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Commit c97dce79 authored by Justin Chen's avatar Justin Chen Committed by Jonathan Cameron
Browse files

iio: adc: ti-ads7950: add GPIO support 



The ADS79XX has GPIO pins that can be used. Add support for the GPIO
pins using the GPIO chip framework.

Signed-off-by: default avatarJustin Chen <justinpopo6@gmail.com>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 13814627

drivers/iio/adc/ti-ads7950.c

+194 −6
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/bitops.h>

#include <linux/device.h>

#include <linux/err.h>

#include <linux/gpio/driver.h>

#include <linux/interrupt.h>

#include <linux/kernel.h>

#include <linux/module.h>
@@ -36,12 +37,15 @@ 
 */

#define TI_ADS7950_VA_MV_ACPI_DEFAULT	5000



#define TI_ADS7950_CR_GPIO	BIT(14)

#define TI_ADS7950_CR_MANUAL	BIT(12)

#define TI_ADS7950_CR_WRITE	BIT(11)

#define TI_ADS7950_CR_CHAN(ch)	((ch) << 7)

#define TI_ADS7950_CR_RANGE_5V	BIT(6)

#define TI_ADS7950_CR_GPIO_DATA	BIT(4)



#define TI_ADS7950_MAX_CHAN	16

#define TI_ADS7950_NUM_GPIOS	4



#define TI_ADS7950_TIMESTAMP_SIZE (sizeof(int64_t) / sizeof(__be16))
@@ -49,6 +53,16 @@ 
#define TI_ADS7950_EXTRACT(val, dec, bits) \

	(((val) >> (dec)) & ((1 << (bits)) - 1))



#define TI_ADS7950_MAN_CMD(cmd)         (TI_ADS7950_CR_MANUAL | (cmd))

#define TI_ADS7950_GPIO_CMD(cmd)        (TI_ADS7950_CR_GPIO | (cmd))



/* Manual mode configuration */

#define TI_ADS7950_MAN_CMD_SETTINGS(st) \

	(TI_ADS7950_MAN_CMD(TI_ADS7950_CR_WRITE | st->cmd_settings_bitmask))

/* GPIO mode configuration */

#define TI_ADS7950_GPIO_CMD_SETTINGS(st) \

	(TI_ADS7950_GPIO_CMD(st->gpio_cmd_settings_bitmask))



struct ti_ads7950_state {

	struct spi_device	*spi;

	struct spi_transfer	ring_xfer;
@@ -58,11 +72,34 @@ struct ti_ads7950_state { 


	/* Lock to protect the spi xfer buffers */

	struct mutex		slock;

	struct gpio_chip	chip;



	struct regulator	*reg;

	unsigned int		vref_mv;



	unsigned int		settings;

	/*

	 * Bitmask of lower 7 bits used for configuration

	 * These bits only can be written when TI_ADS7950_CR_WRITE

	 * is set, otherwise it retains its original state.

	 * [0-3] GPIO signal

	 * [4]   Set following frame to return GPIO signal values

	 * [5]   Powers down device

	 * [6]   Sets Vref range1(2.5v) or range2(5v)

	 *

	 * Bits present on Manual/Auto1/Auto2 commands

	 */

	unsigned int		cmd_settings_bitmask;



	/*

	 * Bitmask of GPIO command

	 * [0-3] GPIO direction

	 * [4-6] Different GPIO alarm mode configurations

	 * [7]   GPIO 2 as device range input

	 * [8]   GPIO 3 as device power down input

	 * [9]   Reset all registers

	 * [10-11] N/A

	 */

	unsigned int		gpio_cmd_settings_bitmask;



	/*

	 * DMA (thus cache coherency maintenance) requires the
@@ -251,7 +288,7 @@ static int ti_ads7950_update_scan_mode(struct iio_dev *indio_dev, 


	len = 0;

	for_each_set_bit(i, active_scan_mask, indio_dev->num_channels) {

		cmd = TI_ADS7950_CR_WRITE | TI_ADS7950_CR_CHAN(i) | st->settings;

		cmd = TI_ADS7950_MAN_CMD(TI_ADS7950_CR_CHAN(i));

		st->tx_buf[len++] = cmd;

	}
@@ -292,8 +329,7 @@ static int ti_ads7950_scan_direct(struct iio_dev *indio_dev, unsigned int ch) 
	int ret, cmd;



	mutex_lock(&st->slock);



	cmd = TI_ADS7950_CR_WRITE | TI_ADS7950_CR_CHAN(ch) | st->settings;

	cmd = TI_ADS7950_MAN_CMD(TI_ADS7950_CR_CHAN(ch));

	st->single_tx = cmd;



	ret = spi_sync(st->spi, &st->scan_single_msg);
@@ -322,7 +358,7 @@ static int ti_ads7950_get_range(struct ti_ads7950_state *st) 
		vref /= 1000;

	}



	if (st->settings & TI_ADS7950_CR_RANGE_5V)

	if (st->cmd_settings_bitmask & TI_ADS7950_CR_RANGE_5V)

		vref *= 2;



	return vref;
@@ -367,6 +403,132 @@ static const struct iio_info ti_ads7950_info = { 
	.update_scan_mode	= ti_ads7950_update_scan_mode,

};



static void ti_ads7950_set(struct gpio_chip *chip, unsigned int offset,

			   int value)

{

	struct ti_ads7950_state *st = gpiochip_get_data(chip);



	mutex_lock(&st->slock);



	if (value)

		st->cmd_settings_bitmask |= BIT(offset);

	else

		st->cmd_settings_bitmask &= ~BIT(offset);



	st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);

	spi_sync(st->spi, &st->scan_single_msg);



	mutex_unlock(&st->slock);

}



static int ti_ads7950_get(struct gpio_chip *chip, unsigned int offset)

{

	struct ti_ads7950_state *st = gpiochip_get_data(chip);

	int ret;



	mutex_lock(&st->slock);



	/* If set as output, return the output */

	if (st->gpio_cmd_settings_bitmask & BIT(offset)) {

		ret = st->cmd_settings_bitmask & BIT(offset);

		goto out;

	}



	/* GPIO data bit sets SDO bits 12-15 to GPIO input */

	st->cmd_settings_bitmask |= TI_ADS7950_CR_GPIO_DATA;

	st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);

	ret = spi_sync(st->spi, &st->scan_single_msg);

	if (ret)

		goto out;



	ret = ((st->single_rx >> 12) & BIT(offset)) ? 1 : 0;



	/* Revert back to original settings */

	st->cmd_settings_bitmask &= ~TI_ADS7950_CR_GPIO_DATA;

	st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);

	ret = spi_sync(st->spi, &st->scan_single_msg);

	if (ret)

		goto out;



out:

	mutex_unlock(&st->slock);



	return ret;

}



static int ti_ads7950_get_direction(struct gpio_chip *chip,

				    unsigned int offset)

{

	struct ti_ads7950_state *st = gpiochip_get_data(chip);



	/* Bitmask is inverted from GPIO framework 0=input/1=output */

	return !(st->gpio_cmd_settings_bitmask & BIT(offset));

}



static int _ti_ads7950_set_direction(struct gpio_chip *chip, int offset,

				     int input)

{

	struct ti_ads7950_state *st = gpiochip_get_data(chip);

	int ret = 0;



	mutex_lock(&st->slock);



	/* Only change direction if needed */

	if (input && (st->gpio_cmd_settings_bitmask & BIT(offset)))

		st->gpio_cmd_settings_bitmask &= ~BIT(offset);

	else if (!input && !(st->gpio_cmd_settings_bitmask & BIT(offset)))

		st->gpio_cmd_settings_bitmask |= BIT(offset);

	else

		goto out;



	st->single_tx = TI_ADS7950_GPIO_CMD_SETTINGS(st);

	ret = spi_sync(st->spi, &st->scan_single_msg);



out:

	mutex_unlock(&st->slock);



	return ret;

}



static int ti_ads7950_direction_input(struct gpio_chip *chip,

				      unsigned int offset)

{

	return _ti_ads7950_set_direction(chip, offset, 1);

}



static int ti_ads7950_direction_output(struct gpio_chip *chip,

				       unsigned int offset, int value)

{

	ti_ads7950_set(chip, offset, value);



	return _ti_ads7950_set_direction(chip, offset, 0);

}



static int ti_ads7950_init_hw(struct ti_ads7950_state *st)

{

	int ret = 0;



	mutex_lock(&st->slock);



	/* Settings for Manual/Auto1/Auto2 commands */

	/* Default to 5v ref */

	st->cmd_settings_bitmask = TI_ADS7950_CR_RANGE_5V;

	st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);

	ret = spi_sync(st->spi, &st->scan_single_msg);

	if (ret)

		goto out;



	/* Settings for GPIO command */

	st->gpio_cmd_settings_bitmask = 0x0;

	st->single_tx = TI_ADS7950_GPIO_CMD_SETTINGS(st);

	ret = spi_sync(st->spi, &st->scan_single_msg);



out:

	mutex_unlock(&st->slock);



	return ret;

}



static int ti_ads7950_probe(struct spi_device *spi)

{

	struct ti_ads7950_state *st;
@@ -391,7 +553,6 @@ static int ti_ads7950_probe(struct spi_device *spi) 
	spi_set_drvdata(spi, indio_dev);



	st->spi = spi;

	st->settings = TI_ADS7950_CR_MANUAL | TI_ADS7950_CR_RANGE_5V;



	info = &ti_ads7950_chip_info[spi_get_device_id(spi)->driver_data];
@@ -459,14 +620,40 @@ static int ti_ads7950_probe(struct spi_device *spi) 
		goto error_disable_reg;

	}



	ret = ti_ads7950_init_hw(st);

	if (ret) {

		dev_err(&spi->dev, "Failed to init adc chip\n");

		goto error_cleanup_ring;

	}



	ret = iio_device_register(indio_dev);

	if (ret) {

		dev_err(&spi->dev, "Failed to register iio device\n");

		goto error_cleanup_ring;

	}



	/* Add GPIO chip */

	st->chip.label = dev_name(&st->spi->dev);

	st->chip.parent = &st->spi->dev;

	st->chip.owner = THIS_MODULE;

	st->chip.base = -1;

	st->chip.ngpio = TI_ADS7950_NUM_GPIOS;

	st->chip.get_direction = ti_ads7950_get_direction;

	st->chip.direction_input = ti_ads7950_direction_input;

	st->chip.direction_output = ti_ads7950_direction_output;

	st->chip.get = ti_ads7950_get;

	st->chip.set = ti_ads7950_set;



	ret = gpiochip_add_data(&st->chip, st);

	if (ret) {

		dev_err(&spi->dev, "Failed to init GPIOs\n");

		goto error_iio_device;

	}



	return 0;



error_iio_device:

	iio_device_unregister(indio_dev);

error_cleanup_ring:

	iio_triggered_buffer_cleanup(indio_dev);

error_disable_reg:
@@ -482,6 +669,7 @@ static int ti_ads7950_remove(struct spi_device *spi) 
	struct iio_dev *indio_dev = spi_get_drvdata(spi);

	struct ti_ads7950_state *st = iio_priv(indio_dev);



	gpiochip_remove(&st->chip);

	iio_device_unregister(indio_dev);

	iio_triggered_buffer_cleanup(indio_dev);

	regulator_disable(st->reg);