media: hi556: Add support for external clock

On some ACPI platforms, such as Chromebooks the ACPI methods to
change the power-state (_PS0 and _PS3) fully take care of powering
on/off the sensor.

On other ACPI platforms, such as e.g. various HP models with IPU6 +
hi556 sensor, the sensor driver must control the sensor's clock itself.

Add support for having the driver control an optional clock.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

diff --git a/drivers/media/i2c/hi556.c b/drivers/media/i2c/hi556.c
index e084f7888e29af39b039f5b2ed3cc51ef2e25a5d..235caadf02dc784acaf1f4d8f8bcd0182e54a844 100644 (file)
--- a/drivers/media/i2c/hi556.c
+++ b/drivers/media/i2c/hi556.c
@@ -3,6 +3,7 @@
 
 #include <asm/unaligned.h>
 #include <linux/acpi.h>
+#include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
@@ -636,6 +637,7 @@ struct hi556 {
 
        /* GPIOs, clocks, etc. */
        struct gpio_desc *reset_gpio;
+       struct clk *clk;
 
        /* Current mode */
        const struct hi556_mode *cur_mode;
@@ -1286,6 +1288,7 @@ static int hi556_suspend(struct device *dev)
        struct hi556 *hi556 = to_hi556(sd);
 
        gpiod_set_value_cansleep(hi556->reset_gpio, 1);
+       clk_disable_unprepare(hi556->clk);
        return 0;
 }
 
@@ -1293,6 +1296,11 @@ static int hi556_resume(struct device *dev)
 {
        struct v4l2_subdev *sd = dev_get_drvdata(dev);
        struct hi556 *hi556 = to_hi556(sd);
+       int ret;
+
+       ret = clk_prepare_enable(hi556->clk);
+       if (ret)
+               return ret;
 
        gpiod_set_value_cansleep(hi556->reset_gpio, 0);
        usleep_range(5000, 5500);
@@ -1324,6 +1332,11 @@ static int hi556_probe(struct i2c_client *client)
                return dev_err_probe(&client->dev, PTR_ERR(hi556->reset_gpio),
                                     "failed to get reset GPIO\n");
 
+       hi556->clk = devm_clk_get_optional(&client->dev, "clk");
+       if (IS_ERR(hi556->clk))
+               return dev_err_probe(&client->dev, PTR_ERR(hi556->clk),
+                                    "failed to get clock\n");
+
        full_power = acpi_dev_state_d0(&client->dev);
        if (full_power) {
                /* Ensure non ACPI managed resources are enabled */