linux-kernel - Re: [PATCH v2 1/4] spi: s3c64xx: changed to PIO mode if there is no DMA

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Message-ID: <e29c3c88-e487-75da-662b-6720a1ef1dc6@samsung.com>
Date:   Wed, 19 Apr 2023 17:31:10 +0900
From:   Jaewon Kim <jaewon02.kim@...sung.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Mark Brown <broonie@...nel.org>, Andi Shyti <andi@...zian.org>,
        Alim Akhtar <alim.akhtar@...sung.com>
Cc:     linux-spi@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Chanho Park <chanho61.park@...sung.com>
Subject: Re: [PATCH v2 1/4] spi: s3c64xx: changed to PIO mode if there is no
 DMA


On 23. 4. 19. 17:03, Krzysztof Kozlowski wrote:
> On 19/04/2023 08:06, Jaewon Kim wrote:
>> Polling mode supported with qurik if there was no DMA in the SOC.
> typo: quirk
> You missed verb in your first part of sentence. I don't understand it.

Sorry, I change this sentence like below.

Polling mode supported as a quirk for SOCs without DMA.

>
>> However, there are cased where we cannot or do not want to use DMA.
>> To support this case, if DMA is not set, it is switched to polling mode.
>>
>> Signed-off-by: Jaewon Kim <jaewon02.kim@...sung.com>
>> ---
>>   drivers/spi/spi-s3c64xx.c                 | 8 ++++++--
>>   include/linux/platform_data/spi-s3c64xx.h | 1 +
>>   2 files changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
>> index 71d324ec9a70..273aa02322d9 100644
>> --- a/drivers/spi/spi-s3c64xx.c
>> +++ b/drivers/spi/spi-s3c64xx.c
>> @@ -19,7 +19,6 @@
>>   #include <linux/platform_data/spi-s3c64xx.h>
>>   
>>   #define MAX_SPI_PORTS		12
>> -#define S3C64XX_SPI_QUIRK_POLL		(1 << 0)
>>   #define S3C64XX_SPI_QUIRK_CS_AUTO	(1 << 1)
>>   #define AUTOSUSPEND_TIMEOUT	2000
>>   
>> @@ -116,7 +115,7 @@
>>   #define S3C64XX_SPI_TRAILCNT		S3C64XX_SPI_MAX_TRAILCNT
>>   
>>   #define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
>> -#define is_polling(x)	(x->port_conf->quirks & S3C64XX_SPI_QUIRK_POLL)
>> +#define is_polling(x)	(x->cntrlr_info->polling)
>>   
>>   #define RXBUSY    (1<<2)
>>   #define TXBUSY    (1<<3)
>> @@ -1067,6 +1066,11 @@ static struct s3c64xx_spi_info *s3c64xx_spi_parse_dt(struct device *dev)
>>   		sci->num_cs = temp;
>>   	}
>>   
>> +	if (!of_find_property(dev->of_node, "dmas", NULL)) {
>> +		dev_warn(dev, "cannot find DMA, changed to PIO mode\n");
> You said it is desired option, so should not be a warning. I would make
> it debug at most.
>
Okay, I will change dev_warn() to dev_dbg().


>> +		sci->polling = 1;
>
>
> Best regards,
> Krzysztof
>
>

Thanks

Jaewon Kim