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author | Girish K S <girishks2000@gmail.com> | 2013-06-21 11:26:12 +0530 |
---|---|---|
committer | Mark Brown <broonie@linaro.org> | 2013-06-25 11:15:33 +0100 |
commit | 3146beec21b64f4551fcf0ac148381d54dc41b1b (patch) | |
tree | b8fd28466973228956af4931df22bbd013c8aeee /drivers/spi | |
parent | 796170733e50405e3039eacdf5cfb2f08f3eb9ba (diff) | |
download | linux-stable-3146beec21b64f4551fcf0ac148381d54dc41b1b.tar.gz linux-stable-3146beec21b64f4551fcf0ac148381d54dc41b1b.tar.bz2 linux-stable-3146beec21b64f4551fcf0ac148381d54dc41b1b.zip |
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: Girish K S <ks.giri@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r-- | drivers/spi/spi-s3c64xx.c | 34 |
1 files changed, 26 insertions, 8 deletions
diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c index 70b221355400..067f442de2d4 100644 --- a/drivers/spi/spi-s3c64xx.c +++ b/drivers/spi/spi-s3c64xx.c @@ -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) @@ -570,14 +571,16 @@ 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; - gpio_set_value(cs->line, - spi->mode & SPI_CS_HIGH ? 0 : 1); + if (sdd->cs_gpio) + gpio_set_value(cs->line, + spi->mode & SPI_CS_HIGH ? 0 : 1); } sdd->tgl_spi = NULL; } cs = spi->controller_data; - gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 1 : 0); + if (sdd->cs_gpio) + gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 1 : 0); /* Start the signals */ writel(0, sdd->regs + S3C64XX_SPI_SLAVE_SEL); @@ -710,7 +713,8 @@ static inline void disable_cs(struct s3c64xx_spi_driver_data *sdd, if (sdd->tgl_spi == spi) sdd->tgl_spi = NULL; - gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 0 : 1); + if (sdd->cs_gpio) + gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 0 : 1); /* Quiese the signals */ writel(S3C64XX_SPI_SLAVE_SIG_INACT, sdd->regs + S3C64XX_SPI_SLAVE_SEL); @@ -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); } - cs->line = of_get_named_gpio(data_np, "cs-gpio", 0); + /* 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 @@ err_gpio_req: 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", |