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

Signed-off-by: Andrey Danin <danind...@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 <marvi...@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

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