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

[Peter Meerwald-Stadler]

> From: Abhisit Sangjan <s.abhisit@xxxxxxxxx>

some more comments in addition to Jonathan's
 
> ---
>  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@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/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)

style, space after if, space around operators

> +                                return ret;
> +                } while ((sgen & 1<<7) && (--try > 0));
> +
> +                if (!try)
> +                        return -ETIME;

most drivers use ETIMEOUT

> +        }
> +
> +        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),

wondering in what unit the drivers reports _TEMP, probably _SCALE needed

> +};
> +
> +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@xxxxxxxxx>");
> +MODULE_DESCRIPTION("IIO ADC interface for TI LMP92001");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:lmp92001-adc");
> 

-- 

Peter Meerwald-Stadler
Mobile: +43 664 24 44 418