From 8d8cdb4a6ccee5b62cc0dc64651c3946364514dc Mon Sep 17 00:00:00 2001
From: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Date: Mon, 10 Feb 2020 16:11:27 -0300
Subject: [PATCH] spi: ath79: Implement the spi_mem interface

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
---
 drivers/spi/spi-ath79.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

--- a/drivers/spi/spi-ath79.c
+++ b/drivers/spi/spi-ath79.c
@@ -15,6 +15,7 @@
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/spi/spi.h>
+#include <linux/spi/spi-mem.h>
 #include <linux/spi/spi_bitbang.h>
 #include <linux/bitops.h>
 #include <linux/clk.h>
@@ -133,6 +134,39 @@ static u32 ath79_spi_txrx_mode0(struct s
 	return ath79_spi_rr(sp, AR71XX_SPI_REG_RDS);
 }
 
+static int ath79_exec_mem_op(struct spi_mem *mem,
+                              const struct spi_mem_op *op)
+{
+	struct ath79_spi *sp = ath79_spidev_to_sp(mem->spi);
+
+	/* Ensures that reading is performed on device connected
+	   to hardware cs0 */
+	if (mem->spi->chip_select || mem->spi->cs_gpiod)
+		return -ENOTSUPP;
+
+	/* Only use for fast-read op. */
+	if (op->cmd.opcode != 0x0b || op->data.dir != SPI_MEM_DATA_IN ||
+	    op->addr.nbytes != 3 || op->dummy.nbytes != 1)
+		return -ENOTSUPP;
+
+	/* disable GPIO mode */
+	ath79_spi_wr(sp, AR71XX_SPI_REG_FS, 0);
+
+	memcpy_fromio(op->data.buf.in, sp->base + op->addr.val, op->data.nbytes);
+
+	/* enable GPIO mode */
+	ath79_spi_wr(sp, AR71XX_SPI_REG_FS, AR71XX_SPI_FS_GPIO);
+
+	/* restore IOC register */
+	ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, sp->ioc_base);
+
+	return 0;
+}
+
+static const struct spi_controller_mem_ops ath79_mem_ops = {
+	.exec_op = ath79_exec_mem_op,
+};
+
 static int ath79_spi_probe(struct platform_device *pdev)
 {
 	struct spi_master *master;
@@ -163,6 +197,7 @@ static int ath79_spi_probe(struct platfo
 		ret = PTR_ERR(sp->base);
 		goto err_put_master;
 	}
+	master->mem_ops = &ath79_mem_ops;
 
 	sp->clk = devm_clk_get(&pdev->dev, "ahb");
 	if (IS_ERR(sp->clk)) {
