openwrt/target/linux/ath79/patches-4.14/461-spi-ath79-add-fast-flash-read.patch

--- a/drivers/spi/spi-ath79.c
+++ b/drivers/spi/spi-ath79.c
@@ -102,9 +102,6 @@ static void ath79_spi_enable(struct ath7
 	/* save CTRL register */
 	sp->reg_ctrl = ath79_spi_rr(sp, AR71XX_SPI_REG_CTRL);
 	sp->ioc_base = ath79_spi_rr(sp, AR71XX_SPI_REG_IOC);
-
-	/* TODO: setup speed? */
-	ath79_spi_wr(sp, AR71XX_SPI_REG_CTRL, 0x43);
 }
 
 static void ath79_spi_disable(struct ath79_spi *sp)
@@ -204,6 +201,38 @@ static u32 ath79_spi_txrx_mode0(struct s
 	return ath79_spi_rr(sp, AR71XX_SPI_REG_RDS);
 }
 
+static bool ath79_spi_flash_read_supported(struct spi_device *spi)
+{
+	if (spi->chip_select || gpio_is_valid(spi->cs_gpio))
+		return false;
+
+	return true;
+}
+
+static int ath79_spi_read_flash_data(struct spi_device *spi,
+				     struct spi_flash_read_message *msg)
+{
+	struct ath79_spi *sp = ath79_spidev_to_sp(spi);
+
+	if (msg->addr_width > 3)
+		return -EOPNOTSUPP;
+
+	/* disable GPIO mode */
+	ath79_spi_wr(sp, AR71XX_SPI_REG_FS, 0);
+
+	memcpy_fromio(msg->buf, sp->base + msg->from, msg->len);
+
+	/* 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);
+
+	msg->retlen = msg->len;
+
+	return 0;
+}
+
 static int ath79_spi_probe(struct platform_device *pdev)
 {
 	struct spi_master *master;
@@ -232,6 +261,8 @@ static int ath79_spi_probe(struct platfo
 		master->bus_num = pdata->bus_num;
 		master->num_chipselect = pdata->num_chipselect;
 	}
+	master->spi_flash_read = ath79_spi_read_flash_data;
+	master->flash_read_supported = ath79_spi_flash_read_supported;
 
 	sp->bitbang.master = master;
 	sp->bitbang.chipselect = ath79_spi_chipselect;