linux-kernel - Re: [PATCH v6 2/6] spi: cadence-quadspi: Disable the DAC for Intel LGM SoC

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Date:   Wed, 4 Nov 2020 17:18:44 +0800
From:   "Ramuthevar, Vadivel MuruganX" 
        <vadivel.muruganx.ramuthevar@...ux.intel.com>
To:     Pratyush Yadav <p.yadav@...com>
Cc:     broonie@...nel.org, vigneshr@...com, tudor.ambarus@...rochip.com,
        linux-kernel@...r.kernel.org, linux-spi@...r.kernel.org,
        robh+dt@...nel.org, devicetree@...r.kernel.org,
        miquel.raynal@...tlin.com, simon.k.r.goldschmidt@...il.com,
        dinguyen@...nel.org, richard@....at, cheol.yong.kim@...el.com,
        qi-ming.wu@...el.com
Subject: Re: [PATCH v6 2/6] spi: cadence-quadspi: Disable the DAC for Intel
 LGM SoC

Hi Pratyush,

Thank you for the review comments...

On 4/11/2020 12:09 am, Pratyush Yadav wrote:
> On 30/10/20 01:31PM, Ramuthevar,Vadivel MuruganX wrote:
>> From: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@...ux.intel.com>
>>
>> On Intel Lightning Mountain(LGM) SoCs QSPI controller do not use
>> Direct Access Controller(DAC).
>>
>> This patch adds a quirk to disable the Direct Access Controller
>> for data transfer instead it uses indirect data transfer.
>>
>> Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@...ux.intel.com>
>> ---
>>   drivers/spi/spi-cadence-quadspi.c | 12 ++++++++++++
>>   1 file changed, 12 insertions(+)
>>
>> diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
>> index d7b10c46fa70..6d6f7c440ece 100644
>> --- a/drivers/spi/spi-cadence-quadspi.c
>> +++ b/drivers/spi/spi-cadence-quadspi.c
>> @@ -1107,6 +1107,13 @@ static void cqspi_controller_init(struct cqspi_st *cqspi)
>>   	writel(reg, cqspi->iobase + CQSPI_REG_CONFIG);
>>   
>>   	cqspi_controller_enable(cqspi, 1);
>> +
>> +	/* Disable direct access controller */
>> +	if (!cqspi->use_direct_mode) {
>> +		reg = readl(cqspi->iobase + CQSPI_REG_CONFIG);
>> +		reg &= ~CQSPI_REG_CONFIG_ENB_DIR_ACC_CTRL;
>> +		writel(reg, cqspi->iobase + CQSPI_REG_CONFIG);
>> +	}
> 
> You did not address my comment here from last time around [0]. Please
> replace this hunk with the one below and test it. Also mention in the
> commit message that the DAC bit resets to 1 so there is no need to
> explicitly set it.
Really sorry for that, I will add the below patch as you have suggested 
and test & confirm , thanks!
> 
> --- 8< ---
> diff --git a/drivers/spi/spi-cadence-quadspi.c
> b/drivers/spi/spi-cadence-quadspi.c
> index d7ad8b198a11..d2c5d448a944 100644
> --- a/drivers/spi/spi-cadence-quadspi.c
> +++ b/drivers/spi/spi-cadence-quadspi.c
> @@ -2156,10 +2156,12 @@ static void cqspi_controller_init(struct cqspi_st *cqspi)
>   	writel(cqspi->fifo_depth * cqspi->fifo_width / 8,
>   	       cqspi->iobase + CQSPI_REG_INDIRECTWRWATERMARK);
>   
> -	/* Enable Direct Access Controller */
> -	reg = readl(cqspi->iobase + CQSPI_REG_CONFIG);
> -	reg |= CQSPI_REG_CONFIG_ENB_DIR_ACC_CTRL;
> -	writel(reg, cqspi->iobase + CQSPI_REG_CONFIG);
> +	/* Disable Direct Access Controller */
> +	if (!cqspi->use_dac_mode) {
> +		reg = readl(cqspi->iobase + CQSPI_REG_CONFIG);
> +		reg &= ~CQSPI_REG_CONFIG_ENB_DIR_ACC_CTRL;
> +		writel(reg, cqspi->iobase + CQSPI_REG_CONFIG);
> +	}
>   
>   	cqspi_controller_enable(cqspi, 1);
>   }
> --- >8 ---
> 
> Same disclaimer as last time: not tested at all.
> 
> [0] https://lore.kernel.org/linux-spi/20201022090146.2uj5gfx73dsfumjl@ti.com/
> 
> PS: Please Cc me in the next revision. I missed 3 revisions in between
> because I'm not subscribed to this list. Otherwise I would have sent
> this much sooner :-)
Sure, I will add you in cc, btw last 3 revisions I did only Rob's review 
comments update w.r.t dt_schema.

Regards
Vadivel
> 
>>   }
>>   
>>   static int cqspi_request_mmap_dma(struct cqspi_st *cqspi)
>> @@ -1388,6 +1395,10 @@ static const struct cqspi_driver_platdata am654_ospi = {
>>   	.quirks = CQSPI_NEEDS_WR_DELAY,
>>   };
>>   
>> +static const struct cqspi_driver_platdata intel_lgm_qspi = {
>> +	.quirks = CQSPI_DISABLE_DAC_MODE,
>> +};
>> +
>>   static const struct of_device_id cqspi_dt_ids[] = {
>>   	{
>>   		.compatible = "cdns,qspi-nor",
>> @@ -1403,6 +1414,7 @@ static const struct of_device_id cqspi_dt_ids[] = {
>>   	},
>>   	{
>>   		.compatible = "intel,lgm-qspi",
>> +		.data = &intel_lgm_qspi,
>>   	},
>>   	{ /* end of table */ }
>>   };
>> -- 
>> 2.11.0
>>
>