diff mbox

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

Message ID 1427745615-5428-3-git-send-email-danindrey@mail.ru
State Superseded, archived
Headers show

Commit Message

Andrey Danin March 30, 2015, 8 p.m. UTC
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(-)

Comments

Wolfram Sang April 3, 2015, 7:57 p.m. UTC | #1
> +/**
> + * 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;
> +
diff mbox

Patch

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;