[U-Boot] [PATCH 1/3] samsung: board: support eMMC reset using DT

[Joonyoung Shim <jy0922.shim@samsung.com>]

+Cc Jaehoon,

On 01/09/2015 03:18 AM, Simon Glass wrote:
> Hi Joonyoung,
> 
> On 7 January 2015 at 22:44, Joonyoung Shim <jy0922.shim@samsung.com> wrote:
>> Some exynos boards require special handling of SD4_nRESET_OUT line for
>> eMMC memory to perform complete reboot e.g. Odroid X2/U3/XU3 boards.
>>
>> This will support eMMC reset using DT from reset_misc of samsung common
>> board file and each board files can support eMMC reset on non DT case.
>>
>> Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
>> ---
>>  board/samsung/common/board.c                   | 27 ++++++++++++++++++++++++++
>>  board/samsung/odroid/odroid.c                  |  2 +-
>>  doc/device-tree-bindings/exynos/emmc-reset.txt | 15 ++++++++++++++
>>  3 files changed, 43 insertions(+), 1 deletion(-)
>>  create mode 100644 doc/device-tree-bindings/exynos/emmc-reset.txt
>>
>> diff --git a/board/samsung/common/board.c b/board/samsung/common/board.c
>> index c04ab3c..3218463 100644
>> --- a/board/samsung/common/board.c
>> +++ b/board/samsung/common/board.c
>> @@ -40,6 +40,8 @@ __weak int exynos_power_init(void)
>>         return 0;
>>  }
>>
>> +__weak void exynos_reset_misc(void) {}
>> +
>>  #if defined CONFIG_EXYNOS_TMU
>>  /* Boot Time Thermal Analysis for SoC temperature threshold breach */
>>  static void boot_temp_check(void)
>> @@ -400,3 +402,28 @@ int misc_init_r(void)
>>         return 0;
>>  }
>>  #endif
>> +
>> +void reset_misc(void)
>> +{
>> +#ifdef CONFIG_OF_CONTROL
> 
> I think all Samsung boards have this defined, so this #ifdef can be removed.
> 

OK, if it is true, we can remove this and i will not to support non DT case.

>> +       struct gpio_desc gpio = {};
>> +       int node;
>> +
>> +       node = fdt_node_offset_by_compatible(gd->fdt_blob, 0,
>> +                       "samsung,emmc-reset");
>> +       if (node < 0)
>> +               return;
>> +
>> +       gpio_request_by_name_nodev(gd->fdt_blob, node, "reset-gpio", 0, &gpio,
>> +                                  GPIOD_IS_OUT);
>> +
>> +       if (dm_gpio_is_valid(&gpio)) {
>> +               /* Reset eMMC*/
>> +               dm_gpio_set_value(&gpio, 0);
>> +               mdelay(10);
> 
> That's a very long reset! Is that what it needs?
> 

Jaehoon, is there any guide about wait time of reset at eMMC spec?

Thanks.