diff options
| author | Linus Walleij | 2019-11-28 09:37:18 +0100 |
|---|---|---|
| committer | Mark Brown | 2019-11-28 13:17:38 +0000 |
| commit | 7251953d784baf7e5416afabe030a0e81de1a938 (patch) | |
| tree | 32f2e2f945597a99da0b0875ee7ad08db17344ea /drivers/spi | |
| parent | 71b8f600b034c7f5780f6fb311dabfe331c64feb (diff) | |
spi: fsl: Handle the single hardwired chipselect case
The Freescale MPC8xxx had a special quirk for handling a
single hardwired chipselect, the case when we're using neither
GPIO nor native chip select: when inspecting the device tree
and finding zero "cs-gpios" on the device node the code would
assume we have a single hardwired chipselect that leaves the
device always selected.
This quirk is not handled by the new core code, so we need
to check the "cs-gpios" explicitly in the driver and set
pdata->max_chipselect = 1 which will later fall through to
the SPI master ->num_chipselect.
Make sure not to assign the chip select handler in this
case: there is no handling needed since the chip is always
selected, and this is what the old code did as well.
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Reported-by: Christophe Leroy <christophe.leroy@c-s.fr>
Fixes: 0f0581b24bd0 ("spi: fsl: Convert to use CS GPIO descriptors")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Christophe Leroy <christophe.leroy@c-s.fr> (No tested the
Link: https://lore.kernel.org/r/20191128083718.39177-3-linus.walleij@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-fsl-spi.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/spi/spi-fsl-spi.c b/drivers/spi/spi-fsl-spi.c index c87e9c4506c2..4b70887cf443 100644 --- a/drivers/spi/spi-fsl-spi.c +++ b/drivers/spi/spi-fsl-spi.c @@ -728,8 +728,18 @@ static int of_fsl_spi_probe(struct platform_device *ofdev) } } #endif - - pdata->cs_control = fsl_spi_cs_control; + /* + * Handle the case where we have one hardwired (always selected) + * device on the first "chipselect". Else we let the core code + * handle any GPIOs or native chip selects and assign the + * appropriate callback for dealing with the CS lines. This isn't + * supported on the GRLIB variant. + */ + ret = gpiod_count(dev, "cs"); + if (ret <= 0) + pdata->max_chipselect = 1; + else + pdata->cs_control = fsl_spi_cs_control; } ret = of_address_to_resource(np, 0, &mem); |