Messages in this thread | | | From | <> | Subject | Re: [PATCH v2 6/8] mtd: spi-nor: core: Add helpers to read/write any register | Date | Mon, 11 Apr 2022 07:29:00 +0000 |
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On 3/22/22 01:13, Michael Walle wrote: > Am 2022-02-28 12:17, schrieb Tudor Ambarus: >> There are manufacturers that use registers indexed by address. Some of >> them support "read/write any register" opcodes. Provide core methods that >> can be used by all manufacturers. SPI NOR controller ops are intentionally >> not supported as we intend to move all the SPI NOR controller drivers >> under the SPI subsystem. >> >> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> >> Tested-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com> >> Reviewed-by: Pratyush Yadav <p.yadav@ti.com> >> --- >> drivers/mtd/spi-nor/core.c | 41 ++++++++++++++++++++++++++++++++++++++ >> drivers/mtd/spi-nor/core.h | 4 ++++ >> 2 files changed, 45 insertions(+) >> >> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c >> index 281e3d25f74c..f1aa1e2ea7c9 100644 >> --- a/drivers/mtd/spi-nor/core.c >> +++ b/drivers/mtd/spi-nor/core.c >> @@ -307,6 +307,47 @@ ssize_t spi_nor_write_data(struct spi_nor *nor, >> loff_t to, size_t len, >> return nor->controller_ops->write(nor, to, len, buf); >> } >> >> +/** >> + * spi_nor_read_reg() - read register to flash memory >> + * @nor: pointer to 'struct spi_nor'. >> + * @op: SPI memory operation. op->data.buf must be DMA-able. >> + * @proto: SPI protocol to use for the register operation. >> + * >> + * Return: zero on success, -errno otherwise >> + */ >> +int spi_nor_read_reg(struct spi_nor *nor, struct spi_mem_op *op, >> + enum spi_nor_protocol proto) >> +{ >> + if (!nor->spimem) >> + return -EOPNOTSUPP; >> + >> + spi_nor_spimem_setup_op(nor, op, proto); >> + return spi_nor_spimem_exec_op(nor, op); >> +} >> + >> +/** >> + * spi_nor_write_reg() - write register to flash memory >> + * @nor: pointer to 'struct spi_nor' >> + * @op: SPI memory operation. op->data.buf must be DMA-able. >> + * @proto: SPI protocol to use for the register operation. >> + * >> + * Return: zero on success, -errno otherwise >> + */ >> +int spi_nor_write_reg(struct spi_nor *nor, struct spi_mem_op *op, >> + enum spi_nor_protocol proto) >> +{ >> + int ret; >> + >> + if (!nor->spimem) >> + return -EOPNOTSUPP; >> + >> + ret = spi_nor_write_enable(nor); >> + if (ret) >> + return ret; >> + spi_nor_spimem_setup_op(nor, op, proto); >> + return spi_nor_spimem_exec_op(nor, op); >> +} >> + >> /** >> * spi_nor_write_enable() - Set write enable latch with Write Enable command. >> * @nor: pointer to 'struct spi_nor'. >> diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h >> index f952061d5c24..7c704475946d 100644 >> --- a/drivers/mtd/spi-nor/core.h >> +++ b/drivers/mtd/spi-nor/core.h >> @@ -554,6 +554,10 @@ ssize_t spi_nor_read_data(struct spi_nor *nor, >> loff_t from, size_t len, >> u8 *buf); >> ssize_t spi_nor_write_data(struct spi_nor *nor, loff_t to, size_t len, >> const u8 *buf); >> +int spi_nor_read_reg(struct spi_nor *nor, struct spi_mem_op *op, >> + enum spi_nor_protocol proto); >> +int spi_nor_write_reg(struct spi_nor *nor, struct spi_mem_op *op, >> + enum spi_nor_protocol proto); > > These look rather odd. I'd expect to see an address and such for > such a "random register read/write". Looks like these functions
There are at least 6 function parameters if we want to explicitly pass function arguments: pointer to nor, opcode, addr.nbytes, addr, buf.nbytes, buf. Not to mention ndummy for reads. A bit too much for me, so I preferred passing spi_mem_op directly.
> don't do much except calling spi_nor_spimem_setup_op() and > exec_op() and don't have anything to do with register access > (except maybe for the write enable). Can't we have a bit more > sophisticated interface in the core? Something that calls into > the flash driver to assemble the spi_mem_op automatically? Assuming
Looks liks some ping-pong, passing spi_mem_op directly is straight forward and can address all manufacturer varieties.
So I prefer keeping these generic methods, it will reduce code duplication.
Thanks, ta
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