Re: [PATCH v2 6/6] of_spi: Initialize cs_gpios and cs_gpio with -EEXIST

Grant Likely
2013-02-11T00:23:25Z

On Tue, 29 Jan 2013 15:53:43 +0100, Andreas Larsson <andreas@gaisler.com> wrote:
> Holes in the cs-gpios DT phandle list is supposed to mark that native
> chipselects is to be used. The value returned from of_get_named_gpio_flags in
> this case is -EEXIST. By initializing cs_gpios and cs_gpio with -EEXIST, this
> and only this errno will indicate to a spi controller driver that a native
> chipselect is to be used.
>
> Signed-off-by: Andreas Larsson <andreas@gaisler.com>

I've left this one off for now. Take a look at the patch I posted and
let me know if you think this one should still be applied.

g.

> ---
> drivers/spi/spi.c | 4 ++--
> include/linux/spi/spi.h | 7 +++++--
> 2 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index 6f1b717..7494bad 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -334,7 +334,7 @@ struct spi_device *spi_alloc_device(struct spi_master *master)
> spi->dev.parent = &master->dev;
> spi->dev.bus = &spi_bus_type;
> spi->dev.release = spidev_release;
> - spi->cs_gpio = -EINVAL;
> + spi->cs_gpio = -EEXIST;
> device_initialize(&spi->dev);
> return spi;
> }
> @@ -1097,7 +1097,7 @@ static int of_spi_register_master(struct spi_master *master)
> }
>
> for (i = 0; i < master->num_chipselect; i++)
> - cs[i] = -EINVAL;
> + cs[i] = -EEXIST;
>
> for (i = 0; i < nb; i++)
> cs[i] = of_get_named_gpio_flags(np, "cs-gpios", i, &flags[i]);
> diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
> index 96b1055..0701882 100644
> --- a/include/linux/spi/spi.h
> +++ b/include/linux/spi/spi.h
> @@ -58,7 +58,8 @@ extern struct bus_type spi_bus_type;
> * @modalias: Name of the driver to use with this device, or an alias
> * for that name. This appears in the sysfs "modalias" attribute
> * for driver coldplugging, and in uevents used for hotplugging
> - * @cs_gpio: Negative or gpio for chip select.
> + * @cs_gpio: Negative or gpio for chip select. Set to -EEXIST when chipselect
> + * should be handled natively by the controller driver
> * @cs_gpio_flags: of_gpio_flags corresponding to cs_gpio
> *
> * A @spi_device is used to interchange data between an SPI slave
> @@ -262,7 +263,9 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
> * @unprepare_transfer_hardware: there are currently no more messages on the
> * queue so the subsystem notifies the driver that it may relax the
> * hardware by issuing this call
> - * @cs_gpios: possible array of negative values or gpios for chip selects
> + * @cs_gpios: possible array of negative values or gpios for chip selects. A
> + * chipselect that should be handled natively by the controller driver is
> + * set to -EEXIST.
> * @cs_gpio_flags: possible array of of_gpio_flags corresponding to cs_gpios
> *
> * Each SPI master controller can communicate with one or more @spi_device
> --
> 1.7.0.4
>

--
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies, Ltd.