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

[Hugues FRUCHET]

Hi Sakari, thks for review.

On 07/09/2017 01:06 AM, Sakari Ailus wrote:
> Hi Hugues,
> 
> On Mon, Jul 03, 2017 at 11:16:04AM +0200, 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);
> 
> gpiod_set_value_cansleep() can manage with NULL gpio parameter, no need to
> check it.

done

> 
>>   }
>>   
>>   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);
> 
> DRIVER_NAME is different from "OV965X". Is this an intended change?

Yes it was to unify namings around a single DRIVER_NAME definition.

> 
>> +		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;
> 
> It'd be nice to declare this next to pdata, rather than after ret and other
> short declarations.

done

> 
>>   
>> -	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);
>> +
>> +	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");
> 
> mutex_destroy() should called on an initialised mutex if probe is going to
> fail. It's certainly not a problem introduced by this patch, but it'd be
> nice to fix that (in a separate patch) now that it's found. The same goes
> for remove below.

Will do.

> 
>> +			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");
>> +			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),
>>   	},
>>   	.probe		= ov965x_probe,
>>   	.remove		= ov965x_remove,
>