Commit a88e34ea authored by Murali Karicheri's avatar Murali Karicheri Committed by Mark Brown
Browse files

spi: davinci: add support to configure gpio cs through dt 



Currently driver supports only configuration of GPIO CS through
platform data. This patch enhances the driver to configure GPIO
CS through DT. Also update the DT binding documentation to
reflect the availability of cs-gpios.

Signed-off-by: default avatarMurali Karicheri <m-karicheri2@ti.com>
Signed-off-by: default avatarGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: default avatarMark Brown <broonie@linaro.org>
parent 7480e755

Documentation/devicetree/bindings/spi/spi-davinci.txt

+8 −1
Original line number Diff line number Diff line
@@ -8,7 +8,8 @@ Required properties: 
	- "ti,dm6441-spi" for SPI used similar to that on DM644x SoC family

	- "ti,da830-spi" for SPI used similar to that on DA8xx SoC family

- reg: Offset and length of SPI controller register space

- num-cs: Number of chip selects

- num-cs: Number of chip selects. This includes internal as well as

	GPIO chip selects.

- ti,davinci-spi-intr-line: interrupt line used to connect the SPI

	IP to the interrupt controller within the SoC. Possible values

	are 0 and 1. Manual says one of the two possible interrupt
@@ -17,6 +18,12 @@ Required properties: 
- interrupts: interrupt number mapped to CPU.

- clocks: spi clk phandle



Optional:

- cs-gpios: gpio chip selects

	For example to have 3 internal CS and 2 GPIO CS, user could define

	cs-gpios = <0>, <0>, <0>, <&gpio1 30 0>, <&gpio1 31 0>;

	where first three are internal CS and last two are GPIO CS.



Example of a NOR flash slave device (n25q032) connected to DaVinci

SPI controller device over the SPI bus.

drivers/spi/spi-davinci.c

+56 −8
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ 
#include <linux/edma.h>

#include <linux/of.h>

#include <linux/of_device.h>

#include <linux/of_gpio.h>

#include <linux/spi/spi.h>

#include <linux/spi/spi_bitbang.h>

#include <linux/slab.h>
@@ -207,17 +208,28 @@ static inline void clear_io_bits(void __iomem *addr, u32 bits) 
static void davinci_spi_chipselect(struct spi_device *spi, int value)

{

	struct davinci_spi *dspi;

	struct device_node *np = spi->dev.of_node;

	struct davinci_spi_platform_data *pdata;

	struct spi_master *master = spi->master;

	u8 chip_sel = spi->chip_select;

	u16 spidat1 = CS_DEFAULT;

	bool gpio_chipsel = false;

	int gpio;



	dspi = spi_master_get_devdata(spi->master);

	pdata = &dspi->pdata;



	if (pdata->chip_sel && chip_sel < pdata->num_chipselect &&

				pdata->chip_sel[chip_sel] != SPI_INTERN_CS)

	if (np && master->cs_gpios != NULL && spi->cs_gpio >= 0) {

		/* SPI core parse and update master->cs_gpio */

		gpio_chipsel = true;

		gpio = spi->cs_gpio;

	} else if (pdata->chip_sel &&

		   chip_sel < pdata->num_chipselect &&

		   pdata->chip_sel[chip_sel] != SPI_INTERN_CS) {

		/* platform data defines chip_sel */

		gpio_chipsel = true;

		gpio = pdata->chip_sel[chip_sel];

	}



	/*

	 * Board specific chip select logic decides the polarity and cs
@@ -225,9 +237,9 @@ static void davinci_spi_chipselect(struct spi_device *spi, int value) 
	 */

	if (gpio_chipsel) {

		if (value == BITBANG_CS_ACTIVE)

			gpio_set_value(pdata->chip_sel[chip_sel], 0);

			gpio_set_value(gpio, 0);

		else

			gpio_set_value(pdata->chip_sel[chip_sel], 1);

			gpio_set_value(gpio, 1);

	} else {

		if (value == BITBANG_CS_ACTIVE) {

			spidat1 |= SPIDAT1_CSHOLD_MASK;
@@ -390,17 +402,41 @@ static int davinci_spi_setup(struct spi_device *spi) 
	int retval = 0;

	struct davinci_spi *dspi;

	struct davinci_spi_platform_data *pdata;

	struct spi_master *master = spi->master;

	struct device_node *np = spi->dev.of_node;

	bool internal_cs = true;



	dspi = spi_master_get_devdata(spi->master);

	pdata = &dspi->pdata;



	if (!(spi->mode & SPI_NO_CS)) {

		if ((pdata->chip_sel == NULL) ||

		    (pdata->chip_sel[spi->chip_select] == SPI_INTERN_CS))

			set_io_bits(dspi->base + SPIPC0, 1 << spi->chip_select);

		if (np && (master->cs_gpios != NULL) && (spi->cs_gpio >= 0)) {

			unsigned long flags;



			flags = GPIOF_DIR_OUT;

			if (spi->mode & SPI_CS_HIGH)

				flags |= GPIOF_INIT_LOW;

			else

				flags |= GPIOF_INIT_HIGH;

			retval = gpio_request_one(spi->cs_gpio,

						  flags, dev_name(&spi->dev));

			if (retval) {

				dev_err(&spi->dev,

					"GPIO %d request failed (%d)\n",

					spi->cs_gpio, retval);

				return retval;

			}

			internal_cs = false;

		} else if (pdata->chip_sel &&

			   spi->chip_select < pdata->num_chipselect &&

			   pdata->chip_sel[spi->chip_select] != SPI_INTERN_CS) {

			internal_cs = false;

		}

	}



	if (internal_cs)

		set_io_bits(dspi->base + SPIPC0, 1 << spi->chip_select);



	if (spi->mode & SPI_READY)

		set_io_bits(dspi->base + SPIPC0, SPIPC0_SPIENA_MASK);
@@ -412,6 +448,15 @@ static int davinci_spi_setup(struct spi_device *spi) 
	return retval;

}



static void davinci_spi_cleanup(struct spi_device *spi)

{

	struct spi_master *master = spi->master;

	struct device_node *np = spi->dev.of_node;



	if (np && (master->cs_gpios != NULL) && (spi->cs_gpio >= 0))

		gpio_free(spi->cs_gpio);

}



static int davinci_spi_check_error(struct davinci_spi *dspi, int int_status)

{

	struct device *sdev = dspi->bitbang.master->dev.parent;
@@ -810,6 +855,8 @@ static int spi_davinci_get_pdata(struct platform_device *pdev, 


	/*

	 * default num_cs is 1 and all chipsel are internal to the chip

	 * indicated by chip_sel being NULL or cs_gpios being NULL or

	 * set to -ENOENT. num-cs includes internal as well as gpios.

	 * indicated by chip_sel being NULL. GPIO based CS is not

	 * supported yet in DT bindings.

	 */
@@ -921,6 +968,7 @@ static int davinci_spi_probe(struct platform_device *pdev) 
	master->num_chipselect = pdata->num_chipselect;

	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 16);

	master->setup = davinci_spi_setup;

	master->cleanup = davinci_spi_cleanup;



	dspi->bitbang.chipselect = davinci_spi_chipselect;

	dspi->bitbang.setup_transfer = davinci_spi_setup_transfer;

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