On Thu, Mar 09, 2017 at 04:18:20PM +0100, Romain Izard wrote:
> The SDHCI controller in the SAMA5D2 chip requires a valid voltage set
> in the power control register, otherwise commands will fail with a
> timeout error.
>
> When using the regulator framework to specify the regulator used by the
> mmc device, the voltage is not configured, and it is not possible to use
> the connected device.
>
> Implement a custom 'set_power' function for this specific hardware, that
> configures the voltage in the register in all cases.
>
> Signed-off-by: Romain Izard <romain.izard.pro@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx #4.9+
Can be added since sdhci_set_power_noreg was introduced in 4.9.
> ---
> drivers/mmc/host/sdhci-of-at91.c | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
> index 2f9ad213377a..291a74955a4c 100644
> --- a/drivers/mmc/host/sdhci-of-at91.c
> +++ b/drivers/mmc/host/sdhci-of-at91.c
> @@ -85,11 +85,30 @@ static void sdhci_at91_set_clock(struct sdhci_host *host, unsigned int clock)
> sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
> }
>
> +/*
> + * In this specific implementation of the SDHCI contoller, the power register
> + * needs to have a valid voltage set even when the power supply is managed by
> + * an external regulator.
> + */
> +static void sdhci_at91_set_power(struct sdhci_host *host, unsigned char mode,
> + unsigned short vdd)
> +{
> + if (!IS_ERR(host->mmc->supply.vmmc)) {
> + struct mmc_host *mmc = host->mmc;
> +
> + spin_unlock_irq(&host->lock);
> + mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
> + spin_lock_irq(&host->lock);
> + }
> + sdhci_set_power_noreg(host, mode, vdd);
> +}
> +
> static const struct sdhci_ops sdhci_at91_sama5d2_ops = {
> .set_clock = sdhci_at91_set_clock,
> .set_bus_width = sdhci_set_bus_width,
> .reset = sdhci_reset,
> .set_uhs_signaling = sdhci_set_uhs_signaling,
> + .set_power = sdhci_at91_set_power,
> };
>
> static const struct sdhci_pltfm_data soc_data_sama5d2 = {
> --
> 2.9.3
>
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