On Mon, Mar 04, 2024 at 08:29:17AM +0100, Frank Oltmanns wrote:
> The Allwinner SoC's typically have an upper and lower limit for their
> clocks' rates. Up until now, support for that has been implemented
> separately for each clock type.
>
> Implement that functionality in the sunxi-ng's common part making use of
> the CCF rate liming capabilities, so that it is available for all clock
> types.
>
> Suggested-by: Maxime Ripard <mripard@xxxxxxxxxx>
> Signed-off-by: Frank Oltmanns <frank@xxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> drivers/clk/sunxi-ng/ccu_common.c | 15 +++++++++++++++
> drivers/clk/sunxi-ng/ccu_common.h | 3 +++
> 2 files changed, 18 insertions(+)
>
> diff --git a/drivers/clk/sunxi-ng/ccu_common.c b/drivers/clk/sunxi-ng/ccu_common.c
> index 8babce55302f..2152063eee16 100644
> --- a/drivers/clk/sunxi-ng/ccu_common.c
> +++ b/drivers/clk/sunxi-ng/ccu_common.c
> @@ -44,6 +44,12 @@ bool ccu_is_better_rate(struct ccu_common *common,
> unsigned long current_rate,
> unsigned long best_rate)
> {
> + if (common->max_rate && current_rate > common->max_rate)
> + return false;
> +
> + if (common->min_rate && current_rate < common->min_rate)
> + return false;
> +
We should use clk_hw_get_rate_range() here, there might be some
additional constraints to the rate range than the hardware ones (ie,
calls to clk_set_rate_range()).
> if (common->features & CCU_FEATURE_CLOSEST_RATE)
> return abs(current_rate - target_rate) < abs(best_rate - target_rate);
>
> @@ -122,7 +128,10 @@ static int sunxi_ccu_probe(struct sunxi_ccu *ccu, struct device *dev,
>
> for (i = 0; i < desc->hw_clks->num ; i++) {
> struct clk_hw *hw = desc->hw_clks->hws[i];
> + struct ccu_common *common = hw_to_ccu_common(hw);
> const char *name;
> + unsigned long min_rate = 0;
> + unsigned long max_rate = ULONG_MAX;
>
> if (!hw)
> continue;
> @@ -136,6 +145,12 @@ static int sunxi_ccu_probe(struct sunxi_ccu *ccu, struct device *dev,
> pr_err("Couldn't register clock %d - %s\n", i, name);
> goto err_clk_unreg;
> }
> +
> + if (common->min_rate)
> + min_rate = common->min_rate;
> + if (common->max_rate)
> + max_rate = common->max_rate;
max_rate should always be set to ULONG_MAX. I would drop the tests for
both here, and warn if max_rate is set to 0.
Maxime
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