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Commit 3146beec authored by Girish K S's avatar Girish K S Committed by Mark Brown
Browse files

spi: s3c64xx: Added provision for dedicated cs pin 



The existing driver supports gpio based /cs signal.
For controller's that have one device per controller,
the slave device's /cs signal might be internally controlled
by the chip select bit of slave select register. They are not
externally asserted/deasserted using gpio pin.

This patch adds support for controllers with dedicated /cs pin.
if "cs-gpio" property doesnt exist in a spi dts node, the controller
would treat the /cs pin as dedicated.

Signed-off-by: default avatarGirish K S <ks.giri@samsung.com>
Signed-off-by: default avatarMark Brown <broonie@linaro.org>
parent 79617073

drivers/spi/spi-s3c64xx.c

+26 −8
Original line number Diff line number Diff line
@@ -208,6 +208,7 @@ struct s3c64xx_spi_driver_data { 
	struct s3c64xx_spi_port_config	*port_conf;

	unsigned int			port_id;

	unsigned long			gpios[4];

	bool				cs_gpio;

};



static void flush_fifo(struct s3c64xx_spi_driver_data *sdd)
@@ -570,6 +571,7 @@ static inline void enable_cs(struct s3c64xx_spi_driver_data *sdd, 
		if (sdd->tgl_spi != spi) { /* if last mssg on diff device */

			/* Deselect the last toggled device */

			cs = sdd->tgl_spi->controller_data;

			if (sdd->cs_gpio)

				gpio_set_value(cs->line,

					spi->mode & SPI_CS_HIGH ? 0 : 1);

		}
@@ -577,6 +579,7 @@ static inline void enable_cs(struct s3c64xx_spi_driver_data *sdd, 
	}



	cs = spi->controller_data;

	if (sdd->cs_gpio)

		gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 1 : 0);



	/* Start the signals */
@@ -710,6 +713,7 @@ static inline void disable_cs(struct s3c64xx_spi_driver_data *sdd, 
	if (sdd->tgl_spi == spi)

		sdd->tgl_spi = NULL;



	if (sdd->cs_gpio)

		gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 0 : 1);



	/* Quiese the signals */
@@ -998,8 +1002,10 @@ static struct s3c64xx_spi_csinfo *s3c64xx_get_slave_ctrldata( 
{

	struct s3c64xx_spi_csinfo *cs;

	struct device_node *slave_np, *data_np = NULL;

	struct s3c64xx_spi_driver_data *sdd;

	u32 fb_delay = 0;



	sdd = spi_master_get_devdata(spi->master);

	slave_np = spi->dev.of_node;

	if (!slave_np) {

		dev_err(&spi->dev, "device node not found\n");
@@ -1019,7 +1025,10 @@ static struct s3c64xx_spi_csinfo *s3c64xx_get_slave_ctrldata( 
		return ERR_PTR(-ENOMEM);

	}



	/* The CS line is asserted/deasserted by the gpio pin */

	if (sdd->cs_gpio)

		cs->line = of_get_named_gpio(data_np, "cs-gpio", 0);



	if (!gpio_is_valid(cs->line)) {

		dev_err(&spi->dev, "chip select gpio is not specified or invalid\n");

		kfree(cs);
@@ -1059,7 +1068,8 @@ static int s3c64xx_spi_setup(struct spi_device *spi) 
		return -ENODEV;

	}



	if (!spi_get_ctldata(spi)) {

	/* Request gpio only if cs line is asserted by gpio pins */

	if (sdd->cs_gpio) {

		err = gpio_request_one(cs->line, GPIOF_OUT_INIT_HIGH,

				       dev_name(&spi->dev));

		if (err) {
@@ -1068,9 +1078,11 @@ static int s3c64xx_spi_setup(struct spi_device *spi) 
				cs->line, err);

			goto err_gpio_req;

		}

		spi_set_ctldata(spi, cs);

	}



	if (!spi_get_ctldata(spi))

		spi_set_ctldata(spi, cs);



	sci = sdd->cntrlr_info;



	spin_lock_irqsave(&sdd->lock, flags);
@@ -1148,8 +1160,10 @@ static int s3c64xx_spi_setup(struct spi_device *spi) 
static void s3c64xx_spi_cleanup(struct spi_device *spi)

{

	struct s3c64xx_spi_csinfo *cs = spi_get_ctldata(spi);

	struct s3c64xx_spi_driver_data *sdd;



	if (cs) {

	sdd = spi_master_get_devdata(spi->master);

	if (cs && sdd->cs_gpio) {

		gpio_free(cs->line);

		if (spi->dev.of_node)

			kfree(cs);
@@ -1326,7 +1340,11 @@ static int s3c64xx_spi_probe(struct platform_device *pdev) 
	sdd->cntrlr_info = sci;

	sdd->pdev = pdev;

	sdd->sfr_start = mem_res->start;

	sdd->cs_gpio = true;

	if (pdev->dev.of_node) {

		if (!of_find_property(pdev->dev.of_node, "cs-gpio", NULL))

			sdd->cs_gpio = false;



		ret = of_alias_get_id(pdev->dev.of_node, "spi");

		if (ret < 0) {

			dev_err(&pdev->dev, "failed to get alias id, errno %d\n",