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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Mark Brown <broonie@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 209/593] spi: Allow to have all native CSs in use along with GPIOs
Date:   Mon, 12 Jul 2021 08:06:09 +0200
Message-Id: <20210712060905.936042667@linuxfoundation.org>
In-Reply-To: <20210712060843.180606720@linuxfoundation.org>
References: <20210712060843.180606720@linuxfoundation.org>
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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

[ 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@linux.intel.com>
Link: https://lore.kernel.org/r/20210420164425.40287-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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