some i2c hid devices have reset gpio, need to control
it in the driver.

Signed-off-by: Lin Huang <h...@rock-chips.com>
---
Changes in v2:
- Add 10us in usleep_range() upper range
- reuse post_power_delay_ms as deassert reset delay
- delete deassert_reset_us property

 drivers/hid/i2c-hid/i2c-hid.c         | 61 +++++++++++++++++++++++++++--------
 include/linux/platform_data/i2c-hid.h |  3 ++
 2 files changed, 50 insertions(+), 14 deletions(-)

diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index 9145c21..9f06135 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -38,6 +38,7 @@
 #include <linux/mutex.h>
 #include <linux/acpi.h>
 #include <linux/of.h>
+#include <linux/gpio/consumer.h>
 #include <linux/regulator/consumer.h>
 
 #include <linux/platform_data/i2c-hid.h>
@@ -793,6 +794,35 @@ struct hid_ll_driver i2c_hid_ll_driver = {
 };
 EXPORT_SYMBOL_GPL(i2c_hid_ll_driver);
 
+static int i2c_hid_hw_power_on(struct i2c_hid *ihid)
+{
+       int ret;
+
+       ret = regulator_enable(ihid->pdata.supply);
+       if (ret < 0)
+               return ret;
+
+       gpiod_set_value_cansleep(ihid->pdata.reset_gpio, 1);
+       if (ihid->pdata.assert_reset_us)
+               usleep_range(ihid->pdata.assert_reset_us,
+                            ihid->pdata.assert_reset_us + 10);
+
+       gpiod_set_value_cansleep(ihid->pdata.reset_gpio, 0);
+
+       /* use for power supply delay or reset deassert delay */
+       if (ihid->pdata.post_power_delay_ms)
+               msleep(ihid->pdata.post_power_delay_ms);
+
+       return ret;
+}
+
+static int i2c_hid_hw_power_off(struct i2c_hid *ihid)
+{
+       gpiod_set_value_cansleep(ihid->pdata.reset_gpio, 1);
+
+       return regulator_disable(ihid->pdata.supply);
+}
+
 static int i2c_hid_init_irq(struct i2c_client *client)
 {
        struct i2c_hid *ihid = i2c_get_clientdata(client);
@@ -934,6 +964,9 @@ static int i2c_hid_of_probe(struct i2c_client *client,
        if (!ret)
                pdata->post_power_delay_ms = val;
 
+       of_property_read_u32(dev->of_node, "assert-reset-us",
+                            &pdata->assert_reset_us);
+
        return 0;
 }
 
@@ -1002,14 +1035,16 @@ static int i2c_hid_probe(struct i2c_client *client,
                goto err;
        }
 
-       ret = regulator_enable(ihid->pdata.supply);
+       ihid->pdata.reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
+                                                        GPIOD_OUT_HIGH);
+       if (IS_ERR(ihid->pdata.reset_gpio))
+               goto err;
+
+       ret = i2c_hid_hw_power_on(ihid);
        if (ret < 0) {
-               dev_err(&client->dev, "Failed to enable regulator: %d\n",
-                       ret);
+               dev_err(&client->dev, "Failed to power on: %d\n", ret);
                goto err;
        }
-       if (ihid->pdata.post_power_delay_ms)
-               msleep(ihid->pdata.post_power_delay_ms);
 
        i2c_set_clientdata(client, ihid);
 
@@ -1086,7 +1121,7 @@ static int i2c_hid_probe(struct i2c_client *client,
        pm_runtime_disable(&client->dev);
 
 err_regulator:
-       regulator_disable(ihid->pdata.supply);
+       i2c_hid_hw_power_off(ihid);
 
 err:
        i2c_hid_free_buffers(ihid);
@@ -1112,8 +1147,7 @@ static int i2c_hid_remove(struct i2c_client *client)
        if (ihid->bufsize)
                i2c_hid_free_buffers(ihid);
 
-       regulator_disable(ihid->pdata.supply);
-
+       i2c_hid_hw_power_off(ihid);
        kfree(ihid);
 
        return 0;
@@ -1165,9 +1199,10 @@ static int i2c_hid_suspend(struct device *dev)
                        hid_warn(hid, "Failed to enable irq wake: %d\n",
                                wake_status);
        } else {
-               ret = regulator_disable(ihid->pdata.supply);
+               ret = i2c_hid_hw_power_off(ihid);
                if (ret < 0)
-                       hid_warn(hid, "Failed to disable supply: %d\n", ret);
+                       hid_warn(hid, "Failed to disable hw power: %d\n",
+                                ret);
        }
 
        return 0;
@@ -1182,11 +1217,9 @@ static int i2c_hid_resume(struct device *dev)
        int wake_status;
 
        if (!device_may_wakeup(&client->dev)) {
-               ret = regulator_enable(ihid->pdata.supply);
+               ret = i2c_hid_hw_power_on(ihid);
                if (ret < 0)
-                       hid_warn(hid, "Failed to enable supply: %d\n", ret);
-               if (ihid->pdata.post_power_delay_ms)
-                       msleep(ihid->pdata.post_power_delay_ms);
+                       hid_warn(hid, "Failed to enable hw power: %d\n", ret);
        } else if (ihid->irq_wake_enabled) {
                wake_status = disable_irq_wake(client->irq);
                if (!wake_status)
diff --git a/include/linux/platform_data/i2c-hid.h 
b/include/linux/platform_data/i2c-hid.h
index 1fb0882..40f1840 100644
--- a/include/linux/platform_data/i2c-hid.h
+++ b/include/linux/platform_data/i2c-hid.h
@@ -14,6 +14,7 @@
 
 #include <linux/types.h>
 
+struct gpio_desc;
 struct regulator;
 
 /**
@@ -37,6 +38,8 @@ struct i2c_hid_platform_data {
        u16 hid_descriptor_address;
        struct regulator *supply;
        int post_power_delay_ms;
+       struct gpio_desc *reset_gpio;
+       int assert_reset_us;
 };
 
 #endif /* __LINUX_I2C_HID_H */
-- 
2.7.4

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