From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Brezillon Subject: Re: [PATCH v2 04/11] spi: spi-mem: allow specifying a command's extension Date: Thu, 27 Feb 2020 17:44:06 +0100 Message-ID: <20200227174406.66bf6f84@collabora.com> References: <20200226093703.19765-1-p.yadav@ti.com> <20200226093703.19765-5-p.yadav@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Tudor Ambarus , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Mark Brown , Rob Herring , Mark Rutland , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Sekhar Nori , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org To: Pratyush Yadav Return-path: In-Reply-To: <20200226093703.19765-5-p.yadav-l0cyMroinI0@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: On Wed, 26 Feb 2020 15:06:56 +0530 Pratyush Yadav wrote: > In xSPI mode, flashes expect 2-byte opcodes. The second byte is called > the "command extension". There can be 3 types of extensions in xSPI: > repeat, invert, and hex. When the extension type is "repeat", the same > opcode is sent twice. When it is "invert", the second byte is the > inverse of the opcode. When it is "hex" an additional opcode byte based > is sent with the command whose value can be anything. > > Signed-off-by: Pratyush Yadav > --- > drivers/spi/spi-mem.c | 23 +++++++++++++++++++++++ > include/linux/spi/spi-mem.h | 24 ++++++++++++++++++++++++ > 2 files changed, 47 insertions(+) > > diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c > index cb13e0878b95..3838ddc9aeec 100644 > --- a/drivers/spi/spi-mem.c > +++ b/drivers/spi/spi-mem.c > @@ -462,6 +462,29 @@ int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op) > } > EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size); > > +int spi_mem_get_cmd_ext(const struct spi_mem_op *op, u8 *ext) > +{ > + switch (op->cmd.ext_type) { > + case SPI_MEM_EXT_INVERT: > + *ext = ~op->cmd.opcode; > + break; > + > + case SPI_MEM_EXT_REPEAT: > + *ext = op->cmd.opcode; > + break; > + > + case SPI_MEM_EXT_HEX: > + *ext = op->cmd.ext; > + break; > + > + default: > + return -EINVAL; > + } > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(spi_mem_get_cmd_ext); > + > static ssize_t spi_mem_no_dirmap_read(struct spi_mem_dirmap_desc *desc, > u64 offs, size_t len, void *buf) > { > diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h > index 4669082b4e3b..06ccab17e4d0 100644 > --- a/include/linux/spi/spi-mem.h > +++ b/include/linux/spi/spi-mem.h > @@ -67,11 +67,31 @@ enum spi_mem_data_dir { > SPI_MEM_DATA_OUT, > }; > > +/** > + * enum spi_mem_cmd_ext - describes the command opcode extension in DTR mode > + * @SPI_MEM_EXT_NONE: no extension. This is the default, and is used in Legacy > + * SPI mode > + * @SPI_MEM_EXT_REPEAT: the extension is same as the opcode > + * @SPI_MEM_EXT_INVERT: the extension is the bitwise inverse of the opcode > + * @SPI_MEM_EXT_HEX: the extension is any hex value. The command and opcode > + * combine to form a 16-bit opcode. > + */ > +enum spi_mem_cmd_ext { > + SPI_MEM_EXT_NONE = 0, > + SPI_MEM_EXT_REPEAT, > + SPI_MEM_EXT_INVERT, > + SPI_MEM_EXT_HEX, > +}; > + > /** > * struct spi_mem_op - describes a SPI memory operation > * @cmd.buswidth: number of IO lines used to transmit the command > * @cmd.opcode: operation opcode > * @cmd.is_dtr: whether the command opcode should be sent in DTR mode or not > + * @cmd.ext_type: type of the command opcode extension in DTR mode > + * @cmd.ext: value of the command opcode extension in DTR mode. It is > + * only set when 'ext_type' is 'SPI_MEM_EXT_HEX'. In all other > + * cases, the extension can be directly derived from the opcode. > * @addr.nbytes: number of address bytes to send. Can be zero if the operation > * does not need to send an address > * @addr.buswidth: number of IO lines used to transmit the address cycles > @@ -97,6 +117,8 @@ struct spi_mem_op { > u8 buswidth; > u8 opcode; > bool is_dtr; > + enum spi_mem_cmd_ext ext_type; > + u8 ext; Could we instead make opcode an u16 (or u8[2]) and pass the number of bytes, as done for the other addr? Mode can be extracted from the opcode/nbytes values if really needed, and the caller would be responsible for filling those fields properly (which shouldn't be too hard) > } cmd; > > struct { > @@ -361,6 +383,8 @@ int spi_mem_driver_register_with_owner(struct spi_mem_driver *drv, > > void spi_mem_driver_unregister(struct spi_mem_driver *drv); > > +int spi_mem_get_cmd_ext(const struct spi_mem_op *op, u8 *ext); > + > #define spi_mem_driver_register(__drv) \ > spi_mem_driver_register_with_owner(__drv, THIS_MODULE) >