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Re: [PATCH 05/11] mmc: sunxi: Support controllers that can use both old and new timings

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On Fri, Jul 14, 2017 at 5:26 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote:
> On 14 July 2017 at 08:42, Chen-Yu Tsai <wens@csie.org> wrote:
>> On the SoCs that introduced the new timing mode for MMC controllers,
>> both the old (where the clock delays are set in the CCU) and new
>> (where the clock delays are set in the MMC controller) timing modes
>> are available, and we have to support them both. However there are
>> two bits that control which mode is active. One is in the CCU, the
>> other is in the MMC controller. The settings on both sides must be
>> the same, or nothing will work.
>>
>> The CCU's get/set_phase callbacks return -ENOTSUPP when the new
>> timing mode is active. This provides a way to know which mode is
>> active on that side, and we can set the bit on the MMC controller
>> side accordingly.

Argh... I forgot to update the commit log... :(

>>
>> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
>> ---
>>  drivers/mmc/host/sunxi-mmc.c | 34 ++++++++++++++++++++++++++++++----
>>  1 file changed, 30 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
>> index 0fb4e4c119e1..56e45c65b52d 100644
>> --- a/drivers/mmc/host/sunxi-mmc.c
>> +++ b/drivers/mmc/host/sunxi-mmc.c
>> @@ -22,6 +22,7 @@
>>  #include <linux/err.h>
>>
>>  #include <linux/clk.h>
>> +#include <linux/clk/sunxi-ng.h>
>
> I don't like this. This looks like an SoC specific hack.
>
>>  #include <linux/gpio.h>
>>  #include <linux/platform_device.h>
>>  #include <linux/spinlock.h>
>> @@ -259,7 +260,7 @@ struct sunxi_mmc_cfg {
>>         /* Does DATA0 needs to be masked while the clock is updated */
>>         bool mask_data0;
>>
>> -       bool needs_new_timings;
>> +       bool has_new_timings;
>>  };
>>
>>  struct sunxi_mmc_host {
>> @@ -293,6 +294,9 @@ struct sunxi_mmc_host {
>>
>>         /* vqmmc */
>>         bool            vqmmc_enabled;
>> +
>> +       /* timings */
>> +       bool            use_new_timings;
>>  };
>>
>>  static int sunxi_mmc_reset_host(struct sunxi_mmc_host *host)
>> @@ -714,7 +718,7 @@ static int sunxi_mmc_clk_set_phase(struct sunxi_mmc_host *host,
>>  {
>>         int index;
>>
>> -       if (!host->cfg->clk_delays)
>> +       if (host->use_new_timings)
>>                 return 0;
>>
>>         /* determine delays */
>> @@ -765,6 +769,15 @@ static int sunxi_mmc_clk_set_rate(struct sunxi_mmc_host *host,
>>             ios->bus_width == MMC_BUS_WIDTH_8)
>>                 clock <<= 1;
>>
>> +       if (host->use_new_timings) {
>> +               ret = sunxi_ccu_set_mmc_timing_mode(host->clk_mmc, true);
>
> Can't this be solved through some other generic API/interface?

The old discussion is here: https://lkml.org/lkml/2017/5/5/77

It is possible to piggy back on existing API, but as Maxime mentioned
back in the discussion, it is confusing.

IIRC Mike said (via Maxime) an SoC specific call was the easy way
to handle this. I don't think there's anything generic about this.
Even if you could have a _set_mode callback for the clks, the modes
would be SoC specific anyway.

ChenYu

>
>> +               if (ret) {
>> +                       dev_err(mmc_dev(mmc),
>> +                               "error setting new timing mode\n");
>> +                       return ret;
>> +               }
>> +       }
>> +
>
> [...]
>
> Kind regards
> Uffe

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[PATCH 00/11] ARM: sun8i: a83t: Add support for MMC controllers Chen-Yu Tsai <wens@csie.org> - 2017-07-14 08:50 +0200
  [PATCH 11/11] ARM: dts: sun8i: a83t: h8homlet: Enable micro-SD card and onboard eMMC Chen-Yu Tsai <wens@csie.org> - 2017-07-14 08:50 +0200
  [PATCH 04/11] mmc: sunxi: Keep default timing phase settings for new timing mode Chen-Yu Tsai <wens@csie.org> - 2017-07-14 08:50 +0200
    Re: [PATCH 04/11] mmc: sunxi: Keep default timing phase settings for  new timing mode Ulf Hansson <ulf.hansson@linaro.org> - 2017-07-14 11:20 +0200
      Re: [PATCH 04/11] mmc: sunxi: Keep default timing phase settings for  new timing mode Chen-Yu Tsai <wens@csie.org> - 2017-07-14 11:50 +0200
    Re: [PATCH 04/11] mmc: sunxi: Keep default timing phase settings for  new timing mode Maxime Ripard <maxime.ripard@free-electrons.com> - 2017-07-17 11:20 +0200
    Re: [PATCH 04/11] mmc: sunxi: Keep default timing phase settings for  new timing mode Ulf Hansson <ulf.hansson@linaro.org> - 2017-07-17 12:40 +0200
  [PATCH 09/11] ARM: dts: sun8i: a83t: Add pingroup for 8-bit eMMC on mmc2 Chen-Yu Tsai <wens@csie.org> - 2017-07-14 08:50 +0200
  [PATCH 01/11] ARM: dts: sun8i: a83t: Switch to CCU device tree binding macros Chen-Yu Tsai <wens@csie.org> - 2017-07-14 08:50 +0200
    Re: [PATCH 01/11] ARM: dts: sun8i: a83t: Switch to CCU device tree  binding macros Maxime Ripard <maxime.ripard@free-electrons.com> - 2017-07-17 11:10 +0200
  [PATCH 02/11] clk: sunxi-ng: Add interface to query or configure MMC timing modes. Chen-Yu Tsai <wens@csie.org> - 2017-07-14 08:50 +0200
    Re: [PATCH 02/11] clk: sunxi-ng: Add interface to query or configure  MMC timing modes. Maxime Ripard <maxime.ripard@free-electrons.com> - 2017-07-17 11:20 +0200
  [PATCH 08/11] ARM: dts: sun8i: a83t: Add MMC controller device nodes Chen-Yu Tsai <wens@csie.org> - 2017-07-14 08:50 +0200
    Re: [PATCH 08/11] ARM: dts: sun8i: a83t: Add MMC controller device  nodes Maxime Ripard <maxime.ripard@free-electrons.com> - 2017-07-17 11:30 +0200
  [PATCH 07/11] mmc: sunxi: Add support for A83T eMMC (MMC2) Chen-Yu Tsai <wens@csie.org> - 2017-07-14 08:50 +0200
    Re: [PATCH 07/11] mmc: sunxi: Add support for A83T eMMC (MMC2) Rob Herring <robh@kernel.org> - 2017-07-17 21:00 +0200
  [PATCH 05/11] mmc: sunxi: Support controllers that can use both old and new timings Chen-Yu Tsai <wens@csie.org> - 2017-07-14 08:50 +0200
    Re: [PATCH 05/11] mmc: sunxi: Support controllers that can use both  old and new timings Ulf Hansson <ulf.hansson@linaro.org> - 2017-07-14 11:30 +0200
      Re: [PATCH 05/11] mmc: sunxi: Support controllers that can use both  old and new timings Chen-Yu Tsai <wens@csie.org> - 2017-07-14 11:50 +0200
        Re: [PATCH 05/11] mmc: sunxi: Support controllers that can use both  old and new timings Ulf Hansson <ulf.hansson@linaro.org> - 2017-07-14 12:00 +0200
          Re: [PATCH 05/11] mmc: sunxi: Support controllers that can use both  old and new timings Maxime Ripard <maxime.ripard@free-electrons.com> - 2017-07-17 11:30 +0200
    Re: [PATCH 05/11] mmc: sunxi: Support controllers that can use both  old and new timings Maxime Ripard <maxime.ripard@free-electrons.com> - 2017-07-17 11:20 +0200

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