[PATCH v7] drm/panel: Add driver for Sony ACX424AKP panel

[Linus Walleij <linus.walleij@linaro.org>]

The Sony ACX424AKP is a command/videomode DSI panel for
mobile devices. It is used on the ST-Ericsson HREF520
reference design. We support video mode by default, but
it is possible to switch the panel into command mode
by using the bool property "dsi-command-mode".

Cc: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
ChangeLog v6->v7:
- Add some Kconfig help text.
- Sort includes alphabetically.
- Move the struct drm_panel first in the state container
  struct since we are subclassing the panel class.
- Put an explicit /* sentinel */ text in the NULL entry
  for compatible.
- Move MTP ID readout to the .prepare() callback.
- Add a verbose comment about the MDDI setting so others
  understand what may be going on.
- Explain why the backlight follows the display and cannot
  be turned on/off
ChangeLog v5->v6:
- Move the "set MDDI" command back to this file. It is a
  local pecularity, we suspect there is a Novatek controller
  inside this display.
ChangeLog v4->v5:
- Bindings were iterated separately so a jump in versioning.
- Add Stephan as reviewer.
ChangeLog v3->v4:
- No changes just resending with the new binding updates.
ChangeLog v2->v3:
- No changes just resending with the new binding updates.
ChangeLog v1->v2:
- Fix up the ID read function to split into reading header,
  version and ID, store the version in the struct.
- Get rid of a surplus semicolon found by the build robot
  while rewriting the above code.
- Use unsigned int in probe() loop.
- Set vrefresh to 60Hz, as good as any, the measured vrefresh
  in continous command mode is ~117 Hz.
- Use a different for() idiom while retrying to read ID
  5 times.
- Drop the sync pulse setting, we are not using this, this
  panel uses an event.
- Use the generic "enforce-video-mode" for video mode
  enforcement.
---
 drivers/gpu/drm/panel/Kconfig                |  11 +
 drivers/gpu/drm/panel/Makefile               |   1 +
 drivers/gpu/drm/panel/panel-sony-acx424akp.c | 550 +++++++++++++++++++
 3 files changed, 562 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-sony-acx424akp.c

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index f152bc4eeb53..7ef8d095aae6 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -316,6 +316,17 @@ config DRM_PANEL_SITRONIX_ST7789V
 	  Say Y here if you want to enable support for the Sitronix
 	  ST7789V controller for 240x320 LCD panels
 
+config DRM_PANEL_SONY_ACX424AKP
+	tristate "Sony ACX424AKP DSI command mode panel"
+	depends on OF
+	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
+	select VIDEOMODE_HELPERS
+	help
+	  Say Y here if you want to enable the Sony ACX424 display
+	  panel. This panel supports DSI in both command and video
+	  mode.
+
 config DRM_PANEL_SONY_ACX565AKM
 	tristate "Sony ACX565AKM panel"
 	depends on GPIOLIB && OF && SPI
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index b6cd39fe0f20..0b51793e3b43 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_DRM_PANEL_SHARP_LS037V7DW01) += panel-sharp-ls037v7dw01.o
 obj-$(CONFIG_DRM_PANEL_SHARP_LS043T1LE01) += panel-sharp-ls043t1le01.o
 obj-$(CONFIG_DRM_PANEL_SITRONIX_ST7701) += panel-sitronix-st7701.o
 obj-$(CONFIG_DRM_PANEL_SITRONIX_ST7789V) += panel-sitronix-st7789v.o
+obj-$(CONFIG_DRM_PANEL_SONY_ACX424AKP) += panel-sony-acx424akp.o
 obj-$(CONFIG_DRM_PANEL_SONY_ACX565AKM) += panel-sony-acx565akm.o
 obj-$(CONFIG_DRM_PANEL_TPO_TD028TTEC1) += panel-tpo-td028ttec1.o
 obj-$(CONFIG_DRM_PANEL_TPO_TD043MTEA1) += panel-tpo-td043mtea1.o
diff --git a/drivers/gpu/drm/panel/panel-sony-acx424akp.c b/drivers/gpu/drm/panel/panel-sony-acx424akp.c
new file mode 100644
index 000000000000..fe33f97cd812
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-sony-acx424akp.c
@@ -0,0 +1,550 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * MIPI-DSI Sony ACX424AKP panel driver. This is a 480x864
+ * AMOLED panel with a command-only DSI interface.
+ *
+ * Copyright (C) Linaro Ltd. 2019
+ * Author: Linus Walleij
+ * Based on code and know-how from Marcus Lorentzon
+ * Copyright (C) ST-Ericsson SA 2010
+ */
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regulator/consumer.h>
+
+#include <video/mipi_display.h>
+
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+#include <drm/drm_print.h>
+
+#define ACX424_DCS_READ_ID1		0xDA
+#define ACX424_DCS_READ_ID2		0xDB
+#define ACX424_DCS_READ_ID3		0xDC
+#define ACX424_DCS_SET_MDDI		0xAE
+
+/*
+ * Sony seems to use vendor ID 0x81
+ */
+#define DISPLAY_SONY_ACX424AKP_ID1	0x811b
+#define DISPLAY_SONY_ACX424AKP_ID2	0x811a
+/*
+ * The third ID looks like a bug, vendor IDs begin at 0x80
+ * and panel 00 ... seems like default values.
+ */
+#define DISPLAY_SONY_ACX424AKP_ID3	0x8000
+
+struct acx424akp {
+	struct drm_panel panel;
+	struct device *dev;
+	struct backlight_device *bl;
+	struct regulator *supply;
+	struct gpio_desc *reset_gpio;
+	bool video_mode;
+};
+
+static const struct drm_display_mode sony_acx424akp_vid_mode = {
+	.clock = 330000,
+	.hdisplay = 480,
+	.hsync_start = 480 + 15,
+	.hsync_end = 480 + 15 + 0,
+	.htotal = 480 + 15 + 0 + 15,
+	.vdisplay = 864,
+	.vsync_start = 864 + 14,
+	.vsync_end = 864 + 14 + 1,
+	.vtotal = 864 + 14 + 1 + 11,
+	.vrefresh = 60,
+	.width_mm = 48,
+	.height_mm = 84,
+	.flags = DRM_MODE_FLAG_PVSYNC,
+};
+
+/*
+ * The timings are not very helpful as the display is used in
+ * command mode using the maximum HS frequency.
+ */
+static const struct drm_display_mode sony_acx424akp_cmd_mode = {
+	.clock = 420160,
+	.hdisplay = 480,
+	.hsync_start = 480 + 154,
+	.hsync_end = 480 + 154 + 16,
+	.htotal = 480 + 154 + 16 + 32,
+	.vdisplay = 864,
+	.vsync_start = 864 + 1,
+	.vsync_end = 864 + 1 + 1,
+	.vtotal = 864 + 1 + 1 + 1,
+	/*
+	 * Some desired refresh rate, experiments at the maximum "pixel"
+	 * clock speed (HS clock 420 MHz) yields around 117Hz.
+	 */
+	.vrefresh = 60,
+	.width_mm = 48,
+	.height_mm = 84,
+};
+
+static inline struct acx424akp *panel_to_acx424akp(struct drm_panel *panel)
+{
+	return container_of(panel, struct acx424akp, panel);
+}
+
+#define FOSC			20 /* 20Mhz */
+#define SCALE_FACTOR_NS_DIV_MHZ	1000
+
+static int acx424akp_set_brightness(struct backlight_device *bl)
+{
+	struct acx424akp *acx = bl_get_data(bl);
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(acx->dev);
+	int period_ns = 1023;
+	int duty_ns = bl->props.brightness;
+	u8 pwm_ratio;
+	u8 pwm_div;
+	u8 par;
+	int ret;
+
+	/* Calculate the PWM duty cycle in n/256's */
+	pwm_ratio = max(((duty_ns * 256) / period_ns) - 1, 1);
+	pwm_div = max(1,
+		      ((FOSC * period_ns) / 256) /
+		      SCALE_FACTOR_NS_DIV_MHZ);
+
+	/* Set up PWM dutycycle ONE byte (differs from the standard) */
+	DRM_DEV_DEBUG(acx->dev, "calculated duty cycle %02x\n", pwm_ratio);
+	ret = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
+				 &pwm_ratio, 1);
+	if (ret < 0) {
+		DRM_DEV_ERROR(acx->dev,
+			      "failed to set display PWM ratio (%d)\n",
+			      ret);
+		return ret;
+	}
+
+	/*
+	 * Sequence to write PWMDIV:
+	 *	address		data
+	 *	0xF3		0xAA   CMD2 Unlock
+	 *	0x00		0x01   Enter CMD2 page 0
+	 *	0X7D		0x01   No reload MTP of CMD2 P1
+	 *	0x22		PWMDIV
+	 *	0x7F		0xAA   CMD2 page 1 lock
+	 */
+	par = 0xaa;
+	ret = mipi_dsi_dcs_write(dsi, 0xf3, &par, 1);
+	if (ret < 0) {
+		DRM_DEV_ERROR(acx->dev,
+			      "failed to unlock CMD 2 (%d)\n",
+			      ret);
+		return ret;
+	}
+	par = 0x01;
+	ret = mipi_dsi_dcs_write(dsi, 0x00, &par, 1);
+	if (ret < 0) {
+		DRM_DEV_ERROR(acx->dev,
+			      "failed to enter page 1 (%d)\n",
+			      ret);
+		return ret;
+	}
+	par = 0x01;
+	ret = mipi_dsi_dcs_write(dsi, 0x7d, &par, 1);
+	if (ret < 0) {
+		DRM_DEV_ERROR(acx->dev,
+			      "failed to disable MTP reload (%d)\n",
+			      ret);
+		return ret;
+	}
+	ret = mipi_dsi_dcs_write(dsi, 0x22, &pwm_div, 1);
+	if (ret < 0) {
+		DRM_DEV_ERROR(acx->dev,
+			      "failed to set PWM divisor (%d)\n",
+			      ret);
+		return ret;
+	}
+	par = 0xaa;
+	ret = mipi_dsi_dcs_write(dsi, 0x7f, &par, 1);
+	if (ret < 0) {
+		DRM_DEV_ERROR(acx->dev,
+			      "failed to lock CMD 2 (%d)\n",
+			      ret);
+		return ret;
+	}
+
+	/* Enable backlight */
+	par = 0x24;
+	ret = mipi_dsi_dcs_write(dsi, MIPI_DCS_WRITE_CONTROL_DISPLAY,
+				 &par, 1);
+	if (ret < 0) {
+		DRM_DEV_ERROR(acx->dev,
+			      "failed to enable display backlight (%d)\n",
+			      ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct backlight_ops acx424akp_bl_ops = {
+	.update_status = acx424akp_set_brightness,
+};
+
+static int acx424akp_read_id(struct acx424akp *acx)
+{
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(acx->dev);
+	u8 vendor, version, panel;
+	u16 val;
+	int ret;
+
+	ret = mipi_dsi_dcs_read(dsi, ACX424_DCS_READ_ID1, &vendor, 1);
+	if (ret < 0) {
+		DRM_DEV_ERROR(acx->dev, "could not vendor ID byte\n");
+		return ret;
+	}
+	ret = mipi_dsi_dcs_read(dsi, ACX424_DCS_READ_ID2, &version, 1);
+	if (ret < 0) {
+		DRM_DEV_ERROR(acx->dev, "could not read device version byte\n");
+		return ret;
+	}
+	ret = mipi_dsi_dcs_read(dsi, ACX424_DCS_READ_ID3, &panel, 1);
+	if (ret < 0) {
+		DRM_DEV_ERROR(acx->dev, "could not read panel ID byte\n");
+		return ret;
+	}
+
+	if (vendor == 0x00) {
+		DRM_DEV_ERROR(acx->dev, "device vendor ID is zero\n");
+		return -ENODEV;
+	}
+
+	val = (vendor << 8) | panel;
+	switch (val) {
+	case DISPLAY_SONY_ACX424AKP_ID1:
+	case DISPLAY_SONY_ACX424AKP_ID2:
+	case DISPLAY_SONY_ACX424AKP_ID3:
+		DRM_DEV_INFO(acx->dev,
+			     "MTP vendor: %02x, version: %02x, panel: %02x\n",
+			     vendor, version, panel);
+		break;
+	default:
+		DRM_DEV_INFO(acx->dev,
+			     "unknown vendor: %02x, version: %02x, panel: %02x\n",
+			     vendor, version, panel);
+		break;
+	}
+
+	return 0;
+}
+
+static int acx424akp_power_on(struct acx424akp *acx)
+{
+	int ret;
+
+	ret = regulator_enable(acx->supply);
+	if (ret) {
+		DRM_DEV_ERROR(acx->dev, "failed to enable supply (%d)\n", ret);
+		return ret;
+	}
+
+	/* Assert RESET */
+	gpiod_set_value_cansleep(acx->reset_gpio, 1);
+	udelay(20);
+	/* De-assert RESET */
+	gpiod_set_value_cansleep(acx->reset_gpio, 0);
+	msleep(11);
+
+	return 0;
+}
+
+static void acx424akp_power_off(struct acx424akp *acx)
+{
+	/* Assert RESET */
+	gpiod_set_value_cansleep(acx->reset_gpio, 1);
+	msleep(11);
+
+	regulator_disable(acx->supply);
+}
+
+static int acx424akp_prepare(struct drm_panel *panel)
+{
+	struct acx424akp *acx = panel_to_acx424akp(panel);
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(acx->dev);
+	const u8 mddi = 3;
+	int ret;
+
+	ret = acx424akp_power_on(acx);
+	if (ret)
+		return ret;
+
+	ret = acx424akp_read_id(acx);
+	if (ret) {
+		DRM_DEV_ERROR(acx->dev, "failed to read panel ID (%d)\n", ret);
+		goto err_power_off;
+	}
+
+	/* Enabe tearing mode: send TE (tearing effect) at VBLANK */
+	ret = mipi_dsi_dcs_set_tear_on(dsi,
+				       MIPI_DSI_DCS_TEAR_MODE_VBLANK);
+	if (ret) {
+		DRM_DEV_ERROR(acx->dev, "failed to enable vblank TE (%d)\n",
+			      ret);
+		goto err_power_off;
+	}
+
+	/*
+	 * Set MDDI
+	 *
+	 * This presumably deactivates the Qualcomm MDDI interface and
+	 * selects DSI, similar code is found in other drivers such as the
+	 * Sharp LS043T1LE01 which makes us suspect that this panel may be
+	 * using a Novatek NT35565 or similar display driver chip that shares
+	 * this command. Due to the lack of documentation we cannot know for
+	 * sure.
+	 */
+	ret = mipi_dsi_dcs_write(dsi, ACX424_DCS_SET_MDDI,
+				 &mddi, sizeof(mddi));
+	if (ret < 0) {
+		DRM_DEV_ERROR(acx->dev, "failed to set MDDI (%d)\n", ret);
+		goto err_power_off;
+	}
+
+	/* Exit sleep mode */
+	ret = mipi_dsi_dcs_exit_sleep_mode(dsi);
+	if (ret) {
+		DRM_DEV_ERROR(acx->dev, "failed to exit sleep mode (%d)\n",
+			      ret);
+		goto err_power_off;
+	}
+	msleep(140);
+
+	ret = mipi_dsi_dcs_set_display_on(dsi);
+	if (ret) {
+		DRM_DEV_ERROR(acx->dev, "failed to turn display on (%d)\n",
+			      ret);
+		goto err_power_off;
+	}
+	if (acx->video_mode) {
+		/* In video mode turn peripheral on */
+		ret = mipi_dsi_turn_on_peripheral(dsi);
+		if (ret) {
+			dev_err(acx->dev, "failed to turn on peripheral\n");
+			goto err_power_off;
+		}
+	}
+
+	acx->bl->props.power = FB_BLANK_NORMAL;
+
+	return 0;
+
+err_power_off:
+	acx424akp_power_off(acx);
+	return ret;
+}
+
+static int acx424akp_unprepare(struct drm_panel *panel)
+{
+	struct acx424akp *acx = panel_to_acx424akp(panel);
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(acx->dev);
+	u8 par;
+	int ret;
+
+	/* Disable backlight */
+	par = 0x00;
+	ret = mipi_dsi_dcs_write(dsi, MIPI_DCS_WRITE_CONTROL_DISPLAY,
+				 &par, 1);
+	if (ret) {
+		DRM_DEV_ERROR(acx->dev,
+			      "failed to disable display backlight (%d)\n",
+			      ret);
+		return ret;
+	}
+
+	ret = mipi_dsi_dcs_set_display_off(dsi);
+	if (ret) {
+		DRM_DEV_ERROR(acx->dev, "failed to turn display off (%d)\n",
+			      ret);
+		return ret;
+	}
+
+	/* Enter sleep mode */
+	ret = mipi_dsi_dcs_enter_sleep_mode(dsi);
+	if (ret) {
+		DRM_DEV_ERROR(acx->dev, "failed to enter sleep mode (%d)\n",
+			      ret);
+		return ret;
+	}
+	msleep(85);
+
+	acx424akp_power_off(acx);
+	acx->bl->props.power = FB_BLANK_POWERDOWN;
+
+	return 0;
+}
+
+static int acx424akp_enable(struct drm_panel *panel)
+{
+	struct acx424akp *acx = panel_to_acx424akp(panel);
+
+	/*
+	 * The backlight is on as long as the display is on
+	 * so no use to call backlight_enable() here.
+	 */
+	acx->bl->props.power = FB_BLANK_UNBLANK;
+
+	return 0;
+}
+
+static int acx424akp_disable(struct drm_panel *panel)
+{
+	struct acx424akp *acx = panel_to_acx424akp(panel);
+
+	/*
+	 * The backlight is on as long as the display is on
+	 * so no use to call backlight_disable() here.
+	 */
+	acx->bl->props.power = FB_BLANK_NORMAL;
+
+	return 0;
+}
+
+static int acx424akp_get_modes(struct drm_panel *panel)
+{
+	struct acx424akp *acx = panel_to_acx424akp(panel);
+	struct drm_connector *connector = panel->connector;
+	struct drm_display_mode *mode;
+
+	if (acx->video_mode)
+		mode = drm_mode_duplicate(panel->drm,
+					  &sony_acx424akp_vid_mode);
+	else
+		mode = drm_mode_duplicate(panel->drm,
+					  &sony_acx424akp_cmd_mode);
+	if (!mode) {
+		DRM_ERROR("bad mode or failed to add mode\n");
+		return -EINVAL;
+	}
+	drm_mode_set_name(mode);
+	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
+
+	connector->display_info.width_mm = mode->width_mm;
+	connector->display_info.height_mm = mode->height_mm;
+
+	drm_mode_probed_add(connector, mode);
+
+	return 1; /* Number of modes */
+}
+
+static const struct drm_panel_funcs acx424akp_drm_funcs = {
+	.disable = acx424akp_disable,
+	.unprepare = acx424akp_unprepare,
+	.prepare = acx424akp_prepare,
+	.enable = acx424akp_enable,
+	.get_modes = acx424akp_get_modes,
+};
+
+static int acx424akp_probe(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	struct acx424akp *acx;
+	int ret;
+
+	acx = devm_kzalloc(dev, sizeof(struct acx424akp), GFP_KERNEL);
+	if (!acx)
+		return -ENOMEM;
+	acx->video_mode = of_property_read_bool(dev->of_node,
+						"enforce-video-mode");
+
+	mipi_dsi_set_drvdata(dsi, acx);
+	acx->dev = dev;
+
+	dsi->lanes = 2;
+	dsi->format = MIPI_DSI_FMT_RGB888;
+	/*
+	 * FIXME: these come from the ST-Ericsson vendor driver for the
+	 * HREF520 and seems to reflect limitations in the PLLs on that
+	 * platform, if you have the datasheet, please cross-check the
+	 * actual max rates.
+	 */
+	dsi->lp_rate = 19200000;
+	dsi->hs_rate = 420160000;
+
+	if (acx->video_mode)
+		/* Burst mode using event for sync */
+		dsi->mode_flags =
+			MIPI_DSI_MODE_VIDEO |
+			MIPI_DSI_MODE_VIDEO_BURST;
+	else
+		dsi->mode_flags =
+			MIPI_DSI_CLOCK_NON_CONTINUOUS |
+			MIPI_DSI_MODE_EOT_PACKET;
+
+	acx->supply = devm_regulator_get(dev, "vddi");
+	if (IS_ERR(acx->supply))
+		return PTR_ERR(acx->supply);
+
+	/* This asserts RESET by default */
+	acx->reset_gpio = devm_gpiod_get_optional(dev, "reset",
+						 GPIOD_OUT_HIGH);
+	if (IS_ERR(acx->reset_gpio)) {
+		ret = PTR_ERR(acx->reset_gpio);
+		if (ret != -EPROBE_DEFER)
+			DRM_DEV_ERROR(dev, "failed to request GPIO (%d)\n",
+				      ret);
+		return ret;
+	}
+
+	drm_panel_init(&acx->panel, dev, &acx424akp_drm_funcs,
+		       DRM_MODE_CONNECTOR_DSI);
+
+	acx->bl = devm_backlight_device_register(dev, "acx424akp", dev, acx,
+						 &acx424akp_bl_ops, NULL);
+	if (IS_ERR(acx->bl)) {
+		DRM_DEV_ERROR(dev, "failed to register backlight device\n");
+		return PTR_ERR(acx->bl);
+	}
+	acx->bl->props.max_brightness = 1023;
+	acx->bl->props.brightness = 512;
+	acx->bl->props.power = FB_BLANK_POWERDOWN;
+
+	ret = drm_panel_add(&acx->panel);
+	if (ret < 0)
+		return ret;
+
+	ret = mipi_dsi_attach(dsi);
+	if (ret < 0) {
+		drm_panel_remove(&acx->panel);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int acx424akp_remove(struct mipi_dsi_device *dsi)
+{
+	struct acx424akp *acx = mipi_dsi_get_drvdata(dsi);
+
+	mipi_dsi_detach(dsi);
+	drm_panel_remove(&acx->panel);
+
+	return 0;
+}
+
+static const struct of_device_id acx424akp_of_match[] = {
+	{ .compatible = "sony,acx424akp" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, acx424akp_of_match);
+
+static struct mipi_dsi_driver acx424akp_driver = {
+	.probe = acx424akp_probe,
+	.remove = acx424akp_remove,
+	.driver = {
+		.name = "panel-sony-acx424akp",
+		.of_match_table = acx424akp_of_match,
+	},
+};
+module_mipi_dsi_driver(acx424akp_driver);
+
+MODULE_AUTHOR("Linus Wallei <linus.walleij@linaro.org>");
+MODULE_DESCRIPTION("MIPI-DSI Sony acx424akp Panel Driver");
+MODULE_LICENSE("GPL v2");
-- 
2.23.0

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