Commit 354b4129 authored by Pratyush Yadav's avatar Pratyush Yadav Committed by Vignesh Raghavendra
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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: default avatarPratyush Yadav <p.yadav@ti.com>
Signed-off-by: default avatarVignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: default avatarTudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20201005153138.6437-8-p.yadav@ti.com
parent 6c6a2b2b

drivers/mtd/spi-nor/core.c

+13 −2
Original line number Diff line number Diff line
@@ -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);