Re: [PATCH v2 2/4] mmc: core: group default initial state

Ulf Hansson
2014-11-05T10:13:33Z

On 4 November 2014 16:07, Johan Rudholm <johan.rudholm@axis.com> wrote:
> mmc_do_hw_reset, mmc_power_up and mmc_power_off all set the same
> group of initial values, simplify by sticking them together.

That's not entirely true. This patch will actually change the
behaviour for the "ios.bus_mode", which isn't exactly what the commit
message are telling us. See more below.

I still think this patch is interesting, since apparently the value of
"ios.bus_mode" hasn't been handled consistently. In principle I like
the approach of this patch, but we need to make sure it's working and
following the specs.

Kind regards
Uffe

>
> Signed-off-by: Johan Rudholm <johanru@axis.com>
> ---
> drivers/mmc/core/core.c | 49 +++++++++++++++++++++++------------------------
> drivers/mmc/core/core.h | 1 +
> 2 files changed, 25 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 5d215ee..2c39d26 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -1088,6 +1088,24 @@ void mmc_set_bus_width(struct mmc_host *host, unsigned int width)
> mmc_host_clk_release(host);
> }
>
> +/*
> + * Set initial state after a power cycle or a hw_reset.
> + */
> +void mmc_set_initial_state(struct mmc_host *host)
> +{
> + if (mmc_host_is_spi(host)) {
> + host->ios.chip_select = MMC_CS_HIGH;
> + host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;
> + } else {
> + host->ios.chip_select = MMC_CS_DONTCARE;
> + host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
> + }
> + host->ios.bus_width = MMC_BUS_WIDTH_1;
> + host->ios.timing = MMC_TIMING_LEGACY;
> +
> + mmc_set_ios(host);
> +}
> +
> /**
> * mmc_vdd_to_ocrbitnum - Convert a voltage to the OCR bit number
> * @vdd: voltage (mV)
> @@ -1534,15 +1552,9 @@ void mmc_power_up(struct mmc_host *host, u32 ocr)
> mmc_host_clk_hold(host);
>
> host->ios.vdd = fls(ocr) - 1;
> - if (mmc_host_is_spi(host))
> - host->ios.chip_select = MMC_CS_HIGH;
> - else
> - host->ios.chip_select = MMC_CS_DONTCARE;
> - host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;

Earlier we used always used MMC_BUSMODE_PUSHPULL, now it will depend on "spi".

> host->ios.power_mode = MMC_POWER_UP;
> - host->ios.bus_width = MMC_BUS_WIDTH_1;
> - host->ios.timing = MMC_TIMING_LEGACY;
> - mmc_set_ios(host);
> + /* Set initial state and call mmc_set_ios */
> + mmc_set_initial_state(host);
>
> /* Try to set signal voltage to 3.3V but fall back to 1.8v or 1.2v */
> if (__mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_330) == 0)
> @@ -1582,14 +1594,9 @@ void mmc_power_off(struct mmc_host *host)
> host->ios.clock = 0;
> host->ios.vdd = 0;
>
> - if (!mmc_host_is_spi(host)) {
> - host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
> - host->ios.chip_select = MMC_CS_DONTCARE;

So in here another change in behaviour, right!?

> - }
> host->ios.power_mode = MMC_POWER_OFF;
> - host->ios.bus_width = MMC_BUS_WIDTH_1;
> - host->ios.timing = MMC_TIMING_LEGACY;
> - mmc_set_ios(host);
> + /* Set initial state and call mmc_set_ios */
> + mmc_set_initial_state(host);
>
> /*
> * Some configurations, such as the 802.11 SDIO card in the OLPC
> @@ -2273,16 +2280,8 @@ static int mmc_do_hw_reset(struct mmc_host *host, int check)
> }
> }
>
> - if (mmc_host_is_spi(host)) {
> - host->ios.chip_select = MMC_CS_HIGH;
> - host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;
> - } else {
> - host->ios.chip_select = MMC_CS_DONTCARE;
> - host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
> - }
> - host->ios.bus_width = MMC_BUS_WIDTH_1;
> - host->ios.timing = MMC_TIMING_LEGACY;
> - mmc_set_ios(host);
> + /* Set initial state and call mmc_set_ios */
> + mmc_set_initial_state(host);
>
> mmc_host_clk_release(host);
>
> diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
> index 443a584..d76597c 100644
> --- a/drivers/mmc/core/core.h
> +++ b/drivers/mmc/core/core.h
> @@ -49,6 +49,7 @@ void mmc_set_driver_type(struct mmc_host *host, unsigned int drv_type);
> void mmc_power_up(struct mmc_host *host, u32 ocr);
> void mmc_power_off(struct mmc_host *host);
> void mmc_power_cycle(struct mmc_host *host, u32 ocr);
> +void mmc_set_initial_state(struct mmc_host *host);
>
> static inline void mmc_delay(unsigned int ms)
> {
> --
> 1.7.2.5
>

Kind regards
Uffe