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

[Hartmut Knaack <knaack.h@gmx.de>]

Jacob Pan schrieb, Am 18.09.2014 01:13:
> 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)
Here is an indentation issue. See [1] how it can look like (although it is fine to have several parameters in every line).

[1] https://git.kernel.org/cgit/linux/kernel/git/jic23/iio.git/tree/drivers/iio/adc/max1363.c?h=testing#n414

>>> +{
>>> +	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.
Yeah, that's probably always a decision between quick exit path vs. low code duplication. They weight pretty equal in this case.
>>> +			}
>>> +		}
>>> +	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;
This one, adc_en ^^^^^ is what I meant. It gets set here and below, but not used again.
I would expect, that you intended to write it to AXP20X_ADC_EN1 at the end of this function.
>>> +	} 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]
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