[PATCH 2/3] staging/nvec: reimplement on top of tegra i2c driver

From: Andrey Danin
Date: Thu Jan 29 2015 - 02:22:58 EST

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

Signed-off-by: Andrey Danin <danindrey@xxxxxxx>
---
drivers/staging/nvec/nvec.c | 379 ++++++++++++++------------------------------
drivers/staging/nvec/nvec.h | 17 +-
2 files changed, 122 insertions(+), 274 deletions(-)

diff --git a/drivers/staging/nvec/nvec.c b/drivers/staging/nvec/nvec.c
index 120b70d..d645c58 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 +39,12 @@

#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_msg_category - Message categories for nvec_msg_alloc()
@@ -327,6 +314,7 @@ struct nvec_msg *nvec_write_sync(struct nvec_chip *nvec,

mutex_unlock(&nvec->sync_write_mutex);

+
return msg;
}
EXPORT_SYMBOL(nvec_write_sync);
@@ -475,11 +463,13 @@ static void nvec_tx_completed(struct nvec_chip *nvec)
{
/* We got an END_TRANS, let's skip this, maybe there's an event */
if (nvec->tx->pos != nvec->tx->size) {
- dev_err(nvec->dev, "premature END_TRANS, resending\n");
+ dev_err(nvec->dev, "premature END_TRANS, resending: pos:%u, size:%u\n",
+ nvec->tx->pos, nvec->tx->size);
nvec->tx->pos = 0;
nvec_gpio_set_value(nvec, 0);
} else {
- nvec->state = 0;
+ nvec->state = ST_NONE;
+ nvec->tx->pos = 0;
}
}

@@ -497,7 +487,7 @@ 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 +504,7 @@ 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);
@@ -523,21 +513,6 @@ static void nvec_rx_completed(struct nvec_chip *nvec)
}

/**
- * 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;
-}
-
-/**
* nvec_tx_set - Set the message to transfer (nvec->tx)
* @nvec: A &struct nvec_chip
*
@@ -566,150 +541,85 @@ static void nvec_tx_set(struct nvec_chip *nvec)
(uint)nvec->tx->size, nvec->tx->data[1]);
}

+
/**
- * nvec_interrupt - Interrupt handler
- * @irq: The IRQ
- * @dev: The nvec device
+ * nvec_slave_cb - I2C slave callback
*
- * 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.
+ * This callback fills our RX buffers and empties our TX
+ * buffers. This uses a finite state machine.
*/
-static irqreturn_t nvec_interrupt(int irq, void *dev)
+static int nvec_slave_cb(struct i2c_client *client,
+ enum i2c_slave_event event, u8 *val)
{
- 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);
- }
+ struct nvec_chip *nvec = i2c_get_clientdata(client);

- 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 {
+ switch (event) {
+ case I2C_SLAVE_REQ_WRITE_END:
+ 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 = 0;
- break;
+ nvec->state = ST_NONE;
+ return -1;
}
- nvec->rx->data[0] = received;
- nvec->rx->pos = 1;
- nvec->state = 2;
+ 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);
+ }
+ nvec->state = ST_TRANS_START;
+ nvec->rx->pos = 0;
+ break;
}
+
+ nvec->rx->data[nvec->rx->pos++] = *val;
+ nvec->state = ST_RX;
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;
- }
+
+ case I2C_SLAVE_REQ_READ_START:
+ if (nvec->state == ST_NONE) {
+ dev_err(&client->dev,
+ "unexpected read without transaction start, state %d\n",
+ nvec->state);
+ return -1;
+ }
+
+ if (nvec->state == ST_RX) {
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 {
+
+ 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 = 0;
+ nvec->state = ST_NONE;
+ break;
}
- 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);
+ nvec->state = ST_TX;
+ *val = nvec->tx->data[nvec->tx->pos];
+ break;

- /* If we have send the first byte */
- if (status == (I2C_SL_IRQ | RNW | RCVD))
+ case I2C_SLAVE_REQ_READ_END:
+ nvec->tx->pos++;
nvec_gpio_set_value(nvec, 1);
+ break;

- 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" : "");
+ 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;
+ }

/*
* TODO: A correct fix needs to be found for this.
@@ -717,44 +627,18 @@ static irqreturn_t nvec_interrupt(int irq, void *dev)
* 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);
-}
+ switch (event) {
+ case I2C_SLAVE_REQ_WRITE_END:
+ case I2C_SLAVE_REQ_READ_END:
+ case I2C_SLAVE_STOP:
+ udelay(100);
+ break;
+ default:
+ break;
+ }

-#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);
+ return 0;
}
-#endif

static void nvec_power_off(void)
{
@@ -767,7 +651,7 @@ 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 +660,39 @@ 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);
-
- 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);
- }
+ ret = i2c_slave_register(client, nvec_slave_cb);
+ if (ret < 0)
+ return ret;

- nvec->base = base;
- nvec->i2c_clk = i2c_clk;
nvec->rx = &nvec->msg_pool[0];

ATOMIC_INIT_NOTIFIER_HEAD(&nvec->notifier_list);
@@ -852,23 +707,14 @@ 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);

@@ -907,12 +753,13 @@ 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);
+ /* TODO: mfd_remove_devices(nvec->dev); ??? */
nvec_unregister_notifier(nvec, &nvec->nvec_status_notifier);
cancel_work_sync(&nvec->rx_work);
cancel_work_sync(&nvec->tx_work);
@@ -938,8 +785,6 @@ 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 +794,6 @@ 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;
@@ -965,9 +809,16 @@ static const struct of_device_id nvidia_nvec_of_match[] = {
};
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", 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 +826,9 @@ 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@xxxxxx>");
MODULE_LICENSE("GPL");
diff --git a/drivers/staging/nvec/nvec.h b/drivers/staging/nvec/nvec.h
index e271375..5e7e17c 100644
--- a/drivers/staging/nvec/nvec.h
+++ b/drivers/staging/nvec/nvec.h
@@ -56,6 +56,13 @@ enum nvec_event_size {
NVEC_VAR_SIZE,
};

+enum nvec_state {
+ ST_NONE,
+ ST_RX,
+ ST_TX,
+ ST_TRANS_START,
+};
+
/**
* enum nvec_msg_type - The type of a message
* @NVEC_SYS: A system request/response
@@ -107,11 +114,6 @@ 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 +139,6 @@ 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

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