[PATCH] spi-imx: remove num-cs support, set num_chipselect to 4

From: Matthias Schiffer
Date: Thu Sep 03 2020 - 10:41:46 EST


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@xxxxxxxxxxxxxxx>
---
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