[PATCH 2/2] iio: adc: Add the TI ads124s08 ADC code

[Dan Murphy <dmurphy@ti.com>]

Introduce the TI ADS124S08 and the ADS124S06 ADC
devices from TI.  The ADS124S08 is the 12 channel ADC
and the ADS124S06 is the 6 channel ADC device

These devices share a common datasheet:
http://www.ti.com/lit/gpn/ads124s08

Signed-off-by: Dan Murphy <dmurphy@ti.com>
---
 drivers/iio/adc/Kconfig        |  10 +
 drivers/iio/adc/Makefile       |   1 +
 drivers/iio/adc/ti-ads124s08.c | 437 +++++++++++++++++++++++++++++++++
 3 files changed, 448 insertions(+)
 create mode 100644 drivers/iio/adc/ti-ads124s08.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index a52fea8749a9..e8c5686e6716 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -887,6 +887,16 @@ config TI_ADS8688
 	  This driver can also be built as a module. If so, the module will be
 	  called ti-ads8688.
 
+config TI_ADS124S08
+	tristate "Texas Instruments ADS124S08"
+	depends on SPI && OF
+	help
+	  If you say yes here you get support for Texas Instruments ADS124S08
+	  and ADS124S06 ADC chips
+
+	  This driver can also be built as a module. If so, the module will be
+	  called ti-ads124s08.
+
 config TI_AM335X_ADC
 	tristate "TI's AM335X ADC driver"
 	depends on MFD_TI_AM335X_TSCADC && HAS_DMA
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index a6e6a0b659e2..d70293abfdba 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -79,6 +79,7 @@ obj-$(CONFIG_TI_ADC161S626) += ti-adc161s626.o
 obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o
 obj-$(CONFIG_TI_ADS7950) += ti-ads7950.o
 obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o
+obj-$(CONFIG_TI_ADS124S08) += ti-ads124s08.o
 obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
 obj-$(CONFIG_TI_TLC4541) += ti-tlc4541.o
 obj-$(CONFIG_TWL4030_MADC) += twl4030-madc.o
diff --git a/drivers/iio/adc/ti-ads124s08.c b/drivers/iio/adc/ti-ads124s08.c
new file mode 100644
index 000000000000..b6fc93f37355
--- /dev/null
+++ b/drivers/iio/adc/ti-ads124s08.c
@@ -0,0 +1,437 @@
+// SPDX-License-Identifier: GPL-2.0
+// TI ADS124S0X chip family driver
+// Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
+
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+
+#include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/sysfs.h>
+
+#define ADS124S08_ID		0x00
+#define ADS124S06_ID		0x01
+
+/* Commands */
+#define ADS124S_CMD_NOP		0x00
+#define ADS124S_CMD_WAKEUP	0x02
+#define ADS124S_CMD_PWRDWN	0x04
+#define ADS124S_CMD_RESET	0x06
+#define ADS124S_CMD_START	0x08
+#define ADS124S_CMD_STOP	0x0a
+#define ADS124S_CMD_SYOCAL	0x16
+#define ADS124S_CMD_SYGCAL	0x17
+#define ADS124S_CMD_SFOCAL	0x19
+#define ADS124S_CMD_RDATA	0x12
+#define ADS124S_CMD_RREG	0x20
+#define ADS124S_CMD_WREG	0x40
+
+/* Registers */
+#define ADS124S0X_ID		0x00
+#define ADS124S0X_STATUS	0x01
+#define ADS124S0X_INPUT_MUX	0x02
+#define ADS124S0X_PGA		0x03
+#define ADS124S0X_DATA_RATE	0x04
+#define ADS124S0X_REF		0x05
+#define ADS124S0X_IDACMAG	0x06
+#define ADS124S0X_IDACMUX	0x07
+#define ADS124S0X_VBIAS		0x08
+#define ADS124S0X_SYS		0x09
+#define ADS124S0X_OFCAL0	0x0a
+#define ADS124S0X_OFCAL1	0x0b
+#define ADS124S0X_OFCAL2	0x0c
+#define ADS124S0X_FSCAL0	0x0d
+#define ADS124S0X_FSCAL1	0x0e
+#define ADS124S0X_FSCAL2	0x0f
+#define ADS124S0X_GPIODAT	0x10
+#define ADS124S0X_GPIOCON	0x11
+
+/* ADS124S0x common channels */
+#define ADS124S0X_AIN0		0x00
+#define ADS124S0X_AIN1		0x01
+#define ADS124S0X_AIN2		0x02
+#define ADS124S0X_AIN3		0x03
+#define ADS124S0X_AIN4		0x04
+#define ADS124S0X_AIN5		0x05
+#define ADS124S08_AINCOM	0x0c
+/* ADS124S08 only channels */
+#define ADS124S08_AIN6		0x06
+#define ADS124S08_AIN7		0x07
+#define ADS124S08_AIN8		0x08
+#define ADS124S08_AIN9		0x09
+#define ADS124S08_AIN10		0x0a
+#define ADS124S08_AIN11		0x0b
+#define ADS124S0X_MAX_CHANNELS	12
+
+#define ADS124S0X_POS_MUX_SHIFT	0x04
+#define ADS124S_INT_REF		0x09
+
+#define ADS124S_START_REG_MASK	0x1f
+#define ADS124S_NUM_BYTES_MASK	0x1f
+
+#define ADS124S_START_CONV	0x01
+#define ADS124S_STOP_CONV	0x00
+
+struct ads124s_chip_info {
+	const struct iio_chan_spec *channels;
+	unsigned int num_channels;
+};
+
+struct ads124s_private {
+	const struct ads124s_chip_info	*chip_info;
+	struct gpio_desc *reset_gpio;
+	struct spi_device *spi;
+	struct regulator *reg;
+	struct mutex lock;
+	unsigned int vref_mv;
+	u8 data[ADS124S0X_MAX_CHANNELS];
+};
+
+#define ADS124S_CHAN(index)					\
+{								\
+	.type = IIO_VOLTAGE,					\
+	.indexed = 1,						\
+	.channel = index,					\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+	.scan_index = index,					\
+	.scan_type = {						\
+		.sign = 'u',					\
+		.realbits = 24,					\
+		.storagebits = 24,				\
+		.endianness = IIO_BE,				\
+	},							\
+}
+
+static const struct iio_chan_spec ads124s06_channels[] = {
+	ADS124S_CHAN(0),
+	ADS124S_CHAN(1),
+	ADS124S_CHAN(2),
+	ADS124S_CHAN(3),
+	ADS124S_CHAN(4),
+	ADS124S_CHAN(5),
+};
+
+static const struct iio_chan_spec ads124s08_channels[] = {
+	ADS124S_CHAN(0),
+	ADS124S_CHAN(1),
+	ADS124S_CHAN(2),
+	ADS124S_CHAN(3),
+	ADS124S_CHAN(4),
+	ADS124S_CHAN(5),
+	ADS124S_CHAN(6),
+	ADS124S_CHAN(7),
+	ADS124S_CHAN(8),
+	ADS124S_CHAN(9),
+	ADS124S_CHAN(10),
+	ADS124S_CHAN(11),
+};
+
+static const struct ads124s_chip_info ads124s_chip_info_tbl[] = {
+	[ADS124S08_ID] = {
+		.channels = ads124s08_channels,
+		.num_channels = ARRAY_SIZE(ads124s08_channels),
+	},
+	[ADS124S06_ID] = {
+		.channels = ads124s06_channels,
+		.num_channels = ARRAY_SIZE(ads124s06_channels),
+	},
+};
+
+static void ads124s_fill_nop(u8 *data, int start, int count)
+{
+	int i;
+
+	for (i = start; i <= count; i++)
+		data[i] = ADS124S_CMD_NOP;
+
+};
+
+static int ads124s_write_cmd(struct iio_dev *indio_dev, u8 command)
+{
+	struct ads124s_private *priv = iio_priv(indio_dev);
+	struct spi_transfer t[] = {
+		{
+			.tx_buf = &priv->data[0],
+			.len = 1,
+		}
+	};
+
+	priv->data[0] = command;
+
+	return spi_sync_transfer(priv->spi, t, ARRAY_SIZE(t));
+}
+
+static int ads124s_write_reg(struct iio_dev *indio_dev, u8 reg, u8 data)
+{
+	struct ads124s_private *priv = iio_priv(indio_dev);
+	struct spi_transfer t[] = {
+		{
+			.tx_buf = &priv->data[0],
+			.len = 3,
+		}
+	};
+
+	priv->data[0] = ADS124S_CMD_WREG | reg;
+	priv->data[1] = 0x0;
+	priv->data[2] = data;
+
+	return spi_sync_transfer(priv->spi, t, ARRAY_SIZE(t));
+}
+
+static int ads124s_reset(struct iio_dev *indio_dev)
+{
+	struct ads124s_private *priv = iio_priv(indio_dev);
+
+	if (priv->reset_gpio) {
+		gpiod_direction_output(priv->reset_gpio, 0);
+		udelay(200);
+		gpiod_direction_output(priv->reset_gpio, 1);
+	} else {
+		return ads124s_write_cmd(indio_dev, ADS124S_CMD_RESET);
+	}
+
+	return 0;
+};
+
+static int ads124s_read(struct iio_dev *indio_dev, unsigned int chan)
+{
+	struct ads124s_private *priv = iio_priv(indio_dev);
+	int ret;
+	u32 tmp;
+	struct spi_transfer t[] = {
+		{
+			.tx_buf = &priv->data[0],
+			.len = 4,
+			.cs_change = 1,
+		}, {
+			.tx_buf = &priv->data[1],
+			.rx_buf = &priv->data[1],
+			.len = 4,
+		},
+	};
+
+	priv->data[0] = ADS124S_CMD_RDATA;
+	ads124s_fill_nop(priv->data, 1, 3);
+
+	ret = spi_sync_transfer(priv->spi, t, ARRAY_SIZE(t));
+	if (ret < 0)
+		return ret;
+
+	tmp = priv->data[2] << 16 | priv->data[3] << 8 | priv->data[4];
+
+	return tmp;
+}
+
+static int ads124s_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long m)
+{
+	struct ads124s_private *priv = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&priv->lock);
+	switch (m) {
+	case IIO_CHAN_INFO_RAW:
+		ret = ads124s_write_reg(indio_dev, ADS124S0X_INPUT_MUX,
+					chan->channel);
+		if (ret) {
+			dev_err(&priv->spi->dev, "Set ADC CH failed\n");
+			goto out;
+		}
+
+		ret = ads124s_write_cmd(indio_dev, ADS124S_START_CONV);
+		if (ret) {
+			dev_err(&priv->spi->dev, "Start ADC converions failed\n");
+			goto out;
+		}
+
+		ret = ads124s_read(indio_dev, chan->channel);
+		if (ret < 0) {
+			dev_err(&priv->spi->dev, "Read ADC failed\n");
+			goto out;
+		} else
+			*val = ret;
+
+		ret = ads124s_write_cmd(indio_dev, ADS124S_STOP_CONV);
+		if (ret) {
+			dev_err(&priv->spi->dev, "Stop ADC converions failed\n");
+			goto out;
+		}
+
+		mutex_unlock(&priv->lock);
+		if (ret < 0)
+			return ret;
+
+		return IIO_VAL_INT;
+	default:
+		break;
+	}
+out:
+	mutex_unlock(&priv->lock);
+	return -EINVAL;
+}
+
+static const struct iio_info ads124s_info = {
+	.read_raw = &ads124s_read_raw,
+};
+
+static irqreturn_t ads124s_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct ads124s_private *priv = iio_priv(indio_dev);
+	u16 buffer[ADS124S0X_MAX_CHANNELS];
+	int i, j = 0;
+	int ret;
+
+	for (i = 0; i < indio_dev->masklength; i++) {
+		if (!test_bit(i, indio_dev->active_scan_mask))
+			continue;
+
+		ret = ads124s_write_reg(indio_dev, ADS124S0X_INPUT_MUX, i);
+		if (ret)
+			dev_err(&priv->spi->dev, "Set ADC CH failed\n");
+
+		ret = ads124s_write_cmd(indio_dev, ADS124S_START_CONV);
+		if (ret)
+			dev_err(&priv->spi->dev, "Start ADC converions failed\n");
+
+		buffer[j] = ads124s_read(indio_dev, i);
+		ret = ads124s_write_cmd(indio_dev, ADS124S_STOP_CONV);
+		if (ret)
+			dev_err(&priv->spi->dev, "Stop ADC converions failed\n");
+
+		j++;
+	}
+
+	iio_push_to_buffers_with_timestamp(indio_dev, buffer,
+			pf->timestamp);
+
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static int ads124s_probe(struct spi_device *spi)
+{
+	struct ads124s_private *ads124s_priv;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*ads124s_priv));
+	if (indio_dev == NULL)
+		return -ENOMEM;
+
+	ads124s_priv = iio_priv(indio_dev);
+
+	ads124s_priv->reg = devm_regulator_get_optional(&spi->dev, "vref");
+	if (!IS_ERR(ads124s_priv->reg)) {
+		ret = regulator_enable(ads124s_priv->reg);
+		if (ret)
+			return ret;
+
+		ads124s_priv->vref_mv = regulator_get_voltage(ads124s_priv->reg);
+		if (ads124s_priv->vref_mv <= 0)
+			goto err_regulator_disable;
+	} else {
+		/* Use internal reference */
+		ads124s_priv->vref_mv = 0;
+	}
+
+	ads124s_priv->reset_gpio = devm_gpiod_get_optional(&spi->dev,
+						   "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(ads124s_priv->reset_gpio))
+		dev_info(&spi->dev, "Reset GPIO not defined\n");
+
+	ads124s_priv->chip_info = &ads124s_chip_info_tbl[spi_get_device_id(spi)->driver_data];
+
+	spi_set_drvdata(spi, indio_dev);
+
+	ads124s_priv->spi = spi;
+
+	indio_dev->name = spi_get_device_id(spi)->name;
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->dev.of_node = spi->dev.of_node;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = ads124s_priv->chip_info->channels;
+	indio_dev->num_channels = ads124s_priv->chip_info->num_channels;
+	indio_dev->info = &ads124s_info;
+
+	mutex_init(&ads124s_priv->lock);
+
+	ret = iio_triggered_buffer_setup(indio_dev, NULL,
+					 ads124s_trigger_handler, NULL);
+	if (ret < 0) {
+		dev_err(&spi->dev, "iio triggered buffer setup failed\n");
+		goto err_regulator_disable;
+	}
+
+	ads124s_reset(indio_dev);
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		goto err_buffer_cleanup;
+
+	return 0;
+
+err_buffer_cleanup:
+	iio_triggered_buffer_cleanup(indio_dev);
+
+err_regulator_disable:
+	if (!IS_ERR(ads124s_priv->reg))
+		regulator_disable(ads124s_priv->reg);
+
+	return ret;
+}
+
+static int ads124s_remove(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+
+	iio_device_unregister(indio_dev);
+	iio_triggered_buffer_cleanup(indio_dev);
+
+	return 0;
+}
+
+static const struct spi_device_id ads124s_id[] = {
+	{ "ads124s08", ADS124S08_ID },
+	{ "ads124s06", ADS124S06_ID },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, ads124s_id);
+
+static const struct of_device_id ads124s_of_table[] = {
+	{ .compatible = "ti,ads124s08" },
+	{ .compatible = "ti,ads124s06" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, ads124s_of_table);
+
+static struct spi_driver ads124s_driver = {
+	.driver = {
+		.name	= "ads124s",
+		.of_match_table = ads124s_of_table,
+	},
+	.probe		= ads124s_probe,
+	.remove		= ads124s_remove,
+	.id_table	= ads124s_id,
+};
+module_spi_driver(ads124s_driver);
+
+MODULE_AUTHOR("Dan Murphy <dmuprhy@ti.com>");
+MODULE_DESCRIPTION("TI TI_ADS12S0X ADC");
+MODULE_LICENSE("GPL v2");
-- 
2.20.0.rc1.10.g7068cbc4ab