Re: [PATCH] pinctrl: zynq: configure SPI SSx pins separately

[Helmut Buchsbaum <helmut.buchsbaum@gmail.com>]

On 04/24/2015 08:21 PM, Sören Brinkmann wrote:
> Hi Helmut,
>
> On Wed, 2015-04-22 at 11:14AM +0200, Helmut Buchsbaum wrote:
>    
>> Since SCLK, MISO and MOSI are the only mandatory signals at Zynq's SPI
>> interfaces, SS0, SS1 and SS2 have to be configured separately as they may
>> be used as simple GPIO lines.
>>
>> This, of course, has to be considered in the devicetree, so pin controller
>> configuration for e.g. an SPI0 using SS0 and SS1 only might look like the
>> following snippet (derived from the example of chapter "17.5.3
>> MIO/EMIO" Routing of Zynq-7000 TRM UG585). So MIO20 can now be used
>> as GPIO instead of being occupied by SPI0 SS2 function:
>>      
> I think this is very valid and correct. Thanks! One doubt I have though:
> [...]
>    
>> @@ -548,10 +591,20 @@ static const char * const qspi0_groups[] = {"qspi0_0_grp"};
>>   static const char * const qspi1_groups[] = {"qspi0_1_grp"};
>>   static const char * const qspi_fbclk_groups[] = {"qspi_fbclk_grp"};
>>   static const char * const qspi_cs1_groups[] = {"qspi_cs1_grp"};
>> -static const char * const spi0_groups[] = {"spi0_0_grp", "spi0_1_grp",
>> -					   "spi0_2_grp"};
>> -static const char * const spi1_groups[] = {"spi1_0_grp", "spi1_1_grp",
>> -					   "spi1_2_grp", "spi1_3_grp"};
>> +static const char * const spi0_groups[] = {"spi0_0_grp", "spi0_0_ss0_grp",
>> +					   "spi0_0_ss1_grp", "spi0_0_ss2_grp",
>> +					   "spi0_1_grp", "spi0_1_ss0_grp",
>> +					   "spi0_1_ss1_grp", "spi0_1_ss2_grp",
>> +					   "spi0_2_grp", "spi0_2_ss0_grp",
>> +					   "spi0_2_ss1_grp", "spi0_2_ss2_grp"};
>> +static const char * const spi1_groups[] = {"spi1_0_grp", "spi1_0_ss0_grp",
>> +					   "spi1_0_ss1_grp", "spi1_0_ss2_grp",
>> +					   "spi1_1_grp", "spi1_1_ss0_grp",
>> +					   "spi1_1_ss1_grp", "spi1_1_ss2_grp",
>> +					   "spi1_2_grp", "spi1_2_ss0_grp",
>> +					   "spi1_2_ss1_grp", "spi1_2_ss2_grp",
>> +					   "spi1_3_grp", "spi1_3_ss0_grp",
>> +					   "spi1_3_ss1_grp", "spi1_3_ss2_grp"};
>>      
> Can we add this to the spiX groups or do we need individual
> spix_ss_groups[] arrays? E.g. for the SD card detect signal and similar
> we have individual groups arrays.
>
> 	Sören
>    

You're right. The cleaner solution is to keep the slave select groups in 
separate spix_ss_groups[] arrays. This also results in additional 
spix_ss pinmux functions. As a result this will be rather similar to the 
PC, WP and CD signals for SDIO. I'll change that and rework my patch.

Thanks,
Helmut

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