On Mon, Oct 27, 2014 at 03:27:17PM +0000, Torsten Fleischer wrote: > From: Torsten Fleischer <torfl6749@xxxxxxxxx> > > 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@xxxxxxxxx> > --- > 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@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
