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Subject: Re: [PATCH 1/3] SPI: Ingenic: Add support for use GPIO as chip select
 line.
To:     Paul Cercueil <paul@crapouillou.net>
Cc:     broonie@kernel.org, robh+dt@kernel.org, krzk+dt@kernel.org,
        linux-spi@vger.kernel.org, linux-mips@vger.kernel.org,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        contact@artur-rojek.eu, dongsheng.qiu@ingenic.com,
        aric.pzqi@ingenic.com, rick.tyliu@ingenic.com,
        sernia.zhou@foxmail.com, zhenwenjin@gmail.com, reimu@sudomaker.com
References: <1650032528-118220-1-git-send-email-zhouyanjie@wanyeetech.com>
 <1650032528-118220-2-git-send-email-zhouyanjie@wanyeetech.com>
 <61ZDAR.SD20HFTWMIBH3@crapouillou.net>
From:   Zhou Yanjie <zhouyanjie@wanyeetech.com>
Message-ID: <d7926a1d-c5e3-6519-6a52-1bd3ca3cf773@wanyeetech.com>
Date:   Sat, 16 Apr 2022 19:55:13 +0800
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Hi Paul,

On 2022/4/15 下午11:00, Paul Cercueil wrote:
> Hi Zhou,
>
> Le ven., avril 15 2022 at 22:22:06 +0800, 周琰杰 (Zhou Yanjie) 
> <zhouyanjie@wanyeetech.com> a écrit :
>> Add support for using GPIOs as chip select lines on Ingenic SoCs.
>>
>> Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
>> ---
>>  drivers/spi/spi-ingenic.c | 11 +++++++++--
>>  1 file changed, 9 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/spi/spi-ingenic.c b/drivers/spi/spi-ingenic.c
>> index 03077a7..672e4ed 100644
>> --- a/drivers/spi/spi-ingenic.c
>> +++ b/drivers/spi/spi-ingenic.c
>> @@ -380,7 +380,7 @@ static int spi_ingenic_probe(struct 
>> platform_device *pdev)
>>      struct spi_controller *ctlr;
>>      struct ingenic_spi *priv;
>>      void __iomem *base;
>> -    int ret;
>> +    int num_cs, ret;
>>
>>      pdata = of_device_get_match_data(dev);
>>      if (!pdata) {
>> @@ -416,6 +416,11 @@ static int spi_ingenic_probe(struct 
>> platform_device *pdev)
>>      if (IS_ERR(priv->flen_field))
>>          return PTR_ERR(priv->flen_field);
>>
>> +    if (of_property_read_u32(dev->of_node, "num-cs", &num_cs)) {
>> +        dev_warn(dev, "Number of chip select lines not specified.\n");
>> +        num_cs = 2;
>> +    }
>> +
>>      platform_set_drvdata(pdev, ctlr);
>>
>>      ctlr->prepare_transfer_hardware = spi_ingenic_prepare_hardware;
>> @@ -429,7 +434,9 @@ static int spi_ingenic_probe(struct 
>> platform_device *pdev)
>>      ctlr->bits_per_word_mask = pdata->bits_per_word_mask;
>>      ctlr->min_speed_hz = 7200;
>>      ctlr->max_speed_hz = 54000000;
>> -    ctlr->num_chipselect = 2;
>> +    ctlr->use_gpio_descriptors = true;
>
> I wonder if this should be set conditionally instead. Maybe set it to 
> "true" if the "num-cs" property exists?
>

I'm not too sure, but it seems some other drivers like "spi-sun6i.c", 
"spi-stm32.c", "spi-s3c64xx.c", "spi-pic32.c", etc. set it unconditionally.


> The rest looks good to me.
>
> Cheers,
> -Paul
>
>> +    ctlr->max_native_cs = 2;
>> +    ctlr->num_chipselect = num_cs;
>>      ctlr->dev.of_node = pdev->dev.of_node;
>>
>>      if (spi_ingenic_request_dma(ctlr, dev))
>> -- 
>> 2.7.4
>>
>