Re: [PATCH v4 2/3] iio/adc: add support for axp288 adc

Jacob Pan
2014-09-17T23:13:29Z

On Thu, 18 Sep 2014 00:20:00 +0200
Hartmut Knaack <knaack.h@gmx.de> wrote:

> Jacob Pan schrieb, Am 17.09.2014 02:11:
> > Platform driver for X-Powers AXP288 ADC, which is a sub-device of
> > the customized AXP288 PMIC for Intel Baytrail-CR platforms. GPADC
> > device enumerates as one of the MFD cell devices. It uses IIO
> > infrastructure to communicate with userspace and consumer drivers.
> >
> > Usages of ADC channels include battery charging and thermal sensors.
> >
> You are progressing, but still a few issues left. One thing is
> indentation in some places (I feel like being pretty annoying about
> this), others are commented in line.
I don't see the indentation issue, perhaps it is the difference in the
editors we use?

> > Based on initial work by:
> > Ramakrishna Pallala <ramakrishna.pallala@intel.com>
> >
> > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> > ---
> > drivers/iio/adc/Kconfig | 8 ++
> > drivers/iio/adc/Makefile | 1 +
> > drivers/iio/adc/axp288_adc.c | 254
> > +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 263
> > insertions(+) create mode 100644 drivers/iio/adc/axp288_adc.c
> >
> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > index 11b048a..db2681b 100644
> > --- a/drivers/iio/adc/Kconfig
> > +++ b/drivers/iio/adc/Kconfig
> > @@ -127,6 +127,14 @@ config AT91_ADC
> > help
> > Say yes here to build support for Atmel AT91 ADC.
> >
> > +config AXP288_ADC
> > + tristate "X-Powers AXP288 ADC driver"
> > + depends on MFD_AXP20X
> > + help
> > + Say yes here to have support for X-Powers power
> > management IC (PMIC) ADC
> > + device. Depending on platform configuration, this
> > general purpose ADC can
> > + be used for sampling sensors such as thermal resistors.
> > +
> > config EXYNOS_ADC
> > tristate "Exynos ADC driver support"
> > depends on ARCH_EXYNOS || (OF && COMPILE_TEST)
> > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> > index ad81b51..19640f9 100644
> > --- a/drivers/iio/adc/Makefile
> > +++ b/drivers/iio/adc/Makefile
> > @@ -14,6 +14,7 @@ obj-$(CONFIG_AD7793) += ad7793.o
> > obj-$(CONFIG_AD7887) += ad7887.o
> > obj-$(CONFIG_AD799X) += ad799x.o
> > obj-$(CONFIG_AT91_ADC) += at91_adc.o
> > +obj-$(CONFIG_AXP288_ADC) += axp288_adc.o
> > obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
> > obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
> > obj-$(CONFIG_MAX1027) += max1027.o
> > diff --git a/drivers/iio/adc/axp288_adc.c
> > b/drivers/iio/adc/axp288_adc.c new file mode 100644
> > index 0000000..333c624
> > --- /dev/null
> > +++ b/drivers/iio/adc/axp288_adc.c
> > @@ -0,0 +1,254 @@
> > +/*
> > + * axp288_adc.c - X-Powers AXP288 PMIC ADC Driver
> > + *
> > + * Copyright (C) 2014 Intel Corporation
> > + *
> > + *
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > + *
> > + * 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; version 2 of the License.
> > + *
> > + * 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/module.h>
> > +#include <linux/kernel.h>
> > +#include <linux/device.h>
> > +#include <linux/regmap.h>
> > +#include <linux/mfd/axp20x.h>
> > +#include <linux/platform_device.h>
> > +
> > +#include <linux/iio/iio.h>
> > +#include <linux/iio/machine.h>
> > +#include <linux/iio/driver.h>
> > +
> > +#define AXP288_ADC_EN_MASK 0xF1
> > +#define AXP288_ADC_TS_PIN_GPADC 0xF2
> > +#define AXP288_ADC_TS_PIN_ON 0xF3
> > +
> > +enum axp288_adc_id {
> > + AXP288_ADC_TS,
> > + AXP288_ADC_PMIC,
> > + AXP288_ADC_GP,
> > + AXP288_ADC_BATT_CHRG_I,
> > + AXP288_ADC_BATT_DISCHRG_I,
> > + AXP288_ADC_BATT_V,
> > + AXP288_ADC_NR_CHAN,
> > +};
> > +
> > +struct axp288_adc_info {
> > + int irq;
> > + struct device *dev;
> > + struct regmap *regmap;
> > +};
> > +
> > +static const struct iio_chan_spec const axp288_adc_channels[] = {
> > + {
> > + .indexed = 1,
> > + .type = IIO_TEMP,
> > + .channel = 0,
> > + .address = AXP288_TS_ADC_H,
> > + .datasheet_name = "CH0",
> > + }, {
> > + .indexed = 1,
> > + .type = IIO_TEMP,
> > + .channel = 1,
> > + .address = AXP288_PMIC_ADC_H,
> > + .datasheet_name = "CH1",
> > + }, {
> > + .indexed = 1,
> > + .type = IIO_TEMP,
> > + .channel = 2,
> > + .address = AXP288_GP_ADC_H,
> > + .datasheet_name = "CH2",
> > + }, {
> > + .indexed = 1,
> > + .type = IIO_CURRENT,
> > + .channel = 3,
> > + .address = AXP20X_BATT_CHRG_I_H,
> > + .datasheet_name = "CH3",
> > + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
> > + }, {
> > + .indexed = 1,
> > + .type = IIO_CURRENT,
> > + .channel = 4,
> > + .address = AXP20X_BATT_DISCHRG_I_H,
> > + .datasheet_name = "CH4",
> > + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
> > + }, {
> > + .indexed = 1,
> > + .type = IIO_VOLTAGE,
> > + .channel = 5,
> > + .address = AXP20X_BATT_V_H,
> > + .datasheet_name = "CH5",
> > + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
> > + },
> > +};
> > +
> > +#define AXP288_ADC_MAP(_adc_channel_label,
> > _consumer_dev_name, \
> > + _consumer_channel) \
> > + { \
> > + .adc_channel_label = _adc_channel_label, \
> > + .consumer_dev_name = _consumer_dev_name, \
> > + .consumer_channel =
> > _consumer_channel, \
> > + }
> > +
> > +/* for consumer drivers */
> > +static struct iio_map axp288_adc_default_maps[] = {
> > + AXP288_ADC_MAP("TS_PIN", "axp288-batt",
> > "axp288-batt-temp"),
> > + AXP288_ADC_MAP("PMIC_TEMP", "axp288-pmic",
> > "axp288-pmic-temp"),
> > + AXP288_ADC_MAP("GPADC", "axp288-gpadc",
> > "axp288-system-temp"),
> > + AXP288_ADC_MAP("BATT_CHG_I", "axp288-chrg",
> > "axp288-chrg-curr"),
> > + AXP288_ADC_MAP("BATT_DISCHRG_I", "axp288-chrg",
> > "axp288-chrg-d-curr"),
> > + AXP288_ADC_MAP("BATT_V", "axp288-batt",
> > "axp288-batt-volt"),
> > + {},
> > +};
> > +
> > +static int axp288_adc_read_raw(struct iio_dev *indio_dev,
> > + struct iio_chan_spec const *chan,
> > + int *val, int *val2, long mask)
> > +{
> > + int ret;
> > + struct axp288_adc_info *info = iio_priv(indio_dev);
> > + u8 buf[2];
> You could use __be16 instead. Then you just need to use
> be16_to_cpu(), shift 4 bits to the right and mask the result with
> 0xFF.
> > +
> > + mutex_lock(&indio_dev->mlock);
> > + switch (mask) {
> > + case IIO_CHAN_INFO_RAW:
> > + /* special case for GPADC sample */
> > + if (chan->address == AXP288_GP_ADC_H) {
> > + ret = regmap_write(info->regmap,
> > AXP288_ADC_TS_PIN_CTRL,
> > + AXP288_ADC_TS_PIN_GPADC);
> > + if (ret) {
> > + dev_err(&indio_dev->dev, "GPADC
> > mode\n");
> > + mutex_unlock(&indio_dev->mlock);
> > + return ret;
> You may even just goto the mutex_unlock at the end of the function.
> Would safe a few bytes here in the source - up to you. More
> interesting is, if the error message is required, as you don't have
> one below, when switching to TS_PIN_ON.
i don't have preference, the previous reviews don't like goto.
> > + }
> > + }
> > + case IIO_CHAN_INFO_PROCESSED:
> > + ret = regmap_bulk_read(info->regmap,
> > chan->address, buf, 2);
> > + if (ret) {
> > + dev_err(&indio_dev->dev, "sample raw data
> > failed\n");
> > + break;
> > + }
> > + *val = (buf[0] << 4) + ((buf[1] >> 4) & 0x0F);
> > + ret = IIO_VAL_INT;
> > + break;
> > + default:
> > + ret = -EINVAL;
> > + }
> > +
> > + if (mask == IIO_CHAN_INFO_RAW && chan->address ==
> > AXP288_GP_ADC_H)
> > + ret = regmap_write(info->regmap,
> > AXP288_ADC_TS_PIN_CTRL,
> > + AXP288_ADC_TS_PIN_ON);
> > +
> > + mutex_unlock(&indio_dev->mlock);
> > +
> > + return ret;
> > +}
> > +
> > +static int axp288_adc_enable(struct regmap *regmap, bool enable)
> > +{
> > + unsigned int pin_on, adc_en;
> > +
> > + if (enable) {
> > + pin_on = AXP288_ADC_TS_PIN_ON;
> > + adc_en = AXP288_ADC_EN_MASK;
> > + } else {
> > + pin_on = ~AXP288_ADC_TS_PIN_ON;
> > + adc_en = ~AXP288_ADC_EN_MASK;
> > + }
> > + if (regmap_write(regmap, AXP288_ADC_TS_PIN_CTRL, pin_on))
> > + return -EIO;
> > +
> > + return regmap_write(regmap, AXP20X_ADC_EN1,
> > ~AXP288_ADC_EN_MASK);
> So, what's the deal about the variable adc_en?
well, I am trying to be consistent with the data sheet. in axp202
datasheet, register 82h is named "ADC Enable 1". In axp288 datasheet,
the same register 82h is named ADC Enable. I am going with adc_en1 to
better scale for more "ADC Enable X".
> > +}
> > +
> > +static const struct iio_info axp288_adc_iio_info = {
> > + .read_raw = &axp288_adc_read_raw,
> > + .driver_module = THIS_MODULE,
> > +};
> > +
> > +static int axp288_adc_probe(struct platform_device *pdev)
> > +{
> > + int ret;
> > + struct axp288_adc_info *info;
> > + struct iio_dev *indio_dev;
> > + struct axp20x_dev *axp20x =
> > dev_get_drvdata(pdev->dev.parent); +
> > + indio_dev = devm_iio_device_alloc(&pdev->dev,
> > sizeof(*info));
> > + if (!indio_dev)
> > + return -ENOMEM;
> > +
> > + info = iio_priv(indio_dev);
> > + info->irq = platform_get_irq(pdev, 0);
> > + if (info->irq < 0) {
> > + dev_err(&pdev->dev, "no irq resource?\n");
> > + return info->irq;
> > + }
> > + platform_set_drvdata(pdev, indio_dev);
> > + info->regmap = axp20x->regmap;
> > + ret = axp288_adc_enable(axp20x->regmap, true);
> > + if (ret) {
> > + dev_err(&pdev->dev, "Unable to enable ADC
> > device\n");
> > + return ret;
> > + }
> > +
> > + indio_dev->dev.parent = &pdev->dev;
> > + indio_dev->name = pdev->name;
> > + indio_dev->channels = axp288_adc_channels;
> > + indio_dev->num_channels = ARRAY_SIZE(axp288_adc_channels);
> > + indio_dev->info = &axp288_adc_iio_info;
> > + indio_dev->modes = INDIO_DIRECT_MODE;
> > + ret = iio_map_array_register(indio_dev,
> > axp288_adc_default_maps);
> > + if (ret < 0)
> > + goto err_disable_dev;
> > +
> > + ret = iio_device_register(indio_dev);
> > + if (ret < 0) {
> > + dev_err(&pdev->dev, "unable to register iio
> > device\n");
> > + goto err_array_unregister;
> > + }
> > +
> > + return 0;
> > +
> > +err_array_unregister:
> > + iio_map_array_unregister(indio_dev);
> > +err_disable_dev:
> > + ret = axp288_adc_enable(axp20x->regmap, false);
> Don't set ret here. We want to return the error code from the
> function that failed above.
> > +
good point. thanks for the review.

> > + return ret;
> > +}
> > +
> > +static int axp288_adc_remove(struct platform_device *pdev)
> > +{
> > + struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> > + struct axp20x_dev *axp20x =
> > dev_get_drvdata(pdev->dev.parent); +
> > + if (axp288_adc_enable(axp20x->regmap, false))
> > + dev_err(&pdev->dev, "Unable to disable ADC
> > device\n");
> > + iio_device_unregister(indio_dev);
> > + iio_map_array_unregister(indio_dev);
> > +
> > + return 0;
> > +}
> > +
> > +static struct platform_driver axp288_adc_driver = {
> > + .probe = axp288_adc_probe,
> > + .remove = axp288_adc_remove,
> > + .driver = {
> > + .name = "axp288_adc",
> > + .owner = THIS_MODULE,
> > + },
> > +};
> > +
> > +module_platform_driver(axp288_adc_driver);
> > +
> > +MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@linux.intel.com>");
> > +MODULE_DESCRIPTION("X-Powers AXP288 ADC Driver");
> > +MODULE_LICENSE("GPL");
> >
>

[Jacob Pan]