[PATCH v2 09/12] clk: boston: Allow to get regmap from parent device

[Jonas Karlman]

Hi Jiaxun,

On 2024-05-16 13:40, Jiaxun Yang wrote:
> In upstream devicetree, clk_boston is a child of syscon node
> and there is no "regmap" property for clk_boston node.
> 
> Try to check parent device first to look for syscon.
> 
> Signed-off-by: Jiaxun Yang <jiaxun.yang at flygoat.com>
> ---
> v2: Move syscon_get_regmap to probe
> ---
>  drivers/clk/clk_boston.c | 37 +++++++++++++++++++++++++------------
>  1 file changed, 25 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/clk/clk_boston.c b/drivers/clk/clk_boston.c
> index 030ff7cc58ec..1985bb0ec334 100644
> --- a/drivers/clk/clk_boston.c
> +++ b/drivers/clk/clk_boston.c
> @@ -12,6 +12,7 @@
>  #include <linux/printk.h>
>  
>  struct clk_boston {
> +	struct udevice *syscon;
>  	struct regmap *regmap;
>  };
>  
> @@ -58,23 +59,33 @@ const struct clk_ops clk_boston_ops = {
>  	.get_rate = clk_boston_get_rate,
>  };
>  
> -static int clk_boston_of_to_plat(struct udevice *dev)
> +static int clk_boston_probe(struct udevice *dev)
>  {
>  	struct clk_boston *state = dev_get_plat(dev);
> -	struct udevice *syscon;
> -	int err;
>  
> -	err = uclass_get_device_by_phandle(UCLASS_SYSCON, dev,
> -					   "regmap", &syscon);
> -	if (err) {
> -		pr_err("unable to find syscon device\n");
> -		return err;
> +	state->regmap = syscon_get_regmap(state->syscon);
> +	if (IS_ERR(state->regmap)) {
> +		pr_err("unable to find regmap\n");
> +		return PTR_ERR(state->regmap);
>  	}
>  
> -	state->regmap = syscon_get_regmap(syscon);
> -	if (!state->regmap) {
> -		pr_err("unable to find regmap\n");
> -		return -ENODEV;
> +	return 0;
> +}
> +
> +static int clk_boston_of_to_plat(struct udevice *dev)
> +{
> +	struct clk_boston *state = dev_get_plat(dev);
> +	int err;
> +
> +	if (dev->parent && device_get_uclass_id(dev->parent) == UCLASS_SYSCON) {
> +		state->syscon = dev->parent;
> +	} else {
> +		err = uclass_get_device_by_phandle(UCLASS_SYSCON, dev,
> +						   "regmap", &state->syscon);

This will trigger a probe of the referenced regmap phandle. To simplify
and avoid probing devices at of_to_plat() stage, you can probably just
rename of_to_plat() to probe() and skip of_to_plat() stage completely.

Regards,
Jonas

> +		if (err) {
> +			pr_err("unable to find syscon device\n");
> +			return err;
> +		}
>  	}
>  
>  	return 0;
> @@ -92,6 +103,8 @@ U_BOOT_DRIVER(clk_boston) = {
>  	.id = UCLASS_CLK,
>  	.of_match = clk_boston_match,
>  	.of_to_plat = clk_boston_of_to_plat,
> +	.probe = clk_boston_probe,
>  	.plat_auto	= sizeof(struct clk_boston),
>  	.ops = &clk_boston_ops,
> +	.flags = DM_FLAG_PRE_RELOC,
>  };
>