Date:   Thu, 31 Aug 2017 01:17:15 +0700
From:   s.abhisit@...il.com
To:     pmeerw@...erw.net
Cc:     jic23@...nel.org, knaack.h@....de, lars@...afoo.de,
        fabrice.gasnier@...com, mike.looijmans@...ic.nl, peda@...ntia.se,
        jeff.dagenais@...il.com, linux-kernel@...r.kernel.org,
        linux-iio@...r.kernel.org, Abhisit Sangjan <s.abhisit@...il.com>
Subject: [PATCH 3/5] lmp92001: mfd: iio: dac: Add support LMP92001

From: Abhisit Sangjan <s.abhisit@...il.com>

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@...il.com>
---
 drivers/iio/dac/Kconfig        |   9 ++
 drivers/iio/dac/Makefile       |   1 +
 drivers/iio/dac/lmp92001-dac.c | 337 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 347 insertions(+)
 create mode 100644 drivers/iio/dac/lmp92001-dac.c

diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index 25bed2d7d2b9..3e0d81606927 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -221,6 +221,15 @@ config DPOT_DAC
 	  To compile this driver as a module, choose M here: the module will be
 	  called dpot-dac.
 
+config LMP92001_DAC
+        tristate "TI LMP92001 DAC Driver"
+        depends on MFD_LMP92001
+        help
+          If you say yes here you get support for TI LMP92001 DACs.
+
+          This driver can also be built as a module. If so, the module will
+          be called lmp92001_dac.
+
 config LPC18XX_DAC
 	tristate "NXP LPC18xx DAC driver"
 	depends on ARCH_LPC18XX || COMPILE_TEST
diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
index 603587cc2f07..516d2beced7b 100644
--- a/drivers/iio/dac/Makefile
+++ b/drivers/iio/dac/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_AD7303) += ad7303.o
 obj-$(CONFIG_AD8801) += ad8801.o
 obj-$(CONFIG_CIO_DAC) += cio-dac.o
 obj-$(CONFIG_DPOT_DAC) += dpot-dac.o
+obj-$(CONFIG_LMP92001_DAC) += lmp92001-dac.o
 obj-$(CONFIG_LPC18XX_DAC) += lpc18xx_dac.o
 obj-$(CONFIG_LTC2632) += ltc2632.o
 obj-$(CONFIG_M62332) += m62332.o
diff --git a/drivers/iio/dac/lmp92001-dac.c b/drivers/iio/dac/lmp92001-dac.c
new file mode 100644
index 000000000000..072026e9895c
--- /dev/null
+++ b/drivers/iio/dac/lmp92001-dac.c
@@ -0,0 +1,337 @@
+/*
+ * lmp92001-dac.c - Support for TI LMP92001 DACs
+ *
+ * Copyright 2016-2017 Celestica Ltd.
+ *
+ * Author: Abhisit Sangjan <s.abhisit@...il.com>
+ *
+ * Inspired by wm831x driver.
+ *
+ * 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/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);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		switch (channel->type) {
+		case IIO_VOLTAGE:
+			mutex_lock(&lmp92001->dac_lock);
+
+			ret = regmap_read(lmp92001->regmap,
+					0x7F + channel->channel, val);
+
+			mutex_unlock(&lmp92001->dac_lock);
+
+			if (ret < 0)
+				return ret;
+
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int lmp92001_write_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);
+	int ret;
+
+	if (val < 0 || val > 4095)
+		return -EINVAL;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		switch (channel->type) {
+		case IIO_VOLTAGE:
+			mutex_lock(&lmp92001->dac_lock);
+
+			ret = regmap_write(lmp92001->regmap,
+					0x7F + channel->channel, val);
+
+			mutex_unlock(&lmp92001->dac_lock);
+
+			if (ret < 0)
+				return ret;
+
+			return 0;
+		default:
+			return -EINVAL;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info lmp92001_info = {
+	.read_raw = lmp92001_read_raw,
+	.write_raw = lmp92001_write_raw,
+	.driver_module = THIS_MODULE,
+};
+
+static ssize_t lmp92001_dvref_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_DEXT ? "external" : "internal");
+}
+
+static ssize_t lmp92001_dvref_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 = 1;
+	else if (strncmp("internal", buf, 8) == 0)
+		cref = 0;
+	else
+		return -EINVAL;
+
+	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CREF, CREF_DEXT,
+					cref);
+	if (ret < 0)
+		return ret;
+
+	return len;
+}
+
+static ssize_t lmp92001_outx_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 cdac;
+	const char *outx;
+	int ret;
+
+	ret = regmap_read(lmp92001->regmap, LMP92001_CDAC, &cdac);
+	if (ret < 0)
+		return ret;
+
+	if (cdac & CDAC_OFF)
+		outx = "hiz";
+	else {
+		if (cdac & CDAC_OLVL)
+			outx = "1 or dac";
+		else
+			outx = "0 or dac";
+	}
+
+	return sprintf(buf, "%s\n", outx);
+}
+
+static ssize_t lmp92001_outx_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 cdac, mask;
+	int ret;
+
+	if (strncmp("hiz", buf, 3) == 0) {
+		cdac = CDAC_OFF;
+		mask = CDAC_OFF;
+	} else if (strncmp("dac", buf, 3) == 0) {
+		cdac = ~CDAC_OFF;
+		mask = CDAC_OFF;
+	} else if (strncmp("0", buf, 1) == 0) {
+		cdac = ~(CDAC_OLVL | CDAC_OFF);
+		mask = CDAC_OLVL | CDAC_OFF;
+	} else if (strncmp("1", buf, 1) == 0) {
+		cdac = CDAC_OLVL;
+		mask = CDAC_OLVL | CDAC_OFF;
+	} else
+		return -EINVAL;
+
+	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CDAC, mask, cdac);
+	if (ret < 0)
+		return ret;
+
+	return len;
+}
+
+static ssize_t lmp92001_gang_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 cdac;
+	int ret;
+
+	ret = regmap_read(lmp92001->regmap, LMP92001_CDAC, &cdac);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%s\n", cdac & CDAC_GANG ? "1" : "0");
+}
+
+static ssize_t lmp92001_gang_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 cdac = 0;
+	int ret;
+
+	if (strncmp("0", buf, 1) == 0)
+		cdac = ~CDAC_GANG;
+	else if (strncmp("1", buf, 1) == 0)
+		cdac = CDAC_GANG;
+	else
+		return -EINVAL;
+
+	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CDAC, CDAC_GANG,
+					cdac);
+	if (ret < 0)
+		return ret;
+
+	return len;
+}
+
+static const struct iio_chan_spec_ext_info lmp92001_ext_info[] = {
+	{
+		.name = "vref",
+		.read = lmp92001_dvref_read,
+		.write = lmp92001_dvref_write,
+		.shared = IIO_SHARED_BY_ALL,
+	}, {
+		.name = "outx",
+		.read = lmp92001_outx_read,
+		.write = lmp92001_outx_write,
+		.shared = IIO_SHARED_BY_ALL,
+	}, {
+		.name = "gang",
+		.read = lmp92001_gang_read,
+		.write = lmp92001_gang_write,
+		.shared = IIO_SHARED_BY_ALL,
+	}, { },
+};
+
+#define LMP92001_CHAN_SPEC(_ch) \
+{ \
+	.channel = _ch, \
+	.type = IIO_VOLTAGE, \
+	.indexed = 1, \
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+		BIT(IIO_CHAN_INFO_SCALE), \
+	.ext_info = lmp92001_ext_info, \
+	.output = 1, \
+}
+
+static const struct iio_chan_spec lmp92001_dac_channels[] = {
+	LMP92001_CHAN_SPEC(1),
+	LMP92001_CHAN_SPEC(2),
+	LMP92001_CHAN_SPEC(3),
+	LMP92001_CHAN_SPEC(4),
+	LMP92001_CHAN_SPEC(5),
+	LMP92001_CHAN_SPEC(6),
+	LMP92001_CHAN_SPEC(7),
+	LMP92001_CHAN_SPEC(8),
+	LMP92001_CHAN_SPEC(9),
+	LMP92001_CHAN_SPEC(10),
+	LMP92001_CHAN_SPEC(11),
+	LMP92001_CHAN_SPEC(12),
+};
+
+static int lmp92001_dac_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;
+	u8 gang = 0, outx = 0, hiz = 0;
+	unsigned int cdac = 0;
+	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->dac_lock);
+
+	indio_dev->name = pdev->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &lmp92001_info;
+	indio_dev->channels = lmp92001_dac_channels;
+	indio_dev->num_channels = ARRAY_SIZE(lmp92001_dac_channels);
+
+	of_property_read_u8(np, "ti,lmp92001-dac-hiz", &hiz);
+	cdac = hiz;
+
+	of_property_read_u8(np, "ti,lmp92001-dac-outx", &outx);
+	cdac |= outx << 1;
+
+	of_property_read_u8(np, "ti,lmp92001-dac-gang", &gang);
+	cdac |= gang << 2;
+
+	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CDAC,
+					CDAC_GANG | CDAC_OLVL | CDAC_OFF, cdac);
+	if (ret < 0)
+		return ret;
+
+	return devm_iio_device_register(&pdev->dev, indio_dev);
+}
+
+static int lmp92001_dac_remove(struct platform_device *pdev)
+{
+	return 0;
+}
+
+static struct platform_driver lmp92001_dac_driver = {
+	.driver.name	= "lmp92001-dac",
+	.probe		= lmp92001_dac_probe,
+	.remove		= lmp92001_dac_remove,
+};
+
+static int __init lmp92001_dac_init(void)
+{
+	return platform_driver_register(&lmp92001_dac_driver);
+}
+subsys_initcall(lmp92001_dac_init);
+
+static void __exit lmp92001_dac_exit(void)
+{
+	platform_driver_unregister(&lmp92001_dac_driver);
+}
+module_exit(lmp92001_dac_exit);
+
+MODULE_AUTHOR("Abhisit Sangjan <s.abhisit@...il.com>");
+MODULE_DESCRIPTION("IIO DAC interface for TI LMP92001");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:lmp92001-dac");
-- 
2.13.0

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