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Date:   Fri, 21 Feb 2020 13:07:33 +0000
From:   Jonathan Cameron <jic23@kernel.org>
To:     Andreas Kemnade <andreas@kemnade.info>
Cc:     knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net,
        lee.jones@linaro.org, b.galvani@gmail.com,
        linus.walleij@linaro.org, linux-kernel@vger.kernel.org,
        linux-iio@vger.kernel.org, phh@phh.me, stefan@agner.ch,
        letux-kernel@openphoenux.org, martin.blumenstingl@googlemail.com
Subject: Re: [PATCH v3 2/4] iio: adc: rn5t618: Add ADC driver for
 RN5T618/RC5T619
Message-ID: <20200221130733.240f0d6d@archlinux>
In-Reply-To: <20200218061725.22420-3-andreas@kemnade.info>
References: <20200218061725.22420-1-andreas@kemnade.info>
        <20200218061725.22420-3-andreas@kemnade.info>
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On Tue, 18 Feb 2020 07:17:23 +0100
Andreas Kemnade <andreas@kemnade.info> wrote:

> Both chips have an A/D converter capable of measuring
> things like VBAT, VUSB and analog inputs.
> 
> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
One trivial comment inline.  Looks good to me and I'm assuming
this will got through the mfd tree.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
> depends on (build and runtime):
> https://lore.kernel.org/lkml/20191220122416.31881-1-andreas@kemnade.info/
> 
> Changes in v3:
> - output scale instead of processed
> - prefixed symbols with RN5T618
> 
> Changes in v2:
> - enum for channels
> - bulk read instead of single byte read for conversion
>   result
> - fix get_virq error handling
> - use devm for registering device and requesting IRQ
> 
>  drivers/iio/adc/Kconfig       |  10 ++
>  drivers/iio/adc/Makefile      |   1 +
>  drivers/iio/adc/rn5t618-adc.c | 258 ++++++++++++++++++++++++++++++++++
>  3 files changed, 269 insertions(+)
>  create mode 100644 drivers/iio/adc/rn5t618-adc.c
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 5d8540b7b427..e7e74e775336 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -766,6 +766,16 @@ config RCAR_GYRO_ADC
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called rcar-gyroadc.
>  
> +config RN5T618_ADC
> +	tristate "ADC for the RN5T618/RC5T619 family of chips"
> +	depends on MFD_RN5T618
> +	help
> +	  Say yes here to build support for the integrated ADC inside the
> +	  RN5T618/619 series PMICs:
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called rn5t618-adc.
> +
>  config ROCKCHIP_SARADC
>  	tristate "Rockchip SARADC driver"
>  	depends on ARCH_ROCKCHIP || (ARM && COMPILE_TEST)
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index a1f1fbec0f87..ea95f89c91cd 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -72,6 +72,7 @@ obj-$(CONFIG_QCOM_VADC_COMMON) += qcom-vadc-common.o
>  obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
>  obj-$(CONFIG_QCOM_PM8XXX_XOADC) += qcom-pm8xxx-xoadc.o
>  obj-$(CONFIG_RCAR_GYRO_ADC) += rcar-gyroadc.o
> +obj-$(CONFIG_RN5T618_ADC) += rn5t618-adc.o
>  obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
>  obj-$(CONFIG_SC27XX_ADC) += sc27xx_adc.o
>  obj-$(CONFIG_SPEAR_ADC) += spear_adc.o
> diff --git a/drivers/iio/adc/rn5t618-adc.c b/drivers/iio/adc/rn5t618-adc.c
> new file mode 100644
> index 000000000000..8396eba0fcb5
> --- /dev/null
> +++ b/drivers/iio/adc/rn5t618-adc.c
> @@ -0,0 +1,258 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * ADC driver for the RICOH RN5T618 power management chip family
> + *
> + * Copyright (C) 2019 Andreas Kemnade
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/device.h>
> +#include <linux/errno.h>
> +#include <linux/interrupt.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/mfd/rn5t618.h>
> +#include <linux/platform_device.h>
> +#include <linux/completion.h>
> +#include <linux/regmap.h>
> +#include <linux/iio/iio.h>
> +#include <linux/slab.h>
> +
> +#define RN5T618_ADC_CONVERSION_TIMEOUT   (msecs_to_jiffies(500))
> +#define RN5T618_REFERENCE_VOLT 2500
> +
> +/* mask for selecting channels for single conversion */
> +#define RN5T618_ADCCNT3_CHANNEL_MASK 0x7
> +/* average 4-time conversion mode */
> +#define RN5T618_ADCCNT3_AVG BIT(3)
> +/* set for starting a single conversion, gets cleared by hw when done */
> +#define RN5T618_ADCCNT3_GODONE BIT(4)
> +/* automatic conversion, period is in ADCCNT2, selected channels are
> + * in ADCCNT1
> + */
> +#define RN5T618_ADCCNT3_AUTO BIT(5)
> +#define RN5T618_ADCEND_IRQ BIT(0)
> +
> +struct rn5t618_adc_data {
> +	struct device *dev;
> +	struct rn5t618 *rn5t618;
> +	struct completion conv_completion;
> +	int irq;
> +};
> +
> +struct rn5t618_channel_ratios {
> +	u16 numerator;
> +	u16 denominator;
> +};
> +
> +enum rn5t618_channels {
> +	LIMMON = 0,
> +	VBAT,
> +	VADP,
> +	VUSB,
> +	VSYS,
> +	VTHM,
> +	AIN1,
> +	AIN0
> +};
> +
> +static const struct rn5t618_channel_ratios rn5t618_ratios[8] = {
> +	[LIMMON] = {50, 32}, /* measured across 20mOhm, amplified by 32 */
> +	[VBAT] = {2, 1},
> +	[VADP] = {3, 1},
> +	[VUSB] = {3, 1},
> +	[VSYS] = {3, 1},
> +	[VTHM] = {1, 1},
> +	[AIN1] = {1, 1},
> +	[AIN0] = {1, 1},
> +};
> +
> +static int rn5t618_read_adc_reg(struct rn5t618 *rn5t618, int reg, u16 *val)
> +{
> +	u8 data[2];
> +	int ret;
> +
> +	ret = regmap_bulk_read(rn5t618->regmap, reg, data, sizeof(data));
> +	if (ret < 0)
> +		return ret;
> +
> +	*val = (data[0] << 4) | (data[1] & 0xF);
> +
> +	return 0;
> +}
> +
> +static irqreturn_t rn5t618_adc_irq(int irq, void *data)
> +{
> +	struct rn5t618_adc_data *adc = data;
> +	unsigned int r = 0;
> +	int ret;
> +
> +	/* clear low & high threshold irqs */
> +	regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC1, 0);
> +	regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC2, 0);
> +
> +	ret = regmap_read(adc->rn5t618->regmap, RN5T618_IR_ADC3, &r);
> +	if (ret < 0)
> +		dev_err(adc->dev, "failed to read IRQ status: %d\n", ret);
> +
> +	regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC3, 0);
> +
> +	if (r & RN5T618_ADCEND_IRQ)
> +		complete(&adc->conv_completion);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int rn5t618_adc_read(struct iio_dev *iio_dev,
> +			    const struct iio_chan_spec *chan,
> +			    int *val, int *val2, long mask)
> +{
> +	struct rn5t618_adc_data *adc = iio_priv(iio_dev);
> +	u16 raw;
> +	int ret;
> +
> +	if (mask == IIO_CHAN_INFO_SCALE) {
> +		*val = RN5T618_REFERENCE_VOLT *
> +		       rn5t618_ratios[chan->channel].numerator;
> +		*val2 = rn5t618_ratios[chan->channel].denominator * 4095;
> +
> +		return IIO_VAL_FRACTIONAL;
> +	}
> +
> +	/* select channel */
> +	ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
> +				 RN5T618_ADCCNT3_CHANNEL_MASK,
> +				 chan->channel);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_write(adc->rn5t618->regmap, RN5T618_EN_ADCIR3,
> +			   RN5T618_ADCEND_IRQ);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
> +				 RN5T618_ADCCNT3_AVG,
> +				 mask == IIO_CHAN_INFO_AVERAGE_RAW ?
> +				 RN5T618_ADCCNT3_AVG : 0);
> +	if (ret < 0)
> +		return ret;
> +
> +	init_completion(&adc->conv_completion);
> +	/* single conversion */
> +	ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
> +				 RN5T618_ADCCNT3_GODONE,
> +				 RN5T618_ADCCNT3_GODONE);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = wait_for_completion_timeout(&adc->conv_completion,
> +					  RN5T618_ADC_CONVERSION_TIMEOUT);
> +	if (ret == 0) {
> +		dev_warn(adc->dev, "timeout waiting for adc result\n");
> +		return -ETIMEDOUT;
> +	}
> +
> +	ret = rn5t618_read_adc_reg(adc->rn5t618,
> +				   RN5T618_ILIMDATAH + 2 * chan->channel,
> +				   &raw);
> +	if (ret < 0)
> +		return ret;
> +
> +	*val = raw;
> +
> +	return IIO_VAL_INT;
> +}
> +
> +static const struct iio_info rn5t618_adc_iio_info = {
> +	.read_raw = &rn5t618_adc_read,
> +};
> +
> +#define RN5T618_ADC_CHANNEL(_channel, _type, _name) { \
> +	.type = _type, \
> +	.channel = _channel, \
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> +			      BIT(IIO_CHAN_INFO_AVERAGE_RAW) | \
> +			      BIT(IIO_CHAN_INFO_SCALE), \
> +	.datasheet_name = _name, \
> +	.indexed = 1. \
> +}
> +
> +static const struct iio_chan_spec rn5t618_adc_iio_channels[] = {
> +	RN5T618_ADC_CHANNEL(LIMMON, IIO_CURRENT, "LIMMON"),
> +	RN5T618_ADC_CHANNEL(VBAT, IIO_VOLTAGE, "VBAT"),
> +	RN5T618_ADC_CHANNEL(VADP, IIO_VOLTAGE, "VADP"),
> +	RN5T618_ADC_CHANNEL(VUSB, IIO_VOLTAGE, "VUSB"),
> +	RN5T618_ADC_CHANNEL(VSYS, IIO_VOLTAGE, "VSYS"),
> +	RN5T618_ADC_CHANNEL(VTHM, IIO_VOLTAGE, "VTHM"),
> +	RN5T618_ADC_CHANNEL(AIN1, IIO_VOLTAGE, "AIN1"),
> +	RN5T618_ADC_CHANNEL(AIN0, IIO_VOLTAGE, "AIN0")
> +};
> +
> +static int rn5t618_adc_probe(struct platform_device *pdev)
> +{
> +	int ret;
> +	struct iio_dev *iio_dev;
> +	struct rn5t618_adc_data *adc;
> +	struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
> +
> +	iio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
> +	if (!iio_dev) {
> +		dev_err(&pdev->dev, "failed allocating iio device\n");
> +		return -ENOMEM;
> +	}
> +
> +	adc = iio_priv(iio_dev);
> +	adc->dev = &pdev->dev;
> +	adc->rn5t618 = rn5t618;
> +
> +	if (rn5t618->irq_data)
> +		adc->irq = regmap_irq_get_virq(rn5t618->irq_data,
> +					       RN5T618_IRQ_ADC);
> +
> +	if (adc->irq <= 0) {
> +		dev_err(&pdev->dev, "get virq failed\n");
> +		return -EINVAL;
> +	}
> +
> +	init_completion(&adc->conv_completion);
> +
> +	iio_dev->name = dev_name(&pdev->dev);
> +	iio_dev->dev.parent = &pdev->dev;
> +	iio_dev->info = &rn5t618_adc_iio_info;
> +	iio_dev->modes = INDIO_DIRECT_MODE;
> +	iio_dev->channels = rn5t618_adc_iio_channels;
> +	iio_dev->num_channels = ARRAY_SIZE(rn5t618_adc_iio_channels);
> +
> +	/* stop any auto-conversion */
> +	ret = regmap_write(rn5t618->regmap, RN5T618_ADCCNT3, 0);
> +	if (ret < 0)
> +		return ret;
> +
> +	platform_set_drvdata(pdev, iio_dev);
> +
> +	ret = devm_request_threaded_irq(adc->dev, adc->irq, NULL,
> +					rn5t618_adc_irq,
> +					IRQF_ONESHOT, dev_name(adc->dev),
> +					adc);
> +	if (ret < 0) {
> +		dev_err(adc->dev, "request irq %d failed: %d\n", adc->irq, ret);
> +		return ret;
> +	}
> +
> +	ret = devm_iio_device_register(adc->dev, iio_dev);

Roll this and the return into one line.

> +
> +	return ret;
> +}
> +
> +static struct platform_driver rn5t618_adc_driver = {
> +	.driver = {
> +		.name   = "rn5t618-adc",
> +	},
> +	.probe = rn5t618_adc_probe,
> +};
> +
> +module_platform_driver(rn5t618_adc_driver);
> +MODULE_ALIAS("platform:rn5t618-adc");
> +MODULE_DESCRIPTION("RICOH RN5T618 ADC driver");
> +MODULE_LICENSE("GPL");