Re: [PATCH 3/3] media: i2c: gc0310: Use devm_v4l2_sensor_clk_get()

[Hans de Goede]

Hi,

On 1-Apr-26 20:16, Sanjay Chitroda wrote:
> From: Sanjay Chitroda <sanjayembeddedse@xxxxxxxxx>
> 
> Several camera sensor drivers access the "clock-frequency" property
> directly to retrieve the external clock rate or handle the external
> clock manually in the driver. While this is valid on a subset of ACPI
> platforms, implementing this logic directly in drivers is deprecated
> and can lead to inconsistent behaviour across drivers.
> 
> This driver supports ACPI platforms only. It currently retrieves the
> external clock rate from the "clock-frequency" property and fails
> probing if the rate does not match the expected value, which is the
> correct policy for ACPI platforms.
> 
> Switch to using the devm_v4l2_sensor_clk_get() helper to standardise
> clock handling. This preserves the existing behaviour on ACPI
> platforms that specify a clock-frequency property without providing
> a clock. On platforms that provide a clock, the helper will program
> the clock to the rate specified by clock-frequency, which is also
> consistent with the driver's expectations.
> 
> Signed-off-by: Sanjay Chitroda <sanjayembeddedse@xxxxxxxxx>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <johannes.goede@xxxxxxxxxxxxxxxx>

Regards,

Hans



> ---
>  drivers/media/i2c/gc0310.c | 29 +++++++++++++----------------
>  1 file changed, 13 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/media/i2c/gc0310.c b/drivers/media/i2c/gc0310.c
> index e538479fee2e..e9e67bd73f51 100644
> --- a/drivers/media/i2c/gc0310.c
> +++ b/drivers/media/i2c/gc0310.c
> @@ -6,6 +6,7 @@
>   * Copyright (c) 2023-2025 Hans de Goede <hansg@xxxxxxxxxx>
>   */
>  
> +#include <linux/clk.h>
>  #include <linux/delay.h>
>  #include <linux/errno.h>
>  #include <linux/gpio/consumer.h>
> @@ -84,6 +85,7 @@
>  #define to_gc0310_sensor(x) container_of(x, struct gc0310_device, sd)
>  
>  struct gc0310_device {
> +	struct clk *clk;
>  	struct device *dev;
>  	struct i2c_client *client;
>  
> @@ -634,7 +636,6 @@ static int gc0310_check_hwcfg(struct device *dev)
>  	};
>  	struct fwnode_handle *ep_fwnode;
>  	unsigned long link_freq_bitmap;
> -	u32 mclk;
>  	int ret;
>  
>  	/*
> @@ -646,21 +647,6 @@ static int gc0310_check_hwcfg(struct device *dev)
>  		return dev_err_probe(dev, -EPROBE_DEFER,
>  				     "waiting for fwnode graph endpoint\n");
>  
> -	ret = fwnode_property_read_u32(dev_fwnode(dev), "clock-frequency",
> -				       &mclk);
> -	if (ret) {
> -		fwnode_handle_put(ep_fwnode);
> -		return dev_err_probe(dev, ret,
> -				     "reading clock-frequency property\n");
> -	}
> -
> -	if (mclk != GC0310_MCLK_FREQ) {
> -		fwnode_handle_put(ep_fwnode);
> -		return dev_err_probe(dev, -EINVAL,
> -				     "external clock %u is not supported\n",
> -				     mclk);
> -	}
> -
>  	ret = v4l2_fwnode_endpoint_alloc_parse(ep_fwnode, &bus_cfg);
>  	fwnode_handle_put(ep_fwnode);
>  	if (ret)
> @@ -684,6 +670,7 @@ static int gc0310_check_hwcfg(struct device *dev)
>  static int gc0310_probe(struct i2c_client *client)
>  {
>  	struct gc0310_device *sensor;
> +	unsigned long freq;
>  	int ret;
>  
>  	ret = gc0310_check_hwcfg(&client->dev);
> @@ -697,6 +684,16 @@ static int gc0310_probe(struct i2c_client *client)
>  	sensor->client = client;
>  	sensor->dev = &client->dev;
>  
> +	sensor->clk = devm_v4l2_sensor_clk_get(sensor->dev, NULL);
> +	if (IS_ERR(sensor->clk))
> +		return dev_err_probe(sensor->dev, PTR_ERR(sensor->clk),
> +				     "failed to get clock\n");
> +
> +	freq = clk_get_rate(sensor->clk);
> +	if (freq != GC0310_MCLK_FREQ)
> +		return dev_err_probe(sensor->dev, -EINVAL,
> +				     "external clock %lu is not supported\n", freq);
> +
>  	sensor->reset = devm_gpiod_get(sensor->dev, "reset", GPIOD_OUT_HIGH);
>  	if (IS_ERR(sensor->reset)) {
>  		return dev_err_probe(sensor->dev, PTR_ERR(sensor->reset),