[PATCH 2/2] spi: mediatek: add cs timing configuration support

[Luhua Xu]

Add configure SPI CS setup/hold/idle delays in terms
of clk count support, and use one period of current
spi speed as default if setup/hold/idle not indicated.

Signed-off-by: Luhua Xu <luhua.xu@xxxxxxxxxxxx>
---
 drivers/spi/spi-mt65xx.c                 | 41 +++++++++++++++++++++++++-------
 include/linux/platform_data/spi-mt65xx.h |  5 ++++
 2 files changed, 37 insertions(+), 9 deletions(-)

diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
index f599cce..98df9d1 100644
--- a/drivers/spi/spi-mt65xx.c
+++ b/drivers/spi/spi-mt65xx.c
@@ -140,6 +140,9 @@ static const struct mtk_spi_compatible mt8183_compat = {
  */
 static const struct mtk_chip_config mtk_default_chip_info = {
 	.sample_sel = 0,
+	.setup_cnt = 0,
+	.hold_cnt = 0,
+	.idle_cnt = 0,
 };
 
 static const struct of_device_id mtk_spi_of_match[] = {
@@ -281,10 +284,13 @@ static void mtk_spi_set_cs(struct spi_device *spi, bool enable)
 }
 
 static void mtk_spi_prepare_transfer(struct spi_master *master,
-				     struct spi_transfer *xfer)
+				     struct spi_transfer *xfer,
+				     struct spi_device *spi)
 {
 	u32 spi_clk_hz, div, sck_time, cs_time, reg_val = 0;
 	struct mtk_spi *mdata = spi_master_get_devdata(master);
+	struct mtk_chip_config *chip_config = spi->controller_data;
+	u32 cs_setup, cs_hold, cs_idle;
 
 	spi_clk_hz = clk_get_rate(mdata->spi_clk);
 	if (xfer->speed_hz < spi_clk_hz / 2)
@@ -295,29 +301,46 @@ static void mtk_spi_prepare_transfer(struct spi_master *master,
 	sck_time = (div + 1) / 2;
 	cs_time = sck_time * 2;
 
+	if (chip_config->setup_cnt)
+		cs_setup = chip_config->setup_cnt;
+	else
+		cs_setup = cs_time;
+
+	if (chip_config->hold_cnt)
+		cs_hold = chip_config->hold_cnt;
+	else
+		cs_hold = cs_time;
+
+	if (chip_config->idle_cnt)
+		cs_idle = chip_config->idle_cnt;
+	else
+		cs_idle = cs_time;
+
 	if (mdata->dev_comp->enhance_timing) {
-		reg_val |= (((sck_time - 1) & 0xffff)
+		reg_val = (((sck_time - 1) & 0xffff)
 			   << SPI_CFG0_SCK_HIGH_OFFSET);
 		reg_val |= (((sck_time - 1) & 0xffff)
 			   << SPI_ADJUST_CFG0_SCK_LOW_OFFSET);
 		writel(reg_val, mdata->base + SPI_CFG2_REG);
-		reg_val |= (((cs_time - 1) & 0xffff)
+
+		reg_val = (((cs_hold - 1) & 0xffff)
 			   << SPI_ADJUST_CFG0_CS_HOLD_OFFSET);
-		reg_val |= (((cs_time - 1) & 0xffff)
+		reg_val |= (((cs_setup - 1) & 0xffff)
 			   << SPI_ADJUST_CFG0_CS_SETUP_OFFSET);
 		writel(reg_val, mdata->base + SPI_CFG0_REG);
 	} else {
 		reg_val |= (((sck_time - 1) & 0xff)
 			   << SPI_CFG0_SCK_HIGH_OFFSET);
 		reg_val |= (((sck_time - 1) & 0xff) << SPI_CFG0_SCK_LOW_OFFSET);
-		reg_val |= (((cs_time - 1) & 0xff) << SPI_CFG0_CS_HOLD_OFFSET);
-		reg_val |= (((cs_time - 1) & 0xff) << SPI_CFG0_CS_SETUP_OFFSET);
+		reg_val |= (((cs_hold - 1) & 0xff) << SPI_CFG0_CS_HOLD_OFFSET);
+		reg_val |= (((cs_setup - 1) & 0xff)
+			   << SPI_CFG0_CS_SETUP_OFFSET);
 		writel(reg_val, mdata->base + SPI_CFG0_REG);
 	}
 
 	reg_val = readl(mdata->base + SPI_CFG1_REG);
 	reg_val &= ~SPI_CFG1_CS_IDLE_MASK;
-	reg_val |= (((cs_time - 1) & 0xff) << SPI_CFG1_CS_IDLE_OFFSET);
+	reg_val |= (((cs_idle - 1) & 0xff) << SPI_CFG1_CS_IDLE_OFFSET);
 	writel(reg_val, mdata->base + SPI_CFG1_REG);
 }
 
@@ -426,7 +449,7 @@ static int mtk_spi_fifo_transfer(struct spi_master *master,
 	mdata->cur_transfer = xfer;
 	mdata->xfer_len = min(MTK_SPI_MAX_FIFO_SIZE, xfer->len);
 	mdata->num_xfered = 0;
-	mtk_spi_prepare_transfer(master, xfer);
+	mtk_spi_prepare_transfer(master, xfer, spi);
 	mtk_spi_setup_packet(master);
 
 	cnt = xfer->len / 4;
@@ -458,7 +481,7 @@ static int mtk_spi_dma_transfer(struct spi_master *master,
 	mdata->cur_transfer = xfer;
 	mdata->num_xfered = 0;
 
-	mtk_spi_prepare_transfer(master, xfer);
+	mtk_spi_prepare_transfer(master, xfer, spi);
 
 	cmd = readl(mdata->base + SPI_CMD_REG);
 	if (xfer->tx_buf)
diff --git a/include/linux/platform_data/spi-mt65xx.h b/include/linux/platform_data/spi-mt65xx.h
index 65fd5ffd2..80d280e 100644
--- a/include/linux/platform_data/spi-mt65xx.h
+++ b/include/linux/platform_data/spi-mt65xx.h
@@ -12,5 +12,10 @@
 /* Board specific platform_data */
 struct mtk_chip_config {
 	u32 sample_sel;
+
+	/* CS timing configuration in terms of clock count */
+	u16 setup_cnt;
+	u16 hold_cnt;
+	u8  idle_cnt;
 };
 #endif
-- 
2.6.4