Re: [PATCH v2 7/9] mmc: sh_mobile_sdhi: Add UHS-I mode support

[Ulf Hansson]

On 4 April 2016 at 17:17, Wolfram Sang  wrote:
>
>> > +   usleep_range(5000, 5500);
>>
>> Why do you need this delay/sleep?
>
> My datasheet says to wait at least 5ms before re-enabling the clock
> after a voltage switch...
>
> Ah, found it in the core. It is doing it for 10ms. Maybe my search
> pattern was not fuzzy enough ;)
>
> Okay, so this delay can go.
>

Thanks for the clarification. I will amend the patch, no need for you
to send a new version!

Kind regards
Uffe

Re: [PATCH v2 7/9] mmc: sh_mobile_sdhi: Add UHS-I mode support

[Ulf Hansson]

On 1 April 2016 at 17:44, Wolfram Sang  wrote:
> From: Wolfram Sang 
>
> Implement voltage switch, supporting modes up to SDR-50.
>
> Based on work by Shinobu Uehara, Rob Taylor, William Towle and Ian Molton.
>
> Signed-off-by: Ben Hutchings 
> Signed-off-by: Wolfram Sang 
> ---
>  Documentation/devicetree/bindings/mmc/tmio_mmc.txt |  3 ++
>  drivers/mmc/host/sh_mobile_sdhi.c  | 50 
> ++
>  2 files changed, 53 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/mmc/tmio_mmc.txt 
> b/Documentation/devicetree/bindings/mmc/tmio_mmc.txt
> index 7fb746dd1a68ca..0f610d4b5b005f 100644
> --- a/Documentation/devicetree/bindings/mmc/tmio_mmc.txt
> +++ b/Documentation/devicetree/bindings/mmc/tmio_mmc.txt
> @@ -26,3 +26,6 @@ Required properties:
>
>  Optional properties:
>  - toshiba,mmc-wrprotect-disable: write-protect detection is unavailable
> +- pinctrl-names: should be "default", "state_uhs"
> +- pinctrl-0: should contain default/high speed pin ctrl
> +- pinctrl-1: should contain uhs mode pin ctrl
> diff --git a/drivers/mmc/host/sh_mobile_sdhi.c 
> b/drivers/mmc/host/sh_mobile_sdhi.c
> index 8fd1d6b29190b6..89e0c5e9fcc668 100644
> --- a/drivers/mmc/host/sh_mobile_sdhi.c
> +++ b/drivers/mmc/host/sh_mobile_sdhi.c
> @@ -32,6 +32,9 @@
>  #include 
>  #include 
>  #include 
> +#include 
> +#include 
> +#include 
>
>  #include "tmio_mmc.h"
>
> @@ -97,6 +100,8 @@ struct sh_mobile_sdhi {
> struct clk *clk;
> struct tmio_mmc_data mmc_data;
> struct tmio_mmc_dma dma_priv;
> +   struct pinctrl *pinctrl;
> +   struct pinctrl_state *pins_default, *pins_uhs;
>  };
>
>  static void sh_mobile_sdhi_sdbuf_width(struct tmio_mmc_host *host, int width)
> @@ -205,6 +210,44 @@ static void sh_mobile_sdhi_clk_disable(struct 
> tmio_mmc_host *host)
> clk_disable_unprepare(priv->clk);
>  }
>
> +static int sh_mobile_sdhi_start_signal_voltage_switch(struct mmc_host *mmc,
> + struct mmc_ios *ios)
> +{
> +   struct tmio_mmc_host *host = mmc_priv(mmc);
> +   struct sh_mobile_sdhi *priv = host_to_priv(host);
> +   struct pinctrl_state *pin_state;
> +   int ret;
> +
> +   switch (ios->signal_voltage) {
> +   case MMC_SIGNAL_VOLTAGE_330:
> +   pin_state = priv->pins_default;
> +   break;
> +   case MMC_SIGNAL_VOLTAGE_180:
> +   pin_state = priv->pins_uhs;
> +   break;
> +   default:
> +   return -EINVAL;
> +   }
> +
> +   /*
> +* If anything is missing, assume signal voltage is fixed at
> +* 3.3V and succeed/fail accordingly.
> +*/
> +   if (IS_ERR(priv->pinctrl) || IS_ERR(pin_state))
> +   return ios->signal_voltage == MMC_SIGNAL_VOLTAGE_330 ? 0 : 
> -EINVAL;
> +
> +   ret = mmc_regulator_set_vqmmc(host->mmc, ios);
> +   if (ret)
> +   return ret;
> +
> +   ret = pinctrl_select_state(priv->pinctrl, pin_state);
> +   if (ret)
> +   return ret;
> +
> +   usleep_range(5000, 5500);

Why do you need this delay/sleep?

> +   return 0;
> +}
> +
>  static int sh_mobile_sdhi_wait_idle(struct tmio_mmc_host *host)
>  {
> int timeout = 1000;
> @@ -296,6 +339,12 @@ static int sh_mobile_sdhi_probe(struct platform_device 
> *pdev)
> goto eprobe;
> }
>
> +   priv->pinctrl = devm_pinctrl_get(>dev);
> +   if (!IS_ERR(priv->pinctrl)) {
> +   priv->pins_default = pinctrl_lookup_state(priv->pinctrl, 
> PINCTRL_STATE_DEFAULT);
> +   priv->pins_uhs = pinctrl_lookup_state(priv->pinctrl, 
> "state_uhs");
> +   }
> +
> host = tmio_mmc_host_alloc(pdev);
> if (!host) {
> ret = -ENOMEM;
> @@ -319,6 +368,7 @@ static int sh_mobile_sdhi_probe(struct platform_device 
> *pdev)
> host->clk_update= sh_mobile_sdhi_clk_update;
> host->clk_disable   = sh_mobile_sdhi_clk_disable;
> host->multi_io_quirk= sh_mobile_sdhi_multi_io_quirk;
> +   host->start_signal_voltage_switch = 
> sh_mobile_sdhi_start_signal_voltage_switch;
>
> /* Orginally registers were 16 bit apart, could be 32 or 64 nowadays 
> */
> if (!host->bus_shift && resource_size(res) > 0x100) /* old way to 
> determine the shift */
> --
> 2.7.0
>
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Kind regards
Uffe