Re: [PATCH v3 3/8] media: i2c: ov5670: Probe clocks with OF

[Sakari Ailus <sakari.ailus@iki.fi>]

Hi Jacopo,

On Tue, Mar 29, 2022 at 11:01:28AM +0200, Jacopo Mondi wrote:
> Add support for probing the main system clock using the common clock
> framework and its OF bindings.
> 
> Maintain ACPI compatibility by falling back to parse 'clock-frequency'.
> 
> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
> ---
>  drivers/media/i2c/ov5670.c | 22 ++++++++++++++++++----
>  1 file changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov5670.c b/drivers/media/i2c/ov5670.c
> index 721441024598..1cc312981c82 100644
> --- a/drivers/media/i2c/ov5670.c
> +++ b/drivers/media/i2c/ov5670.c
> @@ -2,6 +2,7 @@
>  // Copyright (c) 2017 Intel Corporation.
>  
>  #include <linux/acpi.h>
> +#include <linux/clk.h>
>  #include <linux/i2c.h>
>  #include <linux/mod_devicetable.h>
>  #include <linux/module.h>
> @@ -2475,13 +2476,10 @@ static int ov5670_probe(struct i2c_client *client)
>  	struct ov5670 *ov5670;
>  	const char *err_msg;
>  	u32 input_clk = 0;
> +	struct clk *clk;
>  	bool full_power;
>  	int ret;
>  
> -	device_property_read_u32(&client->dev, "clock-frequency", &input_clk);
> -	if (input_clk != 19200000)
> -		return -EINVAL;
> -
>  	ov5670 = devm_kzalloc(&client->dev, sizeof(*ov5670), GFP_KERNEL);
>  	if (!ov5670) {
>  		ret = -ENOMEM;
> @@ -2489,6 +2487,22 @@ static int ov5670_probe(struct i2c_client *client)
>  		goto error_print;
>  	}
>  
> +	/* OF uses the common clock framework, ACPI uses "clock-frequency". */
> +	if (is_of_node(dev_fwnode(&client->dev))) {
> +		clk = devm_clk_get(&client->dev, NULL);
> +		if (IS_ERR(clk))
> +			return dev_err_probe(&client->dev, PTR_ERR(clk),
> +					     "error getting clock\n");
> +
> +		input_clk = clk_get_rate(clk);
> +	} else {
> +		device_property_read_u32(&client->dev, "clock-frequency",
> +					 &input_clk);
> +	}
> +
> +	if (input_clk != 19200000)
> +		return -EINVAL;

You could tell what that wrong frequency is. Up to you.

> +
>  	/* Initialize subdev */
>  	v4l2_i2c_subdev_init(&ov5670->sd, client, &ov5670_subdev_ops);
>  

-- 
Regards,

Sakari Ailus