Re: [PATCH] drivers: mmc: sdhci: update max frequency only if undefined

From: Dong Aisheng
Date: Thu Jun 18 2015 - 03:33:59 EST


On Thu, Jun 18, 2015 at 12:57:07PM +0530, Suneel Garapati wrote:
> f_max parameter of mmc structure is updated unconditionally.
> If dt property max-frequency is assigned, this update is
> overwriting the dt property value which is undesired.
>
> Signed-off-by: Suneel Garapati <suneel.garapati@xxxxxxxxxx>
> ---
> drivers/mmc/host/sdhci.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index bc14452..c2917d5 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -3047,7 +3047,10 @@ int sdhci_add_host(struct sdhci_host *host)
> * Set host parameters.
> */
> mmc->ops = &sdhci_ops;
> - mmc->f_max = host->max_clk;
> +
> + if(!mmc->f_max)
> + mmc->f_max = host->max_clk;
> +

This is probably not going to work properly.
mmc->f_max will be overwritten again if host->clk_mul enabled.
And you did not do sanity check if f_max from device tree is valid.

Please see:
http://www.spinics.net/lists/arm-kernel/msg426167.html
I already sent a proper fix.

Regards
Dong Aisheng

> if (host->ops->get_min_clock)
> mmc->f_min = host->ops->get_min_clock(host);
> else if (host->version >= SDHCI_SPEC_300) {
> --
> 2.1.2
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