Re: [PATCH v3 6/9] mtd: spi-nor: core: Add helpers to read/write any register

Michael Walle
2022-04-19T11:27:31Z

Am 2022-04-11 11:10, 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>

I still don't like it because the function doesn't do
anything what the function name might suggest. The read
just executes an op, the write executes an op with a
write enable before. All the behavior is determined by the
'op' argument.

Anyway,
Reviewed-by: Michael Walle <michael@walle.cc>

> ---
> v3: no changes
>
> 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 6165dc7bfd17..42794328d3b6 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);
> int spi_nor_erase_sector(struct spi_nor *nor, u32 addr);
>
> int spi_nor_otp_read_secr(struct spi_nor *nor, loff_t addr, size_t
> len, u8 *buf);

--
-michael