linux-kernel - [PATCH v7 02/20] spi: spi-mem: allow specifying a command's extension

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Date:   Fri, 22 May 2020 15:42:43 +0530
From:   Pratyush Yadav <p.yadav@...com>
To:     Tudor Ambarus <tudor.ambarus@...rochip.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        Mark Brown <broonie@...nel.org>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Ludovic Desroches <ludovic.desroches@...rochip.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <linux-spi@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>
CC:     Pratyush Yadav <p.yadav@...com>, Sekhar Nori <nsekhar@...com>,
        Boris Brezillon <boris.brezillon@...labora.com>,
        Mason Yang <masonccyang@...c.com.tw>
Subject: [PATCH v7 02/20] spi: spi-mem: allow specifying a command's extension

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.

So, make opcode a 16-bit value and add a 'nbytes', similar to how
multiple address widths are handled.

Signed-off-by: Pratyush Yadav <p.yadav@...com>
---
 drivers/spi/spi-mem.c       | 5 ++++-
 include/linux/spi/spi-mem.h | 6 +++++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index 93e255287ab9..29dcd1d62710 100644
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -159,6 +159,9 @@ bool spi_mem_default_supports_op(struct spi_mem *mem,
 	if (op->cmd.dtr || op->addr.dtr || op->dummy.dtr || op->data.dtr)
 		return false;
 
+	if (op->cmd.nbytes != 1)
+		return false;
+
 	return true;
 }
 EXPORT_SYMBOL_GPL(spi_mem_default_supports_op);
@@ -173,7 +176,7 @@ static bool spi_mem_buswidth_is_valid(u8 buswidth)
 
 static int spi_mem_check_op(const struct spi_mem_op *op)
 {
-	if (!op->cmd.buswidth)
+	if (!op->cmd.buswidth || !op->cmd.nbytes)
 		return -EINVAL;
 
 	if ((op->addr.nbytes && !op->addr.buswidth) ||
diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
index e3dcb956bf61..159463cc659c 100644
--- a/include/linux/spi/spi-mem.h
+++ b/include/linux/spi/spi-mem.h
@@ -17,6 +17,7 @@
 	{							\
 		.buswidth = __buswidth,				\
 		.opcode = __opcode,				\
+		.nbytes = 1,					\
 	}
 
 #define SPI_MEM_OP_ADDR(__nbytes, __val, __buswidth)		\
@@ -69,6 +70,8 @@ enum spi_mem_data_dir {
 
 /**
  * struct spi_mem_op - describes a SPI memory operation
+ * @cmd.nbytes: number of opcode bytes (only 1 or 2 are valid). The opcode is
+ *		sent MSB-first.
  * @cmd.buswidth: number of IO lines used to transmit the command
  * @cmd.opcode: operation opcode
  * @cmd.dtr: whether the command opcode should be sent in DTR mode or not
@@ -94,9 +97,10 @@ enum spi_mem_data_dir {
  */
 struct spi_mem_op {
 	struct {
+		u8 nbytes;
 		u8 buswidth;
 		u8 dtr : 1;
-		u8 opcode;
+		u16 opcode;
 	} cmd;
 
 	struct {
-- 
2.26.2