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

[Apurva Nandan <a-nandan@xxxxxx>]

Hi Miquèl,

On 07/08/21 12:36 am, Miquel Raynal wrote:
> Hi Apurva,
>
> Apurva Nandan <a-nandan@xxxxxx> 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@xxxxxx>
> > ---
> >   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
>
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> http://lists.infradead.org/mailman/listinfo/linux-mtd/

Thanks,
Apurva Nandan