Re: [PATCH 2/2] media: ov2740: Add support for external clock

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 11/20/23 17:32, Sakari Ailus wrote:
> Hi Hans,
> 
> On Mon, Nov 20, 2023 at 11:00:14AM +0100, Hans de Goede wrote:
>> Hi Bingbu,
>>
>> On 11/20/23 05:06, Bingbu Cao wrote:
>>>
>>> Hans,
>>>
>>> On 11/15/23 8:38 PM, Hans de Goede wrote:
>>>> 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 ThinkPad models with
>>>> IPU6 + ov2740 sensor, the sensor driver must control the reset GPIO
>>>> and the sensor's clock itself.
>>>>
>>>> Add support for having the driver control an optional clock.
>>>>
>>>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>>>> ---
>>>>  drivers/media/i2c/ov2740.c | 12 ++++++++++++
>>>>  1 file changed, 12 insertions(+)
>>>>
>>>> diff --git a/drivers/media/i2c/ov2740.c b/drivers/media/i2c/ov2740.c
>>>> index e5f9569a229d..0a87d0920eb8 100644
>>>> --- a/drivers/media/i2c/ov2740.c
>>>> +++ b/drivers/media/i2c/ov2740.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>
>>>> @@ -336,6 +337,7 @@ struct ov2740 {
>>>>  
>>>>  	/* GPIOs, clocks */
>>>>  	struct gpio_desc *reset_gpio;
>>>> +	struct clk *clk;
>>>>  
>>>>  	/* Current mode */
>>>>  	const struct ov2740_mode *cur_mode;
>>>> @@ -1068,6 +1070,7 @@ static int ov2740_suspend(struct device *dev)
>>>>  	struct ov2740 *ov2740 = to_ov2740(sd);
>>>>  
>>>>  	gpiod_set_value_cansleep(ov2740->reset_gpio, 1);
>>>> +	clk_disable_unprepare(ov2740->clk);
>>>>  	return 0;
>>>>  }
>>>>  
>>>> @@ -1075,6 +1078,11 @@ static int ov2740_resume(struct device *dev)
>>>>  {
>>>>  	struct v4l2_subdev *sd = dev_get_drvdata(dev);
>>>>  	struct ov2740 *ov2740 = to_ov2740(sd);
>>>> +	int ret;
>>>> +
>>>> +	ret = clk_prepare_enable(ov2740->clk);
>>>> +	if (ret)
>>>> +		return ret;
>>>>  
>>>>  	gpiod_set_value_cansleep(ov2740->reset_gpio, 0);
>>>>  	msleep(20);
>>>> @@ -1102,6 +1110,10 @@ static int ov2740_probe(struct i2c_client *client)
>>>>  		return dev_err_probe(dev, PTR_ERR(ov2740->reset_gpio),
>>>>  				     "failed to get reset GPIO\n");
>>>>  
>>>> +	ov2740->clk = devm_clk_get_optional(dev, "clk");
>>>> +	if (IS_ERR(ov2740->clk))
>>>> +		return dev_err_probe(dev, PTR_ERR(ov2740->clk), "failed to get clock\n");
>>>> +
>>>
>>> I am not very sure that the 80-char rule is still valid for checkpatch.pl.
>>
>> checkpatch.pl defaults to allowing longer lines (<100 chars) now,
>> but you are right that the linux-media maintainers prefer 80.
>>
>> Still there is an exception to not split strings running
>> over the limit and this line ends with a string,
>> so I think that this is fine.
> 
> The rule is not to split strings in order to satisfy alignment rules. IOW
> the line should be wrapped before the string. :-)

Ok, will fix for v2.

Regards,

Hans