Hi Chris,
On Sat, Jan 21, 2017 at 4:06 AM, Chris Brandt <[email protected]> wrote:
> Some controllers have 2 clock sources instead of 1. The 2nd clock
> is for the internal card detect logic and must be enabled/disabled
> along with the main core clock for proper operation.
>
> Signed-off-by: Chris Brandt <[email protected]>
> ---
> v4:
> * add technical explanation within probe routine
> v3:
> * add more clarification to the commit log
> v2:
> * changed clk2 to clk_cd
> * disable clk if clk_cd enable fails
> * changed clock name from "carddetect" to "cd"
Thanks for the updates!
> ---
> drivers/mmc/host/sh_mobile_sdhi.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/drivers/mmc/host/sh_mobile_sdhi.c
> b/drivers/mmc/host/sh_mobile_sdhi.c
> index 59db14b..360d922 100644
> --- a/drivers/mmc/host/sh_mobile_sdhi.c
> +++ b/drivers/mmc/host/sh_mobile_sdhi.c
> @@ -143,6 +143,7 @@ MODULE_DEVICE_TABLE(of, sh_mobile_sdhi_of_match);
>
> struct sh_mobile_sdhi {
> struct clk *clk;
> + struct clk *clk_cd;
> struct tmio_mmc_data mmc_data;
> struct tmio_mmc_dma dma_priv;
> struct pinctrl *pinctrl;
> @@ -190,6 +191,12 @@ static int sh_mobile_sdhi_clk_enable(struct
> tmio_mmc_host *host)
> if (ret < 0)
> return ret;
>
> + ret = clk_prepare_enable(priv->clk_cd);
> + if (ret < 0) {
> + clk_disable_unprepare(priv->clk);
> + return ret;
> + }
> +
As enabling the "core" clock but not the "cd" clock is not a valid setting,
shouldn't the cd clock be enabled first?
> /*
> * The clock driver may not know what maximum frequency
> * actually works, so it should be set with the max-frequency
> @@ -255,6 +262,8 @@ static void sh_mobile_sdhi_clk_disable(struct
> tmio_mmc_host *host)
> struct sh_mobile_sdhi *priv = host_to_priv(host);
>
> clk_disable_unprepare(priv->clk);
> + if (priv->clk_cd)
No need to check for a NULL pointer first.
> + clk_disable_unprepare(priv->clk_cd);
Disabling is already done in the correct order ;-)
> }
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
