Hi,
On 12 May 2017 at 12:16, Jean-Jacques Hiblot <jjhib...@ti.com> wrote:
> mmc/sd specification requires vdd to be disabled for 1 ms
> and then enabled again during power cycle. Add a
> function in mmc core to perform power cycle and set
> the io signal to it's initial state.
>
> Signed-off-by: Kishon Vijay Abraham I <kis...@ti.com>
> Signed-off-by: Jean-Jacques Hiblot <jjhib...@ti.com>
> ---
> drivers/mmc/mmc.c | 50 +++++++++++++++++++++++++++++++++++++++++---------
> 1 file changed, 41 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
> index d40a22b..032260b 100644
> --- a/drivers/mmc/mmc.c
> +++ b/drivers/mmc/mmc.c
> @@ -30,6 +30,7 @@ static const unsigned int sd_au_size[] = {
> SZ_16M / 512, (SZ_16M + SZ_8M) / 512, SZ_32M / 512, SZ_64M / 512,
> };
> static int mmc_set_signal_voltage(struct mmc *mmc, uint signal_voltage);
> +static void mmc_power_cycle(struct mmc *mmc);
>
> #if CONFIG_IS_ENABLED(MMC_TINY)
> static struct mmc mmc_static;
> @@ -1915,6 +1916,45 @@ static int mmc_power_init(struct mmc *mmc)
> return 0;
> }
>
> +static void mmc_set_initial_state(struct mmc *mmc)
Function comment
> +{
> + int err;
> +
> + /* First try to set 3.3V. If it fails set to 1.8V */
> + err = mmc_set_signal_voltage(mmc, MMC_SIGNAL_VOLTAGE_330);
> + if (err != 0)
> + err = mmc_set_signal_voltage(mmc, MMC_SIGNAL_VOLTAGE_180);
> + if (err != 0)
> + printf("failed to set signal voltage\n");
> +
> + mmc_set_bus_width(mmc, 1);
> + mmc_set_clock(mmc, 1);
> + mmc_select_mode(mmc, MMC_LEGACY);
> +}
> +
> +static void mmc_power_up(struct mmc *mmc)
> +{
> + mmc_set_initial_state(mmc);
> + mmc_set_vdd(mmc, true);
> + udelay(10000);
Eek. Please add a comment as to why
> +}
> +
> +static void mmc_power_off(struct mmc *mmc)
> +{
> + mmc_set_vdd(mmc, false);
> +}
> +
> +static void mmc_power_cycle(struct mmc *mmc)
> +{
> + mmc_power_off(mmc);
> + /*
> + * SD spec recommends at least 1ms of delay. Let's wait for 2ms
> + * to be on the safer side.
> + */
> + udelay(2000);
> + mmc_power_up(mmc);
> +}
> +
> int mmc_start_init(struct mmc *mmc)
> {
> bool no_card;
> @@ -1952,16 +1992,8 @@ int mmc_start_init(struct mmc *mmc)
> return err;
> #endif
> mmc->ddr_mode = 0;
> - mmc_set_vdd(mmc, true);
> - /* First try to set 3.3V. If it fails set to 1.8V */
> - err = mmc_set_signal_voltage(mmc, MMC_SIGNAL_VOLTAGE_330);
> - if (err != 0)
> - err = mmc_set_signal_voltage(mmc, MMC_SIGNAL_VOLTAGE_180);
> - if (err != 0)
> - printf("failed to set signal voltage\n");
Return error? Also please add some mmc: to your message.
>
> - mmc_set_bus_width(mmc, 1);
> - mmc_set_clock(mmc, 1);
> + mmc_power_cycle(mmc);
>
> /* Reset the Card */
> err = mmc_go_idle(mmc);
> --
> 1.9.1
>
Regards,
Simon
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