Re: [PATCH v2 3/7] [media] ov9650: add device tree support

From: Sylwester Nawrocki
Date: Wed Jul 12 2017 - 15:33:24 EST

On 07/03/2017 11:16 AM, Hugues Fruchet wrote:
> Allows use of device tree configuration data.
> If no device tree data is there, configuration is taken from platform data.
> In order to keep GPIOs configuration compatible between both way of doing,
> GPIOs are switched to descriptor-based interface.
>
> Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
> Signed-off-by: Hugues Fruchet <hugues.fruchet@xxxxxx>
> ---
> drivers/media/i2c/Kconfig | 2 +-
> drivers/media/i2c/ov9650.c | 77 ++++++++++++++++++++++++++++++++++------------
> 2 files changed, 59 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 121b3b5..168115c 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -615,7 +615,7 @@ config VIDEO_OV7670
>
> config VIDEO_OV9650
> tristate "OmniVision OV9650/OV9652 sensor support"
> - depends on I2C && VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
> + depends on GPIOLIB && I2C && VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
> ---help---
> This is a V4L2 sensor-level driver for the Omnivision
> OV9650 and OV9652 camera sensors.
> diff --git a/drivers/media/i2c/ov9650.c b/drivers/media/i2c/ov9650.c
> index 1e4e99e..7e9a902 100644
> --- a/drivers/media/i2c/ov9650.c
> +++ b/drivers/media/i2c/ov9650.c
> @@ -11,12 +11,14 @@
> * it under the terms of the GNU General Public License version 2 as
> * published by the Free Software Foundation.
> */
> +#include <linux/clk.h>
> #include <linux/delay.h>
> #include <linux/gpio.h>
> #include <linux/i2c.h>
> #include <linux/kernel.h>
> #include <linux/media.h>
> #include <linux/module.h>
> +#include <linux/of_gpio.h>
> #include <linux/ratelimit.h>
> #include <linux/slab.h>
> #include <linux/string.h>
> @@ -249,9 +251,10 @@ struct ov965x {
> struct v4l2_subdev sd;
> struct media_pad pad;
> enum v4l2_mbus_type bus_type;
> - int gpios[NUM_GPIOS];
> + struct gpio_desc *gpios[NUM_GPIOS];
> /* External master clock frequency */
> unsigned long mclk_frequency;
> + struct clk *clk;
>
> /* Protects the struct fields below */
> struct mutex lock;
> @@ -511,10 +514,10 @@ static int ov965x_set_color_matrix(struct ov965x *ov965x)
> return 0;
> }
>
> -static void ov965x_gpio_set(int gpio, int val)
> +static void ov965x_gpio_set(struct gpio_desc *gpio, int val)
> {
> - if (gpio_is_valid(gpio))
> - gpio_set_value(gpio, val);
> + if (gpio)
> + gpiod_set_value_cansleep(gpio, val);
> }
>
> static void __ov965x_set_power(struct ov965x *ov965x, int on)
> @@ -1406,24 +1409,28 @@ static int ov965x_configure_gpios(struct ov965x *ov965x,
> const struct ov9650_platform_data *pdata)
> {
> int ret, i;
> + int gpios[NUM_GPIOS];
>
> - ov965x->gpios[GPIO_PWDN] = pdata->gpio_pwdn;
> - ov965x->gpios[GPIO_RST] = pdata->gpio_reset;
> + gpios[GPIO_PWDN] = pdata->gpio_pwdn;
> + gpios[GPIO_RST] = pdata->gpio_reset;
>
> - for (i = 0; i < ARRAY_SIZE(ov965x->gpios); i++) {
> - int gpio = ov965x->gpios[i];
> + for (i = 0; i < ARRAY_SIZE(gpios); i++) {
> + int gpio = gpios[i];
>
> if (!gpio_is_valid(gpio))
> continue;
> ret = devm_gpio_request_one(&ov965x->client->dev, gpio,
> - GPIOF_OUT_INIT_HIGH, "OV965X");
> - if (ret < 0)
> + GPIOF_OUT_INIT_HIGH, DRIVER_NAME);
> + if (ret < 0) {
> + dev_err(&ov965x->client->dev,
> + "Failed to request gpio%d (%d)\n", gpio, ret);
> return ret;
> + }
> v4l2_dbg(1, debug, &ov965x->sd, "set gpio %d to 1\n", gpio);
>
> gpio_set_value(gpio, 1);
> gpio_export(gpio, 0);
> - ov965x->gpios[i] = gpio;
> + ov965x->gpios[i] = gpio_to_desc(gpio);
> }
>
> return 0;
> @@ -1469,14 +1476,10 @@ static int ov965x_probe(struct i2c_client *client,
> struct v4l2_subdev *sd;
> struct ov965x *ov965x;
> int ret;
> + struct device_node *np = client->dev.of_node;
>
> - if (pdata == NULL) {
> - dev_err(&client->dev, "platform data not specified\n");
> - return -EINVAL;
> - }
> -
> - if (pdata->mclk_frequency == 0) {
> - dev_err(&client->dev, "MCLK frequency not specified\n");
> + if (!pdata && !np) {
> + dev_err(&client->dev, "Platform data or device tree data must be provided\n");
> return -EINVAL;
> }
>
> @@ -1486,7 +1489,35 @@ static int ov965x_probe(struct i2c_client *client,
>
> mutex_init(&ov965x->lock);
> ov965x->client = client;
> - ov965x->mclk_frequency = pdata->mclk_frequency;
> + mutex_init(&ov965x->lock);

Are you initializing the mutex twice?

> + if (np) {
> + /* Device tree */
> + ov965x->gpios[GPIO_RST] =
> + devm_gpiod_get_optional(&client->dev, "resetb",
> + GPIOD_OUT_LOW);
> + ov965x->gpios[GPIO_PWDN] =
> + devm_gpiod_get_optional(&client->dev, "pwdn",
> + GPIOD_OUT_HIGH);
> +
> + ov965x->clk = devm_clk_get(&client->dev, NULL);
> + if (IS_ERR(ov965x->clk)) {
> + dev_err(&client->dev, "Could not get clock\n");
> + return PTR_ERR(ov965x->clk);
> + }
> + ov965x->mclk_frequency = clk_get_rate(ov965x->clk);
> + } else {
> + /* Platform data */
> + ret = ov965x_configure_gpios(ov965x, pdata);
> + if (ret < 0)
> + return ret;
> +
> + if (pdata->mclk_frequency == 0) {
> + dev_err(&client->dev, "MCLK frequency is mandatory\n");

I think the original message ("MCLK frequency not specified\n") was more
helpful.

Why you don't need this check in DT case? The clock is defined as mandatory
in the DT binding.

> + return -EINVAL;
> + }
> + ov965x->mclk_frequency = pdata->mclk_frequency;
> + }
>
> sd = &ov965x->sd;
> v4l2_i2c_subdev_init(sd, client, &ov965x_subdev_ops);
> @@ -1551,9 +1582,17 @@ static int ov965x_remove(struct i2c_client *client)
> };
> MODULE_DEVICE_TABLE(i2c, ov965x_id);
>
> +static const struct of_device_id ov965x_of_match[] = {
> + { .compatible = "ovti,ov9650", },
> + { .compatible = "ovti,ov9652", },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, ov965x_of_match);
> +
> static struct i2c_driver ov965x_i2c_driver = {
> .driver = {
> .name = DRIVER_NAME,
> + .of_match_table = of_match_ptr(ov965x_of_match),

You don't need of_match_ptr() as ov965x_of_match table is always built in.

> },

Otherwise looks good.