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Commit d9c73bb8 authored by Baruch Siach's avatar Baruch Siach Committed by Mark Brown
Browse files

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: default avatarBaruch Siach <baruch@tkos.co.il>
Signed-off-by: default avatarMark Brown <broonie@linaro.org>
parent 20e5ea19

drivers/spi/spi-dw-mmio.c

+22 −0
Original line number Diff line number Diff line
@@ -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;

drivers/spi/spi-dw.c

+12 −6
Original line number Diff line number Diff line
@@ -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;

}

drivers/spi/spi-dw.h

+11 −5
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 


#include <linux/io.h>

#include <linux/scatterlist.h>

#include <linux/gpio.h>



/* Register offsets */

#define DW_SPI_CTRL0			0x00
@@ -178,14 +179,19 @@ 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);



	if (active)

		dw_writel(dws, DW_SPI_SER, 1 << cs);

}