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mtd: spi-nor: core: do 2 byte reads for SR and FSR in DTR mode 

Some controllers, like the cadence qspi controller, have trouble reading
only 1 byte in DTR mode. So, do 2 byte reads for SR and FSR commands in
DTR mode, and then discard the second byte.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20201005153138.6437-8-p.yadav@ti.com
This commit is contained in:
Pratyush Yadav 2020-10-05 21:01:30 +05:30 committed by Vignesh Raghavendra
parent 6c6a2b2b8e
commit 354b412967
1 changed files with 13 additions and 2 deletions
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15
drivers/mtd/spi-nor/core.c
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@ -370,7 +370,7 @@ int spi_nor_write_disable(struct spi_nor *nor)
* spi_nor_read_sr() - Read the Status Register.
* @nor: pointer to 'struct spi_nor'.
* @sr: pointer to a DMA-able buffer where the value of the
* Status Register will be written.
* Status Register will be written. Should be at least 2 bytes.
*
* Return: 0 on success, -errno otherwise.
*/
@ -388,6 +388,11 @@ static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) {
op.addr.nbytes = nor->params->rdsr_addr_nbytes;
op.dummy.nbytes = nor->params->rdsr_dummy;
/*
* We don't want to read only one byte in DTR mode. So,
* read 2 and then discard the second byte.
*/
op.data.nbytes = 2;
}
spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
@ -408,7 +413,8 @@ static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
* spi_nor_read_fsr() - Read the Flag Status Register.
* @nor: pointer to 'struct spi_nor'
* @fsr: pointer to a DMA-able buffer where the value of the
* Flag Status Register will be written.
* Flag Status Register will be written. Should be at least 2
* bytes.
*
* Return: 0 on success, -errno otherwise.
*/
@ -426,6 +432,11 @@ static int spi_nor_read_fsr(struct spi_nor *nor, u8 *fsr)
if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR) {
op.addr.nbytes = nor->params->rdsr_addr_nbytes;
op.dummy.nbytes = nor->params->rdsr_dummy;
/*
* We don't want to read only one byte in DTR mode. So,
* read 2 and then discard the second byte.
*/
op.data.nbytes = 2;
}
spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);