[PATCH] mmc: sdhci-brcmstb: use clk_get_rate(base_clk) in PM resume

[PATCH] mmc: sdhci-brcmstb: use clk_get_rate(base_clk) in PM resume

[Kamal Dasu]

Use clk_get_rate for base_clk on resume before setting new rate.
This change ensures that the clock api returns current rate
and sets the clock to the desired rate and honors CLK_GET_NO_CACHE
attribute used by clock api.

Fixes: 97904a59855c (mmc: sdhci-brcmstb: Add ability to increase max clock rate for 72116b0)
Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
---
 drivers/mmc/host/sdhci-brcmstb.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-brcmstb.c b/drivers/mmc/host/sdhci-brcmstb.c
index 28e9cf995c41..aff36a933ebe 100644
--- a/drivers/mmc/host/sdhci-brcmstb.c
+++ b/drivers/mmc/host/sdhci-brcmstb.c
@@ -406,7 +406,14 @@ static int sdhci_brcmstb_resume(struct device *dev)
 	ret = sdhci_pltfm_resume(dev);
 	if (!ret && priv->base_freq_hz) {
 		ret = clk_prepare_enable(priv->base_clk);
-		if (!ret)
+		/*
+		 * Note: using clk_get_rate() below as clk_get_rate()
+		 * honors CLK_GET_RATE_NOCACHE attribute, but clk_set_rate()
+		 * may do implicit get_rate() calls that do not honor
+		 * CLK_GET_RATE_NOCACHE.
+		 */
+		if (!ret &&
+		    (clk_get_rate(priv->base_clk) != priv->base_freq_hz))
 			ret = clk_set_rate(priv->base_clk, priv->base_freq_hz);
 	}
 
-- 
2.17.1


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Re: [PATCH] mmc: sdhci-brcmstb: use clk_get_rate(base_clk) in PM resume

[Florian Fainelli]

On 7/14/22 10:41, Kamal Dasu wrote:
> Use clk_get_rate for base_clk on resume before setting new rate.
> This change ensures that the clock api returns current rate
> and sets the clock to the desired rate and honors CLK_GET_NO_CACHE
> attribute used by clock api.
> 
> Fixes: 97904a59855c (mmc: sdhci-brcmstb: Add ability to increase max clock rate for 72116b0)
> Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>

Acked-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

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Re: [PATCH] mmc: sdhci-brcmstb: use clk_get_rate(base_clk) in PM resume

[Ulf Hansson]

On Thu, 14 Jul 2022 at 19:42, Kamal Dasu <kdasu.kdev@gmail.com> wrote:
>
> Use clk_get_rate for base_clk on resume before setting new rate.
> This change ensures that the clock api returns current rate
> and sets the clock to the desired rate and honors CLK_GET_NO_CACHE
> attribute used by clock api.
>
> Fixes: 97904a59855c (mmc: sdhci-brcmstb: Add ability to increase max clock rate for 72116b0)
> Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>

Applied for next, thanks!

Kind regards
Uffe


> ---
>  drivers/mmc/host/sdhci-brcmstb.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-brcmstb.c b/drivers/mmc/host/sdhci-brcmstb.c
> index 28e9cf995c41..aff36a933ebe 100644
> --- a/drivers/mmc/host/sdhci-brcmstb.c
> +++ b/drivers/mmc/host/sdhci-brcmstb.c
> @@ -406,7 +406,14 @@ static int sdhci_brcmstb_resume(struct device *dev)
>         ret = sdhci_pltfm_resume(dev);
>         if (!ret && priv->base_freq_hz) {
>                 ret = clk_prepare_enable(priv->base_clk);
> -               if (!ret)
> +               /*
> +                * Note: using clk_get_rate() below as clk_get_rate()
> +                * honors CLK_GET_RATE_NOCACHE attribute, but clk_set_rate()
> +                * may do implicit get_rate() calls that do not honor
> +                * CLK_GET_RATE_NOCACHE.
> +                */
> +               if (!ret &&
> +                   (clk_get_rate(priv->base_clk) != priv->base_freq_hz))
>                         ret = clk_set_rate(priv->base_clk, priv->base_freq_hz);
>         }
>
> --
> 2.17.1
>

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