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From:   Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
To:     Mark Brown <broonie@kernel.org>, Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>
Cc:     Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org,
        Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Subject: [PATCH] spi-imx: remove num-cs support, set num_chipselect to 4
Date:   Thu,  3 Sep 2020 16:40:28 +0200
Message-Id: <20200903144028.20416-1-matthias.schiffer@ew.tq-group.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The num-cs property is not considered useful, and no in-tree Device
Trees define it for spi-imx.

The default value to be used when no cs-gpios are defined is set to 4 to
give access to all native CS pins of modern i.MX SoCs (i.MX6 and newer).

In older SoCs, the number of CS pins varies (for example the i.MX27 has 3
CS pins on CSPI1 and CSPI2, and only a single CS on CSPI3). Attempting
to use the nonexisting CS pin would be an easy to notice DT
misconfiguration; making the driver catch this doesn't seem worthwhile.

Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
---
 drivers/spi/spi-imx.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 197f60632072..aece8482739b 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -1581,7 +1581,6 @@ static int spi_imx_probe(struct platform_device *pdev)
 	const struct spi_imx_devtype_data *devtype_data = of_id ? of_id->data :
 		(struct spi_imx_devtype_data *)pdev->id_entry->driver_data;
 	bool slave_mode;
-	u32 val;
 
 	slave_mode = devtype_data->has_slavemode &&
 			of_property_read_bool(np, "spi-slave");
@@ -1605,6 +1604,7 @@ static int spi_imx_probe(struct platform_device *pdev)
 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
 	master->bus_num = np ? -1 : pdev->id;
 	master->use_gpio_descriptors = true;
+	master->num_chipselect = 4;
 
 	spi_imx = spi_master_get_devdata(master);
 	spi_imx->bitbang.master = master;
@@ -1613,17 +1613,6 @@ static int spi_imx_probe(struct platform_device *pdev)
 
 	spi_imx->devtype_data = devtype_data;
 
-	/*
-	 * Get number of chip selects from device properties. This can be
-	 * coming from device tree or boardfiles, if it is not defined,
-	 * a default value of 3 chip selects will be used, as all the legacy
-	 * board files have <= 3 chip selects.
-	 */
-	if (!device_property_read_u32(&pdev->dev, "num-cs", &val))
-		master->num_chipselect = val;
-	else
-		master->num_chipselect = 3;
-
 	spi_imx->bitbang.setup_transfer = spi_imx_setupxfer;
 	spi_imx->bitbang.txrx_bufs = spi_imx_transfer;
 	spi_imx->bitbang.master->setup = spi_imx_setup;
-- 
2.17.1