[PATCH v2 3/5] spi: dw: add support for gpio controlled chip select

[Baruch Siach]

Signed-off-by: Baruch Siach <bar...@tkos.co.il>
---
 drivers/spi/spi-dw.c | 26 +++++++++++++++++++++++---
 drivers/spi/spi-dw.h |  6 +++++-
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
index bf98d63d92b3..69b8772b3ed8 100644
--- a/drivers/spi/spi-dw.c
+++ b/drivers/spi/spi-dw.c
@@ -24,6 +24,7 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/spi/spi.h>
+#include <linux/gpio.h>
 
 #include "spi-dw.h"
 
@@ -265,6 +266,8 @@ static void giveback(struct dw_spi *dws)
        struct spi_transfer *last_transfer;
        unsigned long flags;
        struct spi_message *msg;
+       int cs_gpio = dws->cur_msg->spi->cs_gpio;
+       u16 mode = dws->cur_msg->spi->mode;
 
        spin_lock_irqsave(&dws->lock, flags);
        msg = dws->cur_msg;
@@ -280,8 +283,12 @@ static void giveback(struct dw_spi *dws)
                                        struct spi_transfer,
                                        transfer_list);
 
-       if (!last_transfer->cs_change && dws->cs_control)
-               dws->cs_control(MRST_SPI_DEASSERT);
+       if (!last_transfer->cs_change) {
+               if (dws->cs_control)
+                       dws->cs_control(MRST_SPI_DEASSERT);
+               if (gpio_is_valid(cs_gpio))
+                       gpio_set_value(cs_gpio, !(mode & SPI_CS_HIGH));
+       }
 
        msg->state = NULL;
        if (msg->complete)
@@ -509,7 +516,8 @@ static void pump_transfers(unsigned long data)
                        dw_writew(dws, DW_SPI_CTRL0, cr0);
 
                spi_set_clk(dws, clk_div ? clk_div : chip->clk_div);
-               spi_chip_sel(dws, spi->chip_select);
+               spi_chip_sel(dws, spi->chip_select, spi->cs_gpio,
+                               spi->mode & SPI_CS_HIGH);
 
                /* Set the interrupt mask, for poll mode just disable all int */
                spi_mask_intr(dws, 0xff);
@@ -615,6 +623,7 @@ static int dw_spi_setup(struct spi_device *spi)
 {
        struct dw_spi_chip *chip_info = NULL;
        struct chip_data *chip;
+       int ret;
 
        /* Only alloc on first setup */
        chip = spi_get_ctldata(spi);
@@ -668,6 +677,17 @@ static int dw_spi_setup(struct spi_device *spi)
                        | (spi->mode  << SPI_MODE_OFFSET)
                        | (chip->tmode << SPI_TMOD_OFFSET);
 
+       if (gpio_is_valid(spi->cs_gpio)) {
+               ret = devm_gpio_request(&spi->dev, spi->cs_gpio,
+                               dev_name(&spi->dev));
+               if (ret)
+                       return ret;
+               ret = gpio_direction_output(spi->cs_gpio,
+                               !(spi->mode & SPI_CS_HIGH));
+               if (ret)
+                       return ret;
+       }
+
        return 0;
 }
 
diff --git a/drivers/spi/spi-dw.h b/drivers/spi/spi-dw.h
index 587643dae11e..4a3a6d764b48 100644
--- a/drivers/spi/spi-dw.h
+++ b/drivers/spi/spi-dw.h
@@ -3,6 +3,7 @@
 
 #include <linux/io.h>
 #include <linux/scatterlist.h>
+#include <linux/gpio.h>
 
 /* Register offsets */
 #define DW_SPI_CTRL0                   0x00
@@ -186,13 +187,16 @@ static inline void spi_set_clk(struct dw_spi *dws, u16 
div)
        dw_writel(dws, DW_SPI_BAUDR, div);
 }
 
-static inline void spi_chip_sel(struct dw_spi *dws, u16 cs)
+static inline void spi_chip_sel(struct dw_spi *dws, u16 cs, int cs_gpio,
+               int gpio_active_val)
 {
        if (cs > dws->num_cs)
                return;
 
        if (dws->cs_control)
                dws->cs_control(1);
+       if (gpio_is_valid(cs_gpio))
+               gpio_set_value(cs_gpio, gpio_active_val);
 
        dw_writel(dws, DW_SPI_SER, 1 << cs);
 }
-- 
1.8.5.2

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