[V2,14/20] spi: tegra114: add support for gpio based cs

Commit Message

Sowjanya Komatineni April 5, 2019, 12:14 a.m. UTC

This patch adds supports for chip select control using GPIO if valid
CS gpio exists.

Signed-off-by: Sowjanya Komatineni <[e-mail]>
---
 drivers/spi/spi-tegra114.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

Comments

Mark Brown April 8, 2019, 6:30 a.m. UTC | #1

On Thu, Apr 04, 2019 at 05:14:13PM -0700, Sowjanya Komatineni wrote:

> +		if (cstate->cs_gpio_valid) {
> +			int val = (spi->mode & SPI_CS_HIGH) ? 1 : 0;
> +
> +			gpio_set_value(spi->cs_gpio, val);
> +		}

This is adding new usage of the numbered GPIO interface but we're in the
process of trying to transition to GPIO descriptors.  Please update this
patch to use descriptors instead.

Please also investigate if it's possible to use the core GPIO chip
select support more.

Patch

diff --git a/drivers/spi/spi-tegra114.c b/drivers/spi/spi-tegra114.c
index f4e39eb3857c..209ec05a349f 100644
--- a/drivers/spi/spi-tegra114.c
+++ b/drivers/spi/spi-tegra114.c
@@ -23,6 +23,7 @@ 
 #include <linux/dma-mapping.h>
 #include <linux/dmapool.h>
 #include <linux/err.h>
+#include <linux/gpio.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
@@ -167,6 +168,10 @@  struct tegra_spi_soc_data {
 	bool has_intr_mask_reg;
 };
 
+struct tegra_spi_client_state {
+	bool cs_gpio_valid;
+};
+
 struct tegra_spi_data {
 	struct device				*dev;
 	struct spi_master			*master;
@@ -726,6 +731,7 @@  static u32 tegra_spi_setup_transfer_one(struct spi_device *spi,
 		struct spi_transfer *t, bool is_first_of_msg)
 {
 	struct tegra_spi_data *tspi = spi_master_get_devdata(spi->master);
+	struct tegra_spi_client_state *cstate = spi->controller_state;
 	u32 speed = t->speed_hz;
 	u8 bits_per_word = t->bits_per_word;
 	u32 command1;
@@ -787,6 +793,12 @@  static u32 tegra_spi_setup_transfer_one(struct spi_device *spi,
 		else
 			command1 &= ~SPI_CS_SW_VAL;
 
+		if (cstate->cs_gpio_valid) {
+			int val = (spi->mode & SPI_CS_HIGH) ? 1 : 0;
+
+			gpio_set_value(spi->cs_gpio, val);
+		}
+
 		tegra_spi_writel(tspi, 0, SPI_COMMAND2);
 	} else {
 		command1 = tspi->command1_reg;
@@ -843,9 +855,20 @@  static int tegra_spi_start_transfer_one(struct spi_device *spi,
 	return ret;
 }
 
+static void tegra_spi_cleanup(struct spi_device *spi)
+{
+	struct tegra_spi_client_state *cstate = spi->controller_state;
+
+	spi->controller_state = NULL;
+	if (cstate && cstate->cs_gpio_valid)
+		gpio_free(spi->cs_gpio);
+	kfree(cstate);
+}
+
 static int tegra_spi_setup(struct spi_device *spi)
 {
 	struct tegra_spi_data *tspi = spi_master_get_devdata(spi->master);
+	struct tegra_spi_client_state *cstate = spi->controller_state;
 	u32 val;
 	unsigned long flags;
 	int ret;
@@ -856,9 +879,40 @@  static int tegra_spi_setup(struct spi_device *spi)
 		spi->mode & SPI_CPHA ? "" : "~",
 		spi->max_speed_hz);
 
+	if (!cstate) {
+		cstate = kzalloc(sizeof(*cstate), GFP_KERNEL);
+		if (!cstate)
+			return -ENOMEM;
+		spi->controller_state = cstate;
+	}
+
+	if (spi->master->cs_gpios && gpio_is_valid(spi->cs_gpio)) {
+		if (!cstate->cs_gpio_valid) {
+			int gpio_flag = GPIOF_OUT_INIT_HIGH;
+
+			if (spi->mode & SPI_CS_HIGH)
+				gpio_flag = GPIOF_OUT_INIT_LOW;
+
+			ret = gpio_request_one(spi->cs_gpio, gpio_flag,
+					       "cs_gpio");
+			if (ret < 0) {
+				dev_err(&spi->dev,
+					"GPIO request failed: %d\n", ret);
+				tegra_spi_cleanup(spi);
+				return ret;
+			}
+			cstate->cs_gpio_valid = true;
+		} else {
+			int val = (spi->mode & SPI_CS_HIGH) ? 0 : 1;
+
+			gpio_set_value(spi->cs_gpio, val);
+		}
+	}
+
 	ret = pm_runtime_get_sync(tspi->dev);
 	if (ret < 0) {
 		dev_err(tspi->dev, "pm runtime failed, e = %d\n", ret);
+		tegra_spi_cleanup(spi);
 		return ret;
 	}
 
@@ -896,8 +950,12 @@  static void tegra_spi_transfer_delay(int delay)
 static void tegra_spi_transfer_end(struct spi_device *spi)
 {
 	struct tegra_spi_data *tspi = spi_master_get_devdata(spi->master);
+	struct tegra_spi_client_state *cstate = spi->controller_state;
 	int cs_val = (spi->mode & SPI_CS_HIGH) ? 0 : 1;
 
+	if (cstate->cs_gpio_valid)
+		gpio_set_value(spi->cs_gpio, cs_val);
+
 	if (cs_val)
 		tspi->command1_reg |= SPI_CS_SW_VAL;
 	else
@@ -1209,6 +1267,7 @@  static int tegra_spi_probe(struct platform_device *pdev)
 			    SPI_LSBYTE_FIRST;
 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
 	master->setup = tegra_spi_setup;
+	master->cleanup = tegra_spi_cleanup;
 	master->transfer_one_message = tegra_spi_transfer_one_message;
 	master->num_chipselect = MAX_CHIP_SELECT;
 	master->auto_runtime_pm = true;