[PATCH RFC] mmc: add slot argument to mmc_of_parse

[Jaehoon Chung]

Hi, All.

This patch is working on progress?
I want to merge this patch for fixing dw-mmc controller problem.

If this patch didn't work on progress, i will send the patch based-on this patch.

Best Regards,
Jaehoon Chung

On 05/14/2014 06:53 PM, Ulf Hansson wrote:
> On 7 May 2014 12:06, Ludovic Desroches <ludovic.desroches at atmel.com> wrote:
>> Some hosts manage several slots. In these case information such as the bus
>> width, chip detect and others are into the slot node. So we have to parse
>> child nodes. If not NULL, slot node will be used instead of the device
>> node.
>>
>> Signed-off-by: Ludovic Desroches <ludovic.desroches at atmel.com>
>> ---
>>
>> Hi,
>>
>> Since this patch is only a RFC, I have not yet updated drivers using this
>> function.
>>
>> I would like to use mmc_of_parse to reduce code duplication. My issue is that
>> atmel mci is a bit different from others mci host since it can provide
>> several slots, so it allocates several mmc hosts. By the way, it is not the
>> only one.
>>
>> When calling mmc_alloc_host, host->parent is set to &pdev->dev. mmc_of_parse
>> uses host->parent->of_node but in my case settings are in the slot nodes so in
>> the child nodes. That's why I would like to have a way to tell which node I
>> want to use.
> 
> Seems reasonable, thanks for working on this!
> 
>>
>>
>> Regards
>>
>> Ludovic
>>
>>
>>
>>  drivers/mmc/core/host.c |    9 +++++++--
>>  1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
>> index fdea825..ed6cea5 100644
>> --- a/drivers/mmc/core/host.c
>> +++ b/drivers/mmc/core/host.c
>> @@ -300,13 +300,15 @@ static inline void mmc_host_clk_sysfs_init(struct mmc_host *host)
>>  /**
>>   *     mmc_of_parse() - parse host's device-tree node
>>   *     @host: host whose node should be parsed.
>> + *     @slot: some devices provide several slots so the node to parse
>> + *     is not the host one.
>>   *
>>   * To keep the rest of the MMC subsystem unaware of whether DT has been
>>   * used to to instantiate and configure this host instance or not, we
>>   * parse the properties and set respective generic mmc-host flags and
>>   * parameters.
>>   */
>> -int mmc_of_parse(struct mmc_host *host)
>> +int mmc_of_parse(struct mmc_host *host, struct device_node *slot)
>>  {
>>         struct device_node *np;
>>         u32 bus_width;
>> @@ -317,7 +319,10 @@ int mmc_of_parse(struct mmc_host *host)
>>         if (!host->parent || !host->parent->of_node)
>>                 return 0;
>>
>> -       np = host->parent->of_node;
>> +       if (slot)
>> +               np = slot;
>> +       else
>> +               np = host->parent->of_node;
>>
>>         /* "bus-width" is translated to MMC_CAP_*_BIT_DATA flags */
>>         if (of_property_read_u32(np, "bus-width", &bus_width) < 0) {
>> --
>> 1.7.9.5
>>
> 
> How about adding a new API, __mmc_of_parse((struct mmc_host *host,
> struct device_node *slot)
> Then let the old API mmc_of_parse() remain as is, but let it call the
> new API with slot == NULL.
> 
> Atmel can then use the new API, but the other drivers can remain as is.
> 
> Kind regards
> Ulf Hansson
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