[7/8] spi: lpspi: Add cs-gpio support

Commit Message

Clark Wang Jan. 7, 2019, 7:47 a.m. UTC

Add cs-gpio feature for LPSPI.
The cs line will be controlled in fsl_lpspi_transfe_one_msg() function.

Still support using the mode without cs-gpio. It depends on if attribute
cs-gpio has been configured in dts file.

Signed-off-by: Clark Wang <[e-mail]>
---
 drivers/spi/spi-fsl-lpspi.c | 89 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 88 insertions(+), 1 deletion(-)

Comments

Mark Brown Jan. 9, 2019, 12:33 p.m. UTC | #1

On Mon, Jan 07, 2019 at 07:47:47AM +0000, Clark Wang wrote:
> Add cs-gpio feature for LPSPI.
> The cs line will be controlled in fsl_lpspi_transfe_one_msg() function.
> 
> Still support using the mode without cs-gpio. It depends on if attribute
> cs-gpio has been configured in dts file.

This is open coding the GPIO - it'd be better to convert to use
transfer_one() so you can use the core GPIO handling but that's not
really directly relevant to this patch so I'm going to apply, just
something it'd be good to work on.

Patch

diff --git a/drivers/spi/spi-fsl-lpspi.c b/drivers/spi/spi-fsl-lpspi.c
index 69635cde0e22..83e15366b739 100644
--- a/drivers/spi/spi-fsl-lpspi.c
+++ b/drivers/spi/spi-fsl-lpspi.c
@@ -9,6 +9,7 @@ 
 #include <linux/completion.h>
 #include <linux/delay.h>
 #include <linux/err.h>
+#include <linux/gpio.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/irq.h>
@@ -16,7 +17,9 @@ 
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_gpio.h>
 #include <linux/pinctrl/consumer.h>
+#include <linux/platform_data/spi-imx.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>
@@ -28,6 +31,10 @@ 
 
 #define FSL_LPSPI_RPM_TIMEOUT 50 /* 50ms */
 
+#define LPSPI_CS_ACTIVE		1
+#define LPSPI_CS_INACTIVE	0
+#define LPSPI_CS_DELAY		100
+
 /* i.MX7ULP LPSPI registers */
 #define IMX7ULP_VERID	0x0
 #define IMX7ULP_PARAM	0x4
@@ -91,6 +98,7 @@  struct fsl_lpspi_data {
 	struct clk *clk_ipg;
 	struct clk *clk_per;
 	bool is_slave;
+	bool hascsgpio;
 
 	void *rx_buf;
 	const void *tx_buf;
@@ -106,6 +114,8 @@  struct fsl_lpspi_data {
 	struct completion xfer_done;
 
 	bool slave_aborted;
+
+	int chipselect[4];
 };
 
 static const struct of_device_id fsl_lpspi_dt_ids[] = {
@@ -178,6 +188,20 @@  static int lpspi_unprepare_xfer_hardware(struct spi_controller *controller)
 	return 0;
 }
 
+static void fsl_lpspi_chipselect(struct spi_device *spi, bool enable)
+{
+	struct fsl_lpspi_data *fsl_lpspi =
+				spi_controller_get_devdata(spi->controller);
+	int gpio = fsl_lpspi->chipselect[spi->chip_select];
+
+	enable = (!!(spi->mode & SPI_CS_HIGH) == enable);
+
+	if (!gpio_is_valid(gpio))
+		return;
+
+	gpio_set_value_cansleep(gpio, enable);
+}
+
 static void fsl_lpspi_write_tx_fifo(struct fsl_lpspi_data *fsl_lpspi)
 {
 	u8 txfifo_cnt;
@@ -422,6 +446,25 @@  static int fsl_lpspi_transfer_one(struct spi_controller *controller,
 	return 0;
 }
 
+static int fsl_lpspi_setup(struct spi_device *spi)
+{
+	struct fsl_lpspi_data *fsl_lpspi =
+				spi_controller_get_devdata(spi->controller);
+	int gpio = fsl_lpspi->chipselect[spi->chip_select];
+
+	dev_dbg(&spi->dev, "%s: mode %d, %u bpw, %d hz\n", __func__,
+		 spi->mode, spi->bits_per_word, spi->max_speed_hz);
+
+	if (gpio_is_valid(gpio)) {
+		gpio_direction_output(gpio,
+				fsl_lpspi->config.mode & SPI_CS_HIGH ? 0 : 1);
+	}
+
+	fsl_lpspi_chipselect(spi, LPSPI_CS_INACTIVE);
+
+	return 0;
+}
+
 static int fsl_lpspi_transfer_one_msg(struct spi_controller *controller,
 				      struct spi_message *msg)
 {
@@ -430,8 +473,12 @@  static int fsl_lpspi_transfer_one_msg(struct spi_controller *controller,
 	struct spi_device *spi = msg->spi;
 	struct spi_transfer *xfer;
 	bool is_first_xfer = true;
+	bool keep_cs = false;
 	int ret = 0;
 
+	if (fsl_lpspi->hascsgpio)
+		fsl_lpspi_chipselect(spi, LPSPI_CS_ACTIVE);
+
 	msg->status = 0;
 	msg->actual_length = 0;
 
@@ -448,10 +495,24 @@  static int fsl_lpspi_transfer_one_msg(struct spi_controller *controller,
 		if (ret < 0)
 			goto complete;
 
+		if (fsl_lpspi->hascsgpio && xfer->cs_change) {
+			if (list_is_last(&xfer->transfer_list,
+					 &msg->transfers)) {
+				keep_cs = true;
+			} else {
+				fsl_lpspi_chipselect(spi, LPSPI_CS_INACTIVE);
+				udelay(10);
+				fsl_lpspi_chipselect(spi, LPSPI_CS_ACTIVE);
+			}
+		}
+
 		msg->actual_length += xfer->len;
 	}
 
 complete:
+	if (fsl_lpspi->hascsgpio && !keep_cs)
+		fsl_lpspi_chipselect(spi, LPSPI_CS_INACTIVE);
+
 	msg->status = ret;
 	spi_finalize_current_message(controller);
 
@@ -531,10 +592,13 @@  static int fsl_lpspi_init_rpm(struct fsl_lpspi_data *fsl_lpspi)
 
 static int fsl_lpspi_probe(struct platform_device *pdev)
 {
+	struct device_node *np = pdev->dev.of_node;
 	struct fsl_lpspi_data *fsl_lpspi;
 	struct spi_controller *controller;
+	struct spi_imx_master *lpspi_platform_info =
+		dev_get_platdata(&pdev->dev);
 	struct resource *res;
-	int ret, irq;
+	int i, ret, irq;
 	u32 temp;
 
 	if (of_property_read_bool((&pdev->dev)->of_node, "spi-slave"))
@@ -558,6 +622,29 @@  static int fsl_lpspi_probe(struct platform_device *pdev)
 	fsl_lpspi->is_slave = of_property_read_bool((&pdev->dev)->of_node,
 						    "spi-slave");
 
+	fsl_lpspi->hascsgpio = false;
+	if (!fsl_lpspi->is_slave) {
+		for (i = 0; i < controller->num_chipselect; i++) {
+			int cs_gpio = of_get_named_gpio(np, "cs-gpios", i);
+
+			if (!gpio_is_valid(cs_gpio) && lpspi_platform_info)
+				cs_gpio = lpspi_platform_info->chipselect[i];
+
+			fsl_lpspi->chipselect[i] = cs_gpio;
+			if (!gpio_is_valid(cs_gpio))
+				continue;
+
+			ret = devm_gpio_request(&pdev->dev,
+					fsl_lpspi->chipselect[i], DRIVER_NAME);
+			if (ret) {
+				dev_err(&pdev->dev, "can't get cs gpios\n");
+				goto out_controller_put;
+			}
+			controller->setup = fsl_lpspi_setup;
+			fsl_lpspi->hascsgpio = true;
+		}
+	}
+
 	controller->transfer_one_message = fsl_lpspi_transfer_one_msg;
 	controller->prepare_transfer_hardware = lpspi_prepare_xfer_hardware;
 	controller->unprepare_transfer_hardware = lpspi_unprepare_xfer_hardware;