linux-kernel - Re: [RFC PATCH] SPI/ACPI: DesignWare: Add ACPI support for Designware SPI driver

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Date:	Sun, 14 Feb 2016 17:47:47 +0800
From:	Jiang Qiu <qiujiang@...wei.com>
To:	Andy Shevchenko <andy.shevchenko@...il.com>
CC:	Mark Brown <broonie@...nel.org>,
	linux-spi <linux-spi@...r.kernel.org>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	<linuxarm@...wei.com>, <haifeng.wei@...wei.com>,
	<charles.chenxin@...wei.com>
Subject: Re: [RFC PATCH] SPI/ACPI: DesignWare: Add ACPI support for Designware
 SPI driver

Hi Andy,

Sorry for late relpy because Chinese new year holiday. See my replies below.


Best Regards
Jiang

在 2016/2/5 23:55, Andy Shevchenko 写道:
> On Fri, Feb 5, 2016 at 9:11 AM, qiujiang <qiujiang@...wei.com> wrote:
>> This patch added ACPI support for DesignWare SPI mmio driver. It
>> was based the corresponding DT driver and compatible for this two
>> way. This patch has been tested on Hisilicon D02 board. It relies
>> on the GPIO patchset.
> My comments below.
As Mark mentioned, I want to ask you how to use this spi-dw-mmio driver for
ACPI binding? Dose it need any other extra patchset?
>
>> @@ -84,8 +87,6 @@ static int dw_spi_mmio_probe(struct platform_device *pdev)
>>          dws->num_cs = num_cs;
>>
>>          if (pdev->dev.of_node) {
>> -               int i;
>> -
>>                  for (i = 0; i < dws->num_cs; i++) {
>>                          int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
>>                                          "cs-gpios", i);
> It seems the driver was never validated with more than one chip select.
> Perhaps someone has to switch to use of_spi_register_master() here.
of_spi_register_master() will be executed in the spi_register_master(), 
but it just saved the
cs_gpios to the spi_master and not used it any more.
>> @@ -104,6 +105,18 @@ static int dw_spi_mmio_probe(struct platform_device *pdev)
>>                  }
>>          }
>>
>> +       if (ACPI_COMPANION(&pdev->dev)) {
>> +               for (i = 0; i < dws->num_cs; i++) {
>> +                       snprintf(propname, sizeof(propname), "cs%d", i);
>> +                       gpiod = devm_gpiod_get(&pdev->dev,
>> +                               propname, GPIOD_ASIS);
>> +                       if (IS_ERR(gpiod)) {
>> +                               dev_err(&pdev->dev, "Get gpio desc failed!\n");
>> +                               return PTR_ERR(gpiod);
>> +                       }
>> +               }
>> +       }
> Like Mark noticed there is also same issue. Do you indeed check the
> configuration with different chip select signals?
As a spi master driver, it seems that multi-chip select must be 
supported, so this check is
necessary, I think.
>