From: Justin Chen <justinpopo6@xxxxxxxxx>
The ADS79XX has GPIO pins that can be used. Add support for the GPIO
pins using the GPIO chip framework.
Signed-off-by: Justin Chen <justinpopo6@xxxxxxxxx>
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
drivers/iio/adc/ti-ads7950.c | 200 +++++++++++++++++++++++++++++++++++++++++--
1 file changed, 194 insertions(+), 6 deletions(-)
diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c
index 1e47bef..2e66e4d 100644
--- a/drivers/iio/adc/ti-ads7950.c
+++ b/drivers/iio/adc/ti-ads7950.c
@@ -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);
--
2.7.4
