linux-kernel - Re: [PATCH 10/13] mtd: spinand: Add octal_dtr_enable() for Winbond manufacturer_ops

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Date:   Fri, 20 Aug 2021 17:01:40 +0530
From:   Apurva Nandan <a-nandan@...com>
To:     Miquel Raynal <miquel.raynal@...tlin.com>
CC:     Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        Mark Brown <broonie@...nel.org>,
        Patrice Chotard <patrice.chotard@...s.st.com>,
        Boris Brezillon <boris.brezillon@...labora.com>,
        <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <linux-spi@...r.kernel.org>, Pratyush Yadav <p.yadav@...com>
Subject: Re: [PATCH 10/13] mtd: spinand: Add octal_dtr_enable() for Winbond
 manufacturer_ops

Hi Miquèl,

On 07/08/21 12:36 am, Miquel Raynal wrote:
> Hi Apurva,
> 
> Apurva Nandan <a-nandan@...com> wrote on Tue, 13 Jul 2021 13:05:35
> +0000:
> 
>> Add implementation of octal_dtr_enable() manufacturer_ops for Winbond.
>> To switch to Ocatl DTR mode, setting programmable dummy cycles and
>> SPI IO mode using the volatile configuration register is required. To
>> function at max 120MHz SPI clock in Octal DTR mode, 12 programmable
>> dummy clock cycle setting is required. (Default number of dummy cycle
>> are 8 clocks)
>>
>> Set the programmable dummy cycle to 12 clocks, and SPI IO mode to
>> Octal DTR with Data Strobe in the VCR. Also, perform a READ ID
>> operation in Octal DTR SPI mode to ensure the switch was successful.
> 
> Commit title should contain "winbond:" (same for the previous patch and
> possibly next ones as well).
> 

Okay, got it!

>> Datasheet: https://www.winbond.com/export/sites/winbond/datasheet/W35N01JW_Datasheet_Brief.pdf
>>
>> Signed-off-by: Apurva Nandan <a-nandan@...com>
>> ---
>>   drivers/mtd/nand/spi/winbond.c | 42 ++++++++++++++++++++++++++++++++++
>>   1 file changed, 42 insertions(+)
>>
>> diff --git a/drivers/mtd/nand/spi/winbond.c b/drivers/mtd/nand/spi/winbond.c
>> index a7052a9ca171..58cda07c15a0 100644
>> --- a/drivers/mtd/nand/spi/winbond.c
>> +++ b/drivers/mtd/nand/spi/winbond.c
>> @@ -16,6 +16,14 @@
>>   
>>   #define WINBOND_CFG_BUF_READ		BIT(3)
>>   
>> +/* Octal DTR SPI mode (8D-8D-8D) with Data Strobe output*/
>> +#define WINBOND_IO_MODE_VCR_OCTAL_DTR	0xE7
>> +#define WINBOND_IO_MODE_VCR_ADDR	0x00
>> +
>> +/* Use 12 dummy clk cycles for using Octal DTR SPI at max 120MHZ */
>> +#define WINBOND_DUMMY_CLK_COUNT		12
>> +#define WINBOND_DUMMY_CLK_VCR_ADDR	0x01
>> +
>>   static SPINAND_OP_VARIANTS(read_cache_variants,
>>   		SPINAND_PAGE_READ_FROM_CACHE_QUADIO_OP(0, 2, NULL, 0),
>>   		SPINAND_PAGE_READ_FROM_CACHE_X4_OP(0, 1, NULL, 0),
>> @@ -142,8 +150,42 @@ static int winbond_write_vcr_op(struct spinand_device *spinand, u8 reg, u8 val)
>>   	return 0;
>>   }
>>   
>> +static int winbond_spinand_octal_dtr_enable(struct spinand_device *spinand)
>> +{
>> +	int ret;
>> +	struct spi_mem_op op;
>> +
>> +	ret = winbond_write_vcr_op(spinand, WINBOND_DUMMY_CLK_VCR_ADDR,
>> +				   WINBOND_DUMMY_CLK_COUNT);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = winbond_write_vcr_op(spinand, WINBOND_IO_MODE_VCR_ADDR,
>> +				   WINBOND_IO_MODE_VCR_OCTAL_DTR);
>> +	if (ret)
>> +		return ret;
>> +
>> +	/* Read flash ID to make sure the switch was successful. */
>> +	op = (struct spi_mem_op)
>> +		SPI_MEM_OP(SPI_MEM_OP_CMD_DTR(2, 0x9f9f, 8),
>> +			   SPI_MEM_OP_NO_ADDR,
>> +			   SPI_MEM_OP_DUMMY_DTR(16, 8),
>> +			   SPI_MEM_OP_DATA_IN_DTR(SPINAND_MAX_ID_LEN,
>> +						  spinand->scratchbuf, 8));
>> +
>> +	ret = spi_mem_exec_op(spinand->spimem, &op);
>> +	if (ret)
>> +		return ret;
>> +
>> +	if (memcmp(spinand->scratchbuf, spinand->id.data, SPINAND_MAX_ID_LEN))
>> +		return -EINVAL;
>> +
>> +	return 0;
>> +}
>> +
>>   static const struct spinand_manufacturer_ops winbond_spinand_manuf_ops = {
>>   	.init = winbond_spinand_init,
>> +	.octal_dtr_enable = winbond_spinand_octal_dtr_enable,
>>   };
>>   
>>   const struct spinand_manufacturer winbond_spinand_manufacturer = {
> 
> 
> 
> 
> Thanks,
> Miquèl
> 
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/
> 

Thanks,
Apurva Nandan

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