[PATCH 2/5] iio: Add support for LMP92001 ADC

[s.abhisit@gmail.com]

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

---
 drivers/iio/adc/Kconfig        |  10 +
 drivers/iio/adc/Makefile       |   1 +
 drivers/iio/adc/lmp92001-adc.c | 479 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 490 insertions(+)
 create mode 100644 drivers/iio/adc/lmp92001-adc.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 614fa41..b623b4d 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -857,4 +857,14 @@ config XILINX_XADC
 	  The driver can also be build as a module. If so, the module will be called
 	  xilinx-xadc.
 
+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.
+
 endmenu
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index b546736a..75b24b1 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -78,3 +78,4 @@ obj-$(CONFIG_VF610_ADC) += vf610_adc.o
 obj-$(CONFIG_VIPERBOARD_ADC) += viperboard_adc.o
 xilinx-xadc-y := xilinx-xadc-core.o xilinx-xadc-events.o
 obj-$(CONFIG_XILINX_XADC) += xilinx-xadc.o
+obj-$(CONFIG_LMP92001_ADC) += lmp92001-adc.o
diff --git a/drivers/iio/adc/lmp92001-adc.c b/drivers/iio/adc/lmp92001-adc.c
new file mode 100644
index 0000000..909ff47
--- /dev/null
+++ b/drivers/iio/adc/lmp92001-adc.c
@@ -0,0 +1,479 @@
+/*
+ * lmp92001-adc.c - Support for TI LMP92001 ADCs
+ *
+ * Copyright 2016-2017 Celestica Ltd.
+ *
+ * Author: Abhisit Sangjan <s.abhisit@gmail.com>
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/iio/iio.h>
+#include <linux/mfd/core.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.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;
+
+        ret = regmap_read(lmp92001->regmap, LMP92001_CGEN, &cgen);
+        if (ret < 0)
+                return ret;
+
+        /*
+         * Is not continuous conversion?
+         * Lock the registers (if needed).
+         * Triggering single-short conversion.
+         * Waiting for conversion successfully.
+         */
+        if (!(cgen & 1))
+        {
+                if (!(cgen & 2))
+                {
+                        ret = regmap_update_bits(lmp92001->regmap,
+                                                        LMP92001_CGEN, 2, 2);
+                        if (ret < 0)
+                                return ret;
+                }
+
+                ret = regmap_write(lmp92001->regmap, LMP92001_CTRIG, 1);
+                if (ret < 0)
+                        return ret;
+
+                try = 10;
+                do {
+                        ret = regmap_read(lmp92001->regmap,
+                                                LMP92001_SGEN, &sgen);
+                        if(ret < 0)
+                                return ret;
+                } while ((sgen & 1<<7) && (--try > 0));
+
+                if (!try)
+                        return -ETIME;
+        }
+
+        ret = regmap_read(lmp92001->regmap, 0x1F + channel->channel, &code);
+        if (ret < 0)
+                return ret;
+
+        switch (mask)
+        {
+        case IIO_CHAN_INFO_RAW:
+                switch (channel->type) {
+                case IIO_VOLTAGE:
+                case IIO_TEMP:
+                        *val = code;
+                        return IIO_VAL_INT;
+                default:
+                        break;
+                }
+                break;
+        default:
+                break;
+        }
+
+        return -EINVAL;
+}
+
+/*
+ * TODO: do your attributes even handler for
+ * Current limit low/high for CH 1-3, 9-11!
+ * In case INT1 and INT2 were connected to i.MX6.
+ */
+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 & 2 ? "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 (strcmp("external\n", buf) == 0)
+                cref = 2;
+        else if (strcmp("internal\n", buf) == 0)
+                cref = 0;
+        else
+                return -EINVAL;
+
+        ret = regmap_update_bits(lmp92001->regmap, LMP92001_CREF, 2, 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 & 1 ? "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 (strcmp("enable\n", buf) == 0)
+                enable = 1;
+        else if (strcmp("disable\n", buf) == 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 & 1 ? "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 (strcmp("continuous\n", buf) == 0)
+                cgen = 1;
+        else if (strcmp("single-shot\n", buf) == 0)
+                cgen = 0;
+        else
+                return -EINVAL;
+
+        /*
+         * Unlock the registers.
+         * Set conversion mode.
+         * Lock the registers.
+         */
+        ret = regmap_update_bits(lmp92001->regmap, LMP92001_CGEN, 2, 0);
+        if (ret < 0)
+                return ret;
+
+        ret = regmap_update_bits(lmp92001->regmap, LMP92001_CGEN, 1, cgen);
+        if (ret < 0)
+                return ret;
+
+        ret = regmap_update_bits(lmp92001->regmap, LMP92001_CGEN, 2, 2);
+        if (ret < 0)
+                return ret;
+
+        return len;
+}
+
+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, \
+        .scan_index = _ch, \
+        .scan_type = { \
+                        .sign = 'u', \
+                        .realbits = 12, \
+                        .storagebits = 16, \
+                        .repeat = 1, \
+                        .endianness = IIO_BE, \
+        }, \
+        .type = _type, \
+        .indexed = 1, \
+        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+        .event_spec = _event, \
+        .num_event_specs = _nevent, \
+        .ext_info = lmp92001_ext_info, \
+}
+
+/*
+ * TODO: do your ext_info for current low/high limit.
+ * Example driver/iio/dac/ad5064.c
+ */
+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;
+        const char *conversion;
+        unsigned int cgen = 0, cad1, cad2, cad3;
+        u32 mask;
+        int ret;
+
+        indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*lmp92001));
+        if (!indio_dev)
+                return -ENOMEM;
+
+        iio_device_set_drvdata(indio_dev, lmp92001);
+
+        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, 0x80, 0x80);
+        if (ret < 0)
+        {
+                dev_err(&pdev->dev,"failed to self reset all registers\n");
+                return ret;
+        }
+
+        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 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 channels 9-16\n");
+                return ret;
+        }
+
+        ret = regmap_update_bits(lmp92001->regmap, LMP92001_CAD3, 1, cad3);
+        if (ret < 0)
+        {
+                dev_err(&pdev->dev, "failed to enable channel 17 (temperature)\n");
+                return ret;
+        }
+
+        ret = of_property_read_string_index(np, "ti,lmp92001-adc-mode", 0,
+                                                &conversion);
+        if (!ret)
+        {
+                if (strcmp("continuous", conversion) == 0)
+                        cgen |= 1;
+                else if (strcmp("single-shot", conversion) == 0)
+                        { /* Okay */ }
+                else
+                        dev_warn(&pdev->dev,
+                        "wrong adc mode! set to single-short conversion\n");
+        }
+        else
+                dev_info(&pdev->dev,
+                "single-short conversion was chosen by default\n");
+
+        /*
+         * Lock the registers and set conversion mode.
+         */
+        ret = regmap_update_bits(lmp92001->regmap,
+                                        LMP92001_CGEN, 3, cgen | 2);
+        if (ret < 0)
+                return ret;
+
+        platform_set_drvdata(pdev, indio_dev);
+
+        return iio_device_register(indio_dev);
+}
+
+static int lmp92001_adc_remove(struct platform_device *pdev)
+{
+        struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+
+        iio_device_unregister(indio_dev);
+
+        return 0;
+}
+
+static struct platform_driver lmp92001_adc_driver = {
+        .driver.name    = "lmp92001-adc",
+        .driver.owner   = THIS_MODULE,
+        .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@gmail.com>");
+MODULE_DESCRIPTION("IIO ADC interface for TI LMP92001");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:lmp92001-adc");
-- 
2.7.4