maybe Dave?

This patch set to introduces the anx7814 slimport transmitter driver. These
new series will replace the old series that can be found here [1]. The reason
why I introduce these new series is because the driver changed significantly.
The old approach used a polled state machine ans was not really well using the
kernel mode setting API. With this new driver I tried to use better the drm API
and use an interrupt driven model.

Changes since v2:
 - Add Acked-by: Rob Herring <robh@kernel.org> for patch 0002
 - Add Tested-by: Nicolas Boichat <drinkcat@chromium.org>
 - Add Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
 - Nicolas Boichat:
   - Get rid of wait_for macro since is only used once.
   - Do not replace the error code if it's readily available to you.

Changes since v1:
 - Add Acked-by: Rob Herring <robh@kernel.org> for patch 0001
 - Dan Carpenter: 
   - Fix missing error code
   - Use meaningful names for goto exit paths
 - Rob Herring:
   - Rename cable-det-gpios for hpd-gpios as is more standard
   - Fix HDMI output for HDMI input
   - Use hpd instead cable_det as is the more standard name.
 - Daniel Kurtz: 
   - Use regmap_bulk in aux_transfer
   - Fix gpio reset polarity.
   - Turn off v10 last so we mirror poweron sequence
   - Fix some error paths.
   - Remove mutex in anx78xx_detect
 - kbuild:
   - WARNING: PTR_ERR_OR_ZERO can be used

[1] https://lwn.net/Articles/666885/

Enric Balletbo i Serra (3):
  of: Add vendor prefix for Analogix Semiconductor
  devicetree: Add ANX7814 SlimPort transmitter binding.
  drm: bridge: anx78xx: Add anx78xx driver support.

 .../devicetree/bindings/vendor-prefixes.txt        |    1 +
 .../devicetree/bindings/video/bridge/anx7814.txt   |   41 +
 drivers/gpu/drm/bridge/Kconfig                     |    8 +
 drivers/gpu/drm/bridge/Makefile                    |    1 +
 drivers/gpu/drm/bridge/anx78xx.c                   | 1403 ++++++++++++++++++++
 drivers/gpu/drm/bridge/anx78xx.h                   |  719 ++++++++++
 6 files changed, 2173 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/video/bridge/anx7814.txt
 create mode 100644 drivers/gpu/drm/bridge/anx78xx.c
 create mode 100644 drivers/gpu/drm/bridge/anx78xx.h

-- 
2.1.0

[PATCH v3 1/3] of: Add vendor prefix for Analogix Semiconductor

[Enric Balletbo i Serra]

Analogix Semiconductor Inc. develops analog and mixed-signal devices for
digital media and communications interconnect applications.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Rob Herring <robh@kernel.org>
---
Changes since v2:
 - None

Changes since v1:
 - Add Acked-by: Rob Herring <robh@kernel.org>

 Documentation/devicetree/bindings/vendor-prefixes.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
index 86740d4..683320a 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.txt
+++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
@@ -22,6 +22,7 @@ amlogic	Amlogic, Inc.
 ampire	Ampire Co., Ltd.
 ams	AMS AG
 amstaos	AMS-Taos Inc.
+analogix	Analogix Semiconductor, Inc.
 apm	Applied Micro Circuits Corporation (APM)
 aptina	Aptina Imaging
 arasan	Arasan Chip Systems
-- 
2.1.0

[PATCH v3 2/3] devicetree: Add ANX7814 SlimPort transmitter binding.

[Enric Balletbo i Serra]

The ANX7814 is an ultra-low power Full-HD (1080p60) SlimPort transmitter
designed for portable devices.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Rob Herring <robh@kernel.org>
---
Changes since v2:
 - Add Acked-by: Rob Herring <robh@kernel.org>

Changes since v1:
 - Rob Herring:
   - Rename cable-det-gpios for hpd-gpios as is more standard
   - Fix HDMI output for HDMI input

 .../devicetree/bindings/video/bridge/anx7814.txt   | 41 ++++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/video/bridge/anx7814.txt

diff --git a/Documentation/devicetree/bindings/video/bridge/anx7814.txt b/Documentation/devicetree/bindings/video/bridge/anx7814.txt
new file mode 100644
index 0000000..0ce4978
--- /dev/null
+++ b/Documentation/devicetree/bindings/video/bridge/anx7814.txt
@@ -0,0 +1,41 @@
+Analogix ANX7814 SlimPort (Full-HD Transmitter)
+-----------------------------------------------
+
+The ANX7814 is an ultra-low power Full-HD (1080p60) SlimPort transmitter
+designed for portable devices.
+
+Required properties:
+
+ - compatible		: "analogix,anx7814"
+ - reg			: I2C address of the device
+ - interrupt-parent	: Should be the phandle of the interrupt controller
+			  that services interrupts for this device
+ - interrupts		: Should contain the INTP interrupt
+ - hpd-gpios		: Which GPIO to use for hpd
+ - pd-gpios		: Which GPIO to use for power down
+ - reset-gpios		: Which GPIO to use for reset
+
+Optional properties:
+
+ - v10-gpios		: Which GPIO to use for V10 control.
+ - Video port for HDMI input, using the DT bindings defined in [1].
+
+[1]: Documentation/devicetree/bindings/media/video-interfaces.txt
+
+Example:
+
+	anx7814: anx7814@38 {
+		compatible = "analogix,anx7814";
+		reg = <0x38>;
+		interrupt-parent = <&gpio0>;
+		interrupts = <99 IRQ_TYPE_LEVEL_LOW>;   /* INTP */
+		hpd-gpios = <&pio 36 GPIO_ACTIVE_HIGH>;
+		pd-gpios = <&pio 33 GPIO_ACTIVE_HIGH>;
+		reset-gpios = <&pio 98 GPIO_ACTIVE_HIGH>;
+		v10-gpios = <&pio 35 GPIO_ACTIVE_HIGH>;
+		port {
+			anx7814_in: endpoint {
+				remote-endpoint = <&hdmi0_out>;
+			};
+		};
+	};
-- 
2.1.0

[PATCH v3 3/3] drm: bridge: anx78xx: Add anx78xx driver support.

[Enric Balletbo i Serra]

Although there are other chips from the same family that can reuse this
driver, at the moment we only tested ANX7814 chip.

The ANX7814 is an ultra-low power Full-HD (1080p60) SlimPort transmitter
designed for portable devices. This driver adds initial support for HDMI
to DP pass-through mode.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Tested-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Daniel Kurtz <djkurtz@chromium.org>
Cc: Nicolas Boichat <drinkcat@chromium.org>
---
Changes since v2:
 - Nicolas Boichat:
   - Get rid of wait_for macro since is only used once.
   - Do not replace the error code if it's readily available to you.
 - Add Tested-by: Nicolas Boichat <drinkcat@chromium.org>
 - Add Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>

Changes since v1:
 - Dan Carpenter: 
   - Fix missing error code
   - Use meaningful names for goto exit paths
 - Rob Herring: 
   - Use hpd instead cable_det as is the more standard name.
 - Daniel Kurtz: 
   - Use regmap_bulk in aux_transfer
   - Fix gpio reset polarity.
   - Turn off v10 last so we mirror poweron sequence
   - Fix some error paths.
   - Remove mutex in anx78xx_detect
 - kbuild:
   - WARNING: PTR_ERR_OR_ZERO can be used

 drivers/gpu/drm/bridge/Kconfig   |    8 +
 drivers/gpu/drm/bridge/Makefile  |    1 +
 drivers/gpu/drm/bridge/anx78xx.c | 1403 ++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/bridge/anx78xx.h |  719 +++++++++++++++++++
 4 files changed, 2131 insertions(+)
 create mode 100644 drivers/gpu/drm/bridge/anx78xx.c
 create mode 100644 drivers/gpu/drm/bridge/anx78xx.h

diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index 27e2022..0f595ae 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -40,4 +40,12 @@ config DRM_PARADE_PS8622
 	---help---
 	  Parade eDP-LVDS bridge chip driver.
 
+config DRM_ANX78XX
+	tristate "Analogix ANX78XX bridge"
+	select DRM_KMS_HELPER
+	select REGMAP_I2C
+	---help---
+	  ANX78XX is a HD video transmitter chip over micro-USB connector
+	  for smartphone device.
+
 endmenu
diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
index f13c33d..8f0d69e 100644
--- a/drivers/gpu/drm/bridge/Makefile
+++ b/drivers/gpu/drm/bridge/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
 obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
 obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
 obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
+obj-$(CONFIG_DRM_ANX78XX) += anx78xx.o
diff --git a/drivers/gpu/drm/bridge/anx78xx.c b/drivers/gpu/drm/bridge/anx78xx.c
new file mode 100644
index 0000000..c782e68
--- /dev/null
+++ b/drivers/gpu/drm/bridge/anx78xx.c
@@ -0,0 +1,1403 @@
+/*
+ * Copyright(c) 2016, Analogix Semiconductor.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Based on anx7808 driver obtained from chromeos with copyright:
+ * Copyright(c) 2013, Google Inc.
+ *
+ */
+#include <linux/async.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_gpio.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+#include <linux/gpio/consumer.h>
+#include <drm/drmP.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_dp_helper.h>
+#include <drm/drm_edid.h>
+
+#include "anx78xx.h"
+
+#define I2C_NUM_ADDRESSES	5
+#define I2C_IDX_TX_P0		0
+#define I2C_IDX_TX_P1		1
+#define I2C_IDX_TX_P2		2
+#define I2C_IDX_RX_P0		3
+#define I2C_IDX_RX_P1		4
+
+#define XTAL_CLK		270 /* 27M */
+#define AUX_CH_BUFFER_SIZE	16
+#define AUX_WAIT_TIMEOUT_MS	15
+
+static const u8 anx78xx_i2c_addresses[] = {
+	[I2C_IDX_TX_P0] = TX_P0,
+	[I2C_IDX_TX_P1] = TX_P1,
+	[I2C_IDX_TX_P2] = TX_P2,
+	[I2C_IDX_RX_P0] = RX_P0,
+	[I2C_IDX_RX_P1] = RX_P1,
+};
+
+struct anx78xx_platform_data {
+	struct gpio_desc *gpiod_hpd;
+	struct gpio_desc *gpiod_pd;
+	struct gpio_desc *gpiod_reset;
+	struct gpio_desc *gpiod_v10;
+
+	int hpd_irq;
+	int intp_irq;
+};
+
+struct anx78xx {
+	struct drm_dp_aux aux;
+	struct drm_bridge bridge;
+	struct i2c_client *client;
+	struct edid *edid;
+	struct drm_connector connector;
+	struct drm_dp_link link;
+	struct anx78xx_platform_data pdata;
+	struct mutex lock;
+
+	/*
+	 * I2C Slave addresses of ANX7814 are mapped as TX_P0, TX_P1, TX_P2,
+	 * RX_P0 and RX_P1.
+	 */
+	struct i2c_client *i2c_dummy[I2C_NUM_ADDRESSES];
+	struct regmap *map[I2C_NUM_ADDRESSES];
+
+	u16 chipid;
+	u8 dpcd[DP_RECEIVER_CAP_SIZE];
+
+	bool powered;
+};
+
+static int anx78xx_set_bits(struct regmap *map, u8 reg, u8 mask)
+{
+	return regmap_update_bits(map, reg, mask, mask);
+}
+
+static int anx78xx_clear_bits(struct regmap *map, u8 reg, u8 mask)
+{
+	return regmap_update_bits(map, reg, mask, 0);
+}
+
+static int anx78xx_aux_op_finished(struct anx78xx *anx78xx)
+{
+	int err;
+	unsigned int aux_ctrl;
+
+	err = regmap_read(anx78xx->map[I2C_IDX_TX_P0], SP_DP_AUX_CH_CTRL2_REG,
+			  &aux_ctrl);
+	if (err)
+		return err;
+
+	if (aux_ctrl & SP_AUX_EN)
+		return -EAGAIN;
+
+	return 0;
+}
+
+static int anx78xx_aux_wait(struct anx78xx *anx78xx)
+{
+	int err;
+	unsigned int status;
+	unsigned long timeout;
+
+	/*
+	 * Does the right thing for modeset paths when run under kdgb or
+	 * similar atomic contexts. Note that it's important that we check the
+	 * condition again after having timed out, since the timeout could be
+	 * due to preemption or similar and we've never had a chance to check
+	 * the condition before the timeout.
+	 */
+	err = 0;
+	timeout = jiffies + msecs_to_jiffies(AUX_WAIT_TIMEOUT_MS) + 1;
+	while (anx78xx_aux_op_finished(anx78xx)) {
+		if (time_after(jiffies, timeout)) {
+			if (anx78xx_aux_op_finished(anx78xx))
+				err = -ETIMEDOUT;
+			break;
+		}
+		if (drm_can_sleep())
+			usleep_range(1000, 2000);
+		else
+			cpu_relax();
+	}
+
+	if (err) {
+		DRM_ERROR("Timed out waiting AUX to finish\n");
+		return -ETIMEDOUT;
+	}
+
+	/* Read the AUX channel access status */
+	err = regmap_read(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_CH_STATUS_REG,
+			  &status);
+	if (err)
+		return err;
+
+	if (status & SP_AUX_STATUS) {
+		DRM_ERROR("Failed to read AUX channel: 0x%02x\n", status);
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int anx78xx_aux_address(struct anx78xx *anx78xx, unsigned int addr)
+{
+	int err = 0;
+
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_7_0_REG,
+			    addr & 0xff);
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_15_8_REG,
+			    (addr & 0xff00) >> 8);
+
+	/*
+	 * DP AUX CH Address Register #2, only update bits[3:0]
+	 * [7:4] RESERVED
+	 * [3:0] AUX_ADDR[19:16], Register control AUX CH address.
+	 */
+	err |= regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
+				  SP_AUX_ADDR_19_16_REG,
+				  SP_AUX_ADDR_19_16_MASK,
+				  (addr & 0xf0000) >> 16);
+
+	if (err)
+		return -EIO;
+
+	return 0;
+}
+
+static ssize_t anx78xx_aux_transfer(struct drm_dp_aux *aux,
+				    struct drm_dp_aux_msg *msg)
+{
+	int err = 0;
+	struct anx78xx *anx78xx = container_of(aux, struct anx78xx, aux);
+	u8 ctrl1 = msg->request;
+	u8 ctrl2 = SP_AUX_EN;
+	u8 *buffer = msg->buffer;
+
+	/* The DP AUX transmit and receive buffer has 16 bytes. */
+	if (WARN_ON(msg->size > AUX_CH_BUFFER_SIZE))
+		return -E2BIG;
+
+	/* Zero-sized messages specify address-only transactions. */
+	if (msg->size < 1)
+		ctrl2 |= SP_ADDR_ONLY;
+	else	/* For non-zero-sized set the length field. */
+		ctrl1 |= (msg->size - 1) << SP_AUX_LENGTH_SHIFT;
+
+	if ((msg->request & DP_AUX_I2C_READ) == 0) {
+		/* When WRITE | MOT write values to data buffer */
+		err = regmap_bulk_write(anx78xx->map[I2C_IDX_TX_P0],
+					SP_DP_BUF_DATA0_REG, buffer,
+					msg->size);
+		if (err)
+			return err;
+	}
+
+	/* Write address and request */
+	err = anx78xx_aux_address(anx78xx, msg->address);
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_DP_AUX_CH_CTRL1_REG,
+			    ctrl1);
+	if (err)
+		return -EIO;
+
+	/* Start transaction */
+	err = regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
+				 SP_DP_AUX_CH_CTRL2_REG, SP_ADDR_ONLY |
+				 SP_AUX_EN, ctrl2);
+	if (err)
+		return err;
+
+	err = anx78xx_aux_wait(anx78xx);
+
+	msg->reply = err ? DP_AUX_I2C_REPLY_NACK : DP_AUX_I2C_REPLY_ACK;
+
+	if ((msg->size > 0) && (msg->request & DP_AUX_I2C_READ)) {
+		/* Read values from data buffer */
+		err = regmap_bulk_read(anx78xx->map[I2C_IDX_TX_P0],
+				       SP_DP_BUF_DATA0_REG, buffer,
+				       msg->size);
+		if (err)
+			return err;
+	}
+
+	err = anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P0],
+				 SP_DP_AUX_CH_CTRL2_REG, SP_ADDR_ONLY);
+	if (err)
+		return err;
+
+	return msg->size;
+}
+
+static int anx78xx_set_hpd(struct anx78xx *anx78xx)
+{
+	int err = 0;
+
+	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_RX_P0],
+				  SP_TMDS_CTRL_BASE + 7, SP_PD_RT);
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL3_REG,
+				SP_HPD_OUT);
+
+	if (err)
+		return -EIO;
+
+	return 0;
+}
+
+static int anx78xx_clear_hpd(struct anx78xx *anx78xx)
+{
+	int err = 0;
+
+	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL3_REG,
+				  SP_HPD_OUT);
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_RX_P0],
+				SP_TMDS_CTRL_BASE + 7, SP_PD_RT);
+
+	if (err)
+		return -EIO;
+
+	return 0;
+}
+
+static const struct reg_sequence tmds_phy_initialization[] = {
+	{ SP_TMDS_CTRL_BASE + 1, 0x90 },
+	{ SP_TMDS_CTRL_BASE + 2, 0xa9 },
+	{ SP_TMDS_CTRL_BASE + 6, 0x92 },
+	{ SP_TMDS_CTRL_BASE + 7, 0x80 },
+	{ SP_TMDS_CTRL_BASE + 20, 0xf2 },
+	{ SP_TMDS_CTRL_BASE + 22, 0xc4 },
+	{ SP_TMDS_CTRL_BASE + 23, 0x18 },
+};
+
+static int anx78xx_rx_initialization(struct anx78xx *anx78xx)
+{
+	int err = 0;
+
+	err |= regmap_write(anx78xx->map[I2C_IDX_RX_P0], SP_HDMI_MUTE_CTRL_REG,
+			    SP_AUD_MUTE | SP_VID_MUTE);
+
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_RX_P0], SP_CHIP_CTRL_REG,
+				SP_MAN_HDMI5V_DET | SP_PLLLOCK_CKDT_EN |
+				SP_DIGITAL_CKDT_EN);
+
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_RX_P0],
+				SP_SOFTWARE_RESET1_REG, SP_HDCP_MAN_RST |
+				SP_SW_MAN_RST | SP_TMDS_RST | SP_VIDEO_RST);
+
+	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_RX_P0],
+				  SP_SOFTWARE_RESET1_REG, SP_HDCP_MAN_RST |
+				  SP_SW_MAN_RST | SP_TMDS_RST | SP_VIDEO_RST);
+
+	/* Sync detect change, GP set mute */
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_RX_P0],
+				SP_AUD_EXCEPTION_ENABLE_BASE + 1, BIT(5) |
+				BIT(6));
+
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_RX_P0],
+				SP_AUD_EXCEPTION_ENABLE_BASE + 3,
+				SP_AEC_EN21);
+
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_RX_P0], SP_AUDVID_CTRL_REG,
+				SP_AVC_EN | SP_AAC_OE | SP_AAC_EN);
+
+	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_RX_P0],
+				  SP_SYSTEM_POWER_DOWN1_REG, SP_PWDN_CTRL);
+
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_RX_P0],
+				SP_VID_DATA_RANGE_CTRL_REG, SP_R2Y_INPUT_LIMIT);
+
+	/* Enable DDC stretch */
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0],
+			    SP_DP_EXTRA_I2C_DEV_ADDR_REG, SP_I2C_EXTRA_ADDR);
+
+	/* TMDS phy initialization */
+	err |= regmap_multi_reg_write(anx78xx->map[I2C_IDX_RX_P0],
+				      tmds_phy_initialization,
+				      ARRAY_SIZE(tmds_phy_initialization));
+
+	err |= anx78xx_clear_hpd(anx78xx);
+
+	if (err)
+		return -EIO;
+
+	return 0;
+}
+
+static const u8 dp_tx_output_precise_tune_bits[20] = {
+	0x01, 0x03, 0x07, 0x7f, 0x71, 0x6b, 0x7f,
+	0x73, 0x7f, 0x7f, 0x00, 0x00, 0x00, 0x00,
+	0x0c, 0x42, 0x1e, 0x3e, 0x72, 0x7e,
+};
+
+static int anx78xx_link_phy_initialization(struct anx78xx *anx78xx)
+{
+	int err = 0;
+
+	/*
+	 * REVISIT : It is writing to a RESERVED bits in Analog Control 0
+	 * register.
+	 */
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P2], SP_ANALOG_CTRL0_REG,
+			    0x02);
+
+	/*
+	 * Write DP TX output emphasis precise tune bits.
+	 */
+	err |= regmap_bulk_write(anx78xx->map[I2C_IDX_TX_P1],
+				 SP_DP_TX_LT_CTRL0_REG,
+				 dp_tx_output_precise_tune_bits,
+				 ARRAY_SIZE(dp_tx_output_precise_tune_bits));
+
+	if (err)
+		return -EIO;
+
+	return 0;
+}
+
+static int anx78xx_xtal_clk_sel(struct anx78xx *anx78xx)
+{
+	int err = 0;
+	unsigned int regval;
+
+	err |= regmap_update_bits(anx78xx->map[I2C_IDX_TX_P2],
+				  SP_ANALOG_DEBUG2_REG,
+				  SP_XTAL_FRQ | SP_FORCE_SW_OFF_BYPASS,
+				  SP_XTAL_FRQ_27M);
+
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_DP_AUX_CH_CTRL3_REG,
+			    XTAL_CLK & SP_WAIT_COUNTER_7_0_MASK);
+
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_DP_AUX_CH_CTRL4_REG,
+			    ((XTAL_CLK & 0xff00) >> 2) | (XTAL_CLK / 10));
+
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0],
+			    SP_I2C_GEN_10US_TIMER0_REG, XTAL_CLK & 0xff);
+
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0],
+			    SP_I2C_GEN_10US_TIMER1_REG,
+			    (XTAL_CLK & 0xff00) >> 8);
+
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_MISC_CTRL_REG,
+			    XTAL_CLK / 10 - 1);
+
+	err |= regmap_read(anx78xx->map[I2C_IDX_RX_P0],
+			   SP_HDMI_US_TIMER_CTRL_REG,
+			   &regval);
+
+	err |= regmap_write(anx78xx->map[I2C_IDX_RX_P0],
+			    SP_HDMI_US_TIMER_CTRL_REG,
+			    (regval & SP_MS_TIMER_MARGIN_10_8_MASK) |
+			    ((((XTAL_CLK / 10) >> 1) - 2) << 3));
+
+	if (err)
+		return -EIO;
+
+	return 0;
+}
+
+static const struct reg_sequence otp_key_protect[] = {
+	{ SP_OTP_KEY_PROTECT1_REG, SP_OTP_PSW1 },
+	{ SP_OTP_KEY_PROTECT2_REG, SP_OTP_PSW2 },
+	{ SP_OTP_KEY_PROTECT3_REG, SP_OTP_PSW3 },
+};
+
+static int anx78xx_tx_initialization(struct anx78xx *anx78xx)
+{
+	int err = 0;
+
+	/* Set terminal resistor to 50 ohm */
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_DP_AUX_CH_CTRL2_REG,
+			    0x30);
+
+	/* Enable aux double diff output */
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P0],
+				SP_DP_AUX_CH_CTRL2_REG, 0x08);
+
+	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P0],
+				  SP_DP_HDCP_CTRL_REG, SP_AUTO_EN |
+				  SP_AUTO_START);
+
+	err |= regmap_multi_reg_write(anx78xx->map[I2C_IDX_TX_P0],
+				      otp_key_protect,
+				      ARRAY_SIZE(otp_key_protect));
+
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P0],
+				SP_HDCP_KEY_COMMAND_REG, SP_DISABLE_SYNC_HDCP);
+
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL8_REG,
+			    SP_VID_VRES_TH);
+
+	/*
+	 * DP HDCP auto authentication wait timer (when downstream starts to
+	 * auth, DP side will wait for this period then do auth automatically)
+	 */
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_HDCP_AUTO_TIMER_REG,
+			    0x00);
+
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P0],
+				SP_DP_HDCP_CTRL_REG, SP_LINK_POLLING);
+
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P0],
+				SP_DP_LINK_DEBUG_CTRL_REG, SP_M_VID_DEBUG);
+
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2],
+				SP_ANALOG_DEBUG2_REG, SP_POWERON_TIME_1P5MS);
+
+	err |= anx78xx_xtal_clk_sel(anx78xx);
+
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_DEFER_CTRL_REG,
+			    SP_DEFER_CTRL_EN | 0x0c);
+
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P0],
+				SP_DP_POLLING_CTRL_REG,
+				SP_AUTO_POLLING_DISABLE);
+
+	/*
+	 * Short the link integrity check timer to speed up bstatus
+	 * polling for HDCP CTS item 1A-07
+	 */
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0],
+			    SP_HDCP_LINK_CHECK_TIMER_REG, 0x1d);
+
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P0],
+				SP_DP_MISC_CTRL_REG, SP_EQ_TRAINING_LOOP);
+
+	/* Power down the main link by default */
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P0],
+				SP_DP_ANALOG_POWER_DOWN_REG, SP_CH0_PD);
+
+	err |= anx78xx_link_phy_initialization(anx78xx);
+
+	/* Gen m_clk with downspreading */
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P0],
+				SP_DP_M_CALCULATION_CTRL_REG, SP_M_GEN_CLK_SEL);
+
+	if (err)
+		return -EIO;
+
+	return 0;
+}
+
+static int anx78xx_enable_interrupts(struct anx78xx *anx78xx)
+{
+	int err = 0;
+
+	/*
+	 * BIT0: INT pin assertion polarity: 1 = assert high
+	 * BIT1: INT pin output type: 0 = push/pull
+	 */
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P2], SP_INT_CTRL_REG, 0x01);
+
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P2],
+			    SP_COMMON_INT_MASK4_REG, SP_HPD_LOST | SP_HPD_PLUG);
+
+	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P2], SP_DP_INT_MASK1_REG,
+			    SP_TRAINING_FINISH);
+
+	err |= regmap_write(anx78xx->map[I2C_IDX_RX_P0], SP_INT_MASK1_REG,
+			    SP_CKDT_CHG | SP_SCDT_CHG);
+
+	if (err)
+		return -EIO;
+
+	return 0;
+}
+
+static void anx78xx_poweron(struct anx78xx *anx78xx)
+{
+	struct anx78xx_platform_data *pdata = &anx78xx->pdata;
+
+	if (WARN_ON(anx78xx->powered))
+		return;
+
+	if (pdata->gpiod_v10) {
+		gpiod_set_value_cansleep(pdata->gpiod_v10, 1);
+		usleep_range(1000, 2000);
+	}
+
+	gpiod_set_value_cansleep(pdata->gpiod_reset, 1);
+	usleep_range(1000, 2000);
+
+	gpiod_set_value_cansleep(pdata->gpiod_pd, 0);
+	usleep_range(1000, 2000);
+
+	gpiod_set_value_cansleep(pdata->gpiod_reset, 0);
+
+	/* Power on registers module */
+	anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_POWERDOWN_CTRL_REG,
+			 SP_HDCP_PD | SP_AUDIO_PD | SP_VIDEO_PD | SP_LINK_PD);
+	anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2], SP_POWERDOWN_CTRL_REG,
+			   SP_REGISTER_PD | SP_TOTAL_PD);
+
+	anx78xx->powered = true;
+}
+
+static void anx78xx_poweroff(struct anx78xx *anx78xx)
+{
+	struct anx78xx_platform_data *pdata = &anx78xx->pdata;
+
+	if (WARN_ON(!anx78xx->powered))
+		return;
+
+	gpiod_set_value_cansleep(pdata->gpiod_reset, 1);
+	usleep_range(1000, 2000);
+
+	gpiod_set_value_cansleep(pdata->gpiod_pd, 1);
+	usleep_range(1000, 2000);
+
+	if (pdata->gpiod_v10) {
+		gpiod_set_value_cansleep(pdata->gpiod_v10, 0);
+		usleep_range(1000, 2000);
+	}
+
+	anx78xx->powered = false;
+}
+
+static int anx78xx_start(struct anx78xx *anx78xx)
+{
+	int err = 0;
+
+	/* Power on all modules */
+	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2],
+				  SP_POWERDOWN_CTRL_REG,
+				  SP_HDCP_PD | SP_AUDIO_PD | SP_VIDEO_PD |
+				  SP_LINK_PD);
+
+	err |= anx78xx_enable_interrupts(anx78xx);
+	err |= anx78xx_rx_initialization(anx78xx);
+	err |= anx78xx_tx_initialization(anx78xx);
+
+	if (err) {
+		DRM_ERROR("Failed SlimPort transmitter initialization\n");
+		anx78xx_poweroff(anx78xx);
+		return -EIO;
+	}
+
+	/*
+	 * This delay seems to help keep the hardware in a good state. Without
+	 * it, there are times where it fails silently.
+	 */
+	usleep_range(10000, 15000);
+
+	return 0;
+}
+
+static int anx78xx_init_gpio(struct anx78xx *anx78xx)
+{
+	struct device *dev = &anx78xx->client->dev;
+	struct anx78xx_platform_data *pdata = &anx78xx->pdata;
+
+	/* GPIO for hpd */
+	pdata->gpiod_hpd = devm_gpiod_get(dev, "hpd", GPIOD_IN);
+	if (IS_ERR(pdata->gpiod_hpd))
+		return PTR_ERR(pdata->gpiod_hpd);
+
+	/* GPIO for chip power down */
+	pdata->gpiod_pd = devm_gpiod_get(dev, "pd", GPIOD_OUT_HIGH);
+	if (IS_ERR(pdata->gpiod_pd))
+		return PTR_ERR(pdata->gpiod_pd);
+
+	/* GPIO for chip reset */
+	pdata->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(pdata->gpiod_reset))
+		return PTR_ERR(pdata->gpiod_reset);
+
+	/* GPIO for V10 power control */
+	pdata->gpiod_v10 = devm_gpiod_get_optional(dev, "v10", GPIOD_OUT_LOW);
+
+	return PTR_ERR_OR_ZERO(pdata->gpiod_v10);
+}
+
+static int anx78xx_dp_link_training(struct anx78xx *anx78xx)
+{
+	int err = 0;
+	u8 dp_bw, regval;
+
+	err |= regmap_write(anx78xx->map[I2C_IDX_RX_P0], SP_HDMI_MUTE_CTRL_REG,
+			    0x0);
+	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2],
+				  SP_POWERDOWN_CTRL_REG,
+				  SP_TOTAL_PD);
+	if (err)
+		return -EIO;
+
+	err = drm_dp_dpcd_readb(&anx78xx->aux, DP_MAX_LINK_RATE, &dp_bw);
+	if (err < 0)
+		return err;
+
+	switch (dp_bw) {
+	case DP_LINK_BW_1_62:
+	case DP_LINK_BW_2_7:
+	case DP_LINK_BW_5_4:
+		break;
+	default:
+		DRM_DEBUG_KMS("Waiting to read DP bandwidth.\n");
+		return -EAGAIN;
+	}
+
+	err = anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL1_REG,
+			       SP_VIDEO_MUTE);
+	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2],
+				  SP_VID_CTRL1_REG, SP_VIDEO_EN);
+	if (err)
+		return -EIO;
+
+	/* Get dpcd info */
+	err = drm_dp_dpcd_read(&anx78xx->aux, DP_DPCD_REV,
+			       &anx78xx->dpcd, DP_RECEIVER_CAP_SIZE);
+	if (err < 0) {
+		DRM_ERROR("Failed to read DPCD\n");
+		return err;
+	}
+
+	/* Clear channel x SERDES power down */
+	err = anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P0],
+				 SP_DP_ANALOG_POWER_DOWN_REG, SP_CH0_PD);
+	if (err)
+		return -EIO;
+
+	/* Check link capabilities */
+	err = drm_dp_link_probe(&anx78xx->aux, &anx78xx->link);
+	if (err < 0) {
+		DRM_ERROR("Failed to probe link capabilities\n");
+		return err;
+	}
+
+	/* Power up the sink */
+	err = drm_dp_link_power_up(&anx78xx->aux, &anx78xx->link);
+	if (err < 0) {
+		DRM_ERROR("Failed to power up DisplayPort link\n");
+		return err;
+	}
+
+	/* Possibly enable downspread on the sink */
+	err = regmap_write(anx78xx->map[I2C_IDX_TX_P0],
+			   SP_DP_DOWNSPREAD_CTRL1_REG, 0);
+	if (err)
+		return err;
+
+	if (anx78xx->dpcd[3] & 0x1) {
+		DRM_DEBUG("Enable downspread on the sink\n");
+		/* 4000PPM */
+		err = regmap_write(anx78xx->map[I2C_IDX_TX_P0],
+				   SP_DP_DOWNSPREAD_CTRL1_REG, 8);
+		if (err)
+			return err;
+
+		err = drm_dp_dpcd_writeb(&anx78xx->aux, DP_DOWNSPREAD_CTRL,
+					 DP_SPREAD_AMP_0_5);
+		if (err < 0)
+			return err;
+	} else {
+		err = drm_dp_dpcd_writeb(&anx78xx->aux, DP_DOWNSPREAD_CTRL, 0);
+		if (err < 0)
+			return err;
+	}
+
+	/* Set the lane count and the link rate on the sink */
+	if (drm_dp_enhanced_frame_cap(anx78xx->dpcd))
+		err = anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P0],
+				       SP_DP_SYSTEM_CTRL_BASE + 4,
+				       SP_ENHANCED_MODE);
+	else
+		err = anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P0],
+					 SP_DP_SYSTEM_CTRL_BASE + 4,
+					 SP_ENHANCED_MODE);
+	if (err)
+		return err;
+
+	regval = drm_dp_link_rate_to_bw_code(anx78xx->link.rate);
+	err = regmap_write(anx78xx->map[I2C_IDX_TX_P0],
+			   SP_DP_MAIN_LINK_BW_SET_REG, regval);
+	if (err)
+		return err;
+
+	err = drm_dp_link_configure(&anx78xx->aux, &anx78xx->link);
+	if (err < 0) {
+		DRM_ERROR("Failed to configure DisplayPort link\n");
+		return err;
+	}
+
+	/* Start training on the source */
+	err = regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_DP_LT_CTRL_REG,
+			   SP_LT_EN);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int anx78xx_config_dp_output(struct anx78xx *anx78xx)
+{
+	int err = 0;
+
+	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL1_REG,
+				  SP_VIDEO_MUTE);
+	/* Enable DP output */
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL1_REG,
+				SP_VIDEO_EN);
+
+	if (err)
+		return -EIO;
+
+	return 0;
+}
+
+static int anx78xx_send_video_infoframe(struct anx78xx *anx78xx,
+					struct hdmi_avi_infoframe *frame)
+{
+	int err;
+	u8 buffer[HDMI_INFOFRAME_HEADER_SIZE + HDMI_AVI_INFOFRAME_SIZE];
+
+	err = hdmi_avi_infoframe_pack(frame, buffer, sizeof(buffer));
+	if (err < 0) {
+		DRM_ERROR("Failed to pack AVI infoframe: %d\n", err);
+		return err;
+	}
+
+	err = anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P0],
+				 SP_PACKET_SEND_CTRL_REG, SP_AVI_IF_EN);
+
+	err |= regmap_bulk_write(anx78xx->map[I2C_IDX_TX_P2],
+				 SP_INFOFRAME_AVI_DB1_REG, buffer,
+				 frame->length);
+
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P0],
+				SP_PACKET_SEND_CTRL_REG, SP_AVI_IF_UD);
+
+	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P0],
+				SP_PACKET_SEND_CTRL_REG, SP_AVI_IF_EN);
+
+	if (err)
+		return -EIO;
+
+	return 0;
+}
+
+static inline struct anx78xx *
+	connector_to_anx78xx(struct drm_connector *connector)
+{
+	return container_of(connector, struct anx78xx, connector);
+}
+
+static int anx78xx_get_downstream_info(struct anx78xx *anx78xx)
+{
+	int err;
+	u8 regval;
+
+	err = drm_dp_dpcd_readb(&anx78xx->aux, DP_SINK_COUNT, &regval);
+	if (err < 0) {
+		DRM_ERROR("Get sink count failed %d\n", err);
+		return err;
+	}
+
+	if (!DP_GET_SINK_COUNT(regval)) {
+		DRM_ERROR("Downstream disconnected\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int anx78xx_get_modes(struct drm_connector *connector)
+{
+	int err, num_modes = 0;
+	struct anx78xx *anx78xx = connector_to_anx78xx(connector);
+
+	if (WARN_ON(!anx78xx->powered))
+		return 0;
+
+	if (anx78xx->edid)
+		return drm_add_edid_modes(connector, anx78xx->edid);
+
+	mutex_lock(&anx78xx->lock);
+
+	err = anx78xx_get_downstream_info(anx78xx);
+	if (err) {
+		DRM_ERROR("Failed to get downstream info: %d\n", err);
+		goto unlock;
+	}
+
+	anx78xx->edid = drm_get_edid(connector, &anx78xx->aux.ddc);
+	if (!anx78xx->edid) {
+		DRM_ERROR("Failed to read edid\n");
+		goto unlock;
+	}
+
+	err = drm_mode_connector_update_edid_property(connector,
+						      anx78xx->edid);
+	if (err) {
+		DRM_ERROR("Failed to update edid property\n");
+		goto unlock;
+	}
+
+	num_modes = drm_add_edid_modes(connector, anx78xx->edid);
+	/* Store the ELD */
+	drm_edid_to_eld(connector, anx78xx->edid);
+
+unlock:
+	mutex_unlock(&anx78xx->lock);
+
+	return num_modes;
+}
+
+static struct drm_encoder *anx78xx_best_encoder(struct drm_connector *connector)
+{
+	struct anx78xx *anx78xx = connector_to_anx78xx(connector);
+
+	return anx78xx->bridge.encoder;
+}
+
+static const struct drm_connector_helper_funcs
+	anx78xx_connector_helper_funcs = {
+	.get_modes = anx78xx_get_modes,
+	.best_encoder = anx78xx_best_encoder,
+};
+
+static enum drm_connector_status anx78xx_detect(struct drm_connector *connector,
+						bool force)
+{
+	struct anx78xx *anx78xx = container_of(connector, struct anx78xx,
+					       connector);
+
+	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
+		      connector->name);
+
+	if (!gpiod_get_value(anx78xx->pdata.gpiod_hpd)) {
+		DRM_DEBUG_KMS("CONNECTOR STATUS DISCONNECTED\n");
+		return connector_status_disconnected;
+	}
+
+	return connector_status_connected;
+}
+
+static void anx78xx_connector_destroy(struct drm_connector *connector)
+{
+	drm_connector_cleanup(connector);
+}
+
+static const struct drm_connector_funcs anx78xx_connector_funcs = {
+	.dpms = drm_atomic_helper_connector_dpms,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.detect = anx78xx_detect,
+	.destroy = anx78xx_connector_destroy,
+	.reset = drm_atomic_helper_connector_reset,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static inline struct anx78xx *bridge_to_anx78xx(struct drm_bridge *bridge)
+{
+	return container_of(bridge, struct anx78xx, bridge);
+}
+
+static int anx78xx_bridge_attach(struct drm_bridge *bridge)
+{
+	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
+	int err;
+
+	if (!bridge->encoder) {
+		DRM_ERROR("Parent encoder object not found");
+		return -ENODEV;
+	}
+
+	/* Register aux channel */
+	anx78xx->aux.name = "DP-AUX";
+	anx78xx->aux.dev = &anx78xx->client->dev;
+	anx78xx->aux.transfer = anx78xx_aux_transfer;
+
+	err = drm_dp_aux_register(&anx78xx->aux);
+	if (err < 0) {
+		DRM_ERROR("Failed to register aux channel: %d\n", err);
+		return err;
+	}
+
+	err = drm_connector_init(bridge->dev, &anx78xx->connector,
+				 &anx78xx_connector_funcs,
+				 DRM_MODE_CONNECTOR_DisplayPort);
+	if (err) {
+		DRM_ERROR("Failed to initialize connector: %d\n", err);
+		return err;
+	}
+
+	drm_connector_helper_add(&anx78xx->connector,
+				 &anx78xx_connector_helper_funcs);
+
+	err = drm_connector_register(&anx78xx->connector);
+	if (err) {
+		DRM_ERROR("Failed to register connector: %d\n", err);
+		return err;
+	}
+
+	anx78xx->connector.polled = DRM_CONNECTOR_POLL_HPD;
+
+	err = drm_mode_connector_attach_encoder(&anx78xx->connector,
+						bridge->encoder);
+	if (err) {
+		DRM_ERROR("Failed to link up connector to encoder: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+static bool anx78xx_bridge_mode_fixup(struct drm_bridge *bridge,
+				      const struct drm_display_mode *mode,
+				      struct drm_display_mode *adjusted_mode)
+{
+	if (mode->flags & DRM_MODE_FLAG_INTERLACE)
+		return false;
+
+	/* Max 1200p at 5.4 Ghz, one lane */
+	if (mode->clock > 154000)
+		return false;
+
+	return true;
+}
+
+static void anx78xx_bridge_disable(struct drm_bridge *bridge)
+{
+	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
+
+	mutex_lock(&anx78xx->lock);
+
+	/* Power off all modules except configuration registers access */
+	anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_POWERDOWN_CTRL_REG,
+			 SP_HDCP_PD | SP_AUDIO_PD | SP_VIDEO_PD | SP_LINK_PD);
+
+	mutex_unlock(&anx78xx->lock);
+}
+
+static void anx78xx_bridge_mode_set(struct drm_bridge *bridge,
+				    struct drm_display_mode *mode,
+				    struct drm_display_mode *adjusted_mode)
+{
+	int err;
+	struct hdmi_avi_infoframe frame;
+	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
+
+	if (WARN_ON(!anx78xx->powered))
+		return;
+
+	mutex_lock(&anx78xx->lock);
+
+	mode = adjusted_mode;
+
+	err = drm_hdmi_avi_infoframe_from_display_mode(&frame, mode);
+	if (err) {
+		DRM_ERROR("Failed to setup AVI infoframe: %d\n", err);
+		goto unlock;
+	}
+
+	err = anx78xx_send_video_infoframe(anx78xx, &frame);
+	if (err)
+		DRM_ERROR("Failed to send AVI infoframe: %d\n", err);
+
+unlock:
+	mutex_unlock(&anx78xx->lock);
+}
+
+static void anx78xx_bridge_enable(struct drm_bridge *bridge)
+{
+	int err;
+	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
+
+	mutex_lock(&anx78xx->lock);
+
+	err = anx78xx_start(anx78xx);
+	if (err)
+		DRM_ERROR("Failed to initialize: %d\n", err);
+
+	err = anx78xx_set_hpd(anx78xx);
+	if (err)
+		DRM_ERROR("Failed to set HPD: %d\n", err);
+
+	mutex_unlock(&anx78xx->lock);
+}
+
+static const struct drm_bridge_funcs anx78xx_bridge_funcs = {
+	.attach		= anx78xx_bridge_attach,
+	.mode_fixup	= anx78xx_bridge_mode_fixup,
+	.disable	= anx78xx_bridge_disable,
+	.mode_set	= anx78xx_bridge_mode_set,
+	.enable		= anx78xx_bridge_enable,
+};
+
+static irqreturn_t anx78xx_hpd_threaded_handler(int unused, void *data)
+{
+	int err;
+	struct anx78xx *anx78xx = data;
+
+	if (anx78xx->powered)
+		return IRQ_HANDLED;
+
+	mutex_lock(&anx78xx->lock);
+
+	/* Cable is pulled, power on the chip */
+	anx78xx_poweron(anx78xx);
+
+	err = anx78xx_enable_interrupts(anx78xx);
+	if (err)
+		DRM_ERROR("Failed to enable interrupts: %d\n", err);
+
+	mutex_unlock(&anx78xx->lock);
+
+	return IRQ_HANDLED;
+}
+
+static int anx78xx_handle_dp_int_1(struct anx78xx *anx78xx, u8 irq)
+{
+	int err;
+
+	DRM_DEBUG_KMS("Handle DP interrupt 1: %02x\n", irq);
+
+	err = regmap_write(anx78xx->map[I2C_IDX_TX_P2], SP_DP_INT_STATUS1_REG,
+			   irq);
+	if (err)
+		return err;
+
+	if (irq & SP_TRAINING_FINISH) {
+		DRM_DEBUG_KMS("IRQ: hardware link training finished\n");
+		err = anx78xx_config_dp_output(anx78xx);
+	}
+
+	return err;
+}
+
+static bool anx78xx_handle_common_int_4(struct anx78xx *anx78xx, u8 irq)
+{
+	int err;
+	bool event = false;
+
+	DRM_DEBUG_KMS("Handle common interrupt 4: %02x\n", irq);
+
+	err = regmap_write(anx78xx->map[I2C_IDX_TX_P2],
+			   SP_COMMON_INT_STATUS4_REG, irq);
+	if (err) {
+		DRM_ERROR("Failed to write SP_COMMON_INT_STATUS4 %d\n", err);
+		return event;
+	}
+
+	if (irq & SP_HPD_LOST) {
+		DRM_DEBUG_KMS("IRQ: Hot plug detect - cable is pulled out\n");
+		event = true;
+		anx78xx_poweroff(anx78xx);
+	} else if (irq & SP_HPD_PLUG) {
+		DRM_DEBUG_KMS("IRQ: Hot plug detect - cable plug\n");
+		event = true;
+		/* Free previous cached EDID if any */
+		kfree(anx78xx->edid);
+		anx78xx->edid = NULL;
+	}
+
+	return event;
+}
+
+static void anx78xx_handle_hdmi_int_1(struct anx78xx *anx78xx, u8 irq)
+{
+	int err;
+	unsigned int regval;
+
+	DRM_DEBUG_KMS("Handle HDMI interrupt 1: %02x\n", irq);
+
+	err = regmap_write(anx78xx->map[I2C_IDX_RX_P0], SP_INT_STATUS1_REG,
+			   irq);
+	if (err) {
+		DRM_ERROR("Write hdmi int 1 failed %d\n", err);
+		return;
+	}
+
+	if ((irq & SP_CKDT_CHG) || (irq & SP_SCDT_CHG)) {
+		DRM_DEBUG_KMS("IRQ: HDMI input detected\n");
+		err = regmap_read(anx78xx->map[I2C_IDX_RX_P0],
+				  SP_SYSTEM_STATUS_REG, &regval);
+		if (err) {
+			DRM_ERROR("Read system status reg failed %d\n", err);
+			return;
+		}
+
+		if (!(regval & SP_TMDS_CLOCK_DET)) {
+			DRM_DEBUG_KMS("IRQ: *** Waiting for HDMI clock ***\n");
+			return;
+		}
+		if (!(regval & SP_TMDS_DE_DET)) {
+			DRM_DEBUG_KMS("IRQ: *** Waiting for HDMI signal ***\n");
+			return;
+		}
+
+		err = anx78xx_dp_link_training(anx78xx);
+		if (err)
+			DRM_ERROR("Failed to start link training: %d\n", err);
+	}
+}
+
+static irqreturn_t anx78xx_intp_threaded_handler(int unused, void *data)
+{
+	struct anx78xx *anx78xx = data;
+	int err;
+	unsigned int irq;
+	bool event = false;
+
+	mutex_lock(&anx78xx->lock);
+
+	err = regmap_read(anx78xx->map[I2C_IDX_TX_P2], SP_DP_INT_STATUS1_REG,
+			  &irq);
+	if (err) {
+		DRM_ERROR("Failed to read dp int 1 status %d\n", err);
+		goto unlock;
+	} else if (irq) {
+		anx78xx_handle_dp_int_1(anx78xx, irq);
+	}
+
+	err = regmap_read(anx78xx->map[I2C_IDX_TX_P2],
+			  SP_COMMON_INT_STATUS4_REG, &irq);
+	if (err) {
+		DRM_ERROR("Failed to read common int 4 status %d\n", err);
+		goto unlock;
+	} else if (irq) {
+		event = anx78xx_handle_common_int_4(anx78xx, irq);
+	}
+
+	/* Make sure we are still powered after handle HPD events */
+	if (!anx78xx->powered)
+		goto unlock;
+
+	err = regmap_read(anx78xx->map[I2C_IDX_RX_P0], SP_INT_STATUS1_REG,
+			  &irq);
+	if (err)
+		DRM_ERROR("Failed to read hdmi int 1 status %d\n", err);
+	else if (irq)
+		anx78xx_handle_hdmi_int_1(anx78xx, irq);
+
+unlock:
+	mutex_unlock(&anx78xx->lock);
+
+	if (event)
+		drm_helper_hpd_irq_event(anx78xx->connector.dev);
+
+	return IRQ_HANDLED;
+}
+
+static void unregister_i2c_dummy_clients(struct anx78xx *anx78xx)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(anx78xx->i2c_dummy); i++)
+		if (anx78xx->i2c_dummy[i])
+			i2c_unregister_device(anx78xx->i2c_dummy[i]);
+}
+
+static const struct regmap_config anx78xx_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static const u16 anx78xx_chipid_list[] = {
+	0x7812,
+	0x7814,
+	0x7818,
+};
+
+static int anx78xx_i2c_probe(struct i2c_client *client,
+			     const struct i2c_device_id *id)
+{
+	struct anx78xx *anx78xx;
+	struct anx78xx_platform_data *pdata;
+	int err, i;
+	unsigned int idl, idh, version;
+	bool found = false;
+
+	anx78xx = devm_kzalloc(&client->dev, sizeof(*anx78xx), GFP_KERNEL);
+	if (!anx78xx)
+		return -ENOMEM;
+
+	pdata = &anx78xx->pdata;
+
+	mutex_init(&anx78xx->lock);
+
+#if IS_ENABLED(CONFIG_OF)
+	anx78xx->bridge.of_node = client->dev.of_node;
+#endif
+
+	anx78xx->client = client;
+	i2c_set_clientdata(client, anx78xx);
+
+	err = anx78xx_init_gpio(anx78xx);
+	if (err) {
+		DRM_ERROR("Failed to initialize gpios\n");
+		return err;
+	}
+
+	pdata->hpd_irq = gpiod_to_irq(pdata->gpiod_hpd);
+	if (pdata->hpd_irq < 0) {
+		DRM_ERROR("Failed to get hpd irq %d\n",
+			  pdata->hpd_irq);
+		return -ENODEV;
+	}
+
+	pdata->intp_irq = client->irq;
+	if (!pdata->intp_irq) {
+		DRM_ERROR("Failed to get CABLE_DET and INTP irq\n");
+		return -ENODEV;
+	}
+
+	/* Map slave addresses of ANX7814 */
+	for (i = 0; i < I2C_NUM_ADDRESSES; i++) {
+		anx78xx->i2c_dummy[i] = i2c_new_dummy(client->adapter,
+						anx78xx_i2c_addresses[i] >> 1);
+		if (!anx78xx->i2c_dummy[i]) {
+			err = -ENOMEM;
+			DRM_ERROR("Failed to reserve i2c bus %02x.\n",
+				  anx78xx_i2c_addresses[i]);
+			goto err_unregister_i2c;
+		}
+
+		anx78xx->map[i] = devm_regmap_init_i2c(anx78xx->i2c_dummy[i],
+						       &anx78xx_regmap_config);
+		if (IS_ERR(anx78xx->map[i])) {
+			err = PTR_ERR(anx78xx->map[i]);
+			DRM_ERROR("Failed regmap initialization %02x.\n",
+				  anx78xx_i2c_addresses[i]);
+			goto err_unregister_i2c;
+		}
+	}
+
+	/* Look for supported chip id */
+	anx78xx_poweron(anx78xx);
+
+	err = regmap_read(anx78xx->map[I2C_IDX_TX_P2], SP_DEVICE_IDL_REG,
+			  &idl);
+	if (err)
+		goto err_poweroff;
+
+	err = regmap_read(anx78xx->map[I2C_IDX_TX_P2], SP_DEVICE_IDH_REG,
+			  &idh);
+	if (err)
+		goto err_poweroff;
+
+	anx78xx->chipid = (u8)idl | ((u8)idh << 8);
+
+	err = regmap_read(anx78xx->map[I2C_IDX_TX_P2], SP_DEVICE_VERSION_REG,
+			  &version);
+	if (err)
+		goto err_poweroff;
+
+	for (i = 0; i < ARRAY_SIZE(anx78xx_chipid_list); i++) {
+		if (anx78xx->chipid == anx78xx_chipid_list[i]) {
+			DRM_INFO("Found ANX%x (ver. %d) SlimPort Transmitter\n",
+				 anx78xx->chipid, version);
+			found = true;
+			break;
+		}
+	}
+
+	if (!found) {
+		DRM_ERROR("ANX%x (ver. %d) not supported by this driver\n",
+			  anx78xx->chipid, version);
+		err = -ENODEV;
+		goto err_poweroff;
+	}
+
+	err = devm_request_threaded_irq(&client->dev, pdata->hpd_irq,
+					NULL,
+					anx78xx_hpd_threaded_handler,
+					IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+					"anx78xx-hpd", anx78xx);
+	if (err) {
+		DRM_ERROR("Failed to request CABLE_DET threaded irq\n");
+		goto err_poweroff;
+	}
+
+	err = devm_request_threaded_irq(&client->dev, pdata->intp_irq, NULL,
+					anx78xx_intp_threaded_handler,
+					IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+					"anx78xx-intp", anx78xx);
+	if (err) {
+		DRM_ERROR("Failed to request INTP threaded irq\n");
+		goto err_poweroff;
+	}
+
+	anx78xx->bridge.funcs = &anx78xx_bridge_funcs;
+	err = drm_bridge_add(&anx78xx->bridge);
+	if (err < 0) {
+		DRM_ERROR("Failed to add drm bridge\n");
+		goto err_poweroff;
+	}
+
+	/* If cable is pulled out, just poweroff and wait for hpd event */
+	if (!gpiod_get_value(anx78xx->pdata.gpiod_hpd))
+		anx78xx_poweroff(anx78xx);
+
+	return 0;
+
+err_poweroff:
+	anx78xx_poweroff(anx78xx);
+
+err_unregister_i2c:
+	unregister_i2c_dummy_clients(anx78xx);
+	return err;
+}
+
+static int anx78xx_i2c_remove(struct i2c_client *client)
+{
+	struct anx78xx *anx78xx = i2c_get_clientdata(client);
+
+	drm_bridge_remove(&anx78xx->bridge);
+
+	unregister_i2c_dummy_clients(anx78xx);
+
+	kfree(anx78xx->edid);
+	anx78xx->edid = NULL;
+
+	return 0;
+}
+
+static const struct i2c_device_id anx78xx_id[] = {
+	{"anx7814", 0},
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(i2c, anx78xx_id);
+
+#if IS_ENABLED(CONFIG_OF)
+static const struct of_device_id anx78xx_match_table[] = {
+	{.compatible = "analogix,anx7814",},
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, anx78xx_match_table);
+#endif
+
+static struct i2c_driver anx78xx_driver = {
+	.driver = {
+		   .name = "anx7814",
+		   .of_match_table = of_match_ptr(anx78xx_match_table),
+		  },
+	.probe = anx78xx_i2c_probe,
+	.remove = anx78xx_i2c_remove,
+	.id_table = anx78xx_id,
+};
+
+module_i2c_driver(anx78xx_driver);
+
+MODULE_DESCRIPTION("ANX78xx SlimPort Transmitter driver");
+MODULE_AUTHOR("Enric Balletbo i Serra <enric.balletbo@collabora.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/gpu/drm/bridge/anx78xx.h b/drivers/gpu/drm/bridge/anx78xx.h
new file mode 100644
index 0000000..38753c8
--- /dev/null
+++ b/drivers/gpu/drm/bridge/anx78xx.h
@@ -0,0 +1,719 @@
+/*
+ * Copyright(c) 2016, Analogix Semiconductor. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef __ANX78xx_H
+#define __ANX78xx_H
+
+#define TX_P0				0x70
+#define TX_P1				0x7a
+#define TX_P2				0x72
+
+#define RX_P0				0x7e
+#define RX_P1				0x80
+
+/***************************************************************/
+/* Register definition of device address 0x7e                  */
+/***************************************************************/
+
+/*
+ * System Control and Status
+ */
+
+/* Software Reset Register 1 */
+#define SP_SOFTWARE_RESET1_REG		0x11
+#define SP_VIDEO_RST			BIT(4)
+#define SP_HDCP_MAN_RST			BIT(2)
+#define SP_TMDS_RST			BIT(1)
+#define SP_SW_MAN_RST			BIT(0)
+
+/* System Status Register */
+#define SP_SYSTEM_STATUS_REG		0x14
+#define SP_TMDS_CLOCK_DET		BIT(1)
+#define SP_TMDS_DE_DET			BIT(0)
+
+/* HDMI Status Register */
+#define SP_HDMI_STATUS_REG		0x15
+#define SP_HDMI_AUD_LAYOUT		BIT(3)
+#define SP_HDMI_DET			BIT(0)
+#  define SP_DVI_MODE			0
+#  define SP_HDMI_MODE			1
+
+/* HDMI Mute Control Register */
+#define SP_HDMI_MUTE_CTRL_REG		0x16
+#define SP_AUD_MUTE			BIT(1)
+#define SP_VID_MUTE			BIT(0)
+
+/* System Power Down Register 1 */
+#define SP_SYSTEM_POWER_DOWN1_REG	0x18
+#define SP_PWDN_CTRL			BIT(0)
+
+/*
+ * Audio and Video Auto Control
+ */
+
+/* Auto Audio and Video Control register */
+#define SP_AUDVID_CTRL_REG		0x20
+#define SP_AVC_OE			BIT(7)
+#define SP_AAC_OE			BIT(6)
+#define SP_AVC_EN			BIT(1)
+#define SP_AAC_EN			BIT(0)
+
+/* Audio Exception Enable Registers */
+#define SP_AUD_EXCEPTION_ENABLE_BASE	(0x24 - 1)
+/* Bits for Audio Exception Enable Register 3 */
+#define SP_AEC_EN21			BIT(5)
+
+/*
+ * Interrupt
+ */
+
+/* Interrupt Status Register 1 */
+#define SP_INT_STATUS1_REG		0x31
+/* Bits for Interrupt Status Register 1 */
+#define SP_HDMI_DVI			BIT(7)
+#define SP_CKDT_CHG			BIT(6)
+#define SP_SCDT_CHG			BIT(5)
+#define SP_PCLK_CHG			BIT(4)
+#define SP_PLL_UNLOCK			BIT(3)
+#define SP_CABLE_PLUG_CHG		BIT(2)
+#define SP_SET_MUTE			BIT(1)
+#define SP_SW_INTR			BIT(0)
+/* Bits for Interrupt Status Register 2 */
+#define SP_HDCP_ERR			BIT(5)
+#define SP_AUDIO_SAMPLE_CHG		BIT(0)	/* undocumented */
+/* Bits for Interrupt Status Register 3 */
+#define SP_AUD_MODE_CHG			BIT(0)
+/* Bits for Interrupt Status Register 5 */
+#define SP_AUDIO_RCV			BIT(0)
+/* Bits for Interrupt Status Register 6 */
+#define SP_INT_STATUS6_REG		0x36
+#define SP_CTS_RCV			BIT(7)
+#define SP_NEW_AUD_PKT			BIT(4)
+#define SP_NEW_AVI_PKT			BIT(1)
+#define SP_NEW_CP_PKT			BIT(0)
+/* Bits for Interrupt Status Register 7 */
+#define SP_NO_VSI			BIT(7)
+#define SP_NEW_VS			BIT(4)
+
+/* Interrupt Mask 1 Status Registers */
+#define SP_INT_MASK1_REG		0x41
+
+/* HDMI US TIMER Control Register */
+#define SP_HDMI_US_TIMER_CTRL_REG	0x49
+#define SP_MS_TIMER_MARGIN_10_8_MASK	0x07
+
+/*
+ * TMDS Control
+ */
+
+/* TMDS Control Registers */
+#define SP_TMDS_CTRL_BASE		(0x50 - 1)
+/* Bits for TMDS Control Register 7 */
+#define SP_PD_RT			BIT(0)
+
+/*
+ * Video Control
+ */
+
+/* Video Status Register */
+#define SP_VIDEO_STATUS_REG		0x70
+#define SP_COLOR_DEPTH_MASK		0xf0
+#define SP_COLOR_DEPTH_SHIFT		4
+#  define SP_COLOR_DEPTH_MODE_LEGACY	0x00
+#  define SP_COLOR_DEPTH_MODE_24BIT	0x04
+#  define SP_COLOR_DEPTH_MODE_30BIT	0x05
+#  define SP_COLOR_DEPTH_MODE_36BIT	0x06
+#  define SP_COLOR_DEPTH_MODE_48BIT	0x07
+
+/* Video Data Range Control Register */
+#define SP_VID_DATA_RANGE_CTRL_REG	0x83
+#define SP_R2Y_INPUT_LIMIT		BIT(1)
+
+/* Pixel Clock High Resolution Counter Registers */
+#define SP_PCLK_HIGHRES_CNT_BASE	(0x8c - 1)
+
+/*
+ * Audio Control
+ */
+
+/* Number of Audio Channels Status Registers */
+#define SP_AUD_CH_STATUS_REG_NUM	6
+
+/* Audio IN S/PDIF Channel Status Registers */
+#define SP_AUD_SPDIF_CH_STATUS_BASE	0xc7
+
+/* Audio IN S/PDIF Channel Status Register 4 */
+#define SP_FS_FREQ_MASK			0x0f
+#  define SP_FS_FREQ_44100HZ		0x00
+#  define SP_FS_FREQ_48000HZ		0x02
+#  define SP_FS_FREQ_32000HZ		0x03
+#  define SP_FS_FREQ_88200HZ		0x08
+#  define SP_FS_FREQ_96000HZ		0x0a
+#  define SP_FS_FREQ_176400HZ		0x0c
+#  define SP_FS_FREQ_192000HZ		0x0e
+
+/*
+ * Micellaneous Control Block
+ */
+
+/* CHIP Control Register */
+#define SP_CHIP_CTRL_REG		0xe3
+#define SP_MAN_HDMI5V_DET		BIT(3)
+#define SP_PLLLOCK_CKDT_EN		BIT(2)
+#define SP_ANALOG_CKDT_EN		BIT(1)
+#define SP_DIGITAL_CKDT_EN		BIT(0)
+
+/* Packet Receiving Status Register */
+#define SP_PACKET_RECEIVING_STATUS_REG	0xf3
+#define SP_AVI_RCVD			BIT(5)
+#define SP_VSI_RCVD			BIT(1)
+
+/***************************************************************/
+/* Register definition of device address 0x80                  */
+/***************************************************************/
+
+/* HDCP BCAPS Shadow Register */
+#define SP_HDCP_BCAPS_SHADOW_REG	0x2a
+#define SP_BCAPS_REPEATER		BIT(5)
+
+/* HDCP Status Register */
+#define SP_RX_HDCP_STATUS_REG		0x3f
+#define SP_AUTH_EN			BIT(4)
+
+/*
+ * InfoFrame and Control Packet Registers
+ */
+
+/* AVI InfoFrame packet checksum */
+#define SP_AVI_INFOFRAME_CHECKSUM	0xa3
+
+/* AVI InfoFrame Registers */
+#define SP_AVI_INFOFRAME_DATA_BASE	0xa4
+
+#define SP_AVI_COLOR_F_MASK		0x60
+#define SP_AVI_COLOR_F_SHIFT		5
+
+/* Audio InfoFrame Registers */
+#define SP_AUD_INFOFRAME_DATA_BASE	0xc4
+#define SP_AUD_INFOFRAME_LAYOUT_MASK	0x0f
+
+/* MPEG/HDMI Vendor Specific InfoFrame Packet type code */
+#define SP_MPEG_VS_INFOFRAME_TYPE_REG	0xe0
+
+/* MPEG/HDMI Vendor Specific InfoFrame Packet length */
+#define SP_MPEG_VS_INFOFRAME_LEN_REG	0xe2
+
+/* MPEG/HDMI Vendor Specific InfoFrame Packet version number */
+#define SP_MPEG_VS_INFOFRAME_VER_REG	0xe1
+
+/* MPEG/HDMI Vendor Specific InfoFrame Packet content */
+#define SP_MPEG_VS_INFOFRAME_DATA_BASE	0xe4
+
+/* General Control Packet Register */
+#define SP_GENERAL_CTRL_PACKET_REG	0x9f
+#define SP_CLEAR_AVMUTE			BIT(4)
+#define SP_SET_AVMUTE			BIT(0)
+
+/***************************************************************/
+/* Register definition of device address 0x70                  */
+/***************************************************************/
+
+/* HDCP Status Register */
+#define SP_TX_HDCP_STATUS_REG		0x00
+#define SP_AUTH_FAIL			BIT(5)
+#define SP_AUTHEN_PASS			BIT(1)
+
+/* HDCP Control Register 0 */
+#define SP_HDCP_CTRL0_REG		0x01
+#define SP_RX_REPEATER			BIT(6)
+#define SP_RE_AUTH			BIT(5)
+#define SP_SW_AUTH_OK			BIT(4)
+#define SP_HARD_AUTH_EN			BIT(3)
+#define SP_HDCP_ENC_EN			BIT(2)
+#define SP_BKSV_SRM_PASS		BIT(1)
+#define SP_KSVLIST_VLD			BIT(0)
+/* HDCP Function Enabled */
+#define SP_HDCP_FUNCTION_ENABLED	(BIT(0) | BIT(1) | BIT(2) | BIT(3))
+
+/* HDCP Receiver BSTATUS Register 0 */
+#define	SP_HDCP_RX_BSTATUS0_REG		0x1b
+/* HDCP Receiver BSTATUS Register 1 */
+#define	SP_HDCP_RX_BSTATUS1_REG		0x1c
+
+/* HDCP Embedded "Blue Screen" Content Registers */
+#define SP_HDCP_VID0_BLUE_SCREEN_REG	0x2c
+#define SP_HDCP_VID1_BLUE_SCREEN_REG	0x2d
+#define SP_HDCP_VID2_BLUE_SCREEN_REG	0x2e
+
+/* HDCP Wait R0 Timing Register */
+#define SP_HDCP_WAIT_R0_TIME_REG	0x40
+
+/* HDCP Link Integrity Check Timer Register */
+#define SP_HDCP_LINK_CHECK_TIMER_REG	0x41
+
+/* HDCP Repeater Ready Wait Timer Register */
+#define SP_HDCP_RPTR_RDY_WAIT_TIME_REG	0x42
+
+/* HDCP Auto Timer Register */
+#define SP_HDCP_AUTO_TIMER_REG		0x51
+
+/* HDCP Key Status Register */
+#define SP_HDCP_KEY_STATUS_REG		0x5e
+
+/* HDCP Key Command Register */
+#define SP_HDCP_KEY_COMMAND_REG		0x5f
+#define SP_DISABLE_SYNC_HDCP		BIT(2)
+
+/* OTP Memory Key Protection Registers */
+#define SP_OTP_KEY_PROTECT1_REG		0x60
+#define SP_OTP_KEY_PROTECT2_REG		0x61
+#define SP_OTP_KEY_PROTECT3_REG		0x62
+#define SP_OTP_PSW1			0xa2
+#define SP_OTP_PSW2			0x7e
+#define SP_OTP_PSW3			0xc6
+
+/* DP System Control Registers */
+#define SP_DP_SYSTEM_CTRL_BASE		(0x80 - 1)
+/* Bits for DP System Control Register 2 */
+#define SP_CHA_STA			BIT(2)
+/* Bits for DP System Control Register 3 */
+#define SP_HPD_STATUS			BIT(6)
+#define SP_STRM_VALID			BIT(2)
+/* Bits for DP System Control Register 4 */
+#define SP_ENHANCED_MODE		BIT(3)
+
+/* DP Video Control Register */
+#define SP_DP_VIDEO_CTRL_REG		0x84
+#define SP_COLOR_F_MASK			0x06
+#define SP_COLOR_F_SHIFT		1
+#define SP_BPC_MASK			0xe0
+#define SP_BPC_SHIFT			5
+#  define SP_BPC_6BITS			0x00
+#  define SP_BPC_8BITS			0x01
+#  define SP_BPC_10BITS			0x02
+#  define SP_BPC_12BITS			0x03
+
+/* DP Audio Control Register */
+#define SP_DP_AUDIO_CTRL_REG		0x87
+#define SP_AUD_EN			BIT(0)
+
+/* 10us Pulse Generate Timer Registers */
+#define SP_I2C_GEN_10US_TIMER0_REG	0x88
+#define SP_I2C_GEN_10US_TIMER1_REG	0x89
+
+/* Packet Send Control Register */
+#define SP_PACKET_SEND_CTRL_REG		0x90
+#define SP_AUD_IF_UP			BIT(7)
+#define SP_AVI_IF_UD			BIT(6)
+#define SP_MPEG_IF_UD			BIT(5)
+#define SP_SPD_IF_UD			BIT(4)
+#define SP_AUD_IF_EN			BIT(3)
+#define SP_AVI_IF_EN			BIT(2)
+#define SP_MPEG_IF_EN			BIT(1)
+#define SP_SPD_IF_EN			BIT(0)
+
+/* DP HDCP Control Register */
+#define SP_DP_HDCP_CTRL_REG		0x92
+#define SP_AUTO_EN			BIT(7)
+#define SP_AUTO_START			BIT(5)
+#define SP_LINK_POLLING			BIT(1)
+
+/* DP Main Link Bandwidth Setting Register */
+#define SP_DP_MAIN_LINK_BW_SET_REG	0xa0
+#define SP_LINK_BW_SET_MASK		0x1f
+#define SP_INITIAL_SLIM_M_AUD_SEL	BIT(5)
+
+/* DP Training Pattern Set Register */
+#define SP_DP_TRAINING_PATTERN_SET_REG	0xa2
+
+/* DP Lane 0 Link Training Control Register */
+#define SP_DP_LANE0_LT_CTRL_REG		0xa3
+#define SP_TX_SW_SET_MASK		0x1b
+#define SP_MAX_PRE_REACH		BIT(5)
+#define SP_MAX_DRIVE_REACH		BIT(4)
+#define SP_PRE_EMP_LEVEL1		BIT(3)
+#define SP_DRVIE_CURRENT_LEVEL1		BIT(0)
+
+/* DP Link Training Control Register */
+#define SP_DP_LT_CTRL_REG		0xa8
+#define SP_LT_ERROR_TYPE_MASK		0x70
+#  define SP_LT_NO_ERROR		0x00
+#  define SP_LT_AUX_WRITE_ERROR		0x01
+#  define SP_LT_MAX_DRIVE_REACHED	0x02
+#  define SP_LT_WRONG_LANE_COUNT_SET	0x03
+#  define SP_LT_LOOP_SAME_5_TIME	0x04
+#  define SP_LT_CR_FAIL_IN_EQ		0x05
+#  define SP_LT_EQ_LOOP_5_TIME		0x06
+#define SP_LT_EN			BIT(0)
+
+/* DP CEP Training Control Registers */
+#define SP_DP_CEP_TRAINING_CTRL0_REG	0xa9
+#define SP_DP_CEP_TRAINING_CTRL1_REG	0xaa
+
+/* DP Debug Register 1 */
+#define SP_DP_DEBUG1_REG		0xb0
+#define SP_DEBUG_PLL_LOCK		BIT(4)
+#define SP_POLLING_EN			BIT(1)
+
+/* DP Polling Control Register */
+#define SP_DP_POLLING_CTRL_REG		0xb4
+#define SP_AUTO_POLLING_DISABLE		BIT(0)
+
+/* DP Link Debug Control Register */
+#define SP_DP_LINK_DEBUG_CTRL_REG	0xb8
+#define SP_M_VID_DEBUG			BIT(5)
+#define SP_NEW_PRBS7			BIT(4)
+#define SP_INSERT_ER			BIT(1)
+#define SP_PRBS31_EN			BIT(0)
+
+/* AUX Misc control Register */
+#define SP_AUX_MISC_CTRL_REG		0xbf
+
+/* DP PLL control Register */
+#define SP_DP_PLL_CTRL_REG		0xc7
+#define SP_PLL_RST			BIT(6)
+
+/* DP Analog Power Down Register */
+#define SP_DP_ANALOG_POWER_DOWN_REG	0xc8
+#define SP_CH0_PD			BIT(0)
+
+/* DP Misc Control Register */
+#define SP_DP_MISC_CTRL_REG		0xcd
+#define SP_EQ_TRAINING_LOOP		BIT(6)
+
+/* DP Extra I2C Device Address Register */
+#define SP_DP_EXTRA_I2C_DEV_ADDR_REG	0xce
+#define SP_I2C_STRETCH_DISABLE		BIT(7)
+
+#define SP_I2C_EXTRA_ADDR		0x50
+
+/* DP Downspread Control Register 1 */
+#define SP_DP_DOWNSPREAD_CTRL1_REG	0xd0
+
+/* DP M Value Calculation Control Register */
+#define SP_DP_M_CALCULATION_CTRL_REG	0xd9
+#define SP_M_GEN_CLK_SEL		BIT(0)
+
+/* AUX Channel Access Status Register */
+#define SP_AUX_CH_STATUS_REG		0xe0
+#define SP_AUX_STATUS			0x0f
+
+/* AUX Channel DEFER Control Register */
+#define SP_AUX_DEFER_CTRL_REG		0xe2
+#define SP_DEFER_CTRL_EN		BIT(7)
+
+/* DP Buffer Data Count Register */
+#define SP_BUF_DATA_COUNT_REG		0xe4
+#define SP_BUF_DATA_COUNT_MASK		0x1f
+#define SP_BUF_CLR			BIT(7)
+
+/* DP AUX Channel Control Register 1 */
+#define SP_DP_AUX_CH_CTRL1_REG		0xe5
+#define SP_AUX_TX_COMM_MASK		0x0f
+#define SP_AUX_LENGTH_MASK		0xf0
+#define SP_AUX_LENGTH_SHIFT		4
+
+/* DP AUX CH Address Register 0 */
+#define SP_AUX_ADDR_7_0_REG		0xe6
+
+/* DP AUX CH Address Register 1 */
+#define SP_AUX_ADDR_15_8_REG		0xe7
+
+/* DP AUX CH Address Register 2 */
+#define SP_AUX_ADDR_19_16_REG		0xe8
+#define SP_AUX_ADDR_19_16_MASK		0x0f
+
+/* DP AUX Channel Control Register 2 */
+#define SP_DP_AUX_CH_CTRL2_REG		0xe9
+#define SP_AUX_SEL_RXCM			BIT(6)
+#define SP_AUX_CHSEL			BIT(3)
+#define SP_AUX_PN_INV			BIT(2)
+#define SP_ADDR_ONLY			BIT(1)
+#define SP_AUX_EN			BIT(0)
+
+/* DP Video Stream Control InfoFrame Register */
+#define SP_DP_3D_VSC_CTRL_REG		0xea
+#define SP_INFO_FRAME_VSC_EN		BIT(0)
+
+/* DP Video Stream Data Byte 1 Register */
+#define SP_DP_VSC_DB1_REG		0xeb
+
+/* DP AUX Channel Control Register 3 */
+#define SP_DP_AUX_CH_CTRL3_REG		0xec
+#define SP_WAIT_COUNTER_7_0_MASK	0xff
+
+/* DP AUX Channel Control Register 4 */
+#define SP_DP_AUX_CH_CTRL4_REG		0xed
+
+/* DP AUX Buffer Data Registers */
+#define SP_DP_BUF_DATA0_REG		0xf0
+
+/***************************************************************/
+/* Register definition of device address 0x72                  */
+/***************************************************************/
+
+/*
+ * Core Register Definitions
+ */
+
+/* Device ID Low Byte Register */
+#define SP_DEVICE_IDL_REG		0x02
+
+/* Device ID High Byte Register */
+#define SP_DEVICE_IDH_REG		0x03
+
+/* Device version register */
+#define SP_DEVICE_VERSION_REG		0x04
+
+/* Power Down Control Register */
+#define SP_POWERDOWN_CTRL_REG		0x05
+#define SP_REGISTER_PD			BIT(7)
+#define SP_HDCP_PD			BIT(5)
+#define SP_AUDIO_PD			BIT(4)
+#define SP_VIDEO_PD			BIT(3)
+#define SP_LINK_PD			BIT(2)
+#define SP_TOTAL_PD			BIT(1)
+
+/* Reset Control Register 1 */
+#define SP_RESET_CTRL1_REG		0x06
+#define SP_MISC_RST			BIT(7)
+#define SP_VIDCAP_RST			BIT(6)
+#define SP_VIDFIF_RST			BIT(5)
+#define SP_AUDFIF_RST			BIT(4)
+#define SP_AUDCAP_RST			BIT(3)
+#define SP_HDCP_RST			BIT(2)
+#define SP_SW_RST			BIT(1)
+#define SP_HW_RST			BIT(0)
+
+/* Reset Control Register 2 */
+#define SP_RESET_CTRL2_REG		0x07
+#define SP_AUX_RST			BIT(2)
+#define SP_SERDES_FIFO_RST		BIT(1)
+#define SP_I2C_REG_RST			BIT(0)
+
+/* Video Control Register 1 */
+#define SP_VID_CTRL1_REG		0x08
+#define SP_VIDEO_EN			BIT(7)
+#define SP_VIDEO_MUTE			BIT(2)
+#define SP_DE_GEN			BIT(1)
+#define SP_DEMUX			BIT(0)
+
+/* Video Control Register 2 */
+#define SP_VID_CTRL2_REG		0x09
+#define SP_IN_COLOR_F_MASK		0x03
+#define SP_IN_YC_BIT_SEL		BIT(2)
+#define SP_IN_BPC_MASK			0x70
+#define SP_IN_BPC_SHIFT			4
+#  define SP_IN_BPC_12BIT		0x03
+#  define SP_IN_BPC_10BIT		0x02
+#  define SP_IN_BPC_8BIT		0x01
+#  define SP_IN_BPC_6BIT		0x00
+#define SP_IN_D_RANGE			BIT(7)
+
+/* Video Control Register 3 */
+#define SP_VID_CTRL3_REG		0x0a
+#define SP_HPD_OUT			BIT(6)
+
+/* Video Control Register 5 */
+#define SP_VID_CTRL5_REG		0x0c
+#define SP_CSC_STD_SEL			BIT(7)
+#define SP_XVYCC_RNG_LMT		BIT(6)
+#define SP_RANGE_Y2R			BIT(5)
+#define SP_CSPACE_Y2R			BIT(4)
+#define SP_RGB_RNG_LMT			BIT(3)
+#define SP_Y_RNG_LMT			BIT(2)
+#define SP_RANGE_R2Y			BIT(1)
+#define SP_CSPACE_R2Y			BIT(0)
+
+/* Video Control Register 6 */
+#define SP_VID_CTRL6_REG		0x0d
+#define SP_TEST_PATTERN_EN		BIT(7)
+#define SP_VIDEO_PROCESS_EN		BIT(6)
+#define SP_VID_US_MODE			BIT(3)
+#define SP_VID_DS_MODE			BIT(2)
+#define SP_UP_SAMPLE			BIT(1)
+#define SP_DOWN_SAMPLE			BIT(0)
+
+/* Video Control Register 8 */
+#define SP_VID_CTRL8_REG		0x0f
+#define SP_VID_VRES_TH			BIT(0)
+
+/* Total Line Status Low Byte Register */
+#define SP_TOTAL_LINE_STAL_REG		0x24
+
+/* Total Line Status High Byte Register */
+#define SP_TOTAL_LINE_STAH_REG		0x25
+
+/* Active Line Status Low Byte Register */
+#define SP_ACT_LINE_STAL_REG		0x26
+
+/* Active Line Status High Byte Register */
+#define SP_ACT_LINE_STAH_REG		0x27
+
+/* Vertical Front Porch Status Register */
+#define SP_V_F_PORCH_STA_REG		0x28
+
+/* Vertical SYNC Width Status Register */
+#define SP_V_SYNC_STA_REG		0x29
+
+/* Vertical Back Porch Status Register */
+#define SP_V_B_PORCH_STA_REG		0x2a
+
+/* Total Pixel Status Low Byte Register */
+#define SP_TOTAL_PIXEL_STAL_REG		0x2b
+
+/* Total Pixel Status High Byte Register */
+#define SP_TOTAL_PIXEL_STAH_REG		0x2c
+
+/* Active Pixel Status Low Byte Register */
+#define SP_ACT_PIXEL_STAL_REG		0x2d
+
+/* Active Pixel Status High Byte Register */
+#define SP_ACT_PIXEL_STAH_REG		0x2e
+
+/* Horizontal Front Porch Status Low Byte Register */
+#define SP_H_F_PORCH_STAL_REG		0x2f
+
+/* Horizontal Front Porch Statys High Byte Register */
+#define SP_H_F_PORCH_STAH_REG		0x30
+
+/* Horizontal SYNC Width Status Low Byte Register */
+#define SP_H_SYNC_STAL_REG		0x31
+
+/* Horizontal SYNC Width Status High Byte Register */
+#define SP_H_SYNC_STAH_REG		0x32
+
+/* Horizontal Back Porch Status Low Byte Register */
+#define SP_H_B_PORCH_STAL_REG		0x33
+
+/* Horizontal Back Porch Status High Byte Register */
+#define SP_H_B_PORCH_STAH_REG		0x34
+
+/* InfoFrame AVI Packet DB1 Register */
+#define SP_INFOFRAME_AVI_DB1_REG	0x70
+
+/* Bit Control Specific Register */
+#define SP_BIT_CTRL_SPECIFIC_REG	0x80
+#define SP_BIT_CTRL_SELECT_SHIFT	1
+#define SP_ENABLE_BIT_CTRL		BIT(0)
+
+/* InfoFrame Audio Packet DB1 Register */
+#define SP_INFOFRAME_AUD_DB1_REG	0x83
+
+/* InfoFrame MPEG Packet DB1 Register */
+#define SP_INFOFRAME_MPEG_DB1_REG	0xb0
+
+/* Audio Channel Status Registers */
+#define SP_AUD_CH_STATUS_BASE		0xd0
+
+/* Audio Channel Num Register 5 */
+#define SP_I2S_CHANNEL_NUM_MASK		0xe0
+#  define SP_I2S_CH_NUM_1		(0x00 << 5)
+#  define SP_I2S_CH_NUM_2		(0x01 << 5)
+#  define SP_I2S_CH_NUM_3		(0x02 << 5)
+#  define SP_I2S_CH_NUM_4		(0x03 << 5)
+#  define SP_I2S_CH_NUM_5		(0x04 << 5)
+#  define SP_I2S_CH_NUM_6		(0x05 << 5)
+#  define SP_I2S_CH_NUM_7		(0x06 << 5)
+#  define SP_I2S_CH_NUM_8		(0x07 << 5)
+#define SP_EXT_VUCP			BIT(2)
+#define SP_VBIT				BIT(1)
+#define SP_AUDIO_LAYOUT			BIT(0)
+
+/* Analog Debug Register 2 */
+#define SP_ANALOG_DEBUG2_REG		0xdd
+#define SP_FORCE_SW_OFF_BYPASS		0x20
+#define SP_XTAL_FRQ			0x1c
+#  define SP_XTAL_FRQ_19M2		(0x00 << 2)
+#  define SP_XTAL_FRQ_24M		(0x01 << 2)
+#  define SP_XTAL_FRQ_25M		(0x02 << 2)
+#  define SP_XTAL_FRQ_26M		(0x03 << 2)
+#  define SP_XTAL_FRQ_27M		(0x04 << 2)
+#  define SP_XTAL_FRQ_38M4		(0x05 << 2)
+#  define SP_XTAL_FRQ_52M		(0x06 << 2)
+#define SP_POWERON_TIME_1P5MS		0x03
+
+/* Analog Control 0 Register */
+#define SP_ANALOG_CTRL0_REG		0xe1
+
+/* Common Interrupt Status Register 1 */
+#define SP_COMMON_INT_STATUS_BASE	(0xf1 - 1)
+#define SP_PLL_LOCK_CHG			0x40
+
+/* Common Interrupt Status Register 2 */
+#define SP_COMMON_INT_STATUS2		0xf2
+#define SP_HDCP_AUTH_CHG		BIT(1)
+#define SP_HDCP_AUTH_DONE		BIT(0)
+
+#define SP_HDCP_LINK_CHECK_FAIL		BIT(0)
+
+/* Common Interrupt Status Register 4 */
+#define SP_COMMON_INT_STATUS4_REG	0xf4
+#define SP_HPD_IRQ			BIT(6)
+#define SP_HPD_ESYNC_ERR		BIT(4)
+#define SP_HPD_CHG			BIT(2)
+#define SP_HPD_LOST			BIT(1)
+#define SP_HPD_PLUG			BIT(0)
+
+/* DP Interrupt Status Register */
+#define SP_DP_INT_STATUS1_REG		0xf7
+#define SP_TRAINING_FINISH		BIT(5)
+#define SP_POLLING_ERR			BIT(4)
+
+/* Common Interrupt Mask Register */
+#define SP_COMMON_INT_MASK_BASE		(0xf8 - 1)
+
+#define SP_COMMON_INT_MASK4_REG		0xfb
+
+/* DP Interrupts Mask Register */
+#define SP_DP_INT_MASK1_REG		0xfe
+
+/* Interrupt Control Register */
+#define SP_INT_CTRL_REG			0xff
+
+/***************************************************************/
+/* Register definition of device address 0x7a                  */
+/***************************************************************/
+
+/* DP TX Link Training Control Register */
+#define SP_DP_TX_LT_CTRL0_REG		0x30
+
+/* PD 1.2 Lint Training 80bit Pattern Register */
+#define SP_DP_LT_80BIT_PATTERN0_REG	0x80
+#define SP_DP_LT_80BIT_PATTERN_REG_NUM	10
+
+/* Audio Interface Control Register 0 */
+#define SP_AUD_INTERFACE_CTRL0_REG	0x5f
+#define SP_AUD_INTERFACE_DISABLE	0x80
+
+/* Audio Interface Control Register 2 */
+#define SP_AUD_INTERFACE_CTRL2_REG	0x60
+#define SP_M_AUD_ADJUST_ST		0x04
+
+/* Audio Interface Control Register 3 */
+#define SP_AUD_INTERFACE_CTRL3_REG	0x62
+
+/* Audio Interface Control Register 4 */
+#define SP_AUD_INTERFACE_CTRL4_REG	0x67
+
+/* Audio Interface Control Register 5 */
+#define SP_AUD_INTERFACE_CTRL5_REG	0x68
+
+/* Audio Interface Control Register 6 */
+#define SP_AUD_INTERFACE_CTRL6_REG	0x69
+
+/* Firmware Version Register */
+#define SP_FW_VER_REG			0xb7
+
+#endif
-- 
2.1.0

Re: [PATCH v3 3/3] drm: bridge: anx78xx: Add anx78xx driver support.

[Thierry Reding]

[-- Attachment #1: Type: text/plain, Size: 18092 bytes --]

On Fri, Apr 08, 2016 at 02:52:52PM +0200, Enric Balletbo i Serra wrote:
> Although there are other chips from the same family that can reuse this
> driver, at the moment we only tested ANX7814 chip.
> 
> The ANX7814 is an ultra-low power Full-HD (1080p60) SlimPort transmitter
> designed for portable devices. This driver adds initial support for HDMI
> to DP pass-through mode.
> 
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> Tested-by: Nicolas Boichat <drinkcat@chromium.org>
> Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
> Cc: Emil Velikov <emil.l.velikov@gmail.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Dan Carpenter <dan.carpenter@oracle.com>
> Cc: Daniel Kurtz <djkurtz@chromium.org>
> Cc: Nicolas Boichat <drinkcat@chromium.org>
> ---
> Changes since v2:
>  - Nicolas Boichat:
>    - Get rid of wait_for macro since is only used once.
>    - Do not replace the error code if it's readily available to you.
>  - Add Tested-by: Nicolas Boichat <drinkcat@chromium.org>
>  - Add Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
> 
> Changes since v1:
>  - Dan Carpenter: 
>    - Fix missing error code
>    - Use meaningful names for goto exit paths
>  - Rob Herring: 
>    - Use hpd instead cable_det as is the more standard name.
>  - Daniel Kurtz: 
>    - Use regmap_bulk in aux_transfer
>    - Fix gpio reset polarity.
>    - Turn off v10 last so we mirror poweron sequence
>    - Fix some error paths.
>    - Remove mutex in anx78xx_detect
>  - kbuild:
>    - WARNING: PTR_ERR_OR_ZERO can be used
> 
>  drivers/gpu/drm/bridge/Kconfig   |    8 +
>  drivers/gpu/drm/bridge/Makefile  |    1 +
>  drivers/gpu/drm/bridge/anx78xx.c | 1403 ++++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/bridge/anx78xx.h |  719 +++++++++++++++++++
>  4 files changed, 2131 insertions(+)
>  create mode 100644 drivers/gpu/drm/bridge/anx78xx.c
>  create mode 100644 drivers/gpu/drm/bridge/anx78xx.h
> 
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index 27e2022..0f595ae 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -40,4 +40,12 @@ config DRM_PARADE_PS8622
>  	---help---
>  	  Parade eDP-LVDS bridge chip driver.
>  
> +config DRM_ANX78XX

The symbol name should include the vendor (DRM_ANALOGIX_ANX78XX) and the
entry needs to be ordered alphabetically (by vendor, then name).

> +	tristate "Analogix ANX78XX bridge"
> +	select DRM_KMS_HELPER
> +	select REGMAP_I2C
> +	---help---
> +	  ANX78XX is a HD video transmitter chip over micro-USB connector
> +	  for smartphone device.

The commit description says the device is a FullHD video transmitter,
but here you say HD. Pick one. Preferably the correct one.

>  endmenu
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index f13c33d..8f0d69e 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -4,3 +4,4 @@ obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>  obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>  obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
>  obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
> +obj-$(CONFIG_DRM_ANX78XX) += anx78xx.o

Same here, the source file should be named analogix-anx78xx.c, and this
needs to be sorted by vendor, then name as well.

> diff --git a/drivers/gpu/drm/bridge/anx78xx.c b/drivers/gpu/drm/bridge/anx78xx.c
[...]
> +#include <linux/async.h>

At least this one doesn't seem to be needed.

> +static int anx78xx_aux_wait(struct anx78xx *anx78xx)
> +{
> +	int err;
> +	unsigned int status;
> +	unsigned long timeout;
> +
> +	/*
> +	 * Does the right thing for modeset paths when run under kdgb or
> +	 * similar atomic contexts. Note that it's important that we check the
> +	 * condition again after having timed out, since the timeout could be
> +	 * due to preemption or similar and we've never had a chance to check
> +	 * the condition before the timeout.
> +	 */

I don't think this is necessary. The AUX code should never be called
from atomic context, there are various other places where we take a
mutex that would trigger warnings.

> +	err = 0;

You can move this up to where the variable is declared.

> +	timeout = jiffies + msecs_to_jiffies(AUX_WAIT_TIMEOUT_MS) + 1;
> +	while (anx78xx_aux_op_finished(anx78xx)) {
> +		if (time_after(jiffies, timeout)) {
> +			if (anx78xx_aux_op_finished(anx78xx))
> +				err = -ETIMEDOUT;

Should this not be !cond? Ah, anx78xx_aux_op_finished() returns an error
code on failure. Perhaps it would be clearer if this either returned a
boolean or the name was changed to reflect the fact that it returns an
error code. _finished() sounds too much like it would return boolean.

To make it clearer what I mean, try reading the above aloud:

	if aux_op_finished, return error

That's the wrong way around.

> +			break;
> +		}
> +		if (drm_can_sleep())
> +			usleep_range(1000, 2000);
> +		else
> +			cpu_relax();
> +	}
> +
> +	if (err) {
> +		DRM_ERROR("Timed out waiting AUX to finish\n");
> +		return -ETIMEDOUT;
> +	}
> +
> +	/* Read the AUX channel access status */
> +	err = regmap_read(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_CH_STATUS_REG,
> +			  &status);
> +	if (err)
> +		return err;
> +
> +	if (status & SP_AUX_STATUS) {
> +		DRM_ERROR("Failed to read AUX channel: 0x%02x\n", status);
> +		return -ETIMEDOUT;
> +	}

Would it make sense to disambiguate these two errors using different
error codes? As it is this function will either return success or
timeout, even though the latter is obviously not a timeout.

> +static int anx78xx_aux_address(struct anx78xx *anx78xx, unsigned int addr)
> +{
> +	int err = 0;
> +
> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_7_0_REG,
> +			    addr & 0xff);
> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_15_8_REG,
> +			    (addr & 0xff00) >> 8);
> +
> +	/*
> +	 * DP AUX CH Address Register #2, only update bits[3:0]
> +	 * [7:4] RESERVED
> +	 * [3:0] AUX_ADDR[19:16], Register control AUX CH address.
> +	 */
> +	err |= regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
> +				  SP_AUX_ADDR_19_16_REG,
> +				  SP_AUX_ADDR_19_16_MASK,
> +				  (addr & 0xf0000) >> 16);

I'm not at all a fan of OR'ing error codes. Presumably if any of these
register accesses fails there's no reason to attempt the subsequent
accesses because the end result will be failure anyway.

> +	/* Write address and request */
> +	err = anx78xx_aux_address(anx78xx, msg->address);
> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_DP_AUX_CH_CTRL1_REG,
> +			    ctrl1);
> +	if (err)
> +		return -EIO;
> +
> +	/* Start transaction */
> +	err = regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
> +				 SP_DP_AUX_CH_CTRL2_REG, SP_ADDR_ONLY |
> +				 SP_AUX_EN, ctrl2);
> +	if (err)
> +		return err;
> +
> +	err = anx78xx_aux_wait(anx78xx);
> +
> +	msg->reply = err ? DP_AUX_I2C_REPLY_NACK : DP_AUX_I2C_REPLY_ACK;

This looks wrong. What if anx78xx_aux_wait() return -ETIMEDOUT? You'll
be setting msg->reply to NACK and return success That doesn't sound
right at all.

> +static int anx78xx_set_hpd(struct anx78xx *anx78xx)
> +{
> +	int err = 0;
> +
> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_RX_P0],
> +				  SP_TMDS_CTRL_BASE + 7, SP_PD_RT);
> +	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL3_REG,
> +				SP_HPD_OUT);

Again, OR'ing of error codes, please don't do it. There are some more
occurrences below.

> +static int anx78xx_init_gpio(struct anx78xx *anx78xx)
> +{
> +	struct device *dev = &anx78xx->client->dev;
> +	struct anx78xx_platform_data *pdata = &anx78xx->pdata;
> +
> +	/* GPIO for hpd */

HPD being an abbreviation it should be capitalized. Similar for a couple
of other abbreviations, some of which are inconsistently capitalized. In
variable names of consumer names, the lowercase variant is fine, but the
variant used in text (messages, comments) should be the all caps one.

> +	pdata->gpiod_hpd = devm_gpiod_get(dev, "hpd", GPIOD_IN);
> +	if (IS_ERR(pdata->gpiod_hpd))
> +		return PTR_ERR(pdata->gpiod_hpd);
> +
> +	/* GPIO for chip power down */
> +	pdata->gpiod_pd = devm_gpiod_get(dev, "pd", GPIOD_OUT_HIGH);
> +	if (IS_ERR(pdata->gpiod_pd))
> +		return PTR_ERR(pdata->gpiod_pd);
> +
> +	/* GPIO for chip reset */
> +	pdata->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> +	if (IS_ERR(pdata->gpiod_reset))
> +		return PTR_ERR(pdata->gpiod_reset);
> +
> +	/* GPIO for V10 power control */
> +	pdata->gpiod_v10 = devm_gpiod_get_optional(dev, "v10", GPIOD_OUT_LOW);

Does this actually supply power? If so it should be modelled as a
regulator.

> +static int anx78xx_dp_link_training(struct anx78xx *anx78xx)
> +{
> +	int err = 0;
> +	u8 dp_bw, regval;
> +
> +	err |= regmap_write(anx78xx->map[I2C_IDX_RX_P0], SP_HDMI_MUTE_CTRL_REG,
> +			    0x0);
> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2],
> +				  SP_POWERDOWN_CTRL_REG,
> +				  SP_TOTAL_PD);
> +	if (err)
> +		return -EIO;
> +
> +	err = drm_dp_dpcd_readb(&anx78xx->aux, DP_MAX_LINK_RATE, &dp_bw);
> +	if (err < 0)
> +		return err;
> +
> +	switch (dp_bw) {
> +	case DP_LINK_BW_1_62:
> +	case DP_LINK_BW_2_7:
> +	case DP_LINK_BW_5_4:
> +		break;
> +	default:
> +		DRM_DEBUG_KMS("Waiting to read DP bandwidth.\n");
> +		return -EAGAIN;
> +	}

That sounds wrong. Either you can read the content and it should be a
valid value (albeit one which you may not support) or you can't. Why do
you need to potentially repeat this read?

> +
> +	err = anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL1_REG,
> +			       SP_VIDEO_MUTE);
> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2],
> +				  SP_VID_CTRL1_REG, SP_VIDEO_EN);
> +	if (err)
> +		return -EIO;
> +
> +	/* Get dpcd info */

s/dpcd/DPCD/

> +	err = drm_dp_dpcd_read(&anx78xx->aux, DP_DPCD_REV,
> +			       &anx78xx->dpcd, DP_RECEIVER_CAP_SIZE);
> +	if (err < 0) {
> +		DRM_ERROR("Failed to read DPCD\n");

It's often useful to output the error code as part of the error message
to make it easier for developers to diagnose problems.

> +		return err;
> +	}
> +
> +	/* Clear channel x SERDES power down */
> +	err = anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P0],
> +				 SP_DP_ANALOG_POWER_DOWN_REG, SP_CH0_PD);
> +	if (err)
> +		return -EIO;
> +
> +	/* Check link capabilities */
> +	err = drm_dp_link_probe(&anx78xx->aux, &anx78xx->link);
> +	if (err < 0) {
> +		DRM_ERROR("Failed to probe link capabilities\n");
> +		return err;
> +	}
> +
> +	/* Power up the sink */
> +	err = drm_dp_link_power_up(&anx78xx->aux, &anx78xx->link);
> +	if (err < 0) {
> +		DRM_ERROR("Failed to power up DisplayPort link\n");
> +		return err;
> +	}
> +
> +	/* Possibly enable downspread on the sink */
> +	err = regmap_write(anx78xx->map[I2C_IDX_TX_P0],
> +			   SP_DP_DOWNSPREAD_CTRL1_REG, 0);
> +	if (err)
> +		return err;
> +
> +	if (anx78xx->dpcd[3] & 0x1) {

This should use the symbolic constants defined in drm_dp_helper.h.
Actually, it should probably add a symbolic constant because we don't
have one yet for bit 0 in the DP_MAX_DOWNSPREAD register.

> +static inline struct anx78xx *
> +	connector_to_anx78xx(struct drm_connector *connector)

The function name should start on the first column. Also you might want
to move this inline function after the struct anx78xx declaration, which
is more consistent with other drivers.

> +static const struct drm_connector_helper_funcs
> +	anx78xx_connector_helper_funcs = {

The structure name should start in the first column as well.

> +	.get_modes = anx78xx_get_modes,
> +	.best_encoder = anx78xx_best_encoder,
> +};
> +
> +static enum drm_connector_status anx78xx_detect(struct drm_connector *connector,
> +						bool force)
> +{
> +	struct anx78xx *anx78xx = container_of(connector, struct anx78xx,
> +					       connector);

Didn't you introduce an inline function for this just a few lines above?

> +	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
> +		      connector->name);
> +
> +	if (!gpiod_get_value(anx78xx->pdata.gpiod_hpd)) {
> +		DRM_DEBUG_KMS("CONNECTOR STATUS DISCONNECTED\n");
> +		return connector_status_disconnected;
> +	}
> +
> +	return connector_status_connected;
> +}

Is it really necessary to add two debug messages here? The DRM core will
already output a message for connector status changes, so this is
unnecessarily noisy in my opinion.

> +static inline struct anx78xx *bridge_to_anx78xx(struct drm_bridge *bridge)
> +{
> +	return container_of(bridge, struct anx78xx, bridge);
> +}

Put this together with the connector cast function.

> +static void anx78xx_bridge_disable(struct drm_bridge *bridge)
> +{
> +	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
> +
> +	mutex_lock(&anx78xx->lock);

Do you really need the locking here and below? I think the DRM core
already ensures that these calls are always serialized.

> +static void anx78xx_bridge_mode_set(struct drm_bridge *bridge,
> +				    struct drm_display_mode *mode,
> +				    struct drm_display_mode *adjusted_mode)
> +{
> +	int err;
> +	struct hdmi_avi_infoframe frame;
> +	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
> +
> +	if (WARN_ON(!anx78xx->powered))
> +		return;
> +
> +	mutex_lock(&anx78xx->lock);
> +
> +	mode = adjusted_mode;
> +
> +	err = drm_hdmi_avi_infoframe_from_display_mode(&frame, mode);

This seems like jumping through hoops. Why not simply pass adjusted_mode
to the function?

> +static const struct drm_bridge_funcs anx78xx_bridge_funcs = {
> +	.attach		= anx78xx_bridge_attach,
> +	.mode_fixup	= anx78xx_bridge_mode_fixup,
> +	.disable	= anx78xx_bridge_disable,
> +	.mode_set	= anx78xx_bridge_mode_set,
> +	.enable		= anx78xx_bridge_enable,
> +};

I'd leave out the tab-padding. Simple spaces will do just fine.

> +static irqreturn_t anx78xx_hpd_threaded_handler(int unused, void *data)

Might as well give the first parameter the proper name (irq).

> +static bool anx78xx_handle_common_int_4(struct anx78xx *anx78xx, u8 irq)
> +{
> +	int err;
> +	bool event = false;
> +
> +	DRM_DEBUG_KMS("Handle common interrupt 4: %02x\n", irq);
> +
> +	err = regmap_write(anx78xx->map[I2C_IDX_TX_P2],
> +			   SP_COMMON_INT_STATUS4_REG, irq);
> +	if (err) {
> +		DRM_ERROR("Failed to write SP_COMMON_INT_STATUS4 %d\n", err);
> +		return event;
> +	}
> +
> +	if (irq & SP_HPD_LOST) {
> +		DRM_DEBUG_KMS("IRQ: Hot plug detect - cable is pulled out\n");
> +		event = true;
> +		anx78xx_poweroff(anx78xx);
> +	} else if (irq & SP_HPD_PLUG) {
> +		DRM_DEBUG_KMS("IRQ: Hot plug detect - cable plug\n");
> +		event = true;
> +		/* Free previous cached EDID if any */
> +		kfree(anx78xx->edid);
> +		anx78xx->edid = NULL;

I think you can free the EDID on unplug, since it becomes stale at that
point already. The DRM core will also remove the EDID data on unplug.

> +static void unregister_i2c_dummy_clients(struct anx78xx *anx78xx)
> +{
> +	int i;

unsigned int

> +
> +	for (i = 0; i < ARRAY_SIZE(anx78xx->i2c_dummy); i++)
> +		if (anx78xx->i2c_dummy[i])
> +			i2c_unregister_device(anx78xx->i2c_dummy[i]);
> +}
> +
> +static const struct regmap_config anx78xx_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +};
> +
> +static const u16 anx78xx_chipid_list[] = {
> +	0x7812,
> +	0x7814,
> +	0x7818,
> +};
> +
> +static int anx78xx_i2c_probe(struct i2c_client *client,
> +			     const struct i2c_device_id *id)
> +{
> +	struct anx78xx *anx78xx;
> +	struct anx78xx_platform_data *pdata;
> +	int err, i;

i should be unsigned int.

> +	unsigned int idl, idh, version;
> +	bool found = false;
> +
> +	anx78xx = devm_kzalloc(&client->dev, sizeof(*anx78xx), GFP_KERNEL);
> +	if (!anx78xx)
> +		return -ENOMEM;
> +
> +	pdata = &anx78xx->pdata;
> +
> +	mutex_init(&anx78xx->lock);
> +
> +#if IS_ENABLED(CONFIG_OF)
> +	anx78xx->bridge.of_node = client->dev.of_node;
> +#endif
> +
> +	anx78xx->client = client;
> +	i2c_set_clientdata(client, anx78xx);
> +
> +	err = anx78xx_init_gpio(anx78xx);
> +	if (err) {
> +		DRM_ERROR("Failed to initialize gpios\n");
> +		return err;
> +	}
> +
> +	pdata->hpd_irq = gpiod_to_irq(pdata->gpiod_hpd);
> +	if (pdata->hpd_irq < 0) {
> +		DRM_ERROR("Failed to get hpd irq %d\n",
> +			  pdata->hpd_irq);
> +		return -ENODEV;
> +	}
> +
> +	pdata->intp_irq = client->irq;
> +	if (!pdata->intp_irq) {
> +		DRM_ERROR("Failed to get CABLE_DET and INTP irq\n");
> +		return -ENODEV;
> +	}
> +
> +	/* Map slave addresses of ANX7814 */
> +	for (i = 0; i < I2C_NUM_ADDRESSES; i++) {
> +		anx78xx->i2c_dummy[i] = i2c_new_dummy(client->adapter,
> +						anx78xx_i2c_addresses[i] >> 1);
> +		if (!anx78xx->i2c_dummy[i]) {
> +			err = -ENOMEM;
> +			DRM_ERROR("Failed to reserve i2c bus %02x.\n",
> +				  anx78xx_i2c_addresses[i]);
> +			goto err_unregister_i2c;
> +		}
> +
> +		anx78xx->map[i] = devm_regmap_init_i2c(anx78xx->i2c_dummy[i],
> +						       &anx78xx_regmap_config);
> +		if (IS_ERR(anx78xx->map[i])) {
> +			err = PTR_ERR(anx78xx->map[i]);
> +			DRM_ERROR("Failed regmap initialization %02x.\n",
> +				  anx78xx_i2c_addresses[i]);
> +			goto err_unregister_i2c;
> +		}
> +	}

That's quite some overhead merely to use regmap... Perhaps there's room
to enhance regmap-i2c to support multiple addresses for the same device?

> +static int anx78xx_i2c_remove(struct i2c_client *client)
> +{
> +	struct anx78xx *anx78xx = i2c_get_clientdata(client);
> +
> +	drm_bridge_remove(&anx78xx->bridge);
> +
> +	unregister_i2c_dummy_clients(anx78xx);
> +
> +	kfree(anx78xx->edid);
> +	anx78xx->edid = NULL;

The memory pointed at by anx78xx will be freed a couple of instructions
later, there's no need to set ->edid to NULL.

Thierry

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Re: [PATCH v3 3/3] drm: bridge: anx78xx: Add anx78xx driver support.

[Thierry Reding]

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On Fri, Apr 08, 2016 at 02:52:52PM +0200, Enric Balletbo i Serra wrote:
> Although there are other chips from the same family that can reuse this
> driver, at the moment we only tested ANX7814 chip.
> 
> The ANX7814 is an ultra-low power Full-HD (1080p60) SlimPort transmitter
> designed for portable devices. This driver adds initial support for HDMI
> to DP pass-through mode.
> 
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> Tested-by: Nicolas Boichat <drinkcat@chromium.org>
> Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
> Cc: Emil Velikov <emil.l.velikov@gmail.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Dan Carpenter <dan.carpenter@oracle.com>
> Cc: Daniel Kurtz <djkurtz@chromium.org>
> Cc: Nicolas Boichat <drinkcat@chromium.org>
> ---
> Changes since v2:
>  - Nicolas Boichat:
>    - Get rid of wait_for macro since is only used once.
>    - Do not replace the error code if it's readily available to you.
>  - Add Tested-by: Nicolas Boichat <drinkcat@chromium.org>
>  - Add Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
> 
> Changes since v1:
>  - Dan Carpenter: 
>    - Fix missing error code
>    - Use meaningful names for goto exit paths
>  - Rob Herring: 
>    - Use hpd instead cable_det as is the more standard name.
>  - Daniel Kurtz: 
>    - Use regmap_bulk in aux_transfer
>    - Fix gpio reset polarity.
>    - Turn off v10 last so we mirror poweron sequence
>    - Fix some error paths.
>    - Remove mutex in anx78xx_detect
>  - kbuild:
>    - WARNING: PTR_ERR_OR_ZERO can be used
> 
>  drivers/gpu/drm/bridge/Kconfig   |    8 +
>  drivers/gpu/drm/bridge/Makefile  |    1 +
>  drivers/gpu/drm/bridge/anx78xx.c | 1403 ++++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/bridge/anx78xx.h |  719 +++++++++++++++++++
>  4 files changed, 2131 insertions(+)
>  create mode 100644 drivers/gpu/drm/bridge/anx78xx.c
>  create mode 100644 drivers/gpu/drm/bridge/anx78xx.h
> 
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index 27e2022..0f595ae 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -40,4 +40,12 @@ config DRM_PARADE_PS8622
>  	---help---
>  	  Parade eDP-LVDS bridge chip driver.
>  
> +config DRM_ANX78XX

The symbol name should include the vendor (DRM_ANALOGIX_ANX78XX) and the
entry needs to be ordered alphabetically (by vendor, then name).

> +	tristate "Analogix ANX78XX bridge"
> +	select DRM_KMS_HELPER
> +	select REGMAP_I2C
> +	---help---
> +	  ANX78XX is a HD video transmitter chip over micro-USB connector
> +	  for smartphone device.

The commit description says the device is a FullHD video transmitter,
but here you say HD. Pick one. Preferably the correct one.

>  endmenu
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index f13c33d..8f0d69e 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -4,3 +4,4 @@ obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>  obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>  obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
>  obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
> +obj-$(CONFIG_DRM_ANX78XX) += anx78xx.o

Same here, the source file should be named analogix-anx78xx.c, and this
needs to be sorted by vendor, then name as well.

> diff --git a/drivers/gpu/drm/bridge/anx78xx.c b/drivers/gpu/drm/bridge/anx78xx.c
[...]
> +#include <linux/async.h>

At least this one doesn't seem to be needed.

> +static int anx78xx_aux_wait(struct anx78xx *anx78xx)
> +{
> +	int err;
> +	unsigned int status;
> +	unsigned long timeout;
> +
> +	/*
> +	 * Does the right thing for modeset paths when run under kdgb or
> +	 * similar atomic contexts. Note that it's important that we check the
> +	 * condition again after having timed out, since the timeout could be
> +	 * due to preemption or similar and we've never had a chance to check
> +	 * the condition before the timeout.
> +	 */

I don't think this is necessary. The AUX code should never be called
from atomic context, there are various other places where we take a
mutex that would trigger warnings.

> +	err = 0;

You can move this up to where the variable is declared.

> +	timeout = jiffies + msecs_to_jiffies(AUX_WAIT_TIMEOUT_MS) + 1;
> +	while (anx78xx_aux_op_finished(anx78xx)) {
> +		if (time_after(jiffies, timeout)) {
> +			if (anx78xx_aux_op_finished(anx78xx))
> +				err = -ETIMEDOUT;

Should this not be !cond? Ah, anx78xx_aux_op_finished() returns an error
code on failure. Perhaps it would be clearer if this either returned a
boolean or the name was changed to reflect the fact that it returns an
error code. _finished() sounds too much like it would return boolean.

To make it clearer what I mean, try reading the above aloud:

	if aux_op_finished, return error

That's the wrong way around.

> +			break;
> +		}
> +		if (drm_can_sleep())
> +			usleep_range(1000, 2000);
> +		else
> +			cpu_relax();
> +	}
> +
> +	if (err) {
> +		DRM_ERROR("Timed out waiting AUX to finish\n");
> +		return -ETIMEDOUT;
> +	}
> +
> +	/* Read the AUX channel access status */
> +	err = regmap_read(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_CH_STATUS_REG,
> +			  &status);
> +	if (err)
> +		return err;
> +
> +	if (status & SP_AUX_STATUS) {
> +		DRM_ERROR("Failed to read AUX channel: 0x%02x\n", status);
> +		return -ETIMEDOUT;
> +	}

Would it make sense to disambiguate these two errors using different
error codes? As it is this function will either return success or
timeout, even though the latter is obviously not a timeout.

> +static int anx78xx_aux_address(struct anx78xx *anx78xx, unsigned int addr)
> +{
> +	int err = 0;
> +
> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_7_0_REG,
> +			    addr & 0xff);
> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_15_8_REG,
> +			    (addr & 0xff00) >> 8);
> +
> +	/*
> +	 * DP AUX CH Address Register #2, only update bits[3:0]
> +	 * [7:4] RESERVED
> +	 * [3:0] AUX_ADDR[19:16], Register control AUX CH address.
> +	 */
> +	err |= regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
> +				  SP_AUX_ADDR_19_16_REG,
> +				  SP_AUX_ADDR_19_16_MASK,
> +				  (addr & 0xf0000) >> 16);

I'm not at all a fan of OR'ing error codes. Presumably if any of these
register accesses fails there's no reason to attempt the subsequent
accesses because the end result will be failure anyway.

> +	/* Write address and request */
> +	err = anx78xx_aux_address(anx78xx, msg->address);
> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_DP_AUX_CH_CTRL1_REG,
> +			    ctrl1);
> +	if (err)
> +		return -EIO;
> +
> +	/* Start transaction */
> +	err = regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
> +				 SP_DP_AUX_CH_CTRL2_REG, SP_ADDR_ONLY |
> +				 SP_AUX_EN, ctrl2);
> +	if (err)
> +		return err;
> +
> +	err = anx78xx_aux_wait(anx78xx);
> +
> +	msg->reply = err ? DP_AUX_I2C_REPLY_NACK : DP_AUX_I2C_REPLY_ACK;

This looks wrong. What if anx78xx_aux_wait() return -ETIMEDOUT? You'll
be setting msg->reply to NACK and return success That doesn't sound
right at all.

> +static int anx78xx_set_hpd(struct anx78xx *anx78xx)
> +{
> +	int err = 0;
> +
> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_RX_P0],
> +				  SP_TMDS_CTRL_BASE + 7, SP_PD_RT);
> +	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL3_REG,
> +				SP_HPD_OUT);

Again, OR'ing of error codes, please don't do it. There are some more
occurrences below.

> +static int anx78xx_init_gpio(struct anx78xx *anx78xx)
> +{
> +	struct device *dev = &anx78xx->client->dev;
> +	struct anx78xx_platform_data *pdata = &anx78xx->pdata;
> +
> +	/* GPIO for hpd */

HPD being an abbreviation it should be capitalized. Similar for a couple
of other abbreviations, some of which are inconsistently capitalized. In
variable names of consumer names, the lowercase variant is fine, but the
variant used in text (messages, comments) should be the all caps one.

> +	pdata->gpiod_hpd = devm_gpiod_get(dev, "hpd", GPIOD_IN);
> +	if (IS_ERR(pdata->gpiod_hpd))
> +		return PTR_ERR(pdata->gpiod_hpd);
> +
> +	/* GPIO for chip power down */
> +	pdata->gpiod_pd = devm_gpiod_get(dev, "pd", GPIOD_OUT_HIGH);
> +	if (IS_ERR(pdata->gpiod_pd))
> +		return PTR_ERR(pdata->gpiod_pd);
> +
> +	/* GPIO for chip reset */
> +	pdata->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> +	if (IS_ERR(pdata->gpiod_reset))
> +		return PTR_ERR(pdata->gpiod_reset);
> +
> +	/* GPIO for V10 power control */
> +	pdata->gpiod_v10 = devm_gpiod_get_optional(dev, "v10", GPIOD_OUT_LOW);

Does this actually supply power? If so it should be modelled as a
regulator.

> +static int anx78xx_dp_link_training(struct anx78xx *anx78xx)
> +{
> +	int err = 0;
> +	u8 dp_bw, regval;
> +
> +	err |= regmap_write(anx78xx->map[I2C_IDX_RX_P0], SP_HDMI_MUTE_CTRL_REG,
> +			    0x0);
> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2],
> +				  SP_POWERDOWN_CTRL_REG,
> +				  SP_TOTAL_PD);
> +	if (err)
> +		return -EIO;
> +
> +	err = drm_dp_dpcd_readb(&anx78xx->aux, DP_MAX_LINK_RATE, &dp_bw);
> +	if (err < 0)
> +		return err;
> +
> +	switch (dp_bw) {
> +	case DP_LINK_BW_1_62:
> +	case DP_LINK_BW_2_7:
> +	case DP_LINK_BW_5_4:
> +		break;
> +	default:
> +		DRM_DEBUG_KMS("Waiting to read DP bandwidth.\n");
> +		return -EAGAIN;
> +	}

That sounds wrong. Either you can read the content and it should be a
valid value (albeit one which you may not support) or you can't. Why do
you need to potentially repeat this read?

> +
> +	err = anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL1_REG,
> +			       SP_VIDEO_MUTE);
> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2],
> +				  SP_VID_CTRL1_REG, SP_VIDEO_EN);
> +	if (err)
> +		return -EIO;
> +
> +	/* Get dpcd info */

s/dpcd/DPCD/

> +	err = drm_dp_dpcd_read(&anx78xx->aux, DP_DPCD_REV,
> +			       &anx78xx->dpcd, DP_RECEIVER_CAP_SIZE);
> +	if (err < 0) {
> +		DRM_ERROR("Failed to read DPCD\n");

It's often useful to output the error code as part of the error message
to make it easier for developers to diagnose problems.

> +		return err;
> +	}
> +
> +	/* Clear channel x SERDES power down */
> +	err = anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P0],
> +				 SP_DP_ANALOG_POWER_DOWN_REG, SP_CH0_PD);
> +	if (err)
> +		return -EIO;
> +
> +	/* Check link capabilities */
> +	err = drm_dp_link_probe(&anx78xx->aux, &anx78xx->link);
> +	if (err < 0) {
> +		DRM_ERROR("Failed to probe link capabilities\n");
> +		return err;
> +	}
> +
> +	/* Power up the sink */
> +	err = drm_dp_link_power_up(&anx78xx->aux, &anx78xx->link);
> +	if (err < 0) {
> +		DRM_ERROR("Failed to power up DisplayPort link\n");
> +		return err;
> +	}
> +
> +	/* Possibly enable downspread on the sink */
> +	err = regmap_write(anx78xx->map[I2C_IDX_TX_P0],
> +			   SP_DP_DOWNSPREAD_CTRL1_REG, 0);
> +	if (err)
> +		return err;
> +
> +	if (anx78xx->dpcd[3] & 0x1) {

This should use the symbolic constants defined in drm_dp_helper.h.
Actually, it should probably add a symbolic constant because we don't
have one yet for bit 0 in the DP_MAX_DOWNSPREAD register.

> +static inline struct anx78xx *
> +	connector_to_anx78xx(struct drm_connector *connector)

The function name should start on the first column. Also you might want
to move this inline function after the struct anx78xx declaration, which
is more consistent with other drivers.

> +static const struct drm_connector_helper_funcs
> +	anx78xx_connector_helper_funcs = {

The structure name should start in the first column as well.

> +	.get_modes = anx78xx_get_modes,
> +	.best_encoder = anx78xx_best_encoder,
> +};
> +
> +static enum drm_connector_status anx78xx_detect(struct drm_connector *connector,
> +						bool force)
> +{
> +	struct anx78xx *anx78xx = container_of(connector, struct anx78xx,
> +					       connector);

Didn't you introduce an inline function for this just a few lines above?

> +	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
> +		      connector->name);
> +
> +	if (!gpiod_get_value(anx78xx->pdata.gpiod_hpd)) {
> +		DRM_DEBUG_KMS("CONNECTOR STATUS DISCONNECTED\n");
> +		return connector_status_disconnected;
> +	}
> +
> +	return connector_status_connected;
> +}

Is it really necessary to add two debug messages here? The DRM core will
already output a message for connector status changes, so this is
unnecessarily noisy in my opinion.

> +static inline struct anx78xx *bridge_to_anx78xx(struct drm_bridge *bridge)
> +{
> +	return container_of(bridge, struct anx78xx, bridge);
> +}

Put this together with the connector cast function.

> +static void anx78xx_bridge_disable(struct drm_bridge *bridge)
> +{
> +	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
> +
> +	mutex_lock(&anx78xx->lock);

Do you really need the locking here and below? I think the DRM core
already ensures that these calls are always serialized.

> +static void anx78xx_bridge_mode_set(struct drm_bridge *bridge,
> +				    struct drm_display_mode *mode,
> +				    struct drm_display_mode *adjusted_mode)
> +{
> +	int err;
> +	struct hdmi_avi_infoframe frame;
> +	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
> +
> +	if (WARN_ON(!anx78xx->powered))
> +		return;
> +
> +	mutex_lock(&anx78xx->lock);
> +
> +	mode = adjusted_mode;
> +
> +	err = drm_hdmi_avi_infoframe_from_display_mode(&frame, mode);

This seems like jumping through hoops. Why not simply pass adjusted_mode
to the function?

> +static const struct drm_bridge_funcs anx78xx_bridge_funcs = {
> +	.attach		= anx78xx_bridge_attach,
> +	.mode_fixup	= anx78xx_bridge_mode_fixup,
> +	.disable	= anx78xx_bridge_disable,
> +	.mode_set	= anx78xx_bridge_mode_set,
> +	.enable		= anx78xx_bridge_enable,
> +};

I'd leave out the tab-padding. Simple spaces will do just fine.

> +static irqreturn_t anx78xx_hpd_threaded_handler(int unused, void *data)

Might as well give the first parameter the proper name (irq).

> +static bool anx78xx_handle_common_int_4(struct anx78xx *anx78xx, u8 irq)
> +{
> +	int err;
> +	bool event = false;
> +
> +	DRM_DEBUG_KMS("Handle common interrupt 4: %02x\n", irq);
> +
> +	err = regmap_write(anx78xx->map[I2C_IDX_TX_P2],
> +			   SP_COMMON_INT_STATUS4_REG, irq);
> +	if (err) {
> +		DRM_ERROR("Failed to write SP_COMMON_INT_STATUS4 %d\n", err);
> +		return event;
> +	}
> +
> +	if (irq & SP_HPD_LOST) {
> +		DRM_DEBUG_KMS("IRQ: Hot plug detect - cable is pulled out\n");
> +		event = true;
> +		anx78xx_poweroff(anx78xx);
> +	} else if (irq & SP_HPD_PLUG) {
> +		DRM_DEBUG_KMS("IRQ: Hot plug detect - cable plug\n");
> +		event = true;
> +		/* Free previous cached EDID if any */
> +		kfree(anx78xx->edid);
> +		anx78xx->edid = NULL;

I think you can free the EDID on unplug, since it becomes stale at that
point already. The DRM core will also remove the EDID data on unplug.

> +static void unregister_i2c_dummy_clients(struct anx78xx *anx78xx)
> +{
> +	int i;

unsigned int

> +
> +	for (i = 0; i < ARRAY_SIZE(anx78xx->i2c_dummy); i++)
> +		if (anx78xx->i2c_dummy[i])
> +			i2c_unregister_device(anx78xx->i2c_dummy[i]);
> +}
> +
> +static const struct regmap_config anx78xx_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +};
> +
> +static const u16 anx78xx_chipid_list[] = {
> +	0x7812,
> +	0x7814,
> +	0x7818,
> +};
> +
> +static int anx78xx_i2c_probe(struct i2c_client *client,
> +			     const struct i2c_device_id *id)
> +{
> +	struct anx78xx *anx78xx;
> +	struct anx78xx_platform_data *pdata;
> +	int err, i;

i should be unsigned int.

> +	unsigned int idl, idh, version;
> +	bool found = false;
> +
> +	anx78xx = devm_kzalloc(&client->dev, sizeof(*anx78xx), GFP_KERNEL);
> +	if (!anx78xx)
> +		return -ENOMEM;
> +
> +	pdata = &anx78xx->pdata;
> +
> +	mutex_init(&anx78xx->lock);
> +
> +#if IS_ENABLED(CONFIG_OF)
> +	anx78xx->bridge.of_node = client->dev.of_node;
> +#endif
> +
> +	anx78xx->client = client;
> +	i2c_set_clientdata(client, anx78xx);
> +
> +	err = anx78xx_init_gpio(anx78xx);
> +	if (err) {
> +		DRM_ERROR("Failed to initialize gpios\n");
> +		return err;
> +	}
> +
> +	pdata->hpd_irq = gpiod_to_irq(pdata->gpiod_hpd);
> +	if (pdata->hpd_irq < 0) {
> +		DRM_ERROR("Failed to get hpd irq %d\n",
> +			  pdata->hpd_irq);
> +		return -ENODEV;
> +	}
> +
> +	pdata->intp_irq = client->irq;
> +	if (!pdata->intp_irq) {
> +		DRM_ERROR("Failed to get CABLE_DET and INTP irq\n");
> +		return -ENODEV;
> +	}
> +
> +	/* Map slave addresses of ANX7814 */
> +	for (i = 0; i < I2C_NUM_ADDRESSES; i++) {
> +		anx78xx->i2c_dummy[i] = i2c_new_dummy(client->adapter,
> +						anx78xx_i2c_addresses[i] >> 1);
> +		if (!anx78xx->i2c_dummy[i]) {
> +			err = -ENOMEM;
> +			DRM_ERROR("Failed to reserve i2c bus %02x.\n",
> +				  anx78xx_i2c_addresses[i]);
> +			goto err_unregister_i2c;
> +		}
> +
> +		anx78xx->map[i] = devm_regmap_init_i2c(anx78xx->i2c_dummy[i],
> +						       &anx78xx_regmap_config);
> +		if (IS_ERR(anx78xx->map[i])) {
> +			err = PTR_ERR(anx78xx->map[i]);
> +			DRM_ERROR("Failed regmap initialization %02x.\n",
> +				  anx78xx_i2c_addresses[i]);
> +			goto err_unregister_i2c;
> +		}
> +	}

That's quite some overhead merely to use regmap... Perhaps there's room
to enhance regmap-i2c to support multiple addresses for the same device?

> +static int anx78xx_i2c_remove(struct i2c_client *client)
> +{
> +	struct anx78xx *anx78xx = i2c_get_clientdata(client);
> +
> +	drm_bridge_remove(&anx78xx->bridge);
> +
> +	unregister_i2c_dummy_clients(anx78xx);
> +
> +	kfree(anx78xx->edid);
> +	anx78xx->edid = NULL;

The memory pointed at by anx78xx will be freed a couple of instructions
later, there's no need to set ->edid to NULL.

Thierry

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Re: [PATCH v3 3/3] drm: bridge: anx78xx: Add anx78xx driver support.

[Enric Balletbo i Serra]

Hi Thierry,

Many thanks for answering and do this accurate report. I'd add a comment 
on something you (see below). Apart from this I'll add your changes and 
send a new version.

On 14/04/16 15:10, Thierry Reding wrote:
> On Fri, Apr 08, 2016 at 02:52:52PM +0200, Enric Balletbo i Serra wrote:
>> Although there are other chips from the same family that can reuse this
>> driver, at the moment we only tested ANX7814 chip.
>>
>> The ANX7814 is an ultra-low power Full-HD (1080p60) SlimPort transmitter
>> designed for portable devices. This driver adds initial support for HDMI
>> to DP pass-through mode.
>>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
>> Tested-by: Nicolas Boichat <drinkcat@chromium.org>
>> Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
>> Cc: Emil Velikov <emil.l.velikov@gmail.com>
>> Cc: Rob Herring <robh@kernel.org>
>> Cc: Dan Carpenter <dan.carpenter@oracle.com>
>> Cc: Daniel Kurtz <djkurtz@chromium.org>
>> Cc: Nicolas Boichat <drinkcat@chromium.org>
>> ---
>> Changes since v2:
>>   - Nicolas Boichat:
>>     - Get rid of wait_for macro since is only used once.
>>     - Do not replace the error code if it's readily available to you.
>>   - Add Tested-by: Nicolas Boichat <drinkcat@chromium.org>
>>   - Add Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
>>
>> Changes since v1:
>>   - Dan Carpenter:
>>     - Fix missing error code
>>     - Use meaningful names for goto exit paths
>>   - Rob Herring:
>>     - Use hpd instead cable_det as is the more standard name.
>>   - Daniel Kurtz:
>>     - Use regmap_bulk in aux_transfer
>>     - Fix gpio reset polarity.
>>     - Turn off v10 last so we mirror poweron sequence
>>     - Fix some error paths.
>>     - Remove mutex in anx78xx_detect
>>   - kbuild:
>>     - WARNING: PTR_ERR_OR_ZERO can be used
>>
>>   drivers/gpu/drm/bridge/Kconfig   |    8 +
>>   drivers/gpu/drm/bridge/Makefile  |    1 +
>>   drivers/gpu/drm/bridge/anx78xx.c | 1403 ++++++++++++++++++++++++++++++++++++++
>>   drivers/gpu/drm/bridge/anx78xx.h |  719 +++++++++++++++++++
>>   4 files changed, 2131 insertions(+)
>>   create mode 100644 drivers/gpu/drm/bridge/anx78xx.c
>>   create mode 100644 drivers/gpu/drm/bridge/anx78xx.h
>>
>> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
>> index 27e2022..0f595ae 100644
>> --- a/drivers/gpu/drm/bridge/Kconfig
>> +++ b/drivers/gpu/drm/bridge/Kconfig
>> @@ -40,4 +40,12 @@ config DRM_PARADE_PS8622
>>   	---help---
>>   	  Parade eDP-LVDS bridge chip driver.
>>
>> +config DRM_ANX78XX
>
> The symbol name should include the vendor (DRM_ANALOGIX_ANX78XX) and the
> entry needs to be ordered alphabetically (by vendor, then name).
>
>> +	tristate "Analogix ANX78XX bridge"
>> +	select DRM_KMS_HELPER
>> +	select REGMAP_I2C
>> +	---help---
>> +	  ANX78XX is a HD video transmitter chip over micro-USB connector
>> +	  for smartphone device.
>
> The commit description says the device is a FullHD video transmitter,
> but here you say HD. Pick one. Preferably the correct one.
>
>>   endmenu
>> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
>> index f13c33d..8f0d69e 100644
>> --- a/drivers/gpu/drm/bridge/Makefile
>> +++ b/drivers/gpu/drm/bridge/Makefile
>> @@ -4,3 +4,4 @@ obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>>   obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>>   obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
>>   obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
>> +obj-$(CONFIG_DRM_ANX78XX) += anx78xx.o
>
> Same here, the source file should be named analogix-anx78xx.c, and this
> needs to be sorted by vendor, then name as well.
>
>> diff --git a/drivers/gpu/drm/bridge/anx78xx.c b/drivers/gpu/drm/bridge/anx78xx.c
> [...]
>> +#include <linux/async.h>
>
> At least this one doesn't seem to be needed.
>
>> +static int anx78xx_aux_wait(struct anx78xx *anx78xx)
>> +{
>> +	int err;
>> +	unsigned int status;
>> +	unsigned long timeout;
>> +
>> +	/*
>> +	 * Does the right thing for modeset paths when run under kdgb or
>> +	 * similar atomic contexts. Note that it's important that we check the
>> +	 * condition again after having timed out, since the timeout could be
>> +	 * due to preemption or similar and we've never had a chance to check
>> +	 * the condition before the timeout.
>> +	 */
>
> I don't think this is necessary. The AUX code should never be called
> from atomic context, there are various other places where we take a
> mutex that would trigger warnings.
>
>> +	err = 0;
>
> You can move this up to where the variable is declared.
>
>> +	timeout = jiffies + msecs_to_jiffies(AUX_WAIT_TIMEOUT_MS) + 1;
>> +	while (anx78xx_aux_op_finished(anx78xx)) {
>> +		if (time_after(jiffies, timeout)) {
>> +			if (anx78xx_aux_op_finished(anx78xx))
>> +				err = -ETIMEDOUT;
>
> Should this not be !cond? Ah, anx78xx_aux_op_finished() returns an error
> code on failure. Perhaps it would be clearer if this either returned a
> boolean or the name was changed to reflect the fact that it returns an
> error code. _finished() sounds too much like it would return boolean.
>
> To make it clearer what I mean, try reading the above aloud:
>
> 	if aux_op_finished, return error
>
> That's the wrong way around.
>
>> +			break;
>> +		}
>> +		if (drm_can_sleep())
>> +			usleep_range(1000, 2000);
>> +		else
>> +			cpu_relax();
>> +	}
>> +
>> +	if (err) {
>> +		DRM_ERROR("Timed out waiting AUX to finish\n");
>> +		return -ETIMEDOUT;
>> +	}
>> +
>> +	/* Read the AUX channel access status */
>> +	err = regmap_read(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_CH_STATUS_REG,
>> +			  &status);
>> +	if (err)
>> +		return err;
>> +
>> +	if (status & SP_AUX_STATUS) {
>> +		DRM_ERROR("Failed to read AUX channel: 0x%02x\n", status);
>> +		return -ETIMEDOUT;
>> +	}
>
> Would it make sense to disambiguate these two errors using different
> error codes? As it is this function will either return success or
> timeout, even though the latter is obviously not a timeout.
>
>> +static int anx78xx_aux_address(struct anx78xx *anx78xx, unsigned int addr)
>> +{
>> +	int err = 0;
>> +
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_7_0_REG,
>> +			    addr & 0xff);
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_15_8_REG,
>> +			    (addr & 0xff00) >> 8);
>> +
>> +	/*
>> +	 * DP AUX CH Address Register #2, only update bits[3:0]
>> +	 * [7:4] RESERVED
>> +	 * [3:0] AUX_ADDR[19:16], Register control AUX CH address.
>> +	 */
>> +	err |= regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
>> +				  SP_AUX_ADDR_19_16_REG,
>> +				  SP_AUX_ADDR_19_16_MASK,
>> +				  (addr & 0xf0000) >> 16);
>
> I'm not at all a fan of OR'ing error codes. Presumably if any of these
> register accesses fails there's no reason to attempt the subsequent
> accesses because the end result will be failure anyway.
>

The patch was implemented first without OR'ing error codes. The reason 
why I changed this is because I received the comments that checking the 
error on every regmap_* didn't help the readability of the driver and is 
likely to not fail if the first call doesn't fail.

For example, originally the code was like this:
   http://pastebin.com/rPgyji8k
but I changed to this
   http://pastebin.com/rPgyji8k

I don't have a hard opinion on this so I'll do what you prefer, but 
before reverting this I just want to make sure that you prefer the first 
option. It's right?

>> +	/* Write address and request */
>> +	err = anx78xx_aux_address(anx78xx, msg->address);
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_DP_AUX_CH_CTRL1_REG,
>> +			    ctrl1);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	/* Start transaction */
>> +	err = regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
>> +				 SP_DP_AUX_CH_CTRL2_REG, SP_ADDR_ONLY |
>> +				 SP_AUX_EN, ctrl2);
>> +	if (err)
>> +		return err;
>> +
>> +	err = anx78xx_aux_wait(anx78xx);
>> +
>> +	msg->reply = err ? DP_AUX_I2C_REPLY_NACK : DP_AUX_I2C_REPLY_ACK;
>
> This looks wrong. What if anx78xx_aux_wait() return -ETIMEDOUT? You'll
> be setting msg->reply to NACK and return success That doesn't sound
> right at all.
>
>> +static int anx78xx_set_hpd(struct anx78xx *anx78xx)
>> +{
>> +	int err = 0;
>> +
>> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_RX_P0],
>> +				  SP_TMDS_CTRL_BASE + 7, SP_PD_RT);
>> +	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL3_REG,
>> +				SP_HPD_OUT);
>
> Again, OR'ing of error codes, please don't do it. There are some more
> occurrences below.
>
>> +static int anx78xx_init_gpio(struct anx78xx *anx78xx)
>> +{
>> +	struct device *dev = &anx78xx->client->dev;
>> +	struct anx78xx_platform_data *pdata = &anx78xx->pdata;
>> +
>> +	/* GPIO for hpd */
>
> HPD being an abbreviation it should be capitalized. Similar for a couple
> of other abbreviations, some of which are inconsistently capitalized. In
> variable names of consumer names, the lowercase variant is fine, but the
> variant used in text (messages, comments) should be the all caps one.
>
>> +	pdata->gpiod_hpd = devm_gpiod_get(dev, "hpd", GPIOD_IN);
>> +	if (IS_ERR(pdata->gpiod_hpd))
>> +		return PTR_ERR(pdata->gpiod_hpd);
>> +
>> +	/* GPIO for chip power down */
>> +	pdata->gpiod_pd = devm_gpiod_get(dev, "pd", GPIOD_OUT_HIGH);
>> +	if (IS_ERR(pdata->gpiod_pd))
>> +		return PTR_ERR(pdata->gpiod_pd);
>> +
>> +	/* GPIO for chip reset */
>> +	pdata->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
>> +	if (IS_ERR(pdata->gpiod_reset))
>> +		return PTR_ERR(pdata->gpiod_reset);
>> +
>> +	/* GPIO for V10 power control */
>> +	pdata->gpiod_v10 = devm_gpiod_get_optional(dev, "v10", GPIOD_OUT_LOW);
>
> Does this actually supply power? If so it should be modelled as a
> regulator.
>
>> +static int anx78xx_dp_link_training(struct anx78xx *anx78xx)
>> +{
>> +	int err = 0;
>> +	u8 dp_bw, regval;
>> +
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_RX_P0], SP_HDMI_MUTE_CTRL_REG,
>> +			    0x0);
>> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2],
>> +				  SP_POWERDOWN_CTRL_REG,
>> +				  SP_TOTAL_PD);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	err = drm_dp_dpcd_readb(&anx78xx->aux, DP_MAX_LINK_RATE, &dp_bw);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	switch (dp_bw) {
>> +	case DP_LINK_BW_1_62:
>> +	case DP_LINK_BW_2_7:
>> +	case DP_LINK_BW_5_4:
>> +		break;
>> +	default:
>> +		DRM_DEBUG_KMS("Waiting to read DP bandwidth.\n");
>> +		return -EAGAIN;
>> +	}
>
> That sounds wrong. Either you can read the content and it should be a
> valid value (albeit one which you may not support) or you can't. Why do
> you need to potentially repeat this read?
>
>> +
>> +	err = anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL1_REG,
>> +			       SP_VIDEO_MUTE);
>> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2],
>> +				  SP_VID_CTRL1_REG, SP_VIDEO_EN);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	/* Get dpcd info */
>
> s/dpcd/DPCD/
>
>> +	err = drm_dp_dpcd_read(&anx78xx->aux, DP_DPCD_REV,
>> +			       &anx78xx->dpcd, DP_RECEIVER_CAP_SIZE);
>> +	if (err < 0) {
>> +		DRM_ERROR("Failed to read DPCD\n");
>
> It's often useful to output the error code as part of the error message
> to make it easier for developers to diagnose problems.
>
>> +		return err;
>> +	}
>> +
>> +	/* Clear channel x SERDES power down */
>> +	err = anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P0],
>> +				 SP_DP_ANALOG_POWER_DOWN_REG, SP_CH0_PD);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	/* Check link capabilities */
>> +	err = drm_dp_link_probe(&anx78xx->aux, &anx78xx->link);
>> +	if (err < 0) {
>> +		DRM_ERROR("Failed to probe link capabilities\n");
>> +		return err;
>> +	}
>> +
>> +	/* Power up the sink */
>> +	err = drm_dp_link_power_up(&anx78xx->aux, &anx78xx->link);
>> +	if (err < 0) {
>> +		DRM_ERROR("Failed to power up DisplayPort link\n");
>> +		return err;
>> +	}
>> +
>> +	/* Possibly enable downspread on the sink */
>> +	err = regmap_write(anx78xx->map[I2C_IDX_TX_P0],
>> +			   SP_DP_DOWNSPREAD_CTRL1_REG, 0);
>> +	if (err)
>> +		return err;
>> +
>> +	if (anx78xx->dpcd[3] & 0x1) {
>
> This should use the symbolic constants defined in drm_dp_helper.h.
> Actually, it should probably add a symbolic constant because we don't
> have one yet for bit 0 in the DP_MAX_DOWNSPREAD register.
>
>> +static inline struct anx78xx *
>> +	connector_to_anx78xx(struct drm_connector *connector)
>
> The function name should start on the first column. Also you might want
> to move this inline function after the struct anx78xx declaration, which
> is more consistent with other drivers.
>
>> +static const struct drm_connector_helper_funcs
>> +	anx78xx_connector_helper_funcs = {
>
> The structure name should start in the first column as well.
>
>> +	.get_modes = anx78xx_get_modes,
>> +	.best_encoder = anx78xx_best_encoder,
>> +};
>> +
>> +static enum drm_connector_status anx78xx_detect(struct drm_connector *connector,
>> +						bool force)
>> +{
>> +	struct anx78xx *anx78xx = container_of(connector, struct anx78xx,
>> +					       connector);
>
> Didn't you introduce an inline function for this just a few lines above?
>
>> +	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
>> +		      connector->name);
>> +
>> +	if (!gpiod_get_value(anx78xx->pdata.gpiod_hpd)) {
>> +		DRM_DEBUG_KMS("CONNECTOR STATUS DISCONNECTED\n");
>> +		return connector_status_disconnected;
>> +	}
>> +
>> +	return connector_status_connected;
>> +}
>
> Is it really necessary to add two debug messages here? The DRM core will
> already output a message for connector status changes, so this is
> unnecessarily noisy in my opinion.
>
>> +static inline struct anx78xx *bridge_to_anx78xx(struct drm_bridge *bridge)
>> +{
>> +	return container_of(bridge, struct anx78xx, bridge);
>> +}
>
> Put this together with the connector cast function.
>
>> +static void anx78xx_bridge_disable(struct drm_bridge *bridge)
>> +{
>> +	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
>> +
>> +	mutex_lock(&anx78xx->lock);
>
> Do you really need the locking here and below? I think the DRM core
> already ensures that these calls are always serialized.
>
>> +static void anx78xx_bridge_mode_set(struct drm_bridge *bridge,
>> +				    struct drm_display_mode *mode,
>> +				    struct drm_display_mode *adjusted_mode)
>> +{
>> +	int err;
>> +	struct hdmi_avi_infoframe frame;
>> +	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
>> +
>> +	if (WARN_ON(!anx78xx->powered))
>> +		return;
>> +
>> +	mutex_lock(&anx78xx->lock);
>> +
>> +	mode = adjusted_mode;
>> +
>> +	err = drm_hdmi_avi_infoframe_from_display_mode(&frame, mode);
>
> This seems like jumping through hoops. Why not simply pass adjusted_mode
> to the function?
>
>> +static const struct drm_bridge_funcs anx78xx_bridge_funcs = {
>> +	.attach		= anx78xx_bridge_attach,
>> +	.mode_fixup	= anx78xx_bridge_mode_fixup,
>> +	.disable	= anx78xx_bridge_disable,
>> +	.mode_set	= anx78xx_bridge_mode_set,
>> +	.enable		= anx78xx_bridge_enable,
>> +};
>
> I'd leave out the tab-padding. Simple spaces will do just fine.
>
>> +static irqreturn_t anx78xx_hpd_threaded_handler(int unused, void *data)
>
> Might as well give the first parameter the proper name (irq).
>
>> +static bool anx78xx_handle_common_int_4(struct anx78xx *anx78xx, u8 irq)
>> +{
>> +	int err;
>> +	bool event = false;
>> +
>> +	DRM_DEBUG_KMS("Handle common interrupt 4: %02x\n", irq);
>> +
>> +	err = regmap_write(anx78xx->map[I2C_IDX_TX_P2],
>> +			   SP_COMMON_INT_STATUS4_REG, irq);
>> +	if (err) {
>> +		DRM_ERROR("Failed to write SP_COMMON_INT_STATUS4 %d\n", err);
>> +		return event;
>> +	}
>> +
>> +	if (irq & SP_HPD_LOST) {
>> +		DRM_DEBUG_KMS("IRQ: Hot plug detect - cable is pulled out\n");
>> +		event = true;
>> +		anx78xx_poweroff(anx78xx);
>> +	} else if (irq & SP_HPD_PLUG) {
>> +		DRM_DEBUG_KMS("IRQ: Hot plug detect - cable plug\n");
>> +		event = true;
>> +		/* Free previous cached EDID if any */
>> +		kfree(anx78xx->edid);
>> +		anx78xx->edid = NULL;
>
> I think you can free the EDID on unplug, since it becomes stale at that
> point already. The DRM core will also remove the EDID data on unplug.
>
>> +static void unregister_i2c_dummy_clients(struct anx78xx *anx78xx)
>> +{
>> +	int i;
>
> unsigned int
>
>> +
>> +	for (i = 0; i < ARRAY_SIZE(anx78xx->i2c_dummy); i++)
>> +		if (anx78xx->i2c_dummy[i])
>> +			i2c_unregister_device(anx78xx->i2c_dummy[i]);
>> +}
>> +
>> +static const struct regmap_config anx78xx_regmap_config = {
>> +	.reg_bits = 8,
>> +	.val_bits = 8,
>> +};
>> +
>> +static const u16 anx78xx_chipid_list[] = {
>> +	0x7812,
>> +	0x7814,
>> +	0x7818,
>> +};
>> +
>> +static int anx78xx_i2c_probe(struct i2c_client *client,
>> +			     const struct i2c_device_id *id)
>> +{
>> +	struct anx78xx *anx78xx;
>> +	struct anx78xx_platform_data *pdata;
>> +	int err, i;
>
> i should be unsigned int.
>
>> +	unsigned int idl, idh, version;
>> +	bool found = false;
>> +
>> +	anx78xx = devm_kzalloc(&client->dev, sizeof(*anx78xx), GFP_KERNEL);
>> +	if (!anx78xx)
>> +		return -ENOMEM;
>> +
>> +	pdata = &anx78xx->pdata;
>> +
>> +	mutex_init(&anx78xx->lock);
>> +
>> +#if IS_ENABLED(CONFIG_OF)
>> +	anx78xx->bridge.of_node = client->dev.of_node;
>> +#endif
>> +
>> +	anx78xx->client = client;
>> +	i2c_set_clientdata(client, anx78xx);
>> +
>> +	err = anx78xx_init_gpio(anx78xx);
>> +	if (err) {
>> +		DRM_ERROR("Failed to initialize gpios\n");
>> +		return err;
>> +	}
>> +
>> +	pdata->hpd_irq = gpiod_to_irq(pdata->gpiod_hpd);
>> +	if (pdata->hpd_irq < 0) {
>> +		DRM_ERROR("Failed to get hpd irq %d\n",
>> +			  pdata->hpd_irq);
>> +		return -ENODEV;
>> +	}
>> +
>> +	pdata->intp_irq = client->irq;
>> +	if (!pdata->intp_irq) {
>> +		DRM_ERROR("Failed to get CABLE_DET and INTP irq\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	/* Map slave addresses of ANX7814 */
>> +	for (i = 0; i < I2C_NUM_ADDRESSES; i++) {
>> +		anx78xx->i2c_dummy[i] = i2c_new_dummy(client->adapter,
>> +						anx78xx_i2c_addresses[i] >> 1);
>> +		if (!anx78xx->i2c_dummy[i]) {
>> +			err = -ENOMEM;
>> +			DRM_ERROR("Failed to reserve i2c bus %02x.\n",
>> +				  anx78xx_i2c_addresses[i]);
>> +			goto err_unregister_i2c;
>> +		}
>> +
>> +		anx78xx->map[i] = devm_regmap_init_i2c(anx78xx->i2c_dummy[i],
>> +						       &anx78xx_regmap_config);
>> +		if (IS_ERR(anx78xx->map[i])) {
>> +			err = PTR_ERR(anx78xx->map[i]);
>> +			DRM_ERROR("Failed regmap initialization %02x.\n",
>> +				  anx78xx_i2c_addresses[i]);
>> +			goto err_unregister_i2c;
>> +		}
>> +	}
>
> That's quite some overhead merely to use regmap... Perhaps there's room
> to enhance regmap-i2c to support multiple addresses for the same device?
>
>> +static int anx78xx_i2c_remove(struct i2c_client *client)
>> +{
>> +	struct anx78xx *anx78xx = i2c_get_clientdata(client);
>> +
>> +	drm_bridge_remove(&anx78xx->bridge);
>> +
>> +	unregister_i2c_dummy_clients(anx78xx);
>> +
>> +	kfree(anx78xx->edid);
>> +	anx78xx->edid = NULL;
>
> The memory pointed at by anx78xx will be freed a couple of instructions
> later, there's no need to set ->edid to NULL.
>
> Thierry
>

Enric

Re: [PATCH v3 3/3] drm: bridge: anx78xx: Add anx78xx driver support.

[Enric Balletbo i Serra]

Hi Thierry,

Many thanks for answering and do this accurate report. I'd add a comment 
on something you (see below). Apart from this I'll add your changes and 
send a new version.

On 14/04/16 15:10, Thierry Reding wrote:
> On Fri, Apr 08, 2016 at 02:52:52PM +0200, Enric Balletbo i Serra wrote:
>> Although there are other chips from the same family that can reuse this
>> driver, at the moment we only tested ANX7814 chip.
>>
>> The ANX7814 is an ultra-low power Full-HD (1080p60) SlimPort transmitter
>> designed for portable devices. This driver adds initial support for HDMI
>> to DP pass-through mode.
>>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>
>> Tested-by: Nicolas Boichat <drinkcat-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
>> Reviewed-by: Nicolas Boichat <drinkcat-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
>> Cc: Emil Velikov <emil.l.velikov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> Cc: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
>> Cc: Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
>> Cc: Daniel Kurtz <djkurtz-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
>> Cc: Nicolas Boichat <drinkcat-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
>> ---
>> Changes since v2:
>>   - Nicolas Boichat:
>>     - Get rid of wait_for macro since is only used once.
>>     - Do not replace the error code if it's readily available to you.
>>   - Add Tested-by: Nicolas Boichat <drinkcat-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
>>   - Add Reviewed-by: Nicolas Boichat <drinkcat-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
>>
>> Changes since v1:
>>   - Dan Carpenter:
>>     - Fix missing error code
>>     - Use meaningful names for goto exit paths
>>   - Rob Herring:
>>     - Use hpd instead cable_det as is the more standard name.
>>   - Daniel Kurtz:
>>     - Use regmap_bulk in aux_transfer
>>     - Fix gpio reset polarity.
>>     - Turn off v10 last so we mirror poweron sequence
>>     - Fix some error paths.
>>     - Remove mutex in anx78xx_detect
>>   - kbuild:
>>     - WARNING: PTR_ERR_OR_ZERO can be used
>>
>>   drivers/gpu/drm/bridge/Kconfig   |    8 +
>>   drivers/gpu/drm/bridge/Makefile  |    1 +
>>   drivers/gpu/drm/bridge/anx78xx.c | 1403 ++++++++++++++++++++++++++++++++++++++
>>   drivers/gpu/drm/bridge/anx78xx.h |  719 +++++++++++++++++++
>>   4 files changed, 2131 insertions(+)
>>   create mode 100644 drivers/gpu/drm/bridge/anx78xx.c
>>   create mode 100644 drivers/gpu/drm/bridge/anx78xx.h
>>
>> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
>> index 27e2022..0f595ae 100644
>> --- a/drivers/gpu/drm/bridge/Kconfig
>> +++ b/drivers/gpu/drm/bridge/Kconfig
>> @@ -40,4 +40,12 @@ config DRM_PARADE_PS8622
>>   	---help---
>>   	  Parade eDP-LVDS bridge chip driver.
>>
>> +config DRM_ANX78XX
>
> The symbol name should include the vendor (DRM_ANALOGIX_ANX78XX) and the
> entry needs to be ordered alphabetically (by vendor, then name).
>
>> +	tristate "Analogix ANX78XX bridge"
>> +	select DRM_KMS_HELPER
>> +	select REGMAP_I2C
>> +	---help---
>> +	  ANX78XX is a HD video transmitter chip over micro-USB connector
>> +	  for smartphone device.
>
> The commit description says the device is a FullHD video transmitter,
> but here you say HD. Pick one. Preferably the correct one.
>
>>   endmenu
>> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
>> index f13c33d..8f0d69e 100644
>> --- a/drivers/gpu/drm/bridge/Makefile
>> +++ b/drivers/gpu/drm/bridge/Makefile
>> @@ -4,3 +4,4 @@ obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>>   obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>>   obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
>>   obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
>> +obj-$(CONFIG_DRM_ANX78XX) += anx78xx.o
>
> Same here, the source file should be named analogix-anx78xx.c, and this
> needs to be sorted by vendor, then name as well.
>
>> diff --git a/drivers/gpu/drm/bridge/anx78xx.c b/drivers/gpu/drm/bridge/anx78xx.c
> [...]
>> +#include <linux/async.h>
>
> At least this one doesn't seem to be needed.
>
>> +static int anx78xx_aux_wait(struct anx78xx *anx78xx)
>> +{
>> +	int err;
>> +	unsigned int status;
>> +	unsigned long timeout;
>> +
>> +	/*
>> +	 * Does the right thing for modeset paths when run under kdgb or
>> +	 * similar atomic contexts. Note that it's important that we check the
>> +	 * condition again after having timed out, since the timeout could be
>> +	 * due to preemption or similar and we've never had a chance to check
>> +	 * the condition before the timeout.
>> +	 */
>
> I don't think this is necessary. The AUX code should never be called
> from atomic context, there are various other places where we take a
> mutex that would trigger warnings.
>
>> +	err = 0;
>
> You can move this up to where the variable is declared.
>
>> +	timeout = jiffies + msecs_to_jiffies(AUX_WAIT_TIMEOUT_MS) + 1;
>> +	while (anx78xx_aux_op_finished(anx78xx)) {
>> +		if (time_after(jiffies, timeout)) {
>> +			if (anx78xx_aux_op_finished(anx78xx))
>> +				err = -ETIMEDOUT;
>
> Should this not be !cond? Ah, anx78xx_aux_op_finished() returns an error
> code on failure. Perhaps it would be clearer if this either returned a
> boolean or the name was changed to reflect the fact that it returns an
> error code. _finished() sounds too much like it would return boolean.
>
> To make it clearer what I mean, try reading the above aloud:
>
> 	if aux_op_finished, return error
>
> That's the wrong way around.
>
>> +			break;
>> +		}
>> +		if (drm_can_sleep())
>> +			usleep_range(1000, 2000);
>> +		else
>> +			cpu_relax();
>> +	}
>> +
>> +	if (err) {
>> +		DRM_ERROR("Timed out waiting AUX to finish\n");
>> +		return -ETIMEDOUT;
>> +	}
>> +
>> +	/* Read the AUX channel access status */
>> +	err = regmap_read(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_CH_STATUS_REG,
>> +			  &status);
>> +	if (err)
>> +		return err;
>> +
>> +	if (status & SP_AUX_STATUS) {
>> +		DRM_ERROR("Failed to read AUX channel: 0x%02x\n", status);
>> +		return -ETIMEDOUT;
>> +	}
>
> Would it make sense to disambiguate these two errors using different
> error codes? As it is this function will either return success or
> timeout, even though the latter is obviously not a timeout.
>
>> +static int anx78xx_aux_address(struct anx78xx *anx78xx, unsigned int addr)
>> +{
>> +	int err = 0;
>> +
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_7_0_REG,
>> +			    addr & 0xff);
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_15_8_REG,
>> +			    (addr & 0xff00) >> 8);
>> +
>> +	/*
>> +	 * DP AUX CH Address Register #2, only update bits[3:0]
>> +	 * [7:4] RESERVED
>> +	 * [3:0] AUX_ADDR[19:16], Register control AUX CH address.
>> +	 */
>> +	err |= regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
>> +				  SP_AUX_ADDR_19_16_REG,
>> +				  SP_AUX_ADDR_19_16_MASK,
>> +				  (addr & 0xf0000) >> 16);
>
> I'm not at all a fan of OR'ing error codes. Presumably if any of these
> register accesses fails there's no reason to attempt the subsequent
> accesses because the end result will be failure anyway.
>

The patch was implemented first without OR'ing error codes. The reason 
why I changed this is because I received the comments that checking the 
error on every regmap_* didn't help the readability of the driver and is 
likely to not fail if the first call doesn't fail.

For example, originally the code was like this:
   http://pastebin.com/rPgyji8k
but I changed to this
   http://pastebin.com/rPgyji8k

I don't have a hard opinion on this so I'll do what you prefer, but 
before reverting this I just want to make sure that you prefer the first 
option. It's right?

>> +	/* Write address and request */
>> +	err = anx78xx_aux_address(anx78xx, msg->address);
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_DP_AUX_CH_CTRL1_REG,
>> +			    ctrl1);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	/* Start transaction */
>> +	err = regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
>> +				 SP_DP_AUX_CH_CTRL2_REG, SP_ADDR_ONLY |
>> +				 SP_AUX_EN, ctrl2);
>> +	if (err)
>> +		return err;
>> +
>> +	err = anx78xx_aux_wait(anx78xx);
>> +
>> +	msg->reply = err ? DP_AUX_I2C_REPLY_NACK : DP_AUX_I2C_REPLY_ACK;
>
> This looks wrong. What if anx78xx_aux_wait() return -ETIMEDOUT? You'll
> be setting msg->reply to NACK and return success That doesn't sound
> right at all.
>
>> +static int anx78xx_set_hpd(struct anx78xx *anx78xx)
>> +{
>> +	int err = 0;
>> +
>> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_RX_P0],
>> +				  SP_TMDS_CTRL_BASE + 7, SP_PD_RT);
>> +	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL3_REG,
>> +				SP_HPD_OUT);
>
> Again, OR'ing of error codes, please don't do it. There are some more
> occurrences below.
>
>> +static int anx78xx_init_gpio(struct anx78xx *anx78xx)
>> +{
>> +	struct device *dev = &anx78xx->client->dev;
>> +	struct anx78xx_platform_data *pdata = &anx78xx->pdata;
>> +
>> +	/* GPIO for hpd */
>
> HPD being an abbreviation it should be capitalized. Similar for a couple
> of other abbreviations, some of which are inconsistently capitalized. In
> variable names of consumer names, the lowercase variant is fine, but the
> variant used in text (messages, comments) should be the all caps one.
>
>> +	pdata->gpiod_hpd = devm_gpiod_get(dev, "hpd", GPIOD_IN);
>> +	if (IS_ERR(pdata->gpiod_hpd))
>> +		return PTR_ERR(pdata->gpiod_hpd);
>> +
>> +	/* GPIO for chip power down */
>> +	pdata->gpiod_pd = devm_gpiod_get(dev, "pd", GPIOD_OUT_HIGH);
>> +	if (IS_ERR(pdata->gpiod_pd))
>> +		return PTR_ERR(pdata->gpiod_pd);
>> +
>> +	/* GPIO for chip reset */
>> +	pdata->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
>> +	if (IS_ERR(pdata->gpiod_reset))
>> +		return PTR_ERR(pdata->gpiod_reset);
>> +
>> +	/* GPIO for V10 power control */
>> +	pdata->gpiod_v10 = devm_gpiod_get_optional(dev, "v10", GPIOD_OUT_LOW);
>
> Does this actually supply power? If so it should be modelled as a
> regulator.
>
>> +static int anx78xx_dp_link_training(struct anx78xx *anx78xx)
>> +{
>> +	int err = 0;
>> +	u8 dp_bw, regval;
>> +
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_RX_P0], SP_HDMI_MUTE_CTRL_REG,
>> +			    0x0);
>> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2],
>> +				  SP_POWERDOWN_CTRL_REG,
>> +				  SP_TOTAL_PD);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	err = drm_dp_dpcd_readb(&anx78xx->aux, DP_MAX_LINK_RATE, &dp_bw);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	switch (dp_bw) {
>> +	case DP_LINK_BW_1_62:
>> +	case DP_LINK_BW_2_7:
>> +	case DP_LINK_BW_5_4:
>> +		break;
>> +	default:
>> +		DRM_DEBUG_KMS("Waiting to read DP bandwidth.\n");
>> +		return -EAGAIN;
>> +	}
>
> That sounds wrong. Either you can read the content and it should be a
> valid value (albeit one which you may not support) or you can't. Why do
> you need to potentially repeat this read?
>
>> +
>> +	err = anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL1_REG,
>> +			       SP_VIDEO_MUTE);
>> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2],
>> +				  SP_VID_CTRL1_REG, SP_VIDEO_EN);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	/* Get dpcd info */
>
> s/dpcd/DPCD/
>
>> +	err = drm_dp_dpcd_read(&anx78xx->aux, DP_DPCD_REV,
>> +			       &anx78xx->dpcd, DP_RECEIVER_CAP_SIZE);
>> +	if (err < 0) {
>> +		DRM_ERROR("Failed to read DPCD\n");
>
> It's often useful to output the error code as part of the error message
> to make it easier for developers to diagnose problems.
>
>> +		return err;
>> +	}
>> +
>> +	/* Clear channel x SERDES power down */
>> +	err = anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P0],
>> +				 SP_DP_ANALOG_POWER_DOWN_REG, SP_CH0_PD);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	/* Check link capabilities */
>> +	err = drm_dp_link_probe(&anx78xx->aux, &anx78xx->link);
>> +	if (err < 0) {
>> +		DRM_ERROR("Failed to probe link capabilities\n");
>> +		return err;
>> +	}
>> +
>> +	/* Power up the sink */
>> +	err = drm_dp_link_power_up(&anx78xx->aux, &anx78xx->link);
>> +	if (err < 0) {
>> +		DRM_ERROR("Failed to power up DisplayPort link\n");
>> +		return err;
>> +	}
>> +
>> +	/* Possibly enable downspread on the sink */
>> +	err = regmap_write(anx78xx->map[I2C_IDX_TX_P0],
>> +			   SP_DP_DOWNSPREAD_CTRL1_REG, 0);
>> +	if (err)
>> +		return err;
>> +
>> +	if (anx78xx->dpcd[3] & 0x1) {
>
> This should use the symbolic constants defined in drm_dp_helper.h.
> Actually, it should probably add a symbolic constant because we don't
> have one yet for bit 0 in the DP_MAX_DOWNSPREAD register.
>
>> +static inline struct anx78xx *
>> +	connector_to_anx78xx(struct drm_connector *connector)
>
> The function name should start on the first column. Also you might want
> to move this inline function after the struct anx78xx declaration, which
> is more consistent with other drivers.
>
>> +static const struct drm_connector_helper_funcs
>> +	anx78xx_connector_helper_funcs = {
>
> The structure name should start in the first column as well.
>
>> +	.get_modes = anx78xx_get_modes,
>> +	.best_encoder = anx78xx_best_encoder,
>> +};
>> +
>> +static enum drm_connector_status anx78xx_detect(struct drm_connector *connector,
>> +						bool force)
>> +{
>> +	struct anx78xx *anx78xx = container_of(connector, struct anx78xx,
>> +					       connector);
>
> Didn't you introduce an inline function for this just a few lines above?
>
>> +	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
>> +		      connector->name);
>> +
>> +	if (!gpiod_get_value(anx78xx->pdata.gpiod_hpd)) {
>> +		DRM_DEBUG_KMS("CONNECTOR STATUS DISCONNECTED\n");
>> +		return connector_status_disconnected;
>> +	}
>> +
>> +	return connector_status_connected;
>> +}
>
> Is it really necessary to add two debug messages here? The DRM core will
> already output a message for connector status changes, so this is
> unnecessarily noisy in my opinion.
>
>> +static inline struct anx78xx *bridge_to_anx78xx(struct drm_bridge *bridge)
>> +{
>> +	return container_of(bridge, struct anx78xx, bridge);
>> +}
>
> Put this together with the connector cast function.
>
>> +static void anx78xx_bridge_disable(struct drm_bridge *bridge)
>> +{
>> +	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
>> +
>> +	mutex_lock(&anx78xx->lock);
>
> Do you really need the locking here and below? I think the DRM core
> already ensures that these calls are always serialized.
>
>> +static void anx78xx_bridge_mode_set(struct drm_bridge *bridge,
>> +				    struct drm_display_mode *mode,
>> +				    struct drm_display_mode *adjusted_mode)
>> +{
>> +	int err;
>> +	struct hdmi_avi_infoframe frame;
>> +	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
>> +
>> +	if (WARN_ON(!anx78xx->powered))
>> +		return;
>> +
>> +	mutex_lock(&anx78xx->lock);
>> +
>> +	mode = adjusted_mode;
>> +
>> +	err = drm_hdmi_avi_infoframe_from_display_mode(&frame, mode);
>
> This seems like jumping through hoops. Why not simply pass adjusted_mode
> to the function?
>
>> +static const struct drm_bridge_funcs anx78xx_bridge_funcs = {
>> +	.attach		= anx78xx_bridge_attach,
>> +	.mode_fixup	= anx78xx_bridge_mode_fixup,
>> +	.disable	= anx78xx_bridge_disable,
>> +	.mode_set	= anx78xx_bridge_mode_set,
>> +	.enable		= anx78xx_bridge_enable,
>> +};
>
> I'd leave out the tab-padding. Simple spaces will do just fine.
>
>> +static irqreturn_t anx78xx_hpd_threaded_handler(int unused, void *data)
>
> Might as well give the first parameter the proper name (irq).
>
>> +static bool anx78xx_handle_common_int_4(struct anx78xx *anx78xx, u8 irq)
>> +{
>> +	int err;
>> +	bool event = false;
>> +
>> +	DRM_DEBUG_KMS("Handle common interrupt 4: %02x\n", irq);
>> +
>> +	err = regmap_write(anx78xx->map[I2C_IDX_TX_P2],
>> +			   SP_COMMON_INT_STATUS4_REG, irq);
>> +	if (err) {
>> +		DRM_ERROR("Failed to write SP_COMMON_INT_STATUS4 %d\n", err);
>> +		return event;
>> +	}
>> +
>> +	if (irq & SP_HPD_LOST) {
>> +		DRM_DEBUG_KMS("IRQ: Hot plug detect - cable is pulled out\n");
>> +		event = true;
>> +		anx78xx_poweroff(anx78xx);
>> +	} else if (irq & SP_HPD_PLUG) {
>> +		DRM_DEBUG_KMS("IRQ: Hot plug detect - cable plug\n");
>> +		event = true;
>> +		/* Free previous cached EDID if any */
>> +		kfree(anx78xx->edid);
>> +		anx78xx->edid = NULL;
>
> I think you can free the EDID on unplug, since it becomes stale at that
> point already. The DRM core will also remove the EDID data on unplug.
>
>> +static void unregister_i2c_dummy_clients(struct anx78xx *anx78xx)
>> +{
>> +	int i;
>
> unsigned int
>
>> +
>> +	for (i = 0; i < ARRAY_SIZE(anx78xx->i2c_dummy); i++)
>> +		if (anx78xx->i2c_dummy[i])
>> +			i2c_unregister_device(anx78xx->i2c_dummy[i]);
>> +}
>> +
>> +static const struct regmap_config anx78xx_regmap_config = {
>> +	.reg_bits = 8,
>> +	.val_bits = 8,
>> +};
>> +
>> +static const u16 anx78xx_chipid_list[] = {
>> +	0x7812,
>> +	0x7814,
>> +	0x7818,
>> +};
>> +
>> +static int anx78xx_i2c_probe(struct i2c_client *client,
>> +			     const struct i2c_device_id *id)
>> +{
>> +	struct anx78xx *anx78xx;
>> +	struct anx78xx_platform_data *pdata;
>> +	int err, i;
>
> i should be unsigned int.
>
>> +	unsigned int idl, idh, version;
>> +	bool found = false;
>> +
>> +	anx78xx = devm_kzalloc(&client->dev, sizeof(*anx78xx), GFP_KERNEL);
>> +	if (!anx78xx)
>> +		return -ENOMEM;
>> +
>> +	pdata = &anx78xx->pdata;
>> +
>> +	mutex_init(&anx78xx->lock);
>> +
>> +#if IS_ENABLED(CONFIG_OF)
>> +	anx78xx->bridge.of_node = client->dev.of_node;
>> +#endif
>> +
>> +	anx78xx->client = client;
>> +	i2c_set_clientdata(client, anx78xx);
>> +
>> +	err = anx78xx_init_gpio(anx78xx);
>> +	if (err) {
>> +		DRM_ERROR("Failed to initialize gpios\n");
>> +		return err;
>> +	}
>> +
>> +	pdata->hpd_irq = gpiod_to_irq(pdata->gpiod_hpd);
>> +	if (pdata->hpd_irq < 0) {
>> +		DRM_ERROR("Failed to get hpd irq %d\n",
>> +			  pdata->hpd_irq);
>> +		return -ENODEV;
>> +	}
>> +
>> +	pdata->intp_irq = client->irq;
>> +	if (!pdata->intp_irq) {
>> +		DRM_ERROR("Failed to get CABLE_DET and INTP irq\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	/* Map slave addresses of ANX7814 */
>> +	for (i = 0; i < I2C_NUM_ADDRESSES; i++) {
>> +		anx78xx->i2c_dummy[i] = i2c_new_dummy(client->adapter,
>> +						anx78xx_i2c_addresses[i] >> 1);
>> +		if (!anx78xx->i2c_dummy[i]) {
>> +			err = -ENOMEM;
>> +			DRM_ERROR("Failed to reserve i2c bus %02x.\n",
>> +				  anx78xx_i2c_addresses[i]);
>> +			goto err_unregister_i2c;
>> +		}
>> +
>> +		anx78xx->map[i] = devm_regmap_init_i2c(anx78xx->i2c_dummy[i],
>> +						       &anx78xx_regmap_config);
>> +		if (IS_ERR(anx78xx->map[i])) {
>> +			err = PTR_ERR(anx78xx->map[i]);
>> +			DRM_ERROR("Failed regmap initialization %02x.\n",
>> +				  anx78xx_i2c_addresses[i]);
>> +			goto err_unregister_i2c;
>> +		}
>> +	}
>
> That's quite some overhead merely to use regmap... Perhaps there's room
> to enhance regmap-i2c to support multiple addresses for the same device?
>
>> +static int anx78xx_i2c_remove(struct i2c_client *client)
>> +{
>> +	struct anx78xx *anx78xx = i2c_get_clientdata(client);
>> +
>> +	drm_bridge_remove(&anx78xx->bridge);
>> +
>> +	unregister_i2c_dummy_clients(anx78xx);
>> +
>> +	kfree(anx78xx->edid);
>> +	anx78xx->edid = NULL;
>
> The memory pointed at by anx78xx will be freed a couple of instructions
> later, there's no need to set ->edid to NULL.
>
> Thierry
>

Enric
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Re: [PATCH v3 3/3] drm: bridge: anx78xx: Add anx78xx driver support.

[Emil Velikov]

Hi Enric,

On 14 April 2016 at 14:42, Enric Balletbo i Serra
<enric.balletbo@collabora.com> wrote:
> The patch was implemented first without OR'ing error codes. The reason why I
> changed this is because I received the comments that checking the error on
> every regmap_* didn't help the readability of the driver and is likely to
> not fail if the first call doesn't fail.
>
> For example, originally the code was like this:
>   http://pastebin.com/rPgyji8k
> but I changed to this
>   http://pastebin.com/rPgyji8k
>
Both links are the same ;-) But I believe we all get what you meant.

Just a side note: many other drivers in DRM subsystem, inconsistently
check the return value of the regmap API. Note sure how likely is any
of it [regmap_foo] to fail and/or how determined people are to handle
every possible error case.

-Emil

Re: [PATCH v3 3/3] drm: bridge: anx78xx: Add anx78xx driver support.

[Enric Balletbo i Serra]

Hi Emil,

On 14/04/16 16:06, Emil Velikov wrote:
> Hi Enric,
>
> On 14 April 2016 at 14:42, Enric Balletbo i Serra
> <enric.balletbo@collabora.com> wrote:
>> The patch was implemented first without OR'ing error codes. The reason why I
>> changed this is because I received the comments that checking the error on
>> every regmap_* didn't help the readability of the driver and is likely to
>> not fail if the first call doesn't fail.
>>
>> For example, originally the code was like this:
>>    http://pastebin.com/rPgyji8k
>> but I changed to this
>>    http://pastebin.com/rPgyji8k
>>
> Both links are the same ;-) But I believe we all get what you meant.
>

Ooops, sorry. This is the other link

http://pastebin.com/e2KpGxHy

> Just a side note: many other drivers in DRM subsystem, inconsistently
> check the return value of the regmap API. Note sure how likely is any
> of it [regmap_foo] to fail and/or how determined people are to handle
> every possible error case.
>
> -Emil
>

Enric

Re: [PATCH v3 3/3] drm: bridge: anx78xx: Add anx78xx driver support.

[Enric Balletbo i Serra]

Hi Emil,

On 14/04/16 16:06, Emil Velikov wrote:
> Hi Enric,
>
> On 14 April 2016 at 14:42, Enric Balletbo i Serra
> <enric.balletbo-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org> wrote:
>> The patch was implemented first without OR'ing error codes. The reason why I
>> changed this is because I received the comments that checking the error on
>> every regmap_* didn't help the readability of the driver and is likely to
>> not fail if the first call doesn't fail.
>>
>> For example, originally the code was like this:
>>    http://pastebin.com/rPgyji8k
>> but I changed to this
>>    http://pastebin.com/rPgyji8k
>>
> Both links are the same ;-) But I believe we all get what you meant.
>

Ooops, sorry. This is the other link

http://pastebin.com/e2KpGxHy

> Just a side note: many other drivers in DRM subsystem, inconsistently
> check the return value of the regmap API. Note sure how likely is any
> of it [regmap_foo] to fail and/or how determined people are to handle
> every possible error case.
>
> -Emil
>

Enric
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Re: [PATCH v3 3/3] drm: bridge: anx78xx: Add anx78xx driver support.

[Thierry Reding]

[-- Attachment #1: Type: text/plain, Size: 1374 bytes --]

On Thu, Apr 14, 2016 at 04:08:43PM +0200, Enric Balletbo i Serra wrote:
> Hi Emil,
> 
> On 14/04/16 16:06, Emil Velikov wrote:
> > Hi Enric,
> > 
> > On 14 April 2016 at 14:42, Enric Balletbo i Serra
> > <enric.balletbo@collabora.com> wrote:
> > > The patch was implemented first without OR'ing error codes. The reason why I
> > > changed this is because I received the comments that checking the error on
> > > every regmap_* didn't help the readability of the driver and is likely to
> > > not fail if the first call doesn't fail.
> > > 
> > > For example, originally the code was like this:
> > >    http://pastebin.com/rPgyji8k
> > > but I changed to this
> > >    http://pastebin.com/rPgyji8k
> > > 
> > Both links are the same ;-) But I believe we all get what you meant.
> > 
> 
> Ooops, sorry. This is the other link
> 
> http://pastebin.com/e2KpGxHy

I like the explicit checks better. Like I said, OR'ing the error codes
makes you loose all context and likely give you many similar failures if
for some reason regmap accesses always fail.

Also you're code most likely is required to run in entirety for an
operation to be successful. If the first part of the operation doesn't
succeed it is natural to assume that the whole operation will fail, so
there's no need (and a waste of time) to attempt any subsequent steps.

Thierry

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Re: [PATCH v3 3/3] drm: bridge: anx78xx: Add anx78xx driver support.

[Thierry Reding]

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On Thu, Apr 14, 2016 at 04:08:43PM +0200, Enric Balletbo i Serra wrote:
> Hi Emil,
> 
> On 14/04/16 16:06, Emil Velikov wrote:
> > Hi Enric,
> > 
> > On 14 April 2016 at 14:42, Enric Balletbo i Serra
> > <enric.balletbo@collabora.com> wrote:
> > > The patch was implemented first without OR'ing error codes. The reason why I
> > > changed this is because I received the comments that checking the error on
> > > every regmap_* didn't help the readability of the driver and is likely to
> > > not fail if the first call doesn't fail.
> > > 
> > > For example, originally the code was like this:
> > >    http://pastebin.com/rPgyji8k
> > > but I changed to this
> > >    http://pastebin.com/rPgyji8k
> > > 
> > Both links are the same ;-) But I believe we all get what you meant.
> > 
> 
> Ooops, sorry. This is the other link
> 
> http://pastebin.com/e2KpGxHy

I like the explicit checks better. Like I said, OR'ing the error codes
makes you loose all context and likely give you many similar failures if
for some reason regmap accesses always fail.

Also you're code most likely is required to run in entirety for an
operation to be successful. If the first part of the operation doesn't
succeed it is natural to assume that the whole operation will fail, so
there's no need (and a waste of time) to attempt any subsequent steps.

Thierry

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Re: [PATCH v3 3/3] drm: bridge: anx78xx: Add anx78xx driver support.

[Enric Balletbo i Serra]

Hi,

Many thanks for dedicate some time to comment the patch, I'm going to 
send a v4 version, see my comments below.

On 14/04/16 15:10, Thierry Reding wrote:
> On Fri, Apr 08, 2016 at 02:52:52PM +0200, Enric Balletbo i Serra wrote:
>> Although there are other chips from the same family that can reuse this
>> driver, at the moment we only tested ANX7814 chip.
>>
>> The ANX7814 is an ultra-low power Full-HD (1080p60) SlimPort transmitter
>> designed for portable devices. This driver adds initial support for HDMI
>> to DP pass-through mode.
>>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
>> Tested-by: Nicolas Boichat <drinkcat@chromium.org>
>> Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
>> Cc: Emil Velikov <emil.l.velikov@gmail.com>
>> Cc: Rob Herring <robh@kernel.org>
>> Cc: Dan Carpenter <dan.carpenter@oracle.com>
>> Cc: Daniel Kurtz <djkurtz@chromium.org>
>> Cc: Nicolas Boichat <drinkcat@chromium.org>
>> ---
>> Changes since v2:
>>   - Nicolas Boichat:
>>     - Get rid of wait_for macro since is only used once.
>>     - Do not replace the error code if it's readily available to you.
>>   - Add Tested-by: Nicolas Boichat <drinkcat@chromium.org>
>>   - Add Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
>>
>> Changes since v1:
>>   - Dan Carpenter:
>>     - Fix missing error code
>>     - Use meaningful names for goto exit paths
>>   - Rob Herring:
>>     - Use hpd instead cable_det as is the more standard name.
>>   - Daniel Kurtz:
>>     - Use regmap_bulk in aux_transfer
>>     - Fix gpio reset polarity.
>>     - Turn off v10 last so we mirror poweron sequence
>>     - Fix some error paths.
>>     - Remove mutex in anx78xx_detect
>>   - kbuild:
>>     - WARNING: PTR_ERR_OR_ZERO can be used
>>
>>   drivers/gpu/drm/bridge/Kconfig   |    8 +
>>   drivers/gpu/drm/bridge/Makefile  |    1 +
>>   drivers/gpu/drm/bridge/anx78xx.c | 1403 ++++++++++++++++++++++++++++++++++++++
>>   drivers/gpu/drm/bridge/anx78xx.h |  719 +++++++++++++++++++
>>   4 files changed, 2131 insertions(+)
>>   create mode 100644 drivers/gpu/drm/bridge/anx78xx.c
>>   create mode 100644 drivers/gpu/drm/bridge/anx78xx.h
>>
>> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
>> index 27e2022..0f595ae 100644
>> --- a/drivers/gpu/drm/bridge/Kconfig
>> +++ b/drivers/gpu/drm/bridge/Kconfig
>> @@ -40,4 +40,12 @@ config DRM_PARADE_PS8622
>>   	---help---
>>   	  Parade eDP-LVDS bridge chip driver.
>>
>> +config DRM_ANX78XX
>
> The symbol name should include the vendor (DRM_ANALOGIX_ANX78XX) and the
> entry needs to be ordered alphabetically (by vendor, then name).
>

Done in v4

>> +	tristate "Analogix ANX78XX bridge"
>> +	select DRM_KMS_HELPER
>> +	select REGMAP_I2C
>> +	---help---
>> +	  ANX78XX is a HD video transmitter chip over micro-USB connector
>> +	  for smartphone device.
>
> The commit description says the device is a FullHD video transmitter,
> but here you say HD. Pick one. Preferably the correct one.
>

FullHD is the correct. I improved also a bit the description based on 
the datasheet. Changed in v4.

>>   endmenu
>> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
>> index f13c33d..8f0d69e 100644
>> --- a/drivers/gpu/drm/bridge/Makefile
>> +++ b/drivers/gpu/drm/bridge/Makefile
>> @@ -4,3 +4,4 @@ obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>>   obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>>   obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
>>   obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
>> +obj-$(CONFIG_DRM_ANX78XX) += anx78xx.o
>
> Same here, the source file should be named analogix-anx78xx.c, and this
> needs to be sorted by vendor, then name as well.
>

Done in v4.

>> diff --git a/drivers/gpu/drm/bridge/anx78xx.c b/drivers/gpu/drm/bridge/anx78xx.c
> [...]
>> +#include <linux/async.h>
>
> At least this one doesn't seem to be needed.
>

Removed.

>> +static int anx78xx_aux_wait(struct anx78xx *anx78xx)
>> +{
>> +	int err;
>> +	unsigned int status;
>> +	unsigned long timeout;
>> +
>> +	/*
>> +	 * Does the right thing for modeset paths when run under kdgb or
>> +	 * similar atomic contexts. Note that it's important that we check the
>> +	 * condition again after having timed out, since the timeout could be
>> +	 * due to preemption or similar and we've never had a chance to check
>> +	 * the condition before the timeout.
>> +	 */
>
> I don't think this is necessary. The AUX code should never be called
> from atomic context, there are various other places where we take a
> mutex that would trigger warnings.
>

Right. Done in v4.

>> +	err = 0;
>
> You can move this up to where the variable is declared.
>

Done in v4.

>> +	timeout = jiffies + msecs_to_jiffies(AUX_WAIT_TIMEOUT_MS) + 1;
>> +	while (anx78xx_aux_op_finished(anx78xx)) {
>> +		if (time_after(jiffies, timeout)) {
>> +			if (anx78xx_aux_op_finished(anx78xx))
>> +				err = -ETIMEDOUT;
>
> Should this not be !cond? Ah, anx78xx_aux_op_finished() returns an error
> code on failure. Perhaps it would be clearer if this either returned a
> boolean or the name was changed to reflect the fact that it returns an
> error code. _finished() sounds too much like it would return boolean.
>
> To make it clearer what I mean, try reading the above aloud:
>
> 	if aux_op_finished, return error
>
> That's the wrong way around.
>

Yes, it's not readable, make sense to change and return a boolean. Done 
in v4.

>> +			break;
>> +		}
>> +		if (drm_can_sleep())
>> +			usleep_range(1000, 2000);
>> +		else
>> +			cpu_relax();
>> +	}
>> +
>> +	if (err) {
>> +		DRM_ERROR("Timed out waiting AUX to finish\n");
>> +		return -ETIMEDOUT;
>> +	}
>> +
>> +	/* Read the AUX channel access status */
>> +	err = regmap_read(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_CH_STATUS_REG,
>> +			  &status);
>> +	if (err)
>> +		return err;
>> +
>> +	if (status & SP_AUX_STATUS) {
>> +		DRM_ERROR("Failed to read AUX channel: 0x%02x\n", status);
>> +		return -ETIMEDOUT;
>> +	}
>
> Would it make sense to disambiguate these two errors using different
> error codes? As it is this function will either return success or
> timeout, even though the latter is obviously not a timeout.
>

Yes makes sense simply return the timeout in both cases. Changed in v4.

>> +static int anx78xx_aux_address(struct anx78xx *anx78xx, unsigned int addr)
>> +{
>> +	int err = 0;
>> +
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_7_0_REG,
>> +			    addr & 0xff);
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_15_8_REG,
>> +			    (addr & 0xff00) >> 8);
>> +
>> +	/*
>> +	 * DP AUX CH Address Register #2, only update bits[3:0]
>> +	 * [7:4] RESERVED
>> +	 * [3:0] AUX_ADDR[19:16], Register control AUX CH address.
>> +	 */
>> +	err |= regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
>> +				  SP_AUX_ADDR_19_16_REG,
>> +				  SP_AUX_ADDR_19_16_MASK,
>> +				  (addr & 0xf0000) >> 16);
>
> I'm not at all a fan of OR'ing error codes. Presumably if any of these
> register accesses fails there's no reason to attempt the subsequent
> accesses because the end result will be failure anyway.
>

Ok, I will remove all these OR'ed error codes and return if anything 
goes wrong.

>> +	/* Write address and request */
>> +	err = anx78xx_aux_address(anx78xx, msg->address);
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_DP_AUX_CH_CTRL1_REG,
>> +			    ctrl1);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	/* Start transaction */
>> +	err = regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
>> +				 SP_DP_AUX_CH_CTRL2_REG, SP_ADDR_ONLY |
>> +				 SP_AUX_EN, ctrl2);
>> +	if (err)
>> +		return err;
>> +
>> +	err = anx78xx_aux_wait(anx78xx);
>> +
>> +	msg->reply = err ? DP_AUX_I2C_REPLY_NACK : DP_AUX_I2C_REPLY_ACK;
>
> This looks wrong. What if anx78xx_aux_wait() return -ETIMEDOUT? You'll
> be setting msg->reply to NACK and return success That doesn't sound
> right at all.
>

Right. Changed in v4.

>> +static int anx78xx_set_hpd(struct anx78xx *anx78xx)
>> +{
>> +	int err = 0;
>> +
>> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_RX_P0],
>> +				  SP_TMDS_CTRL_BASE + 7, SP_PD_RT);
>> +	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL3_REG,
>> +				SP_HPD_OUT);
>
> Again, OR'ing of error codes, please don't do it. There are some more
> occurrences below.
>

Done in v4.

>> +static int anx78xx_init_gpio(struct anx78xx *anx78xx)
>> +{
>> +	struct device *dev = &anx78xx->client->dev;
>> +	struct anx78xx_platform_data *pdata = &anx78xx->pdata;
>> +
>> +	/* GPIO for hpd */
>
> HPD being an abbreviation it should be capitalized. Similar for a couple
> of other abbreviations, some of which are inconsistently capitalized. In
> variable names of consumer names, the lowercase variant is fine, but the
> variant used in text (messages, comments) should be the all caps one.
>

Capitalized some HPD, HDMI and DP abbreviations.


>> +	pdata->gpiod_hpd = devm_gpiod_get(dev, "hpd", GPIOD_IN);
>> +	if (IS_ERR(pdata->gpiod_hpd))
>> +		return PTR_ERR(pdata->gpiod_hpd);
>> +
>> +	/* GPIO for chip power down */
>> +	pdata->gpiod_pd = devm_gpiod_get(dev, "pd", GPIOD_OUT_HIGH);
>> +	if (IS_ERR(pdata->gpiod_pd))
>> +		return PTR_ERR(pdata->gpiod_pd);
>> +
>> +	/* GPIO for chip reset */
>> +	pdata->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
>> +	if (IS_ERR(pdata->gpiod_reset))
>> +		return PTR_ERR(pdata->gpiod_reset);
>> +
>> +	/* GPIO for V10 power control */
>> +	pdata->gpiod_v10 = devm_gpiod_get_optional(dev, "v10", GPIOD_OUT_LOW);
>
> Does this actually supply power? If so it should be modelled as a
> regulator.
>

Ok, done in v4.

>> +static int anx78xx_dp_link_training(struct anx78xx *anx78xx)
>> +{
>> +	int err = 0;
>> +	u8 dp_bw, regval;
>> +
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_RX_P0], SP_HDMI_MUTE_CTRL_REG,
>> +			    0x0);
>> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2],
>> +				  SP_POWERDOWN_CTRL_REG,
>> +				  SP_TOTAL_PD);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	err = drm_dp_dpcd_readb(&anx78xx->aux, DP_MAX_LINK_RATE, &dp_bw);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	switch (dp_bw) {
>> +	case DP_LINK_BW_1_62:
>> +	case DP_LINK_BW_2_7:
>> +	case DP_LINK_BW_5_4:
>> +		break;
>> +	default:
>> +		DRM_DEBUG_KMS("Waiting to read DP bandwidth.\n");
>> +		return -EAGAIN;
>> +	}
>
> That sounds wrong. Either you can read the content and it should be a
> valid value (albeit one which you may not support) or you can't. Why do
> you need to potentially repeat this read?
>

Right, changed in v4.

>> +
>> +	err = anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL1_REG,
>> +			       SP_VIDEO_MUTE);
>> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2],
>> +				  SP_VID_CTRL1_REG, SP_VIDEO_EN);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	/* Get dpcd info */
>
> s/dpcd/DPCD/
>

Done in v4.

>> +	err = drm_dp_dpcd_read(&anx78xx->aux, DP_DPCD_REV,
>> +			       &anx78xx->dpcd, DP_RECEIVER_CAP_SIZE);
>> +	if (err < 0) {
>> +		DRM_ERROR("Failed to read DPCD\n");
>
> It's often useful to output the error code as part of the error message
> to make it easier for developers to diagnose problems.
>

Ok, there are more places that the error code is missing, I'll add all 
error codes. Done in v4.

>> +		return err;
>> +	}
>> +
>> +	/* Clear channel x SERDES power down */
>> +	err = anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P0],
>> +				 SP_DP_ANALOG_POWER_DOWN_REG, SP_CH0_PD);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	/* Check link capabilities */
>> +	err = drm_dp_link_probe(&anx78xx->aux, &anx78xx->link);
>> +	if (err < 0) {
>> +		DRM_ERROR("Failed to probe link capabilities\n");
>> +		return err;
>> +	}
>> +
>> +	/* Power up the sink */
>> +	err = drm_dp_link_power_up(&anx78xx->aux, &anx78xx->link);
>> +	if (err < 0) {
>> +		DRM_ERROR("Failed to power up DisplayPort link\n");
>> +		return err;
>> +	}
>> +
>> +	/* Possibly enable downspread on the sink */
>> +	err = regmap_write(anx78xx->map[I2C_IDX_TX_P0],
>> +			   SP_DP_DOWNSPREAD_CTRL1_REG, 0);
>> +	if (err)
>> +		return err;
>> +
>> +	if (anx78xx->dpcd[3] & 0x1) {
>
> This should use the symbolic constants defined in drm_dp_helper.h.
> Actually, it should probably add a symbolic constant because we don't
> have one yet for bit 0 in the DP_MAX_DOWNSPREAD register.
>

I'll add the new constant in DP_MAX_DOWNSPREAD and send a patch within 
these series. Done in v4.

>> +static inline struct anx78xx *
>> +	connector_to_anx78xx(struct drm_connector *connector)
>
> The function name should start on the first column. Also you might want
> to move this inline function after the struct anx78xx declaration, which
> is more consistent with other drivers.
>

Done in v4.

>> +static const struct drm_connector_helper_funcs
>> +	anx78xx_connector_helper_funcs = {
>
> The structure name should start in the first column as well.
>

Done in v4.

>> +	.get_modes = anx78xx_get_modes,
>> +	.best_encoder = anx78xx_best_encoder,
>> +};
>> +
>> +static enum drm_connector_status anx78xx_detect(struct drm_connector *connector,
>> +						bool force)
>> +{
>> +	struct anx78xx *anx78xx = container_of(connector, struct anx78xx,
>> +					       connector);
>
> Didn't you introduce an inline function for this just a few lines above?
>

Yes, replaced in v4

>> +	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
>> +		      connector->name);
>> +
>> +	if (!gpiod_get_value(anx78xx->pdata.gpiod_hpd)) {
>> +		DRM_DEBUG_KMS("CONNECTOR STATUS DISCONNECTED\n");
>> +		return connector_status_disconnected;
>> +	}
>> +
>> +	return connector_status_connected;
>> +}
>
> Is it really necessary to add two debug messages here? The DRM core will
> already output a message for connector status changes, so this is
> unnecessarily noisy in my opinion.
>

Ok, removed in v4.

>> +static inline struct anx78xx *bridge_to_anx78xx(struct drm_bridge *bridge)
>> +{
>> +	return container_of(bridge, struct anx78xx, bridge);
>> +}
>
> Put this together with the connector cast function.
>

Done in v4.

>> +static void anx78xx_bridge_disable(struct drm_bridge *bridge)
>> +{
>> +	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
>> +
>> +	mutex_lock(&anx78xx->lock);
>
> Do you really need the locking here and below? I think the DRM core
> already ensures that these calls are always serialized.
>

Hmm, guess I can remove this from bridge_enable/disable calls, but I 
observed that sometimes the display is wrong (I see artefacts) if I 
remove the lock from mode_set for example, I just want to make sure all 
INTP interrupts are handled. It works with the lock but maybe there is 
another problem behind this.

>> +static void anx78xx_bridge_mode_set(struct drm_bridge *bridge,
>> +				    struct drm_display_mode *mode,
>> +				    struct drm_display_mode *adjusted_mode)
>> +{
>> +	int err;
>> +	struct hdmi_avi_infoframe frame;
>> +	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
>> +
>> +	if (WARN_ON(!anx78xx->powered))
>> +		return;
>> +
>> +	mutex_lock(&anx78xx->lock);
>> +
>> +	mode = adjusted_mode;
>> +
>> +	err = drm_hdmi_avi_infoframe_from_display_mode(&frame, mode);
>
> This seems like jumping through hoops. Why not simply pass adjusted_mode
> to the function?
>

Fixed in v4.

>> +static const struct drm_bridge_funcs anx78xx_bridge_funcs = {
>> +	.attach		= anx78xx_bridge_attach,
>> +	.mode_fixup	= anx78xx_bridge_mode_fixup,
>> +	.disable	= anx78xx_bridge_disable,
>> +	.mode_set	= anx78xx_bridge_mode_set,
>> +	.enable		= anx78xx_bridge_enable,
>> +};
>
> I'd leave out the tab-padding. Simple spaces will do just fine.
>

Done in v4.

>> +static irqreturn_t anx78xx_hpd_threaded_handler(int unused, void *data)
>
> Might as well give the first parameter the proper name (irq).
>

Done in v4.

>> +static bool anx78xx_handle_common_int_4(struct anx78xx *anx78xx, u8 irq)
>> +{
>> +	int err;
>> +	bool event = false;
>> +
>> +	DRM_DEBUG_KMS("Handle common interrupt 4: %02x\n", irq);
>> +
>> +	err = regmap_write(anx78xx->map[I2C_IDX_TX_P2],
>> +			   SP_COMMON_INT_STATUS4_REG, irq);
>> +	if (err) {
>> +		DRM_ERROR("Failed to write SP_COMMON_INT_STATUS4 %d\n", err);
>> +		return event;
>> +	}
>> +
>> +	if (irq & SP_HPD_LOST) {
>> +		DRM_DEBUG_KMS("IRQ: Hot plug detect - cable is pulled out\n");
>> +		event = true;
>> +		anx78xx_poweroff(anx78xx);
>> +	} else if (irq & SP_HPD_PLUG) {
>> +		DRM_DEBUG_KMS("IRQ: Hot plug detect - cable plug\n");
>> +		event = true;
>> +		/* Free previous cached EDID if any */
>> +		kfree(anx78xx->edid);
>> +		anx78xx->edid = NULL;
>
> I think you can free the EDID on unplug, since it becomes stale at that
> point already. The DRM core will also remove the EDID data on unplug.
>

Yes, done in v4.

>> +static void unregister_i2c_dummy_clients(struct anx78xx *anx78xx)
>> +{
>> +	int i;
>
> unsigned int
>

Done in v4.

>> +
>> +	for (i = 0; i < ARRAY_SIZE(anx78xx->i2c_dummy); i++)
>> +		if (anx78xx->i2c_dummy[i])
>> +			i2c_unregister_device(anx78xx->i2c_dummy[i]);
>> +}
>> +
>> +static const struct regmap_config anx78xx_regmap_config = {
>> +	.reg_bits = 8,
>> +	.val_bits = 8,
>> +};
>> +
>> +static const u16 anx78xx_chipid_list[] = {
>> +	0x7812,
>> +	0x7814,
>> +	0x7818,
>> +};
>> +
>> +static int anx78xx_i2c_probe(struct i2c_client *client,
>> +			     const struct i2c_device_id *id)
>> +{
>> +	struct anx78xx *anx78xx;
>> +	struct anx78xx_platform_data *pdata;
>> +	int err, i;
>
> i should be unsigned int.
>

Done in v4.

>> +	unsigned int idl, idh, version;
>> +	bool found = false;
>> +
>> +	anx78xx = devm_kzalloc(&client->dev, sizeof(*anx78xx), GFP_KERNEL);
>> +	if (!anx78xx)
>> +		return -ENOMEM;
>> +
>> +	pdata = &anx78xx->pdata;
>> +
>> +	mutex_init(&anx78xx->lock);
>> +
>> +#if IS_ENABLED(CONFIG_OF)
>> +	anx78xx->bridge.of_node = client->dev.of_node;
>> +#endif
>> +
>> +	anx78xx->client = client;
>> +	i2c_set_clientdata(client, anx78xx);
>> +
>> +	err = anx78xx_init_gpio(anx78xx);
>> +	if (err) {
>> +		DRM_ERROR("Failed to initialize gpios\n");
>> +		return err;
>> +	}
>> +
>> +	pdata->hpd_irq = gpiod_to_irq(pdata->gpiod_hpd);
>> +	if (pdata->hpd_irq < 0) {
>> +		DRM_ERROR("Failed to get hpd irq %d\n",
>> +			  pdata->hpd_irq);
>> +		return -ENODEV;
>> +	}
>> +
>> +	pdata->intp_irq = client->irq;
>> +	if (!pdata->intp_irq) {
>> +		DRM_ERROR("Failed to get CABLE_DET and INTP irq\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	/* Map slave addresses of ANX7814 */
>> +	for (i = 0; i < I2C_NUM_ADDRESSES; i++) {
>> +		anx78xx->i2c_dummy[i] = i2c_new_dummy(client->adapter,
>> +						anx78xx_i2c_addresses[i] >> 1);
>> +		if (!anx78xx->i2c_dummy[i]) {
>> +			err = -ENOMEM;
>> +			DRM_ERROR("Failed to reserve i2c bus %02x.\n",
>> +				  anx78xx_i2c_addresses[i]);
>> +			goto err_unregister_i2c;
>> +		}
>> +
>> +		anx78xx->map[i] = devm_regmap_init_i2c(anx78xx->i2c_dummy[i],
>> +						       &anx78xx_regmap_config);
>> +		if (IS_ERR(anx78xx->map[i])) {
>> +			err = PTR_ERR(anx78xx->map[i]);
>> +			DRM_ERROR("Failed regmap initialization %02x.\n",
>> +				  anx78xx_i2c_addresses[i]);
>> +			goto err_unregister_i2c;
>> +		}
>> +	}
>
> That's quite some overhead merely to use regmap... Perhaps there's room
> to enhance regmap-i2c to support multiple addresses for the same device?
>

Yes it is, guess this is also used on other drivers, so will make sense 
enhance regmap-i2c, but let me do this on a future regmap-i2c patch 
series ;)

>> +static int anx78xx_i2c_remove(struct i2c_client *client)
>> +{
>> +	struct anx78xx *anx78xx = i2c_get_clientdata(client);
>> +
>> +	drm_bridge_remove(&anx78xx->bridge);
>> +
>> +	unregister_i2c_dummy_clients(anx78xx);
>> +
>> +	kfree(anx78xx->edid);
>> +	anx78xx->edid = NULL;
>
> The memory pointed at by anx78xx will be freed a couple of instructions
> later, there's no need to set ->edid to NULL.
>

Done in v4.

> Thierry
>

Thanks,
- Enric

Re: [PATCH v3 3/3] drm: bridge: anx78xx: Add anx78xx driver support.

[Enric Balletbo i Serra]

Hi,

Many thanks for dedicate some time to comment the patch, I'm going to 
send a v4 version, see my comments below.

On 14/04/16 15:10, Thierry Reding wrote:
> On Fri, Apr 08, 2016 at 02:52:52PM +0200, Enric Balletbo i Serra wrote:
>> Although there are other chips from the same family that can reuse this
>> driver, at the moment we only tested ANX7814 chip.
>>
>> The ANX7814 is an ultra-low power Full-HD (1080p60) SlimPort transmitter
>> designed for portable devices. This driver adds initial support for HDMI
>> to DP pass-through mode.
>>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>
>> Tested-by: Nicolas Boichat <drinkcat-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
>> Reviewed-by: Nicolas Boichat <drinkcat-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
>> Cc: Emil Velikov <emil.l.velikov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> Cc: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
>> Cc: Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
>> Cc: Daniel Kurtz <djkurtz-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
>> Cc: Nicolas Boichat <drinkcat-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
>> ---
>> Changes since v2:
>>   - Nicolas Boichat:
>>     - Get rid of wait_for macro since is only used once.
>>     - Do not replace the error code if it's readily available to you.
>>   - Add Tested-by: Nicolas Boichat <drinkcat-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
>>   - Add Reviewed-by: Nicolas Boichat <drinkcat-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
>>
>> Changes since v1:
>>   - Dan Carpenter:
>>     - Fix missing error code
>>     - Use meaningful names for goto exit paths
>>   - Rob Herring:
>>     - Use hpd instead cable_det as is the more standard name.
>>   - Daniel Kurtz:
>>     - Use regmap_bulk in aux_transfer
>>     - Fix gpio reset polarity.
>>     - Turn off v10 last so we mirror poweron sequence
>>     - Fix some error paths.
>>     - Remove mutex in anx78xx_detect
>>   - kbuild:
>>     - WARNING: PTR_ERR_OR_ZERO can be used
>>
>>   drivers/gpu/drm/bridge/Kconfig   |    8 +
>>   drivers/gpu/drm/bridge/Makefile  |    1 +
>>   drivers/gpu/drm/bridge/anx78xx.c | 1403 ++++++++++++++++++++++++++++++++++++++
>>   drivers/gpu/drm/bridge/anx78xx.h |  719 +++++++++++++++++++
>>   4 files changed, 2131 insertions(+)
>>   create mode 100644 drivers/gpu/drm/bridge/anx78xx.c
>>   create mode 100644 drivers/gpu/drm/bridge/anx78xx.h
>>
>> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
>> index 27e2022..0f595ae 100644
>> --- a/drivers/gpu/drm/bridge/Kconfig
>> +++ b/drivers/gpu/drm/bridge/Kconfig
>> @@ -40,4 +40,12 @@ config DRM_PARADE_PS8622
>>   	---help---
>>   	  Parade eDP-LVDS bridge chip driver.
>>
>> +config DRM_ANX78XX
>
> The symbol name should include the vendor (DRM_ANALOGIX_ANX78XX) and the
> entry needs to be ordered alphabetically (by vendor, then name).
>

Done in v4

>> +	tristate "Analogix ANX78XX bridge"
>> +	select DRM_KMS_HELPER
>> +	select REGMAP_I2C
>> +	---help---
>> +	  ANX78XX is a HD video transmitter chip over micro-USB connector
>> +	  for smartphone device.
>
> The commit description says the device is a FullHD video transmitter,
> but here you say HD. Pick one. Preferably the correct one.
>

FullHD is the correct. I improved also a bit the description based on 
the datasheet. Changed in v4.

>>   endmenu
>> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
>> index f13c33d..8f0d69e 100644
>> --- a/drivers/gpu/drm/bridge/Makefile
>> +++ b/drivers/gpu/drm/bridge/Makefile
>> @@ -4,3 +4,4 @@ obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>>   obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>>   obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
>>   obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
>> +obj-$(CONFIG_DRM_ANX78XX) += anx78xx.o
>
> Same here, the source file should be named analogix-anx78xx.c, and this
> needs to be sorted by vendor, then name as well.
>

Done in v4.

>> diff --git a/drivers/gpu/drm/bridge/anx78xx.c b/drivers/gpu/drm/bridge/anx78xx.c
> [...]
>> +#include <linux/async.h>
>
> At least this one doesn't seem to be needed.
>

Removed.

>> +static int anx78xx_aux_wait(struct anx78xx *anx78xx)
>> +{
>> +	int err;
>> +	unsigned int status;
>> +	unsigned long timeout;
>> +
>> +	/*
>> +	 * Does the right thing for modeset paths when run under kdgb or
>> +	 * similar atomic contexts. Note that it's important that we check the
>> +	 * condition again after having timed out, since the timeout could be
>> +	 * due to preemption or similar and we've never had a chance to check
>> +	 * the condition before the timeout.
>> +	 */
>
> I don't think this is necessary. The AUX code should never be called
> from atomic context, there are various other places where we take a
> mutex that would trigger warnings.
>

Right. Done in v4.

>> +	err = 0;
>
> You can move this up to where the variable is declared.
>

Done in v4.

>> +	timeout = jiffies + msecs_to_jiffies(AUX_WAIT_TIMEOUT_MS) + 1;
>> +	while (anx78xx_aux_op_finished(anx78xx)) {
>> +		if (time_after(jiffies, timeout)) {
>> +			if (anx78xx_aux_op_finished(anx78xx))
>> +				err = -ETIMEDOUT;
>
> Should this not be !cond? Ah, anx78xx_aux_op_finished() returns an error
> code on failure. Perhaps it would be clearer if this either returned a
> boolean or the name was changed to reflect the fact that it returns an
> error code. _finished() sounds too much like it would return boolean.
>
> To make it clearer what I mean, try reading the above aloud:
>
> 	if aux_op_finished, return error
>
> That's the wrong way around.
>

Yes, it's not readable, make sense to change and return a boolean. Done 
in v4.

>> +			break;
>> +		}
>> +		if (drm_can_sleep())
>> +			usleep_range(1000, 2000);
>> +		else
>> +			cpu_relax();
>> +	}
>> +
>> +	if (err) {
>> +		DRM_ERROR("Timed out waiting AUX to finish\n");
>> +		return -ETIMEDOUT;
>> +	}
>> +
>> +	/* Read the AUX channel access status */
>> +	err = regmap_read(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_CH_STATUS_REG,
>> +			  &status);
>> +	if (err)
>> +		return err;
>> +
>> +	if (status & SP_AUX_STATUS) {
>> +		DRM_ERROR("Failed to read AUX channel: 0x%02x\n", status);
>> +		return -ETIMEDOUT;
>> +	}
>
> Would it make sense to disambiguate these two errors using different
> error codes? As it is this function will either return success or
> timeout, even though the latter is obviously not a timeout.
>

Yes makes sense simply return the timeout in both cases. Changed in v4.

>> +static int anx78xx_aux_address(struct anx78xx *anx78xx, unsigned int addr)
>> +{
>> +	int err = 0;
>> +
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_7_0_REG,
>> +			    addr & 0xff);
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_15_8_REG,
>> +			    (addr & 0xff00) >> 8);
>> +
>> +	/*
>> +	 * DP AUX CH Address Register #2, only update bits[3:0]
>> +	 * [7:4] RESERVED
>> +	 * [3:0] AUX_ADDR[19:16], Register control AUX CH address.
>> +	 */
>> +	err |= regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
>> +				  SP_AUX_ADDR_19_16_REG,
>> +				  SP_AUX_ADDR_19_16_MASK,
>> +				  (addr & 0xf0000) >> 16);
>
> I'm not at all a fan of OR'ing error codes. Presumably if any of these
> register accesses fails there's no reason to attempt the subsequent
> accesses because the end result will be failure anyway.
>

Ok, I will remove all these OR'ed error codes and return if anything 
goes wrong.

>> +	/* Write address and request */
>> +	err = anx78xx_aux_address(anx78xx, msg->address);
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_DP_AUX_CH_CTRL1_REG,
>> +			    ctrl1);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	/* Start transaction */
>> +	err = regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
>> +				 SP_DP_AUX_CH_CTRL2_REG, SP_ADDR_ONLY |
>> +				 SP_AUX_EN, ctrl2);
>> +	if (err)
>> +		return err;
>> +
>> +	err = anx78xx_aux_wait(anx78xx);
>> +
>> +	msg->reply = err ? DP_AUX_I2C_REPLY_NACK : DP_AUX_I2C_REPLY_ACK;
>
> This looks wrong. What if anx78xx_aux_wait() return -ETIMEDOUT? You'll
> be setting msg->reply to NACK and return success That doesn't sound
> right at all.
>

Right. Changed in v4.

>> +static int anx78xx_set_hpd(struct anx78xx *anx78xx)
>> +{
>> +	int err = 0;
>> +
>> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_RX_P0],
>> +				  SP_TMDS_CTRL_BASE + 7, SP_PD_RT);
>> +	err |= anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL3_REG,
>> +				SP_HPD_OUT);
>
> Again, OR'ing of error codes, please don't do it. There are some more
> occurrences below.
>

Done in v4.

>> +static int anx78xx_init_gpio(struct anx78xx *anx78xx)
>> +{
>> +	struct device *dev = &anx78xx->client->dev;
>> +	struct anx78xx_platform_data *pdata = &anx78xx->pdata;
>> +
>> +	/* GPIO for hpd */
>
> HPD being an abbreviation it should be capitalized. Similar for a couple
> of other abbreviations, some of which are inconsistently capitalized. In
> variable names of consumer names, the lowercase variant is fine, but the
> variant used in text (messages, comments) should be the all caps one.
>

Capitalized some HPD, HDMI and DP abbreviations.


>> +	pdata->gpiod_hpd = devm_gpiod_get(dev, "hpd", GPIOD_IN);
>> +	if (IS_ERR(pdata->gpiod_hpd))
>> +		return PTR_ERR(pdata->gpiod_hpd);
>> +
>> +	/* GPIO for chip power down */
>> +	pdata->gpiod_pd = devm_gpiod_get(dev, "pd", GPIOD_OUT_HIGH);
>> +	if (IS_ERR(pdata->gpiod_pd))
>> +		return PTR_ERR(pdata->gpiod_pd);
>> +
>> +	/* GPIO for chip reset */
>> +	pdata->gpiod_reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
>> +	if (IS_ERR(pdata->gpiod_reset))
>> +		return PTR_ERR(pdata->gpiod_reset);
>> +
>> +	/* GPIO for V10 power control */
>> +	pdata->gpiod_v10 = devm_gpiod_get_optional(dev, "v10", GPIOD_OUT_LOW);
>
> Does this actually supply power? If so it should be modelled as a
> regulator.
>

Ok, done in v4.

>> +static int anx78xx_dp_link_training(struct anx78xx *anx78xx)
>> +{
>> +	int err = 0;
>> +	u8 dp_bw, regval;
>> +
>> +	err |= regmap_write(anx78xx->map[I2C_IDX_RX_P0], SP_HDMI_MUTE_CTRL_REG,
>> +			    0x0);
>> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2],
>> +				  SP_POWERDOWN_CTRL_REG,
>> +				  SP_TOTAL_PD);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	err = drm_dp_dpcd_readb(&anx78xx->aux, DP_MAX_LINK_RATE, &dp_bw);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	switch (dp_bw) {
>> +	case DP_LINK_BW_1_62:
>> +	case DP_LINK_BW_2_7:
>> +	case DP_LINK_BW_5_4:
>> +		break;
>> +	default:
>> +		DRM_DEBUG_KMS("Waiting to read DP bandwidth.\n");
>> +		return -EAGAIN;
>> +	}
>
> That sounds wrong. Either you can read the content and it should be a
> valid value (albeit one which you may not support) or you can't. Why do
> you need to potentially repeat this read?
>

Right, changed in v4.

>> +
>> +	err = anx78xx_set_bits(anx78xx->map[I2C_IDX_TX_P2], SP_VID_CTRL1_REG,
>> +			       SP_VIDEO_MUTE);
>> +	err |= anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2],
>> +				  SP_VID_CTRL1_REG, SP_VIDEO_EN);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	/* Get dpcd info */
>
> s/dpcd/DPCD/
>

Done in v4.

>> +	err = drm_dp_dpcd_read(&anx78xx->aux, DP_DPCD_REV,
>> +			       &anx78xx->dpcd, DP_RECEIVER_CAP_SIZE);
>> +	if (err < 0) {
>> +		DRM_ERROR("Failed to read DPCD\n");
>
> It's often useful to output the error code as part of the error message
> to make it easier for developers to diagnose problems.
>

Ok, there are more places that the error code is missing, I'll add all 
error codes. Done in v4.

>> +		return err;
>> +	}
>> +
>> +	/* Clear channel x SERDES power down */
>> +	err = anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P0],
>> +				 SP_DP_ANALOG_POWER_DOWN_REG, SP_CH0_PD);
>> +	if (err)
>> +		return -EIO;
>> +
>> +	/* Check link capabilities */
>> +	err = drm_dp_link_probe(&anx78xx->aux, &anx78xx->link);
>> +	if (err < 0) {
>> +		DRM_ERROR("Failed to probe link capabilities\n");
>> +		return err;
>> +	}
>> +
>> +	/* Power up the sink */
>> +	err = drm_dp_link_power_up(&anx78xx->aux, &anx78xx->link);
>> +	if (err < 0) {
>> +		DRM_ERROR("Failed to power up DisplayPort link\n");
>> +		return err;
>> +	}
>> +
>> +	/* Possibly enable downspread on the sink */
>> +	err = regmap_write(anx78xx->map[I2C_IDX_TX_P0],
>> +			   SP_DP_DOWNSPREAD_CTRL1_REG, 0);
>> +	if (err)
>> +		return err;
>> +
>> +	if (anx78xx->dpcd[3] & 0x1) {
>
> This should use the symbolic constants defined in drm_dp_helper.h.
> Actually, it should probably add a symbolic constant because we don't
> have one yet for bit 0 in the DP_MAX_DOWNSPREAD register.
>

I'll add the new constant in DP_MAX_DOWNSPREAD and send a patch within 
these series. Done in v4.

>> +static inline struct anx78xx *
>> +	connector_to_anx78xx(struct drm_connector *connector)
>
> The function name should start on the first column. Also you might want
> to move this inline function after the struct anx78xx declaration, which
> is more consistent with other drivers.
>

Done in v4.

>> +static const struct drm_connector_helper_funcs
>> +	anx78xx_connector_helper_funcs = {
>
> The structure name should start in the first column as well.
>

Done in v4.

>> +	.get_modes = anx78xx_get_modes,
>> +	.best_encoder = anx78xx_best_encoder,
>> +};
>> +
>> +static enum drm_connector_status anx78xx_detect(struct drm_connector *connector,
>> +						bool force)
>> +{
>> +	struct anx78xx *anx78xx = container_of(connector, struct anx78xx,
>> +					       connector);
>
> Didn't you introduce an inline function for this just a few lines above?
>

Yes, replaced in v4

>> +	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
>> +		      connector->name);
>> +
>> +	if (!gpiod_get_value(anx78xx->pdata.gpiod_hpd)) {
>> +		DRM_DEBUG_KMS("CONNECTOR STATUS DISCONNECTED\n");
>> +		return connector_status_disconnected;
>> +	}
>> +
>> +	return connector_status_connected;
>> +}
>
> Is it really necessary to add two debug messages here? The DRM core will
> already output a message for connector status changes, so this is
> unnecessarily noisy in my opinion.
>

Ok, removed in v4.

>> +static inline struct anx78xx *bridge_to_anx78xx(struct drm_bridge *bridge)
>> +{
>> +	return container_of(bridge, struct anx78xx, bridge);
>> +}
>
> Put this together with the connector cast function.
>

Done in v4.

>> +static void anx78xx_bridge_disable(struct drm_bridge *bridge)
>> +{
>> +	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
>> +
>> +	mutex_lock(&anx78xx->lock);
>
> Do you really need the locking here and below? I think the DRM core
> already ensures that these calls are always serialized.
>

Hmm, guess I can remove this from bridge_enable/disable calls, but I 
observed that sometimes the display is wrong (I see artefacts) if I 
remove the lock from mode_set for example, I just want to make sure all 
INTP interrupts are handled. It works with the lock but maybe there is 
another problem behind this.

>> +static void anx78xx_bridge_mode_set(struct drm_bridge *bridge,
>> +				    struct drm_display_mode *mode,
>> +				    struct drm_display_mode *adjusted_mode)
>> +{
>> +	int err;
>> +	struct hdmi_avi_infoframe frame;
>> +	struct anx78xx *anx78xx = bridge_to_anx78xx(bridge);
>> +
>> +	if (WARN_ON(!anx78xx->powered))
>> +		return;
>> +
>> +	mutex_lock(&anx78xx->lock);
>> +
>> +	mode = adjusted_mode;
>> +
>> +	err = drm_hdmi_avi_infoframe_from_display_mode(&frame, mode);
>
> This seems like jumping through hoops. Why not simply pass adjusted_mode
> to the function?
>

Fixed in v4.

>> +static const struct drm_bridge_funcs anx78xx_bridge_funcs = {
>> +	.attach		= anx78xx_bridge_attach,
>> +	.mode_fixup	= anx78xx_bridge_mode_fixup,
>> +	.disable	= anx78xx_bridge_disable,
>> +	.mode_set	= anx78xx_bridge_mode_set,
>> +	.enable		= anx78xx_bridge_enable,
>> +};
>
> I'd leave out the tab-padding. Simple spaces will do just fine.
>

Done in v4.

>> +static irqreturn_t anx78xx_hpd_threaded_handler(int unused, void *data)
>
> Might as well give the first parameter the proper name (irq).
>

Done in v4.

>> +static bool anx78xx_handle_common_int_4(struct anx78xx *anx78xx, u8 irq)
>> +{
>> +	int err;
>> +	bool event = false;
>> +
>> +	DRM_DEBUG_KMS("Handle common interrupt 4: %02x\n", irq);
>> +
>> +	err = regmap_write(anx78xx->map[I2C_IDX_TX_P2],
>> +			   SP_COMMON_INT_STATUS4_REG, irq);
>> +	if (err) {
>> +		DRM_ERROR("Failed to write SP_COMMON_INT_STATUS4 %d\n", err);
>> +		return event;
>> +	}
>> +
>> +	if (irq & SP_HPD_LOST) {
>> +		DRM_DEBUG_KMS("IRQ: Hot plug detect - cable is pulled out\n");
>> +		event = true;
>> +		anx78xx_poweroff(anx78xx);
>> +	} else if (irq & SP_HPD_PLUG) {
>> +		DRM_DEBUG_KMS("IRQ: Hot plug detect - cable plug\n");
>> +		event = true;
>> +		/* Free previous cached EDID if any */
>> +		kfree(anx78xx->edid);
>> +		anx78xx->edid = NULL;
>
> I think you can free the EDID on unplug, since it becomes stale at that
> point already. The DRM core will also remove the EDID data on unplug.
>

Yes, done in v4.

>> +static void unregister_i2c_dummy_clients(struct anx78xx *anx78xx)
>> +{
>> +	int i;
>
> unsigned int
>

Done in v4.

>> +
>> +	for (i = 0; i < ARRAY_SIZE(anx78xx->i2c_dummy); i++)
>> +		if (anx78xx->i2c_dummy[i])
>> +			i2c_unregister_device(anx78xx->i2c_dummy[i]);
>> +}
>> +
>> +static const struct regmap_config anx78xx_regmap_config = {
>> +	.reg_bits = 8,
>> +	.val_bits = 8,
>> +};
>> +
>> +static const u16 anx78xx_chipid_list[] = {
>> +	0x7812,
>> +	0x7814,
>> +	0x7818,
>> +};
>> +
>> +static int anx78xx_i2c_probe(struct i2c_client *client,
>> +			     const struct i2c_device_id *id)
>> +{
>> +	struct anx78xx *anx78xx;
>> +	struct anx78xx_platform_data *pdata;
>> +	int err, i;
>
> i should be unsigned int.
>

Done in v4.

>> +	unsigned int idl, idh, version;
>> +	bool found = false;
>> +
>> +	anx78xx = devm_kzalloc(&client->dev, sizeof(*anx78xx), GFP_KERNEL);
>> +	if (!anx78xx)
>> +		return -ENOMEM;
>> +
>> +	pdata = &anx78xx->pdata;
>> +
>> +	mutex_init(&anx78xx->lock);
>> +
>> +#if IS_ENABLED(CONFIG_OF)
>> +	anx78xx->bridge.of_node = client->dev.of_node;
>> +#endif
>> +
>> +	anx78xx->client = client;
>> +	i2c_set_clientdata(client, anx78xx);
>> +
>> +	err = anx78xx_init_gpio(anx78xx);
>> +	if (err) {
>> +		DRM_ERROR("Failed to initialize gpios\n");
>> +		return err;
>> +	}
>> +
>> +	pdata->hpd_irq = gpiod_to_irq(pdata->gpiod_hpd);
>> +	if (pdata->hpd_irq < 0) {
>> +		DRM_ERROR("Failed to get hpd irq %d\n",
>> +			  pdata->hpd_irq);
>> +		return -ENODEV;
>> +	}
>> +
>> +	pdata->intp_irq = client->irq;
>> +	if (!pdata->intp_irq) {
>> +		DRM_ERROR("Failed to get CABLE_DET and INTP irq\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	/* Map slave addresses of ANX7814 */
>> +	for (i = 0; i < I2C_NUM_ADDRESSES; i++) {
>> +		anx78xx->i2c_dummy[i] = i2c_new_dummy(client->adapter,
>> +						anx78xx_i2c_addresses[i] >> 1);
>> +		if (!anx78xx->i2c_dummy[i]) {
>> +			err = -ENOMEM;
>> +			DRM_ERROR("Failed to reserve i2c bus %02x.\n",
>> +				  anx78xx_i2c_addresses[i]);
>> +			goto err_unregister_i2c;
>> +		}
>> +
>> +		anx78xx->map[i] = devm_regmap_init_i2c(anx78xx->i2c_dummy[i],
>> +						       &anx78xx_regmap_config);
>> +		if (IS_ERR(anx78xx->map[i])) {
>> +			err = PTR_ERR(anx78xx->map[i]);
>> +			DRM_ERROR("Failed regmap initialization %02x.\n",
>> +				  anx78xx_i2c_addresses[i]);
>> +			goto err_unregister_i2c;
>> +		}
>> +	}
>
> That's quite some overhead merely to use regmap... Perhaps there's room
> to enhance regmap-i2c to support multiple addresses for the same device?
>

Yes it is, guess this is also used on other drivers, so will make sense 
enhance regmap-i2c, but let me do this on a future regmap-i2c patch 
series ;)

>> +static int anx78xx_i2c_remove(struct i2c_client *client)
>> +{
>> +	struct anx78xx *anx78xx = i2c_get_clientdata(client);
>> +
>> +	drm_bridge_remove(&anx78xx->bridge);
>> +
>> +	unregister_i2c_dummy_clients(anx78xx);
>> +
>> +	kfree(anx78xx->edid);
>> +	anx78xx->edid = NULL;
>
> The memory pointed at by anx78xx will be freed a couple of instructions
> later, there's no need to set ->edid to NULL.
>

Done in v4.

> Thierry
>

Thanks,
- Enric
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Re: [PATCH v3 3/3] drm: bridge: anx78xx: Add anx78xx driver support.

[Thierry Reding]

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On Mon, Apr 18, 2016 at 01:23:54PM +0200, Enric Balletbo i Serra wrote:
> On 14/04/16 15:10, Thierry Reding wrote:
> > On Fri, Apr 08, 2016 at 02:52:52PM +0200, Enric Balletbo i Serra wrote:
[...]
> > > +	/* Map slave addresses of ANX7814 */
> > > +	for (i = 0; i < I2C_NUM_ADDRESSES; i++) {
> > > +		anx78xx->i2c_dummy[i] = i2c_new_dummy(client->adapter,
> > > +						anx78xx_i2c_addresses[i] >> 1);
> > > +		if (!anx78xx->i2c_dummy[i]) {
> > > +			err = -ENOMEM;
> > > +			DRM_ERROR("Failed to reserve i2c bus %02x.\n",
> > > +				  anx78xx_i2c_addresses[i]);
> > > +			goto err_unregister_i2c;
> > > +		}
> > > +
> > > +		anx78xx->map[i] = devm_regmap_init_i2c(anx78xx->i2c_dummy[i],
> > > +						       &anx78xx_regmap_config);
> > > +		if (IS_ERR(anx78xx->map[i])) {
> > > +			err = PTR_ERR(anx78xx->map[i]);
> > > +			DRM_ERROR("Failed regmap initialization %02x.\n",
> > > +				  anx78xx_i2c_addresses[i]);
> > > +			goto err_unregister_i2c;
> > > +		}
> > > +	}
> > 
> > That's quite some overhead merely to use regmap... Perhaps there's room
> > to enhance regmap-i2c to support multiple addresses for the same device?
> > 
> 
> Yes it is, guess this is also used on other drivers, so will make sense
> enhance regmap-i2c, but let me do this on a future regmap-i2c patch series
> ;)

Yes, improving this in a follow-up patch seems fine, especially since
this already seems to be a common pattern.

I'll try to take a look at v4 hopefully within the week.

Thierry

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Re: [PATCH v3 3/3] drm: bridge: anx78xx: Add anx78xx driver support.

[Thierry Reding]

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On Mon, Apr 18, 2016 at 01:23:54PM +0200, Enric Balletbo i Serra wrote:
> On 14/04/16 15:10, Thierry Reding wrote:
> > On Fri, Apr 08, 2016 at 02:52:52PM +0200, Enric Balletbo i Serra wrote:
[...]
> > > +	/* Map slave addresses of ANX7814 */
> > > +	for (i = 0; i < I2C_NUM_ADDRESSES; i++) {
> > > +		anx78xx->i2c_dummy[i] = i2c_new_dummy(client->adapter,
> > > +						anx78xx_i2c_addresses[i] >> 1);
> > > +		if (!anx78xx->i2c_dummy[i]) {
> > > +			err = -ENOMEM;
> > > +			DRM_ERROR("Failed to reserve i2c bus %02x.\n",
> > > +				  anx78xx_i2c_addresses[i]);
> > > +			goto err_unregister_i2c;
> > > +		}
> > > +
> > > +		anx78xx->map[i] = devm_regmap_init_i2c(anx78xx->i2c_dummy[i],
> > > +						       &anx78xx_regmap_config);
> > > +		if (IS_ERR(anx78xx->map[i])) {
> > > +			err = PTR_ERR(anx78xx->map[i]);
> > > +			DRM_ERROR("Failed regmap initialization %02x.\n",
> > > +				  anx78xx_i2c_addresses[i]);
> > > +			goto err_unregister_i2c;
> > > +		}
> > > +	}
> > 
> > That's quite some overhead merely to use regmap... Perhaps there's room
> > to enhance regmap-i2c to support multiple addresses for the same device?
> > 
> 
> Yes it is, guess this is also used on other drivers, so will make sense
> enhance regmap-i2c, but let me do this on a future regmap-i2c patch series
> ;)

Yes, improving this in a follow-up patch seems fine, especially since
this already seems to be a common pattern.

I'll try to take a look at v4 hopefully within the week.

Thierry

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