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authorBaruch Siach <baruch@tkos.co.il>2014-01-31 12:07:47 +0200
committerMark Brown <broonie@linaro.org>2014-04-24 18:09:05 +0100
commitd9c73bb8a3a5e4b76d2ad55da00d9ea776475c81 (patch)
treef711caf00b7025672dc919e5896a597535588111 /drivers/spi
parent20e5ea191524b482e1b4aa12b5ff4684717f44b8 (diff)
downloadlinux-d9c73bb8a3a5e4b76d2ad55da00d9ea776475c81.tar.bz2
spi: dw: add support for gpio controlled chip select
Also, use this opportunity to let spi_chip_sel() handle chip-select deactivation as well. Signed-off-by: Baruch Siach <baruch@tkos.co.il> Signed-off-by: Mark Brown <broonie@linaro.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spi-dw-mmio.c22
-rw-r--r--drivers/spi/spi-dw.c18
-rw-r--r--drivers/spi/spi-dw.h16
3 files changed, 45 insertions, 11 deletions
diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
index 1492f5ee9aaa..a5cba14ac3d2 100644
--- a/drivers/spi/spi-dw-mmio.c
+++ b/drivers/spi/spi-dw-mmio.c
@@ -16,6 +16,7 @@
#include <linux/spi/spi.h>
#include <linux/scatterlist.h>
#include <linux/module.h>
+#include <linux/of_gpio.h>
#include "spi-dw.h"
@@ -70,6 +71,27 @@ static int dw_spi_mmio_probe(struct platform_device *pdev)
dws->num_cs = 4;
dws->max_freq = clk_get_rate(dwsmmio->clk);
+ if (pdev->dev.of_node) {
+ int i;
+
+ for (i = 0; i < dws->num_cs; i++) {
+ int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
+ "cs-gpios", i);
+
+ if (cs_gpio == -EPROBE_DEFER) {
+ ret = cs_gpio;
+ goto out;
+ }
+
+ if (gpio_is_valid(cs_gpio)) {
+ ret = devm_gpio_request(&pdev->dev, cs_gpio,
+ dev_name(&pdev->dev));
+ if (ret)
+ goto out;
+ }
+ }
+ }
+
ret = dw_spi_add_host(&pdev->dev, dws);
if (ret)
goto out;
diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
index 357869a704d6..9965e1b84832 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"
@@ -36,9 +37,6 @@
#define DONE_STATE ((void *)2)
#define ERROR_STATE ((void *)-1)
-#define MRST_SPI_DEASSERT 0
-#define MRST_SPI_ASSERT 1
-
/* Slave spi_dev related */
struct chip_data {
u16 cr0;
@@ -272,8 +270,8 @@ static void giveback(struct dw_spi *dws)
last_transfer = list_last_entry(&msg->transfers, struct spi_transfer,
transfer_list);
- if (!last_transfer->cs_change && dws->cs_control)
- dws->cs_control(MRST_SPI_DEASSERT);
+ if (!last_transfer->cs_change)
+ spi_chip_sel(dws, dws->cur_msg->spi, 0);
spi_finalize_current_message(dws->master);
}
@@ -493,7 +491,7 @@ 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, 1);
/* Set the interrupt mask, for poll mode just disable all int */
spi_mask_intr(dws, 0xff);
@@ -544,6 +542,7 @@ 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);
@@ -597,6 +596,13 @@ 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 = 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 3fd7ab599ab4..6d2acad34f64 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
@@ -178,15 +179,20 @@ 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, struct spi_device *spi,
+ int active)
{
- if (cs > dws->num_cs)
- return;
+ u16 cs = spi->chip_select;
+ int gpio_val = active ? (spi->mode & SPI_CS_HIGH) :
+ !(spi->mode & SPI_CS_HIGH);
if (dws->cs_control)
- dws->cs_control(1);
+ dws->cs_control(active);
+ if (gpio_is_valid(spi->cs_gpio))
+ gpio_set_value(spi->cs_gpio, gpio_val);
- dw_writel(dws, DW_SPI_SER, 1 << cs);
+ if (active)
+ dw_writel(dws, DW_SPI_SER, 1 << cs);
}
/* Disable IRQ bits */