[PATCH v2 0/4] arm: tegra: implement NVEC driver using tegra i2c.

[PATCH v2 0/4] arm: tegra: implement NVEC driver using tegra i2c.

[Andrey Danin]

NVEC driver contains code to manage tegra i2c controller in slave mode.
I2C slave support was implemented in linux kernel. The goal of this
patch serie is to implement I2C slave mode in tegra drived and rework
NVEC driver to use it.

Patches are based on i2c for-next.

Changes for v2:
- rebased on top of new i2c slave framework.
- old code is removed in separate patch
- documentation patch is integrated to main nvec patch


Thanks in advance

Andrey Danin (4):
  i2c: tegra: implement slave mode
  staging/nvec: reimplement on top of tegra i2c driver
  staging/nvec: remove old code
  dt: paz00: define nvec as child of i2c bus

 .../devicetree/bindings/nvec/nvidia,nvec.txt       |  21 +-
 arch/arm/boot/dts/tegra20-paz00.dts                |  22 +-
 drivers/i2c/busses/Kconfig                         |   1 +
 drivers/i2c/busses/i2c-tegra.c                     | 119 ++++++
 drivers/staging/nvec/nvec.c                        | 411 +++++++--------------
 drivers/staging/nvec/nvec.h                        |  10 -
 6 files changed, 269 insertions(+), 315 deletions(-)

-- 
1.9.1

[PATCH v2 1/4] i2c: tegra: implement slave mode

[Andrey Danin]

Initialization code is based on NVEC driver.

There is a HW bug in AP20 that was also mentioned in kernel sources
for Toshiba AC100.

Signed-off-by: Andrey Danin <danindrey@mail.ru>
---
Changes for v2:
- remove hack from tegra_i2c_clock_disable
- replace slave status helper functions with local variables
- add constant for default delay count value
- add 10-bit address support
- remove read_slave_start_delay init as zero
- don't reset controller during slave registration
- slave isr returns int instead of bool
- make status related variables in slave u32 instead of unsigned int
- enable i2c slave in Kconfig
- rebase on top of new i2c slave framework
- delay workaround was added from nvec

---
 drivers/i2c/busses/Kconfig     |   1 +
 drivers/i2c/busses/i2c-tegra.c | 119 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 120 insertions(+)

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index db09881..a2b259b 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -852,6 +852,7 @@ config I2C_SUN6I_P2WI
 config I2C_TEGRA
 	tristate "NVIDIA Tegra internal I2C controller"
 	depends on ARCH_TEGRA
+	select I2C_SLAVE
 	help
 	  If you say yes to this option, support will be included for the
 	  I2C controller embedded in NVIDIA Tegra SOCs
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 1bcd75e..e378827 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -42,8 +42,17 @@
 #define I2C_SL_CNFG				0x020
 #define I2C_SL_CNFG_NACK			(1<<1)
 #define I2C_SL_CNFG_NEWSL			(1<<2)
+#define I2C_SL_RCVD				0x024
+#define I2C_SL_STATUS				0x028
+#define I2C_SL_ST_IRQ				(1<<3)
+#define I2C_SL_ST_END_TRANS			(1<<4)
+#define I2C_SL_ST_RCVD				(1<<2)
+#define I2C_SL_ST_RNW				(1<<1)
 #define I2C_SL_ADDR1				0x02c
 #define I2C_SL_ADDR2				0x030
+#define I2C_SL_ADDR2_TEN_BIT_MODE		1
+#define I2C_SL_DELAY_COUNT			0x03c
+#define I2C_SL_DELAY_COUNT_DEFAULT		0x1E
 #define I2C_TX_FIFO				0x050
 #define I2C_RX_FIFO				0x054
 #define I2C_PACKET_TRANSFER_STATUS		0x058
@@ -125,6 +134,8 @@ enum msg_end_type {
  * @clk_divisor_std_fast_mode: Clock divisor in standard/fast mode. It is
  *		applicable if there is no fast clock source i.e. single clock
  *		source.
+ * @slave_read_start_delay: Workaround for AP20 I2C Slave Controller bug. Delay
+ *              before writing data byte into register I2C_SL_RCVD.
  */
 
 struct tegra_i2c_hw_feature {
@@ -133,6 +144,7 @@ struct tegra_i2c_hw_feature {
 	bool has_single_clk_source;
 	int clk_divisor_hs_mode;
 	int clk_divisor_std_fast_mode;
+	int slave_read_start_delay;
 };
 
 /**
@@ -173,6 +185,7 @@ struct tegra_i2c_dev {
 	int msg_read;
 	u32 bus_clk_rate;
 	bool is_suspended;
+	struct i2c_client *slave;
 };
 
 static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val, unsigned long reg)
@@ -461,12 +474,78 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 	return err;
 }
 
+static void tegra_i2c_slave_write(struct tegra_i2c_dev *i2c_dev, u32 val)
+{
+	i2c_writel(i2c_dev, val, I2C_SL_RCVD);
+
+	/*
+	 * TODO: A correct fix needs to be found for this.
+	 *
+	 * We experience less incomplete messages with this delay than without
+	 * it, but we don't know why. Help is appreciated.
+	 */
+	udelay(100);
+}
+
+static int tegra_i2c_slave_isr(int irq, struct tegra_i2c_dev *i2c_dev)
+{
+	u32 status;
+	u8 value;
+	u8 dummy;
+	u32 is_slave_irq, is_read, is_trans_start, is_trans_end;
+
+	if (!i2c_dev->slave || !i2c_dev->slave->slave_cb)
+		return -EINVAL;
+
+	status = i2c_readl(i2c_dev, I2C_SL_STATUS);
+
+	is_slave_irq = (status & I2C_SL_ST_IRQ);
+	is_read = (status & I2C_SL_ST_RNW);
+	is_trans_start = (status & I2C_SL_ST_RCVD);
+	is_trans_end = (status & I2C_SL_ST_END_TRANS);
+
+	if (!is_slave_irq)
+		return -EINVAL;
+
+	/* master sent stop */
+	if (is_trans_end) {
+		i2c_slave_event(i2c_dev->slave, I2C_SLAVE_STOP, &dummy);
+		if (!is_trans_start)
+			return 0;
+	}
+
+	if (is_read) {
+		/* i2c master reads data from us */
+		i2c_slave_event(i2c_dev->slave,
+				is_trans_start ? I2C_SLAVE_READ_REQUESTED
+					       : I2C_SLAVE_READ_PROCESSED,
+				&value);
+		if (is_trans_start && i2c_dev->hw->slave_read_start_delay)
+			udelay(i2c_dev->hw->slave_read_start_delay);
+		tegra_i2c_slave_write(i2c_dev, value);
+	} else {
+		/* i2c master sends data to us */
+		value = i2c_readl(i2c_dev, I2C_SL_RCVD);
+		if (is_trans_start)
+			tegra_i2c_slave_write(i2c_dev, 0);
+		i2c_slave_event(i2c_dev->slave,
+				is_trans_start ? I2C_SLAVE_WRITE_REQUESTED
+					       : I2C_SLAVE_WRITE_RECEIVED,
+				&value);
+	}
+
+	return 0;
+}
+
 static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 {
 	u32 status;
 	const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
 	struct tegra_i2c_dev *i2c_dev = dev_id;
 
+	if (!tegra_i2c_slave_isr(irq, i2c_dev))
+		return IRQ_HANDLED;
+
 	status = i2c_readl(i2c_dev, I2C_INT_STATUS);
 
 	if (status == 0) {
@@ -664,9 +743,48 @@ static u32 tegra_i2c_func(struct i2c_adapter *adap)
 	return ret;
 }
 
+static int tegra_reg_slave(struct i2c_client *slave)
+{
+	struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(slave->adapter);
+	int addr2 = 0;
+
+	if (i2c_dev->slave)
+		return -EBUSY;
+
+	i2c_dev->slave = slave;
+
+	tegra_i2c_clock_enable(i2c_dev);
+
+	i2c_writel(i2c_dev, I2C_SL_CNFG_NEWSL, I2C_SL_CNFG);
+	i2c_writel(i2c_dev, I2C_SL_DELAY_COUNT_DEFAULT, I2C_SL_DELAY_COUNT);
+
+	if (slave->addr > 0x7F)
+		addr2 = (slave->addr >> 7) | I2C_SL_ADDR2_TEN_BIT_MODE;
+
+	i2c_writel(i2c_dev, slave->addr, I2C_SL_ADDR1);
+	i2c_writel(i2c_dev, addr2, I2C_SL_ADDR2);
+
+	return 0;
+}
+
+static int tegra_unreg_slave(struct i2c_client *slave)
+{
+	struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(slave->adapter);
+
+	WARN_ON(!i2c_dev->slave);
+
+	i2c_writel(i2c_dev, 0, I2C_SL_CNFG);
+
+	i2c_dev->slave = NULL;
+
+	return 0;
+}
+
 static const struct i2c_algorithm tegra_i2c_algo = {
 	.master_xfer	= tegra_i2c_xfer,
 	.functionality	= tegra_i2c_func,
+	.reg_slave	= tegra_reg_slave,
+	.unreg_slave	= tegra_unreg_slave,
 };
 
 static const struct tegra_i2c_hw_feature tegra20_i2c_hw = {
@@ -675,6 +793,7 @@ static const struct tegra_i2c_hw_feature tegra20_i2c_hw = {
 	.has_single_clk_source = false,
 	.clk_divisor_hs_mode = 3,
 	.clk_divisor_std_fast_mode = 0,
+	.slave_read_start_delay = 8,
 };
 
 static const struct tegra_i2c_hw_feature tegra30_i2c_hw = {
-- 
1.9.1

[PATCH v2 2/4] staging/nvec: reimplement on top of tegra i2c driver

[Andrey Danin]

Remove i2c controller related code and use tegra i2c driver in slave mode.
Update nvec documentation.

Signed-off-by: Andrey Danin <danindrey@mail.ru>
---
Changes for v2:
- remove extra new line
- keep old functions to simplify review
- move nvec_state enum to nvec.c
- use nvec-slave instead of nvec in dts to keep ABI compatibility
- rebased on top of new i2c slave framework
- delay workaround moved to tegra-i2c
- documentation patch is integrated in this commit
- reverted a log message to minimize changes

---
 .../devicetree/bindings/nvec/nvidia,nvec.txt       |  21 +-
 drivers/staging/nvec/nvec.c                        | 258 +++++++++++++--------
 drivers/staging/nvec/nvec.h                        |  10 -
 3 files changed, 169 insertions(+), 120 deletions(-)

diff --git a/Documentation/devicetree/bindings/nvec/nvidia,nvec.txt b/Documentation/devicetree/bindings/nvec/nvidia,nvec.txt
index 5ae601e..aba34095 100644
--- a/Documentation/devicetree/bindings/nvec/nvidia,nvec.txt
+++ b/Documentation/devicetree/bindings/nvec/nvidia,nvec.txt
@@ -1,21 +1,6 @@
 NVIDIA compliant embedded controller
 
 Required properties:
-- compatible : should be "nvidia,nvec".
-- reg : the iomem of the i2c slave controller
-- interrupts : the interrupt line of the i2c slave controller
-- clock-frequency : the frequency of the i2c bus
-- gpios : the gpio used for ec request
-- slave-addr: the i2c address of the slave controller
-- clocks : Must contain an entry for each entry in clock-names.
-  See ../clocks/clock-bindings.txt for details.
-- clock-names : Must include the following entries:
-  Tegra20/Tegra30:
-  - div-clk
-  - fast-clk
-  Tegra114:
-  - div-clk
-- resets : Must contain an entry for each entry in reset-names.
-  See ../reset/reset.txt for details.
-- reset-names : Must include the following entries:
-  - i2c
+- compatible : should be "nvidia,nvec-slave".
+- reg: the i2c address of the slave controller
+- request-gpios : the gpio used for ec request
diff --git a/drivers/staging/nvec/nvec.c b/drivers/staging/nvec/nvec.c
index 5868ebb..f4c5527 100644
--- a/drivers/staging/nvec/nvec.c
+++ b/drivers/staging/nvec/nvec.c
@@ -25,8 +25,8 @@
 #include <linux/err.h>
 #include <linux/gpio.h>
 #include <linux/interrupt.h>
+#include <linux/i2c.h>
 #include <linux/io.h>
-#include <linux/irq.h>
 #include <linux/of.h>
 #include <linux/of_gpio.h>
 #include <linux/list.h>
@@ -39,25 +39,19 @@
 
 #include "nvec.h"
 
-#define I2C_CNFG			0x00
-#define I2C_CNFG_PACKET_MODE_EN		(1<<10)
-#define I2C_CNFG_NEW_MASTER_SFM		(1<<11)
-#define I2C_CNFG_DEBOUNCE_CNT_SHIFT	12
-
-#define I2C_SL_CNFG		0x20
-#define I2C_SL_NEWSL		(1<<2)
-#define I2C_SL_NACK		(1<<1)
-#define I2C_SL_RESP		(1<<0)
-#define I2C_SL_IRQ		(1<<3)
-#define END_TRANS		(1<<4)
-#define RCVD			(1<<2)
-#define RNW			(1<<1)
-
-#define I2C_SL_RCVD		0x24
-#define I2C_SL_STATUS		0x28
-#define I2C_SL_ADDR1		0x2c
-#define I2C_SL_ADDR2		0x30
-#define I2C_SL_DELAY_COUNT	0x3c
+
+#define I2C_SL_ST_END_TRANS			(1<<4)
+#define I2C_SL_ST_IRQ				(1<<3)
+#define I2C_SL_ST_RCVD				(1<<2)
+#define I2C_SL_ST_RNW				(1<<1)
+
+
+enum nvec_state {
+	ST_NONE,
+	ST_RX,
+	ST_TX,
+	ST_TRANS_START,
+};
 
 /**
  * enum nvec_msg_category - Message categories for nvec_msg_alloc()
@@ -479,7 +473,7 @@ static void nvec_tx_completed(struct nvec_chip *nvec)
 		nvec->tx->pos = 0;
 		nvec_gpio_set_value(nvec, 0);
 	} else {
-		nvec->state = 0;
+		nvec->state = ST_NONE;
 	}
 }
 
@@ -497,7 +491,7 @@ static void nvec_rx_completed(struct nvec_chip *nvec)
 			   (uint) nvec->rx->pos);
 
 		nvec_msg_free(nvec, nvec->rx);
-		nvec->state = 0;
+		nvec->state = ST_NONE;
 
 		/* Battery quirk - Often incomplete, and likes to crash */
 		if (nvec->rx->data[0] == NVEC_BAT)
@@ -514,7 +508,7 @@ static void nvec_rx_completed(struct nvec_chip *nvec)
 
 	spin_unlock(&nvec->rx_lock);
 
-	nvec->state = 0;
+	nvec->state = ST_NONE;
 
 	if (!nvec_msg_is_event(nvec->rx))
 		complete(&nvec->ec_transfer);
@@ -522,6 +516,7 @@ static void nvec_rx_completed(struct nvec_chip *nvec)
 	schedule_work(&nvec->rx_work);
 }
 
+#if 0
 /**
  * nvec_invalid_flags - Send an error message about invalid flags and jump
  * @nvec: The nvec device
@@ -536,6 +531,7 @@ static void nvec_invalid_flags(struct nvec_chip *nvec, unsigned int status,
 	if (reset)
 		nvec->state = 0;
 }
+#endif /* FIXME: remove old code */
 
 /**
  * nvec_tx_set - Set the message to transfer (nvec->tx)
@@ -566,6 +562,8 @@ static void nvec_tx_set(struct nvec_chip *nvec)
 		(uint)nvec->tx->size, nvec->tx->data[1]);
 }
 
+
+#if 0
 /**
  * nvec_interrupt - Interrupt handler
  * @irq: The IRQ
@@ -755,6 +753,115 @@ static void nvec_disable_i2c_slave(struct nvec_chip *nvec)
 	clk_disable_unprepare(nvec->i2c_clk);
 }
 #endif
+#endif /* FIXME: remove old code. */
+
+
+/**
+ * nvec_slave_cb - I2C slave callback
+ *
+ * This callback fills our RX buffers and empties our TX
+ * buffers. This uses a finite state machine.
+ */
+static int nvec_slave_cb(struct i2c_client *client,
+		enum i2c_slave_event event, u8 *val)
+{
+	struct nvec_chip *nvec = i2c_get_clientdata(client);
+
+	switch (event) {
+	case I2C_SLAVE_WRITE_REQUESTED:
+		/* Alloc new msg only if prev transaction finished */
+		if (nvec->state == ST_NONE)
+			nvec->rx = nvec_msg_alloc(nvec, NVEC_MSG_RX);
+
+		/* Should not happen in a normal world */
+		if (unlikely(nvec->rx == NULL)) {
+			nvec->state = ST_NONE;
+			return -1;
+		}
+		nvec->rx->pos = 0;
+
+		if (client->addr != ((*val) >> 1)) {
+			dev_err(&client->dev,
+				"received address 0x%02x, expected 0x%02x\n",
+				((*val) >> 1), client->addr);
+			return -1;
+		}
+		nvec->state = ST_TRANS_START;
+		break;
+
+	case I2C_SLAVE_WRITE_RECEIVED:
+		if (nvec->state != ST_TRANS_START &&
+		    nvec->state != ST_RX) {
+			dev_err(&client->dev,
+				"unexpected write: state %d\n",
+				nvec->state);
+			return -1;
+		}
+		if (nvec->rx->pos >= NVEC_MSG_SIZE) {
+			dev_err(&client->dev,
+				"write buffer overflow: state %d\n",
+				nvec->state);
+			return -1;
+		}
+		nvec->rx->data[nvec->rx->pos++] = *val;
+		nvec->state = ST_RX;
+		break;
+
+	case I2C_SLAVE_READ_REQUESTED:
+		if (nvec->state != ST_RX) {
+			dev_err(&client->dev,
+				"unexpected read request: state %d\n",
+				nvec->state);
+			return -1;
+		}
+		nvec_msg_free(nvec, nvec->rx);
+		nvec_tx_set(nvec);
+		/* Should not happen in a normal world */
+		if (!nvec->tx) {
+			dev_err(&client->dev,
+				"can't alloc tx msg: state %d\n",
+				nvec->state);
+			return -1;
+		}
+		nvec_gpio_set_value(nvec, 1);
+		/* fallthrough */
+	case I2C_SLAVE_READ_PROCESSED:
+		if (nvec->state != ST_RX &&
+		    nvec->state != ST_TX) {
+			dev_err(&client->dev,
+				"unexpected read: state %d\n",
+				nvec->state);
+			return -1;
+		}
+
+		if (!nvec->tx || nvec->tx->pos >= nvec->tx->size) {
+			dev_err(nvec->dev,
+				"tx buffer underflow on %p (%u > %u)\n",
+				nvec->tx,
+				(uint) (nvec->tx ? nvec->tx->pos : 0),
+				(uint) (nvec->tx ? nvec->tx->size : 0));
+			nvec->state = ST_NONE;
+			break;
+		}
+
+		nvec->state = ST_TX;
+		*val = nvec->tx->data[nvec->tx->pos++];
+		break;
+
+	case I2C_SLAVE_STOP:
+		if (nvec->state == ST_TX)
+			nvec_tx_completed(nvec);
+		else if (nvec->state == ST_RX)
+			nvec_rx_completed(nvec);
+		nvec->state = ST_NONE;
+		break;
+
+	default:
+		return 0;
+	}
+
+	return 0;
+}
 
 static void nvec_power_off(void)
 {
@@ -767,7 +874,7 @@ static void nvec_power_off(void)
 /*
  *  Parse common device tree data
  */
-static int nvec_i2c_parse_dt_pdata(struct nvec_chip *nvec)
+static int nvec_i2c_parse_dt(struct nvec_chip *nvec)
 {
 	nvec->gpio = of_get_named_gpio(nvec->dev->of_node, "request-gpios", 0);
 
@@ -776,68 +883,39 @@ static int nvec_i2c_parse_dt_pdata(struct nvec_chip *nvec)
 		return -ENODEV;
 	}
 
-	if (of_property_read_u32(nvec->dev->of_node, "slave-addr",
-				&nvec->i2c_addr)) {
-		dev_err(nvec->dev, "no i2c address specified");
-		return -ENODEV;
-	}
-
 	return 0;
 }
 
-static int tegra_nvec_probe(struct platform_device *pdev)
+static int nvec_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
-	int err, ret;
-	struct clk *i2c_clk;
+	int ret;
 	struct nvec_chip *nvec;
 	struct nvec_msg *msg;
-	struct resource *res;
-	void __iomem *base;
-	char	get_firmware_version[] = { NVEC_CNTL, GET_FIRMWARE_VERSION },
+	char    get_firmware_version[] = { NVEC_CNTL, GET_FIRMWARE_VERSION },
 		unmute_speakers[] = { NVEC_OEM0, 0x10, 0x59, 0x95 },
 		enable_event[7] = { NVEC_SYS, CNF_EVENT_REPORTING, true };
 
-	if (!pdev->dev.of_node) {
-		dev_err(&pdev->dev, "must be instantiated using device tree\n");
+
+	if (!client->dev.of_node) {
+		dev_err(&client->dev, "must be instantiated using device tree\n");
 		return -ENODEV;
 	}
 
-	nvec = devm_kzalloc(&pdev->dev, sizeof(struct nvec_chip), GFP_KERNEL);
+	nvec = devm_kzalloc(&client->dev, sizeof(struct nvec_chip), GFP_KERNEL);
 	if (nvec == NULL)
 		return -ENOMEM;
 
-	platform_set_drvdata(pdev, nvec);
-	nvec->dev = &pdev->dev;
+	nvec->dev = &client->dev;
+	ret = nvec_i2c_parse_dt(nvec);
+	if (ret < 0)
+		return ret;
 
-	err = nvec_i2c_parse_dt_pdata(nvec);
-	if (err < 0)
-		return err;
+	i2c_set_clientdata(client, nvec);
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	base = devm_ioremap_resource(&pdev->dev, res);
-	if (IS_ERR(base))
-		return PTR_ERR(base);
+	ret = i2c_slave_register(client, nvec_slave_cb);
+	if (ret < 0)
+		return ret;
 
-	nvec->irq = platform_get_irq(pdev, 0);
-	if (nvec->irq < 0) {
-		dev_err(&pdev->dev, "no irq resource?\n");
-		return -ENODEV;
-	}
-
-	i2c_clk = devm_clk_get(&pdev->dev, "div-clk");
-	if (IS_ERR(i2c_clk)) {
-		dev_err(nvec->dev, "failed to get controller clock\n");
-		return -ENODEV;
-	}
-
-	nvec->rst = devm_reset_control_get(&pdev->dev, "i2c");
-	if (IS_ERR(nvec->rst)) {
-		dev_err(nvec->dev, "failed to get controller reset\n");
-		return PTR_ERR(nvec->rst);
-	}
-
-	nvec->base = base;
-	nvec->i2c_clk = i2c_clk;
 	nvec->rx = &nvec->msg_pool[0];
 
 	ATOMIC_INIT_NOTIFIER_HEAD(&nvec->notifier_list);
@@ -852,23 +930,14 @@ static int tegra_nvec_probe(struct platform_device *pdev)
 	INIT_WORK(&nvec->rx_work, nvec_dispatch);
 	INIT_WORK(&nvec->tx_work, nvec_request_master);
 
-	err = devm_gpio_request_one(&pdev->dev, nvec->gpio, GPIOF_OUT_INIT_HIGH,
-					"nvec gpio");
-	if (err < 0) {
+	ret = devm_gpio_request_one(&client->dev, nvec->gpio,
+			GPIOF_OUT_INIT_HIGH,
+			"nvec gpio");
+	if (ret < 0) {
 		dev_err(nvec->dev, "couldn't request gpio\n");
 		return -ENODEV;
 	}
 
-	err = devm_request_irq(&pdev->dev, nvec->irq, nvec_interrupt, 0,
-				"nvec", nvec);
-	if (err) {
-		dev_err(nvec->dev, "couldn't request irq\n");
-		return -ENODEV;
-	}
-	disable_irq(nvec->irq);
-
-	tegra_init_i2c_slave(nvec);
-
 	/* enable event reporting */
 	nvec_toggle_global_events(nvec, true);
 
@@ -907,9 +976,10 @@ static int tegra_nvec_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static int tegra_nvec_remove(struct platform_device *pdev)
+
+static int nvec_remove(struct i2c_client *client)
 {
-	struct nvec_chip *nvec = platform_get_drvdata(pdev);
+	struct nvec_chip *nvec = i2c_get_clientdata(client);
 
 	nvec_toggle_global_events(nvec, false);
 	mfd_remove_devices(nvec->dev);
@@ -938,8 +1008,6 @@ static int nvec_suspend(struct device *dev)
 	msg = nvec_write_sync(nvec, ap_suspend, sizeof(ap_suspend));
 	nvec_msg_free(nvec, msg);
 
-	nvec_disable_i2c_slave(nvec);
-
 	return 0;
 }
 
@@ -949,7 +1017,6 @@ static int nvec_resume(struct device *dev)
 	struct nvec_chip *nvec = platform_get_drvdata(pdev);
 
 	dev_dbg(nvec->dev, "resuming\n");
-	tegra_init_i2c_slave(nvec);
 	nvec_toggle_global_events(nvec, true);
 
 	return 0;
@@ -960,14 +1027,21 @@ static SIMPLE_DEV_PM_OPS(nvec_pm_ops, nvec_suspend, nvec_resume);
 
 /* Match table for of_platform binding */
 static const struct of_device_id nvidia_nvec_of_match[] = {
-	{ .compatible = "nvidia,nvec", },
+	{ .compatible = "nvidia,nvec-slave", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, nvidia_nvec_of_match);
 
-static struct platform_driver nvec_device_driver = {
-	.probe   = tegra_nvec_probe,
-	.remove  = tegra_nvec_remove,
+static const struct i2c_device_id nvidia_nvec_i2c_table[] = {
+	{ "nvec-slave", 0 },
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, nvidia_nvec_i2c_table);
+
+static struct i2c_driver i2c_nvec_device_driver = {
+	.probe   = nvec_probe,
+	.remove  = nvec_remove,
+	.id_table = nvidia_nvec_i2c_table,
 	.driver  = {
 		.name = "nvec",
 		.pm = &nvec_pm_ops,
@@ -975,9 +1049,9 @@ static struct platform_driver nvec_device_driver = {
 	}
 };
 
-module_platform_driver(nvec_device_driver);
+module_i2c_driver(i2c_nvec_device_driver);
 
-MODULE_ALIAS("platform:nvec");
+MODULE_ALIAS("i2c:nvec");
 MODULE_DESCRIPTION("NVIDIA compliant embedded controller interface");
 MODULE_AUTHOR("Marc Dietrich <marvin24@gmx.de>");
 MODULE_LICENSE("GPL");
diff --git a/drivers/staging/nvec/nvec.h b/drivers/staging/nvec/nvec.h
index e271375..ad6a556 100644
--- a/drivers/staging/nvec/nvec.h
+++ b/drivers/staging/nvec/nvec.h
@@ -107,11 +107,6 @@ struct nvec_msg {
  * struct nvec_chip - A single connection to an NVIDIA Embedded controller
  * @dev: The device
  * @gpio: The same as for &struct nvec_platform_data
- * @irq: The IRQ of the I2C device
- * @i2c_addr: The address of the I2C slave
- * @base: The base of the memory mapped region of the I2C device
- * @i2c_clk: The clock of the I2C device
- * @rst: The reset of the I2C device
  * @notifier_list: Notifiers to be called on received messages, see
  *                 nvec_register_notifier()
  * @rx_data: Received messages that have to be processed
@@ -137,11 +132,6 @@ struct nvec_msg {
 struct nvec_chip {
 	struct device *dev;
 	int gpio;
-	int irq;
-	int i2c_addr;
-	void __iomem *base;
-	struct clk *i2c_clk;
-	struct reset_control *rst;
 	struct atomic_notifier_head notifier_list;
 	struct list_head rx_data, tx_data;
 	struct notifier_block nvec_status_notifier;
-- 
1.9.1

[PATCH v2 3/4] staging/nvec: remove old code

[Andrey Danin]

Signed-off-by: Andrey Danin <danindrey@mail.ru>
---
Changes for v2:
- it is initial verion

---
 drivers/staging/nvec/nvec.c | 211 --------------------------------------------
 1 file changed, 211 deletions(-)

diff --git a/drivers/staging/nvec/nvec.c b/drivers/staging/nvec/nvec.c
index f4c5527..f39f516 100644
--- a/drivers/staging/nvec/nvec.c
+++ b/drivers/staging/nvec/nvec.c
@@ -516,23 +516,6 @@ static void nvec_rx_completed(struct nvec_chip *nvec)
 	schedule_work(&nvec->rx_work);
 }
 
-#if 0
-/**
- * nvec_invalid_flags - Send an error message about invalid flags and jump
- * @nvec: The nvec device
- * @status: The status flags
- * @reset: Whether we shall jump to state 0.
- */
-static void nvec_invalid_flags(struct nvec_chip *nvec, unsigned int status,
-			       bool reset)
-{
-	dev_err(nvec->dev, "unexpected status flags 0x%02x during state %i\n",
-		status, nvec->state);
-	if (reset)
-		nvec->state = 0;
-}
-#endif /* FIXME: remove old code */
-
 /**
  * nvec_tx_set - Set the message to transfer (nvec->tx)
  * @nvec: A &struct nvec_chip
@@ -562,200 +545,6 @@ static void nvec_tx_set(struct nvec_chip *nvec)
 		(uint)nvec->tx->size, nvec->tx->data[1]);
 }
 
-
-#if 0
-/**
- * nvec_interrupt - Interrupt handler
- * @irq: The IRQ
- * @dev: The nvec device
- *
- * Interrupt handler that fills our RX buffers and empties our TX
- * buffers. This uses a finite state machine with ridiculous amounts
- * of error checking, in order to be fairly reliable.
- */
-static irqreturn_t nvec_interrupt(int irq, void *dev)
-{
-	unsigned long status;
-	unsigned int received = 0;
-	unsigned char to_send = 0xff;
-	const unsigned long irq_mask = I2C_SL_IRQ | END_TRANS | RCVD | RNW;
-	struct nvec_chip *nvec = dev;
-	unsigned int state = nvec->state;
-
-	status = readl(nvec->base + I2C_SL_STATUS);
-
-	/* Filter out some errors */
-	if ((status & irq_mask) == 0 && (status & ~irq_mask) != 0) {
-		dev_err(nvec->dev, "unexpected irq mask %lx\n", status);
-		return IRQ_HANDLED;
-	}
-	if ((status & I2C_SL_IRQ) == 0) {
-		dev_err(nvec->dev, "Spurious IRQ\n");
-		return IRQ_HANDLED;
-	}
-
-	/* The EC did not request a read, so it send us something, read it */
-	if ((status & RNW) == 0) {
-		received = readl(nvec->base + I2C_SL_RCVD);
-		if (status & RCVD)
-			writel(0, nvec->base + I2C_SL_RCVD);
-	}
-
-	if (status == (I2C_SL_IRQ | RCVD))
-		nvec->state = 0;
-
-	switch (nvec->state) {
-	case 0:		/* Verify that its a transfer start, the rest later */
-		if (status != (I2C_SL_IRQ | RCVD))
-			nvec_invalid_flags(nvec, status, false);
-		break;
-	case 1:		/* command byte */
-		if (status != I2C_SL_IRQ) {
-			nvec_invalid_flags(nvec, status, true);
-		} else {
-			nvec->rx = nvec_msg_alloc(nvec, NVEC_MSG_RX);
-			/* Should not happen in a normal world */
-			if (unlikely(nvec->rx == NULL)) {
-				nvec->state = 0;
-				break;
-			}
-			nvec->rx->data[0] = received;
-			nvec->rx->pos = 1;
-			nvec->state = 2;
-		}
-		break;
-	case 2:		/* first byte after command */
-		if (status == (I2C_SL_IRQ | RNW | RCVD)) {
-			udelay(33);
-			if (nvec->rx->data[0] != 0x01) {
-				dev_err(nvec->dev,
-					"Read without prior read command\n");
-				nvec->state = 0;
-				break;
-			}
-			nvec_msg_free(nvec, nvec->rx);
-			nvec->state = 3;
-			nvec_tx_set(nvec);
-			BUG_ON(nvec->tx->size < 1);
-			to_send = nvec->tx->data[0];
-			nvec->tx->pos = 1;
-		} else if (status == (I2C_SL_IRQ)) {
-			BUG_ON(nvec->rx == NULL);
-			nvec->rx->data[1] = received;
-			nvec->rx->pos = 2;
-			nvec->state = 4;
-		} else {
-			nvec_invalid_flags(nvec, status, true);
-		}
-		break;
-	case 3:		/* EC does a block read, we transmit data */
-		if (status & END_TRANS) {
-			nvec_tx_completed(nvec);
-		} else if ((status & RNW) == 0 || (status & RCVD)) {
-			nvec_invalid_flags(nvec, status, true);
-		} else if (nvec->tx && nvec->tx->pos < nvec->tx->size) {
-			to_send = nvec->tx->data[nvec->tx->pos++];
-		} else {
-			dev_err(nvec->dev, "tx buffer underflow on %p (%u > %u)\n",
-				nvec->tx,
-				(uint) (nvec->tx ? nvec->tx->pos : 0),
-				(uint) (nvec->tx ? nvec->tx->size : 0));
-			nvec->state = 0;
-		}
-		break;
-	case 4:		/* EC does some write, we read the data */
-		if ((status & (END_TRANS | RNW)) == END_TRANS)
-			nvec_rx_completed(nvec);
-		else if (status & (RNW | RCVD))
-			nvec_invalid_flags(nvec, status, true);
-		else if (nvec->rx && nvec->rx->pos < NVEC_MSG_SIZE)
-			nvec->rx->data[nvec->rx->pos++] = received;
-		else
-			dev_err(nvec->dev,
-				"RX buffer overflow on %p: Trying to write byte %u of %u\n",
-				nvec->rx, nvec->rx ? nvec->rx->pos : 0,
-				NVEC_MSG_SIZE);
-		break;
-	default:
-		nvec->state = 0;
-	}
-
-	/* If we are told that a new transfer starts, verify it */
-	if ((status & (RCVD | RNW)) == RCVD) {
-		if (received != nvec->i2c_addr)
-			dev_err(nvec->dev,
-			"received address 0x%02x, expected 0x%02x\n",
-			received, nvec->i2c_addr);
-		nvec->state = 1;
-	}
-
-	/* Send data if requested, but not on end of transmission */
-	if ((status & (RNW | END_TRANS)) == RNW)
-		writel(to_send, nvec->base + I2C_SL_RCVD);
-
-	/* If we have send the first byte */
-	if (status == (I2C_SL_IRQ | RNW | RCVD))
-		nvec_gpio_set_value(nvec, 1);
-
-	dev_dbg(nvec->dev,
-		"Handled: %s 0x%02x, %s 0x%02x in state %u [%s%s%s]\n",
-		(status & RNW) == 0 ? "received" : "R=",
-		received,
-		(status & (RNW | END_TRANS)) ? "sent" : "S=",
-		to_send,
-		state,
-		status & END_TRANS ? " END_TRANS" : "",
-		status & RCVD ? " RCVD" : "",
-		status & RNW ? " RNW" : "");
-
-
-	/*
-	 * TODO: A correct fix needs to be found for this.
-	 *
-	 * We experience less incomplete messages with this delay than without
-	 * it, but we don't know why. Help is appreciated.
-	 */
-	udelay(100);
-
-	return IRQ_HANDLED;
-}
-
-static void tegra_init_i2c_slave(struct nvec_chip *nvec)
-{
-	u32 val;
-
-	clk_prepare_enable(nvec->i2c_clk);
-
-	reset_control_assert(nvec->rst);
-	udelay(2);
-	reset_control_deassert(nvec->rst);
-
-	val = I2C_CNFG_NEW_MASTER_SFM | I2C_CNFG_PACKET_MODE_EN |
-	    (0x2 << I2C_CNFG_DEBOUNCE_CNT_SHIFT);
-	writel(val, nvec->base + I2C_CNFG);
-
-	clk_set_rate(nvec->i2c_clk, 8 * 80000);
-
-	writel(I2C_SL_NEWSL, nvec->base + I2C_SL_CNFG);
-	writel(0x1E, nvec->base + I2C_SL_DELAY_COUNT);
-
-	writel(nvec->i2c_addr>>1, nvec->base + I2C_SL_ADDR1);
-	writel(0, nvec->base + I2C_SL_ADDR2);
-
-	enable_irq(nvec->irq);
-}
-
-#ifdef CONFIG_PM_SLEEP
-static void nvec_disable_i2c_slave(struct nvec_chip *nvec)
-{
-	disable_irq(nvec->irq);
-	writel(I2C_SL_NEWSL | I2C_SL_NACK, nvec->base + I2C_SL_CNFG);
-	clk_disable_unprepare(nvec->i2c_clk);
-}
-#endif
-#endif /* FIXME: remove old code. */
-
-
 /**
  * nvec_slave_cb - I2C slave callback
  *
-- 
1.9.1

[PATCH v2 4/4] dt: paz00: define nvec as child of i2c bus

[Andrey Danin]

NVEC driver was reimplemented to use tegra i2c. Use common i2c bindings
for NVEC node.

Signed-off-by: Andrey Danin <danindrey@mail.ru>
---
Changes for v2:
- swap reg and request-gpios properties
- use nvec-slave instead of nvec to keep ABI compatibility
- place doc in separate patch

---
 arch/arm/boot/dts/tegra20-paz00.dts | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/arch/arm/boot/dts/tegra20-paz00.dts b/arch/arm/boot/dts/tegra20-paz00.dts
index ed7e100..cd5e6ef 100644
--- a/arch/arm/boot/dts/tegra20-paz00.dts
+++ b/arch/arm/boot/dts/tegra20-paz00.dts
@@ -288,20 +288,16 @@
 		clock-frequency = <100000>;
 	};
 
-	nvec@7000c500 {
-		compatible = "nvidia,nvec";
-		reg = <0x7000c500 0x100>;
-		interrupts = <GIC_SPI 92 IRQ_TYPE_LEVEL_HIGH>;
-		#address-cells = <1>;
-		#size-cells = <0>;
+	i2c@7000c500 {
+		status = "okay";
 		clock-frequency = <80000>;
-		request-gpios = <&gpio TEGRA_GPIO(V, 2) GPIO_ACTIVE_HIGH>;
-		slave-addr = <138>;
-		clocks = <&tegra_car TEGRA20_CLK_I2C3>,
-		         <&tegra_car TEGRA20_CLK_PLL_P_OUT3>;
-		clock-names = "div-clk", "fast-clk";
-		resets = <&tegra_car 67>;
-		reset-names = "i2c";
+
+		nvec: nvec@45 {
+			compatible = "nvidia,nvec-slave";
+			reg = <0x45>;
+			request-gpios = <&gpio TEGRA_GPIO(V, 2)
+				GPIO_ACTIVE_HIGH>;
+		};
 	};
 
 	i2c@7000d000 {
-- 
1.9.1

Re: [PATCH v2 1/4] i2c: tegra: implement slave mode

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 988 bytes --]

> +static void tegra_i2c_slave_write(struct tegra_i2c_dev *i2c_dev, u32 val)
> +{
> +	i2c_writel(i2c_dev, val, I2C_SL_RCVD);
> +
> +	/*
> +	 * TODO: A correct fix needs to be found for this.
> +	 *
> +	 * We experience less incomplete messages with this delay than without
> +	 * it, but we don't know why. Help is appreciated.
> +	 */

Uh oh. So I assume this is another reason for staging?

> +	if (!i2c_dev->slave || !i2c_dev->slave->slave_cb)
> +		return -EINVAL;

The core checks for slave_cb being valid.

> +		i2c_slave_event(i2c_dev->slave, I2C_SLAVE_STOP, &dummy);

You could use value here, too, or?

> +	if (!tegra_i2c_slave_isr(irq, i2c_dev))
> +		return IRQ_HANDLED;

Minor nit: I'd prefer == 0 here, since it reads "if not slave_isr return
handled".

> +	if (slave->addr > 0x7F)
> +		addr2 = (slave->addr >> 7) | I2C_SL_ADDR2_TEN_BIT_MODE;

Nope. There are 10 bit encodings of addresses 0x000-0x07f, too. So, you
need to check for the flag (slave->flags & I2C_CLIENT_TEN).


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Re: [PATCH v2 0/4] arm: tegra: implement NVEC driver using tegra i2c.

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 465 bytes --]

On Mon, Mar 30, 2015 at 11:00:11PM +0300, Andrey Danin wrote:
> NVEC driver contains code to manage tegra i2c controller in slave mode.
> I2C slave support was implemented in linux kernel. The goal of this
> patch serie is to implement I2C slave mode in tegra drived and rework
> NVEC driver to use it.

Thanks. Looks pretty good already. If being I2C slave was the reason for
this driver being in staging, we soon need to think of a proper place
outside staging.


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Re: [PATCH v2 2/4] staging/nvec: reimplement on top of tegra i2c driver

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 1802 bytes --]

> +/**
> + * nvec_slave_cb - I2C slave callback
> + *
> + * This callback fills our RX buffers and empties our TX
> + * buffers. This uses a finite state machine.
> + */
> +static int nvec_slave_cb(struct i2c_client *client,
> +		enum i2c_slave_event event, u8 *val)
> +{
> +	struct nvec_chip *nvec = i2c_get_clientdata(client);
> +
> +	switch (event) {
> +	case I2C_SLAVE_WRITE_REQUESTED:
> +		/* Alloc new msg only if prev transaction finished */
> +		if (nvec->state == ST_NONE)
> +			nvec->rx = nvec_msg_alloc(nvec, NVEC_MSG_RX);
> +
> +		/* Should not happen in a normal world */
> +		if (unlikely(nvec->rx == NULL)) {
> +			nvec->state = ST_NONE;
> +			return -1;
> +		}
> +		nvec->rx->pos = 0;
> +
> +		if (client->addr != ((*val) >> 1)) {

Uh, I2C_SLAVE_WRITE_REQUESTED should not use val.

> +			dev_err(&client->dev,
> +				"received address 0x%02x, expected 0x%02x\n",
> +				((*val) >> 1), client->addr);
> +			return -1;
> +		}
> +		nvec->state = ST_TRANS_START;
> +		break;
> +
...

> +	case I2C_SLAVE_READ_PROCESSED:
> +		if (nvec->state != ST_RX &&
> +		    nvec->state != ST_TX) {
> +			dev_err(&client->dev,
> +				"unexpected read: state %d\n",
> +				nvec->state);
> +			return -1;
> +		}
> +
> +		if (!nvec->tx || nvec->tx->pos >= nvec->tx->size) {
> +			dev_err(nvec->dev,
> +				"tx buffer underflow on %p (%u > %u)\n",
> +				nvec->tx,
> +				(uint) (nvec->tx ? nvec->tx->pos : 0),
> +				(uint) (nvec->tx ? nvec->tx->size : 0));
> +			nvec->state = ST_NONE;
> +			break;
> +		}
> +
> +		nvec->state = ST_TX;
> +		*val = nvec->tx->data[nvec->tx->pos++];

Are you sure you want to increase the pointer here? Remember that this
byte is requested but might not be sent out if the remote master stops
the transfer after the previous byte using NACK instead of ACK.

> +		break;
> +

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Re: [PATCH v2 1/4] i2c: tegra: implement slave mode

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 1325 bytes --]

On Fri, Apr 03, 2015 at 09:46:26PM +0200, Wolfram Sang wrote:
> > +static void tegra_i2c_slave_write(struct tegra_i2c_dev *i2c_dev, u32 val)
> > +{
> > +	i2c_writel(i2c_dev, val, I2C_SL_RCVD);
> > +
> > +	/*
> > +	 * TODO: A correct fix needs to be found for this.
> > +	 *
> > +	 * We experience less incomplete messages with this delay than without
> > +	 * it, but we don't know why. Help is appreciated.
> > +	 */
> 
> Uh oh. So I assume this is another reason for staging?

I think we can live with this upstream, no need for staging.

> > +	if (!i2c_dev->slave || !i2c_dev->slave->slave_cb)
> > +		return -EINVAL;
> 
> The core checks for slave_cb being valid.
> 
> > +		i2c_slave_event(i2c_dev->slave, I2C_SLAVE_STOP, &dummy);
> 
> You could use value here, too, or?
> 
> > +	if (!tegra_i2c_slave_isr(irq, i2c_dev))
> > +		return IRQ_HANDLED;
> 
> Minor nit: I'd prefer == 0 here, since it reads "if not slave_isr return
> handled".
> 
> > +	if (slave->addr > 0x7F)
> > +		addr2 = (slave->addr >> 7) | I2C_SL_ADDR2_TEN_BIT_MODE;
> 
> Nope. There are 10 bit encodings of addresses 0x000-0x07f, too. So, you
> need to check for the flag (slave->flags & I2C_CLIENT_TEN).

If you'd fix up these and resend, I'll happily include this patch for 4.3
already.

Thanks,

   Wolfram


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