Re: [PATCH v4 2/2] clk: scmi: add set/get_parent support

[Cristian Marussi <cristian.marussi@arm.com>]

On Tue, Oct 03, 2023 at 07:48:49PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> SCMI v3.2 adds set/get parent clock commands, so update the clk driver
> to support them.
> 

Hi,

in general LGTM, BUT I have just spotted one more *bad* thing that have to be
fixe down below which I have missed previously, my bad.

> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>  drivers/clk/clk-scmi.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 57 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
> index 2e1337b511eb..e7a27fda561b 100644
> --- a/drivers/clk/clk-scmi.c
> +++ b/drivers/clk/clk-scmi.c
> @@ -24,6 +24,7 @@ struct scmi_clk {
>  	struct clk_hw hw;
>  	const struct scmi_clock_info *info;
>  	const struct scmi_protocol_handle *ph;
> +	struct clk_parent_data *parent_data;
>  };
>  
>  #define to_scmi_clk(clk) container_of(clk, struct scmi_clk, hw)
> @@ -78,6 +79,43 @@ static int scmi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
>  	return scmi_proto_clk_ops->rate_set(clk->ph, clk->id, rate);
>  }
>  
> +static int scmi_clk_set_parent(struct clk_hw *hw, u8 parent_index)
> +{
> +	struct scmi_clk *clk = to_scmi_clk(hw);
> +
> +	return scmi_proto_clk_ops->parent_set(clk->ph, clk->id, parent_index);
> +}
> +
> +static u8 scmi_clk_get_parent(struct clk_hw *hw)
> +{
> +	struct scmi_clk *clk = to_scmi_clk(hw);
> +	u32 parent_id, p_idx;
> +	int ret;
> +
> +	ret = scmi_proto_clk_ops->parent_get(clk->ph, clk->id, &parent_id);
> +	if (ret)
> +		return 0;
> +
> +	for (p_idx = 0; p_idx < clk->info->num_parents; p_idx++) {
> +		if (clk->parent_data[p_idx].index == parent_id)
> +			break;
> +	}
> +
> +	if (p_idx == clk->info->num_parents)
> +		return 0;
> +
> +	return p_idx;
> +}
> +
> +static int scmi_clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
> +{
> +	/*
> +	 * Suppose all the requested rates are supported, and let firmware
> +	 * to handle the left work.
> +	 */
> +	return 0;
> +}
> +
>  static int scmi_clk_enable(struct clk_hw *hw)
>  {
>  	struct scmi_clk *clk = to_scmi_clk(hw);
> @@ -139,6 +177,9 @@ static const struct clk_ops scmi_clk_ops = {
>  	.set_rate = scmi_clk_set_rate,
>  	.prepare = scmi_clk_enable,
>  	.unprepare = scmi_clk_disable,
> +	.set_parent = scmi_clk_set_parent,
> +	.get_parent = scmi_clk_get_parent,
> +	.determine_rate = scmi_clk_determine_rate,
>  };
>  
>  static const struct clk_ops scmi_atomic_clk_ops = {
> @@ -148,6 +189,9 @@ static const struct clk_ops scmi_atomic_clk_ops = {
>  	.enable = scmi_clk_atomic_enable,
>  	.disable = scmi_clk_atomic_disable,
>  	.is_enabled = scmi_clk_atomic_is_enabled,
> +	.set_parent = scmi_clk_set_parent,
> +	.get_parent = scmi_clk_get_parent,
> +	.determine_rate = scmi_clk_determine_rate,
>  };
>  
>  static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk,
> @@ -158,9 +202,10 @@ static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk,
>  
>  	struct clk_init_data init = {
>  		.flags = CLK_GET_RATE_NOCACHE,
> -		.num_parents = 0,
> +		.num_parents = sclk->info->num_parents,
>  		.ops = scmi_ops,
>  		.name = sclk->info->name,
> +		.parent_data = sclk->parent_data,
>  	};
>  
>  	sclk->hw.init = &init;
> @@ -250,6 +295,17 @@ static int scmi_clocks_probe(struct scmi_device *sdev)
>  		else
>  			scmi_ops = &scmi_clk_ops;
>  
> +		/* Initialize clock parent data. */
> +		if (sclk->info->num_parents > 0) {
> +			sclk->parent_data = devm_kcalloc(dev, sclk->info->num_parents,
> +							 sizeof(*sclk->parent_data), GFP_KERNEL);
> +

Here, you missed to check the return value of devm_kcalloc() before carrying on.

> +			for (int i = 0; i < sclk->info->num_parents; i++) {
> +				sclk->parent_data[i].index = sclk->info->parents[i];
> +				sclk->parent_data[i].hw = hws[sclk->info->parents[i]];
> +			}
> +		}
> +

Other than this, FWIW:

Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>

Thanks,
Cristian