linux-kernel - [PATCH v2 03/11] spi: spi-mem: allow specifying whether an op is DTR or not

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Date:   Wed, 26 Feb 2020 15:06:55 +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>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>
CC:     Pratyush Yadav <p.yadav@...com>, <linux-mtd@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <linux-spi@...r.kernel.org>,
        <devicetree@...r.kernel.org>, Sekhar Nori <nsekhar@...com>
Subject: [PATCH v2 03/11] spi: spi-mem: allow specifying whether an op is DTR or not

Each phase is given a separate 'is_dtr' field so mixed protocols like
4S-4D-4D can be supported.

Also add the mode bits SPI_RX_DTR and SPI_TX_DTR so controllers can
specify whether they support DTR modes or not.

Signed-off-by: Pratyush Yadav <p.yadav@...com>
---
 drivers/spi/spi-mem.c       | 23 +++++++++++++++++++++++
 include/linux/spi/spi-mem.h |  8 ++++++++
 2 files changed, 31 insertions(+)

diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index e5a46f0eb93b..cb13e0878b95 100644
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -99,6 +99,16 @@ void spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
 }
 EXPORT_SYMBOL_GPL(spi_controller_dma_unmap_mem_op_data);
 
+static int spi_check_dtr_req(struct spi_mem *mem, bool tx)
+{
+	u32 mode = mem->spi->mode;
+
+	if ((tx && (mode & SPI_TX_DTR)) || (!tx && (mode & SPI_RX_DTR)))
+		return 0;
+
+	return -ENOTSUPP;
+}
+
 static int spi_check_buswidth_req(struct spi_mem *mem, u8 buswidth, bool tx)
 {
 	u32 mode = mem->spi->mode;
@@ -154,6 +164,19 @@ bool spi_mem_default_supports_op(struct spi_mem *mem,
 				   op->data.dir == SPI_MEM_DATA_OUT))
 		return false;
 
+	if (op->cmd.is_dtr && spi_check_dtr_req(mem, true))
+		return false;
+
+	if (op->addr.is_dtr && spi_check_dtr_req(mem, true))
+		return false;
+
+	if (op->dummy.is_dtr && spi_check_dtr_req(mem, true))
+		return false;
+
+	if (op->data.dir != SPI_MEM_NO_DATA && op->data.is_dtr &&
+	    spi_check_dtr_req(mem, op->data.dir == SPI_MEM_DATA_OUT))
+		return false;
+
 	return true;
 }
 EXPORT_SYMBOL_GPL(spi_mem_default_supports_op);
diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
index af9ff2f0f1b2..4669082b4e3b 100644
--- a/include/linux/spi/spi-mem.h
+++ b/include/linux/spi/spi-mem.h
@@ -71,6 +71,7 @@ enum spi_mem_data_dir {
  * 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
  * @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
@@ -78,10 +79,13 @@ enum spi_mem_data_dir {
  *	      Note that only @addr.nbytes are taken into account in this
  *	      address value, so users should make sure the value fits in the
  *	      assigned number of bytes.
+ * @addr.is_dtr: whether the address should be sent in DTR mode or not
  * @dummy.nbytes: number of dummy bytes to send after an opcode or address. Can
  *		  be zero if the operation does not require dummy bytes
  * @dummy.buswidth: number of IO lanes used to transmit the dummy bytes
+ * @dummy.is_dtr: whether the dummy bytes should be sent in DTR mode or not
  * @data.buswidth: number of IO lanes used to send/receive the data
+ * @data.is_dtr: whether the data should be sent in DTR mode or not
  * @data.dir: direction of the transfer
  * @data.nbytes: number of data bytes to send/receive. Can be zero if the
  *		 operation does not involve transferring data
@@ -92,21 +96,25 @@ struct spi_mem_op {
 	struct {
 		u8 buswidth;
 		u8 opcode;
+		bool is_dtr;
 	} cmd;
 
 	struct {
 		u8 nbytes;
 		u8 buswidth;
 		u64 val;
+		bool is_dtr;
 	} addr;
 
 	struct {
 		u8 nbytes;
 		u8 buswidth;
+		bool is_dtr;
 	} dummy;
 
 	struct {
 		u8 buswidth;
+		bool is_dtr;
 		enum spi_mem_data_dir dir;
 		unsigned int nbytes;
 		union {
-- 
2.25.0