[PATCH 5.10 209/593] spi: Allow to have all native CSs in use along with GPIOs

From: Greg Kroah-Hartman
Date: Mon Jul 12 2021 - 02:52:29 EST


From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

[ Upstream commit dbaca8e56ea3f23fa215f48c2d46dd03ede06e02 ]

The commit 7d93aecdb58d ("spi: Add generic support for unused native cs
with cs-gpios") excludes the valid case for the controllers that doesn't
need to switch native CS in order to perform the transfer, i.e. when

0 native
... ...
<n> - 1 native
<n> GPIO
<n> + 1 GPIO
... ...

where <n> defines maximum of native CSs supported by the controller.

To allow this, bail out from spi_get_gpio_descs() conditionally for
the controllers which explicitly marked with SPI_MASTER_GPIO_SS.

Fixes: 7d93aecdb58d ("spi: Add generic support for unused native cs with cs-gpios")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210420164425.40287-1-andriy.shevchenko@xxxxxxxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/spi/spi.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index bd8b1f79dce2..a1a85f0baf7c 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2615,8 +2615,9 @@ static int spi_get_gpio_descs(struct spi_controller *ctlr)
}

ctlr->unused_native_cs = ffz(native_cs_mask);
- if (num_cs_gpios && ctlr->max_native_cs &&
- ctlr->unused_native_cs >= ctlr->max_native_cs) {
+
+ if ((ctlr->flags & SPI_MASTER_GPIO_SS) && num_cs_gpios &&
+ ctlr->max_native_cs && ctlr->unused_native_cs >= ctlr->max_native_cs) {
dev_err(dev, "No unused native chip select available\n");
return -EINVAL;
}
--
2.30.2