[PATCH 2/5] lmp92001: mfd: iio: adc: Add support LMP92001

[s . abhisit]

From: Abhisit Sangjan <s.abhisit@xxxxxxxxx>

TI LMP92001 Analog System Monitor and Controller

8-bit GPIOs.
12 DACs with 12-bit resolution.

The GPIOs and DACs are shared port function with Cy function pin to
take control the pin suddenly from external hardware.
DAC's referance voltage selectable for Internal/External.

16 + 1 ADCs with 12-bit resolution.

Built-in internal Temperature Sensor on channel 17.
Window Comparator Function is supported on channel 1-3 and 9-11 for
monitoring with interrupt signal (pending to implement for interrupt).
ADC's referance voltage selectable for Internal/External.

Signed-off-by: Abhisit Sangjan <s.abhisit@xxxxxxxxx>
---
 drivers/iio/adc/Kconfig        |  10 +
 drivers/iio/adc/Makefile       |   1 +
 drivers/iio/adc/lmp92001-adc.c | 476 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 487 insertions(+)
 create mode 100644 drivers/iio/adc/lmp92001-adc.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 614fa41559b1..2adeba543ac7 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -331,6 +331,16 @@ config IMX7D_ADC
 	  This driver can also be built as a module. If so, the module will be
 	  called imx7d_adc.
 
+config LMP92001_ADC
+       tristate "TI LMP92001 ADC Driver"
+       depends on MFD_LMP92001
+       help
+         If you say yes here you get support for TI LMP92001 ADCs
+         conversion.
+
+         This driver can also be built as a module. If so, the module will
+         be called lmp92001_adc.
+
 config LP8788_ADC
 	tristate "LP8788 ADC driver"
 	depends on MFD_LP8788
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index b546736a5541..2ed89862090b 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -31,6 +31,7 @@ obj-$(CONFIG_HI8435) += hi8435.o
 obj-$(CONFIG_HX711) += hx711.o
 obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
 obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
+obj-$(CONFIG_LMP92001_ADC) += lmp92001-adc.o
 obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
 obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o
 obj-$(CONFIG_LPC32XX_ADC) += lpc32xx_adc.o
diff --git a/drivers/iio/adc/lmp92001-adc.c b/drivers/iio/adc/lmp92001-adc.c
new file mode 100644
index 000000000000..f706a364337d
--- /dev/null
+++ b/drivers/iio/adc/lmp92001-adc.c
@@ -0,0 +1,476 @@
+/*
+ * lmp92001-adc.c - Support for TI LMP92001 ADCs
+ *
+ * Copyright 2016-2017 Celestica Ltd.
+ *
+ * Author: Abhisit Sangjan <s.abhisit@xxxxxxxxx>
+ *
+ * Inspired by wm831x and ad5064 drivers.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/iio/iio.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <linux/mfd/lmp92001/core.h>
+
+static int lmp92001_read_raw(struct iio_dev *indio_dev,
+	struct iio_chan_spec const *channel, int *val, int *val2, long mask)
+{
+	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
+	unsigned int code, cgen, sgen, try;
+	int ret;
+
+	mutex_lock(&lmp92001->adc_lock);
+
+	ret = regmap_read(lmp92001->regmap, LMP92001_CGEN, &cgen);
+	if (ret < 0)
+		goto exit;
+
+	/*
+	 * Is not continuous conversion?
+	 * Lock the HW registers (if needed).
+	 * Triggering single-short conversion.
+	 * Waiting for conversion successful.
+	 */
+	if (!(cgen & CGEN_STRT)) {
+		if (!(cgen & CGEN_LCK)) {
+			ret = regmap_update_bits(lmp92001->regmap,
+					LMP92001_CGEN, CGEN_LCK, CGEN_LCK);
+			if (ret < 0)
+				goto exit;
+		}
+
+		/* Writing any value to trigger Single-Shot conversion. */
+		ret = regmap_write(lmp92001->regmap, LMP92001_CTRIG, 1);
+		if (ret < 0)
+			goto exit;
+
+		/* In case of conversion is in-progress, repeat for 10 times. */
+		try = 10;
+		do {
+			ret = regmap_read(lmp92001->regmap,
+						LMP92001_SGEN, &sgen);
+			if (ret < 0)
+				goto exit;
+		} while ((sgen & CGEN_RST) && (--try > 0));
+
+		if (!try) {
+			ret = -ETIME;
+			goto exit;
+		}
+	}
+
+	ret = regmap_read(lmp92001->regmap, 0x1F + channel->channel, &code);
+	if (ret < 0)
+		goto exit;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		switch (channel->type) {
+		case IIO_VOLTAGE:
+		case IIO_TEMP:
+			*val = code;
+			ret = IIO_VAL_INT;
+			goto exit;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	/* In case of no match channel info/type is return here. */
+	ret = -EINVAL;
+
+exit:
+	mutex_unlock(&lmp92001->adc_lock);
+
+	return ret;
+}
+
+static const struct iio_info lmp92001_info = {
+	.read_raw = lmp92001_read_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static ssize_t lmp92001_avref_read(struct iio_dev *indio_dev,
+	uintptr_t private, struct iio_chan_spec const *channel, char *buf)
+{
+	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
+	unsigned int cref;
+	int ret;
+
+	ret = regmap_read(lmp92001->regmap, LMP92001_CREF, &cref);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%s\n", (cref & CREF_AEXT) ? "external" : "internal");
+}
+
+static ssize_t lmp92001_avref_write(struct iio_dev *indio_dev,
+	uintptr_t private, struct iio_chan_spec const *channel,
+	const char *buf, size_t len)
+{
+	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
+	unsigned int cref;
+	int ret;
+
+	if (strncmp("external", buf, 8) == 0)
+		cref = 2;
+	else if (strncmp("internal", buf, 8) == 0)
+		cref = 0;
+	else
+		return -EINVAL;
+
+	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CREF, CREF_AEXT,
+					cref);
+	if (ret < 0)
+		return ret;
+
+	return len;
+}
+
+static ssize_t lmp92001_enable_read(struct iio_dev *indio_dev,
+	uintptr_t private, struct iio_chan_spec const *channel, char *buf)
+{
+	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
+	unsigned int reg, cad;
+	int ret;
+
+	switch (channel->channel) {
+	case 1 ... 8:
+		reg = LMP92001_CAD1;
+		break;
+	case 9 ... 16:
+		reg = LMP92001_CAD2;
+		break;
+	case 17:
+		reg = LMP92001_CAD3;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = regmap_read(lmp92001->regmap, reg, &cad);
+	if (ret < 0)
+		return ret;
+
+	if (channel->channel <= 8)
+		cad >>= channel->channel - 1;
+	else if (channel->channel > 8)
+		cad >>= channel->channel - 9;
+	else if (channel->channel > 16)
+		cad >>= channel->channel - 17;
+	else
+		return -EINVAL;
+
+	return sprintf(buf, "%s\n", cad & BIT(0) ? "enable" : "disable");
+}
+
+static ssize_t lmp92001_enable_write(struct iio_dev *indio_dev,
+	uintptr_t private, struct iio_chan_spec const *channel,
+	const char *buf, size_t len)
+{
+	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
+	unsigned int reg, enable, shif, mask;
+	int ret;
+
+	switch (channel->channel) {
+	case 1 ... 8:
+		reg = LMP92001_CAD1;
+		shif = (channel->channel - 1);
+		break;
+	case 9 ... 16:
+		reg = LMP92001_CAD2;
+		shif = (channel->channel - 9);
+		break;
+	case 17:
+		reg = LMP92001_CAD3;
+		shif = (channel->channel - 17);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (strncmp("enable", buf, 6) == 0)
+		enable = 1;
+	else if (strncmp("disable", buf, 7) == 0)
+		enable = 0;
+	else
+		return -EINVAL;
+
+	enable <<= shif;
+	mask = 1 << shif;
+
+	ret = regmap_update_bits(lmp92001->regmap, reg, mask, enable);
+	if (ret < 0)
+		return ret;
+
+	return len;
+}
+
+static ssize_t lmp92001_mode_read(struct iio_dev *indio_dev,
+	uintptr_t private, struct iio_chan_spec const *channel, char *buf)
+{
+	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
+	unsigned int cgen;
+	int ret;
+
+	ret = regmap_read(lmp92001->regmap, LMP92001_CGEN, &cgen);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%s\n",
+			cgen & BIT(0) ? "continuous" : "single-shot");
+}
+
+static ssize_t lmp92001_mode_write(struct iio_dev *indio_dev,
+	uintptr_t private, struct iio_chan_spec const *channel,
+	const char *buf, size_t len)
+{
+	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
+	unsigned int cgen;
+	int ret;
+
+	if (strncmp("continuous", buf, 10) == 0)
+		cgen = 1;
+	else if (strncmp("single-shot", buf, 11) == 0)
+		cgen = 0;
+	else
+		return -EINVAL;
+
+	mutex_lock(&lmp92001->adc_lock);
+
+	/*
+	 * Unlock the HW registers.
+	 * Set conversion mode.
+	 * Lock the HW registers.
+	 */
+	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CGEN, CGEN_LCK, 0);
+	if (ret < 0)
+		goto exit;
+
+	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CGEN, CGEN_STRT,
+					cgen);
+	if (ret < 0)
+		goto exit;
+
+	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CGEN, CGEN_LCK,
+					CGEN_LCK);
+	if (ret < 0)
+		goto exit;
+
+	return len;
+
+exit:
+	mutex_unlock(&lmp92001->adc_lock);
+
+	return ret;
+}
+
+static const struct iio_chan_spec_ext_info lmp92001_ext_info[] = {
+	{
+		.name = "vref",
+		.read = lmp92001_avref_read,
+		.write = lmp92001_avref_write,
+		.shared = IIO_SHARED_BY_ALL,
+	}, {
+		.name = "en",
+		.read = lmp92001_enable_read,
+		.write = lmp92001_enable_write,
+		.shared = IIO_SEPARATE,
+	}, {
+		.name = "mode",
+		.read = lmp92001_mode_read,
+		.write = lmp92001_mode_write,
+		.shared = IIO_SHARED_BY_ALL,
+	}, { },
+};
+
+static const struct iio_event_spec lmp92001_events[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
+			BIT(IIO_EV_INFO_VALUE),
+	}, {
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
+			BIT(IIO_EV_INFO_VALUE),
+	}, { },
+};
+
+#define LMP92001_CHAN_SPEC(_ch, _type, _event, _nevent) \
+{ \
+	.channel = _ch, \
+	.type = _type, \
+	.indexed = 1, \
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+		BIT(IIO_CHAN_INFO_SCALE), \
+	.event_spec = _event, \
+	.num_event_specs = _nevent, \
+	.ext_info = lmp92001_ext_info, \
+}
+
+static const struct iio_chan_spec lmp92001_adc_channels[] = {
+	LMP92001_CHAN_SPEC(1, IIO_VOLTAGE, lmp92001_events,
+			ARRAY_SIZE(lmp92001_events)),
+	LMP92001_CHAN_SPEC(2, IIO_VOLTAGE, lmp92001_events,
+			ARRAY_SIZE(lmp92001_events)),
+	LMP92001_CHAN_SPEC(3, IIO_VOLTAGE, lmp92001_events,
+			ARRAY_SIZE(lmp92001_events)),
+	LMP92001_CHAN_SPEC(4, IIO_VOLTAGE, NULL, 0),
+	LMP92001_CHAN_SPEC(5, IIO_VOLTAGE, NULL, 0),
+	LMP92001_CHAN_SPEC(6, IIO_VOLTAGE, NULL, 0),
+	LMP92001_CHAN_SPEC(7, IIO_VOLTAGE, NULL, 0),
+	LMP92001_CHAN_SPEC(8, IIO_VOLTAGE, NULL, 0),
+	LMP92001_CHAN_SPEC(9, IIO_VOLTAGE, lmp92001_events,
+			ARRAY_SIZE(lmp92001_events)),
+	LMP92001_CHAN_SPEC(10, IIO_VOLTAGE, lmp92001_events,
+			ARRAY_SIZE(lmp92001_events)),
+	LMP92001_CHAN_SPEC(11, IIO_VOLTAGE, lmp92001_events,
+			ARRAY_SIZE(lmp92001_events)),
+	LMP92001_CHAN_SPEC(12, IIO_VOLTAGE, NULL, 0),
+	LMP92001_CHAN_SPEC(13, IIO_VOLTAGE, NULL, 0),
+	LMP92001_CHAN_SPEC(14, IIO_VOLTAGE, NULL, 0),
+	LMP92001_CHAN_SPEC(15, IIO_VOLTAGE, NULL, 0),
+	LMP92001_CHAN_SPEC(16, IIO_VOLTAGE, NULL, 0),
+	LMP92001_CHAN_SPEC(17,    IIO_TEMP, NULL, 0),
+};
+
+static int lmp92001_adc_probe(struct platform_device *pdev)
+{
+	struct lmp92001 *lmp92001 = dev_get_drvdata(pdev->dev.parent);
+	struct iio_dev *indio_dev;
+	struct device_node *np = pdev->dev.of_node;
+	unsigned int cgen = 0, cad1, cad2, cad3;
+	u32 mask;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, 0);
+	if (!indio_dev)
+		return -ENOMEM;
+
+	iio_device_set_drvdata(indio_dev, lmp92001);
+
+	mutex_init(&lmp92001->adc_lock);
+
+	indio_dev->name = pdev->name;
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &lmp92001_info;
+	indio_dev->channels = lmp92001_adc_channels;
+	indio_dev->num_channels = ARRAY_SIZE(lmp92001_adc_channels);
+
+	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CGEN,
+					CGEN_RST, CGEN_RST);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to self reset all registers\n");
+		return ret;
+	}
+
+	/*
+	 * Turn on all of them, if you are pretty sure they are must be
+	 * real-time update or specify which channel is needed to be used to
+	 * save conversion time for a cycle.
+	 */
+	ret = of_property_read_u32(np, "ti,lmp92001-adc-mask", &mask);
+	if (ret < 0) {
+		cad1 = cad2 = cad3 = 0xFF;
+		dev_info(&pdev->dev, "turn on all of channels by default\n");
+	} else {
+		cad1 = mask & 0xFF;
+		cad2 = (mask >> 8) & 0xFF;
+		cad3 = (mask >> 16) & 0xFF;
+	}
+
+	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CAD1, 0xFF, cad1);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to enable/disable channels 1-8\n");
+		return ret;
+	}
+
+	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CAD2, 0xFF, cad2);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to enable/disable channels 9-16\n");
+		return ret;
+	}
+
+	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CAD3, BIT(0), cad3);
+	if (ret < 0) {
+		dev_err(&pdev->dev,
+			"failed to enable/disable channel 17 (temperature)\n");
+		return ret;
+	}
+
+	cgen |= 1; /* Continuous conversion is default. */
+
+	/* Lock the HW registers and set conversion mode. */
+	ret = regmap_update_bits(lmp92001->regmap,
+					LMP92001_CGEN, CGEN_LCK | CGEN_STRT,
+					cgen | CGEN_LCK);
+	if (ret < 0)
+		return ret;
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	return devm_iio_device_register(&pdev->dev, indio_dev);
+}
+
+static int lmp92001_adc_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
+
+	/*
+	 * To stop ADC conversion to save power
+	 *
+	 * Unlock the HW registers.
+	 * Set conversion mode to single-shot.
+	 * Lock the HW registers.
+	 */
+	regmap_update_bits(lmp92001->regmap, LMP92001_CGEN, CGEN_LCK, 0);
+	regmap_update_bits(lmp92001->regmap, LMP92001_CGEN, CGEN_STRT, 0);
+	regmap_update_bits(lmp92001->regmap, LMP92001_CGEN, CGEN_LCK, CGEN_LCK);
+
+	return 0;
+}
+
+static struct platform_driver lmp92001_adc_driver = {
+	.driver.name	= "lmp92001-adc",
+	.probe		= lmp92001_adc_probe,
+	.remove		= lmp92001_adc_remove,
+};
+
+static int __init lmp92001_adc_init(void)
+{
+	return platform_driver_register(&lmp92001_adc_driver);
+}
+subsys_initcall(lmp92001_adc_init);
+
+static void __exit lmp92001_adc_exit(void)
+{
+	platform_driver_unregister(&lmp92001_adc_driver);
+}
+module_exit(lmp92001_adc_exit);
+
+MODULE_AUTHOR("Abhisit Sangjan <s.abhisit@xxxxxxxxx>");
+MODULE_DESCRIPTION("IIO ADC interface for TI LMP92001");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:lmp92001-adc");
-- 
2.13.0