| Message ID | 1414423637-2817-1-git-send-email-torfl6749@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Oct 27, 2014 at 03:27:17PM +0000, Torsten Fleischer wrote: > From: Torsten Fleischer <torfl6749@gmail.com> > > Use an empty 'cs-gpios' property if a single device is connected which > has no chip select. > This refers to the discussion at https://lkml.org/lkml/2013/11/13/62. > > Signed-off-by: Torsten Fleischer <torfl6749@gmail.com> > --- > Documentation/devicetree/bindings/spi/spi-gpio.txt | 6 ++++-- > drivers/spi/spi-gpio.c | 10 +++++++--- > 2 files changed, 11 insertions(+), 5 deletions(-) > > diff --git a/Documentation/devicetree/bindings/spi/spi-gpio.txt b/Documentation/devicetree/bindings/spi/spi-gpio.txt > index 8a824be..ad8795f 100644 > --- a/Documentation/devicetree/bindings/spi/spi-gpio.txt > +++ b/Documentation/devicetree/bindings/spi/spi-gpio.txt > @@ -8,8 +8,10 @@ Required properties: > - gpio-sck: GPIO spec for the SCK line to use > - gpio-miso: GPIO spec for the MISO line to use > - gpio-mosi: GPIO spec for the MOSI line to use > - - cs-gpios: GPIOs to use for chipselect lines > - - num-chipselects: number of chipselect lines > + - cs-gpios: GPIOs to use for chipselect lines. Leave this property empty if > + a single device with no chip select is connected. > + - num-chipselects: Number of chipselect lines. Has to be "1" even if a single > + device with no chip select is connected. Why not just have num-chipselectes = <0>, and no cs-gpios property? That would match the HW, and is unambigious as the author has to state explicitly that there are no chipselects. Mark. > > Example: > > diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c > index 9f59553..b343818a 100644 > --- a/drivers/spi/spi-gpio.c > +++ b/drivers/spi/spi-gpio.c > @@ -461,9 +461,13 @@ static int spi_gpio_probe(struct platform_device *pdev) > * property of the node. > */ > > - for (i = 0; i < SPI_N_CHIPSEL; i++) > - spi_gpio->cs_gpios[i] = > - of_get_named_gpio(np, "cs-gpios", i); > + if ((SPI_N_CHIPSEL == 1) && > + (of_gpio_named_count(np, "cs-gpios") == 0)) > + spi_gpio->cs_gpios[0] = SPI_GPIO_NO_CHIPSELECT; > + else > + for (i = 0; i < SPI_N_CHIPSEL; i++) > + spi_gpio->cs_gpios[i] = > + of_get_named_gpio(np, "cs-gpios", i); > } > #endif > > -- > 1.8.4.5 > > -- > To unsubscribe from this list: send the line "unsubscribe devicetree" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- 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
2014-10-27 18:30 GMT+01:00 Mark Rutland <mark.rutland@arm.com>: > On Mon, Oct 27, 2014 at 03:27:17PM +0000, Torsten Fleischer wrote: >> From: Torsten Fleischer <torfl6749@gmail.com> >> >> Use an empty 'cs-gpios' property if a single device is connected which >> has no chip select. >> This refers to the discussion at https://lkml.org/lkml/2013/11/13/62. >> >> Signed-off-by: Torsten Fleischer <torfl6749@gmail.com> >> --- >> Documentation/devicetree/bindings/spi/spi-gpio.txt | 6 ++++-- >> drivers/spi/spi-gpio.c | 10 +++++++--- >> 2 files changed, 11 insertions(+), 5 deletions(-) >> >> diff --git a/Documentation/devicetree/bindings/spi/spi-gpio.txt b/Documentation/devicetree/bindings/spi/spi-gpio.txt >> index 8a824be..ad8795f 100644 >> --- a/Documentation/devicetree/bindings/spi/spi-gpio.txt >> +++ b/Documentation/devicetree/bindings/spi/spi-gpio.txt >> @@ -8,8 +8,10 @@ Required properties: >> - gpio-sck: GPIO spec for the SCK line to use >> - gpio-miso: GPIO spec for the MISO line to use >> - gpio-mosi: GPIO spec for the MOSI line to use >> - - cs-gpios: GPIOs to use for chipselect lines >> - - num-chipselects: number of chipselect lines >> + - cs-gpios: GPIOs to use for chipselect lines. Leave this property empty if >> + a single device with no chip select is connected. >> + - num-chipselects: Number of chipselect lines. Has to be "1" even if a single >> + device with no chip select is connected. > > Why not just have num-chipselectes = <0>, and no cs-gpios property? > > That would match the HW, and is unambigious as the author has to state > explicitly that there are no chipselects. Thanks for the objection. I agree to your proposal. This is a clearer way to describe such a hardware. I will send an updated patch. Torsten -- 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/Documentation/devicetree/bindings/spi/spi-gpio.txt b/Documentation/devicetree/bindings/spi/spi-gpio.txt index 8a824be..ad8795f 100644 --- a/Documentation/devicetree/bindings/spi/spi-gpio.txt +++ b/Documentation/devicetree/bindings/spi/spi-gpio.txt @@ -8,8 +8,10 @@ Required properties: - gpio-sck: GPIO spec for the SCK line to use - gpio-miso: GPIO spec for the MISO line to use - gpio-mosi: GPIO spec for the MOSI line to use - - cs-gpios: GPIOs to use for chipselect lines - - num-chipselects: number of chipselect lines + - cs-gpios: GPIOs to use for chipselect lines. Leave this property empty if + a single device with no chip select is connected. + - num-chipselects: Number of chipselect lines. Has to be "1" even if a single + device with no chip select is connected. Example: diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c index 9f59553..b343818a 100644 --- a/drivers/spi/spi-gpio.c +++ b/drivers/spi/spi-gpio.c @@ -461,9 +461,13 @@ static int spi_gpio_probe(struct platform_device *pdev) * property of the node. */ - for (i = 0; i < SPI_N_CHIPSEL; i++) - spi_gpio->cs_gpios[i] = - of_get_named_gpio(np, "cs-gpios", i); + if ((SPI_N_CHIPSEL == 1) && + (of_gpio_named_count(np, "cs-gpios") == 0)) + spi_gpio->cs_gpios[0] = SPI_GPIO_NO_CHIPSELECT; + else + for (i = 0; i < SPI_N_CHIPSEL; i++) + spi_gpio->cs_gpios[i] = + of_get_named_gpio(np, "cs-gpios", i); } #endif