| Message ID | 1428528961-7838-1-git-send-email-mwelling@ieee.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Apr 08, 2015 at 04:36:01PM -0500, Michael Welling wrote: > This patch allows for GPIOs specified in the devicetree to be used as SPI chipselects > on TI OMAP2 SoCs. Please keep your commit messages under 80 columns. > + if (gpio_is_valid(spi->cs_gpio)) { > + if (gpio_request(spi->cs_gpio, dev_name(&spi->dev)) == 0) > + gpio_direction_output(spi->cs_gpio, > + !(spi->mode & SPI_CS_HIGH)); > + } For this to work we need to be sure that unspecified GPIOs are invalid which isn't normally the default - zero tends to be a valid GPIO and that's also the default for otherwise uninitialized data. Is there something that takes care of this?
I noticed a response to my message on the mailing lists that did not appear in my mailbox. Not sure where it went. Sorry about the over 80 characters in the commit log. As for the question about the uninitialized GPIOs, it is taken care in the core SPI driver. The cs_gpio struct member is initialized to -ENOENT in spi_alloc_device: http://lxr.free-electrons.com/source/drivers/spi/spi.c#L353 If there are GPIOs specified in the devicetree the value is updated: http://lxr.free-electrons.com/source/drivers/spi/spi.c#L440 On Wed, Apr 08, 2015 at 04:36:01PM -0500, Michael Welling wrote: > This patch allows for GPIOs specified in the devicetree to be used as SPI chipselects > on TI OMAP2 SoCs. > > Tested on the AM3354. > > Signed-off-by: Michael Welling <mwelling@ieee.org> > --- > drivers/spi/spi-omap2-mcspi.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c > index 4df8942..464dec9 100644 > --- a/drivers/spi/spi-omap2-mcspi.c > +++ b/drivers/spi/spi-omap2-mcspi.c > @@ -35,6 +35,7 @@ > #include <linux/gcd.h> > > #include <linux/spi/spi.h> > +#include <linux/gpio.h> > > #include <linux/platform_data/spi-omap2-mcspi.h> > > @@ -246,6 +247,9 @@ static void omap2_mcspi_force_cs(struct spi_device *spi, int cs_active) > { > u32 l; > > + if (gpio_is_valid(spi->cs_gpio)) > + gpio_set_value(spi->cs_gpio, (cs_active) ? 0 : 1); > + This may need to be changed to reflect the value of the spi->mode SPI_CS_HIGH bit. It seems that I assumed that the chipselects are active low above. > l = mcspi_cached_chconf0(spi); > if (cs_active) > l |= OMAP2_MCSPI_CHCONF_FORCE; > @@ -1015,6 +1019,12 @@ static int omap2_mcspi_setup(struct spi_device *spi) > if (ret < 0) > return ret; > > + if (gpio_is_valid(spi->cs_gpio)) { > + if (gpio_request(spi->cs_gpio, dev_name(&spi->dev)) == 0) > + gpio_direction_output(spi->cs_gpio, > + !(spi->mode & SPI_CS_HIGH)); > + } > + > ret = omap2_mcspi_setup_transfer(spi, NULL); > pm_runtime_mark_last_busy(mcspi->dev); > pm_runtime_put_autosuspend(mcspi->dev); > -- > 1.7.9.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c index 4df8942..464dec9 100644 --- a/drivers/spi/spi-omap2-mcspi.c +++ b/drivers/spi/spi-omap2-mcspi.c @@ -35,6 +35,7 @@ #include <linux/gcd.h> #include <linux/spi/spi.h> +#include <linux/gpio.h> #include <linux/platform_data/spi-omap2-mcspi.h> @@ -246,6 +247,9 @@ static void omap2_mcspi_force_cs(struct spi_device *spi, int cs_active) { u32 l; + if (gpio_is_valid(spi->cs_gpio)) + gpio_set_value(spi->cs_gpio, (cs_active) ? 0 : 1); + l = mcspi_cached_chconf0(spi); if (cs_active) l |= OMAP2_MCSPI_CHCONF_FORCE; @@ -1015,6 +1019,12 @@ static int omap2_mcspi_setup(struct spi_device *spi) if (ret < 0) return ret; + if (gpio_is_valid(spi->cs_gpio)) { + if (gpio_request(spi->cs_gpio, dev_name(&spi->dev)) == 0) + gpio_direction_output(spi->cs_gpio, + !(spi->mode & SPI_CS_HIGH)); + } + ret = omap2_mcspi_setup_transfer(spi, NULL); pm_runtime_mark_last_busy(mcspi->dev); pm_runtime_put_autosuspend(mcspi->dev);
This patch allows for GPIOs specified in the devicetree to be used as SPI chipselects on TI OMAP2 SoCs. Tested on the AM3354. Signed-off-by: Michael Welling <mwelling@ieee.org> --- drivers/spi/spi-omap2-mcspi.c | 10 ++++++++++ 1 file changed, 10 insertions(+)