spi: imx/fsl-lpspi: Convert to GPIO descriptors

This converts the two Freescale i.MX SPI drivers
Freescale i.MX (CONFIG_SPI_IMX) and Freescale i.MX LPSPI
(CONFIG_SPI_FSL_LPSPI) to use GPIO descriptors handled in
the SPI core for GPIO chip selects whether defined in
the device tree or a board file.

The reason why both are converted at the same time is
that they were both using the same platform data and
platform device population helpers when using
board files intertwining the code so this gives a cleaner
cut.

The platform device creation was passing a platform data
container from each boardfile down to the driver using
struct spi_imx_master from <linux/platform_data/spi-imx.h>,
but this was only conveying the number of chipselects and
an int * array of the chipselect GPIO numbers.

The imx27 and imx31 platforms had code passing the
now-unused platform data when creating the platform devices,
this has been repurposed to pass around GPIO descriptor
tables. The platform data struct that was just passing an
array of integers and number of chip selects for the GPIO
lines has been removed.

The number of chipselects used to be passed from the board
file, because this number also limits the number of native
chipselects that the platform can use. To deal with this we
just augment the i.MX (CONFIG_SPI_IMX) driver to support 3
chipselects if the platform does not define "num-cs" as a
device property (such as from the device tree). This covers
all the legacy boards as these use <= 3 native chip selects
(or GPIO lines, and in that case the number of chip selects
is determined by the core from the number of available
GPIO lines). Any new boards should use device tree, so
this is a reasonable simplification to cover all old
boards.

The LPSPI driver never assigned the number of chipselects
and thus always fall back to the core default of 1 chip
select if no GPIOs are defined in the device tree.

The Freescale i.MX driver was already partly utilizing
the SPI core to obtain the GPIO numbers from the device tree,
so this completes the transtion to let the core handle all
of it.

All board files and the core i.MX boardfile registration
code is augmented to account for these changes.

This has been compile-tested with the imx_v4_v5_defconfig
and the imx_v6_v7_defconfig.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Shawn Guo <shawnguo@kernel.org>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Robin Gong <yibin.gong@nxp.com>
Cc: Trent Piepho <tpiepho@impinj.com>
Cc: Clark Wang <xiaoning.wang@nxp.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Link: https://lore.kernel.org/r/20200625200252.207614-1-linus.walleij@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 16 insertions, 76 deletions

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 2b8d339f1936..fdc25f549378 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -8,7 +8,6 @@
 #include <linux/dmaengine.h>
 #include <linux/dma-mapping.h>
 #include <linux/err.h>
-#include <linux/gpio.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/irq.h>
@@ -21,10 +20,9 @@
 #include <linux/types.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
-#include <linux/of_gpio.h>
+#include <linux/property.h>
 
 #include <linux/platform_data/dma-imx.h>
-#include <linux/platform_data/spi-imx.h>
 
 #define DRIVER_NAME "spi_imx"
 
@@ -723,7 +721,7 @@ static int mx31_prepare_transfer(struct spi_imx_data *spi_imx,
 		reg |= MX31_CSPICTRL_POL;
 	if (spi->mode & SPI_CS_HIGH)
 		reg |= MX31_CSPICTRL_SSPOL;
-	if (!gpio_is_valid(spi->cs_gpio))
+	if (!spi->cs_gpiod)
 		reg |= (spi->chip_select) <<
 			(is_imx35_cspi(spi_imx) ? MX35_CSPICTRL_CS_SHIFT :
 						  MX31_CSPICTRL_CS_SHIFT);
@@ -824,7 +822,7 @@ static int mx21_prepare_transfer(struct spi_imx_data *spi_imx,
 		reg |= MX21_CSPICTRL_POL;
 	if (spi->mode & SPI_CS_HIGH)
 		reg |= MX21_CSPICTRL_SSPOL;
-	if (!gpio_is_valid(spi->cs_gpio))
+	if (!spi->cs_gpiod)
 		reg |= spi->chip_select << MX21_CSPICTRL_CS_SHIFT;
 
 	writel(reg, spi_imx->base + MXC_CSPICTRL);
@@ -1056,20 +1054,6 @@ static const struct of_device_id spi_imx_dt_ids[] = {
 };
 MODULE_DEVICE_TABLE(of, spi_imx_dt_ids);
 
-static void spi_imx_chipselect(struct spi_device *spi, int is_active)
-{
-	int active = is_active != BITBANG_CS_INACTIVE;
-	int dev_is_lowactive = !(spi->mode & SPI_CS_HIGH);
-
-	if (spi->mode & SPI_NO_CS)
-		return;
-
-	if (!gpio_is_valid(spi->cs_gpio))
-		return;
-
-	gpio_set_value(spi->cs_gpio, dev_is_lowactive ^ active);
-}
-
 static void spi_imx_set_burst_len(struct spi_imx_data *spi_imx, int n_bits)
 {
 	u32 ctrl;
@@ -1533,15 +1517,6 @@ static int spi_imx_setup(struct spi_device *spi)
 	dev_dbg(&spi->dev, "%s: mode %d, %u bpw, %d hz\n", __func__,
 		 spi->mode, spi->bits_per_word, spi->max_speed_hz);
 
-	if (spi->mode & SPI_NO_CS)
-		return 0;
-
-	if (gpio_is_valid(spi->cs_gpio))
-		gpio_direction_output(spi->cs_gpio,
-				      spi->mode & SPI_CS_HIGH ? 0 : 1);
-
-	spi_imx_chipselect(spi, BITBANG_CS_INACTIVE);
-
 	return 0;
 }
 
@@ -1599,20 +1574,14 @@ static int spi_imx_probe(struct platform_device *pdev)
 	struct device_node *np = pdev->dev.of_node;
 	const struct of_device_id *of_id =
 			of_match_device(spi_imx_dt_ids, &pdev->dev);
-	struct spi_imx_master *mxc_platform_info =
-			dev_get_platdata(&pdev->dev);
 	struct spi_master *master;
 	struct spi_imx_data *spi_imx;
 	struct resource *res;
-	int i, ret, irq, spi_drctl;
+	int ret, irq, spi_drctl;
 	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;
-
-	if (!np && !mxc_platform_info) {
-		dev_err(&pdev->dev, "can't get the platform data\n");
-		return -EINVAL;
-	}
+	u32 val;
 
 	slave_mode = devtype_data->has_slavemode &&
 			of_property_read_bool(np, "spi-slave");
@@ -1635,6 +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;
 
 	spi_imx = spi_master_get_devdata(master);
 	spi_imx->bitbang.master = master;
@@ -1643,28 +1613,17 @@ static int spi_imx_probe(struct platform_device *pdev)
 
 	spi_imx->devtype_data = devtype_data;
 
-	/* Get number of chip selects, either platform data or OF */
-	if (mxc_platform_info) {
-		master->num_chipselect = mxc_platform_info->num_chipselect;
-		if (mxc_platform_info->chipselect) {
-			master->cs_gpios = devm_kcalloc(&master->dev,
-				master->num_chipselect, sizeof(int),
-				GFP_KERNEL);
-			if (!master->cs_gpios)
-				return -ENOMEM;
-
-			for (i = 0; i < master->num_chipselect; i++)
-				master->cs_gpios[i] = mxc_platform_info->chipselect[i];
-		}
-	} else {
-		u32 num_cs;
-
-		if (!of_property_read_u32(np, "num-cs", &num_cs))
-			master->num_chipselect = num_cs;
-		/* If not preset, default value of 1 is used */
-	}
+	/*
+	 * 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.chipselect = spi_imx_chipselect;
 	spi_imx->bitbang.setup_transfer = spi_imx_setupxfer;
 	spi_imx->bitbang.txrx_bufs = spi_imx_transfer;
 	spi_imx->bitbang.master->setup = spi_imx_setup;
@@ -1749,31 +1708,12 @@ static int spi_imx_probe(struct platform_device *pdev)
 		goto out_clk_put;
 	}
 
-	/* Request GPIO CS lines, if any */
-	if (!spi_imx->slave_mode && master->cs_gpios) {
-		for (i = 0; i < master->num_chipselect; i++) {
-			if (!gpio_is_valid(master->cs_gpios[i]))
-				continue;
-
-			ret = devm_gpio_request(&pdev->dev,
-						master->cs_gpios[i],
-						DRIVER_NAME);
-			if (ret) {
-				dev_err(&pdev->dev, "Can't get CS GPIO %i\n",
-					master->cs_gpios[i]);
-				goto out_spi_bitbang;
-			}
-		}
-	}
-
 	dev_info(&pdev->dev, "probed\n");
 
 	clk_disable(spi_imx->clk_ipg);
 	clk_disable(spi_imx->clk_per);
 	return ret;
 
-out_spi_bitbang:
-	spi_bitbang_stop(&spi_imx->bitbang);
 out_clk_put:
 	clk_disable_unprepare(spi_imx->clk_ipg);
 out_put_per: