[LINUX PATCH 1/5] mmc: Workaround for the issue in auto tuning mode.

Russell King - ARM Linux
2016-01-19T17:57:58Z

On Tue, Jan 19, 2016 at 07:47:31PM +0530, P L Sai Krishna wrote:
> +void arasan_tune_sdclk(struct sdhci_host *host)

static?

> +{
> + unsigned int clock;
> +
> + clock = host->clock;

Maybe combine the above two lines:

unsigned int clock = host->clock;

?

> +
> + /*
> + * As per controller erratum, program the SDCLK Frequency
> + * Select of clock control register with a value, say
> + * clock/2. Wait for the Internal clock stable and program
> + * the desired frequency.
> + */
> + host->ops->set_clock(host, clock/2);

The comment above says "wait for the internal clock stable" - I see
no wait in here. Does the code actually conform with the comment?

Please also use "clock / 2" as per coding style, thanks

> +
> + host->ops->set_clock(host, host->clock);

Maybe replace host->clock with clock?

> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index d622435..8b064cd 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2043,6 +2043,11 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
> err = -EIO;
> }
>
> + if ((host->quirks2 & SDHCI_QUIRK2_BROKEN_TUNING) &&
> + (tuning_loop_counter >= 0) && (ctrl & SDHCI_CTRL_TUNED_CLK)) {
> + host->ops->tune_clk(host);
> + }

Do we need this "SDHCI_QUIRK2_BROKEN_TUNING" quirk at all? What's wrong
with:

if (host->ops->tune_clk && tuning_loop_counter >= 0 &&
ctrl & SDHCI_CTRL_TUNED_CLK)
host->ops->tune_clk(host);

here?

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