Re: [RESEND 10/14] iio: adc: mt6370: Add Mediatek MT6370 support

From: ChiaEn Wu
Date: Thu Jun 02 2022 - 14:22:53 EST

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Hi Jonathan,

Sorry for sending the same email again. I miss to reply all in the last email..

Thanks for your valuable suggestions!

Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> 於 2022年5月31日週二下午9:21寫道：

>
> On Tue, 31 May 2022 19:18:56 +0800
> ChiaEn Wu <peterwu.pub@xxxxxxxxx> wrote:
>
> > From: ChiaEn Wu <chiaen_wu@xxxxxxxxxxx>
> >
> > Add Mediatek MT6370 ADC support.
> >
> > Signed-off-by: ChiaEn Wu <chiaen_wu@xxxxxxxxxxx>
>
> Hi ChiaEn,
>
> A few comments inline.
>
> Thanks,
>
> Jonathan
>
> > ---
> > drivers/iio/adc/Kconfig | 9 ++
> > drivers/iio/adc/Makefile | 1 +
> > drivers/iio/adc/mt6370-adc.c | 257 +++++++++++++++++++++++++++++++++++
> > 3 files changed, 267 insertions(+)
> > create mode 100644 drivers/iio/adc/mt6370-adc.c
> >
> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > index 71ab0a06aa82..d7932dd9b773 100644
> > --- a/drivers/iio/adc/Kconfig
> > +++ b/drivers/iio/adc/Kconfig
> > @@ -737,6 +737,15 @@ config MEDIATEK_MT6360_ADC
> > is used in smartphones and tablets and supports a 11 channel
> > general purpose ADC.
> >
> > +config MEDIATEK_MT6370_ADC
> > + tristate "Mediatek MT6370 ADC driver"
> > + depends on MFD_MT6370
> > + help
> > + Say Y here to enable MT6370 ADC support.
> > + Integrated for System Monitoring includes
>
> The wrapping of this text needs cleaning up.
>
> > + is used in smartphones and tablets and supports a 9 channel
> > + general purpose ADC.
> > +
> > config MEDIATEK_MT6577_AUXADC
> > tristate "MediaTek AUXADC driver"
> > depends on ARCH_MEDIATEK || COMPILE_TEST
> > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> > index 39d806f6d457..0ce285c7e2d0 100644
> > --- a/drivers/iio/adc/Makefile
> > +++ b/drivers/iio/adc/Makefile
> > @@ -68,6 +68,7 @@ obj-$(CONFIG_MCP320X) += mcp320x.o
> > obj-$(CONFIG_MCP3422) += mcp3422.o
> > obj-$(CONFIG_MCP3911) += mcp3911.o
> > obj-$(CONFIG_MEDIATEK_MT6360_ADC) += mt6360-adc.o
> > +obj-$(CONFIG_MEDIATEK_MT6370_ADC) += mt6370-adc.o
> > obj-$(CONFIG_MEDIATEK_MT6577_AUXADC) += mt6577_auxadc.o
> > obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
> > obj-$(CONFIG_MESON_SARADC) += meson_saradc.o
> > diff --git a/drivers/iio/adc/mt6370-adc.c b/drivers/iio/adc/mt6370-adc.c
> > new file mode 100644
> > index 000000000000..3320ebca17ad
> > --- /dev/null
> > +++ b/drivers/iio/adc/mt6370-adc.c
> > @@ -0,0 +1,257 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +#include <dt-bindings/iio/adc/mediatek,mt6370_adc.h>
> > +#include <linux/bits.h>
> > +#include <linux/bitfield.h>
> > +#include <linux/iio/iio.h>
> > +#include <linux/irq.h>
>
> Not seeing any interrupt support in here.

Sorry for that I forgot remove this line, I'll refine it in the next patch.

>
>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +
> > +#define MT6370_REG_CHG_CTRL3 0x113 /* AICR */
> > +#define MT6370_REG_CHG_CTRL7 0x117 /* ICHG */
> > +#define MT6370_REG_CHG_ADC 0x121
> > +#define MT6370_REG_ADC_DATA_H 0x14C
> > +
> > +#define MT6370_ADC_START_MASK BIT(0)
> > +#define MT6370_ADC_IN_SEL_MASK GENMASK(7, 4)
> > +#define MT6370_AICR_ICHG_MASK GENMASK(7, 2)
> > +
> > +#define MT6370_ADC_CHAN_SHIFT 4
>
> Prefer using a mask and then FIELD_PREP

OK, I got it!

>
> > +
> > +#define MT6370_AICR_400MA 0x6
> > +#define MT6370_ICHG_500MA 0x4
> > +#define MT6370_ICHG_900MA 0x8
> > +
> > +#define ADC_CONV_TIME_US 35000
> > +#define ADC_CONV_POLLING_TIME 1000
> > +
> > +struct mt6370_adc_data {
> > + struct device *dev;
> > + struct regmap *regmap;
> > + struct mutex lock;
>
> All locks need documentation. What is the scope of the lock?
> Looks like it protects device state when doing setup, wait for read, read
> cycles.

This mutex lock is for preventing the different adc channel from being
read at the same time.
So, if I just change its name to adc_chan_lock or adc_lock and add the
comment for this mutex lock, does this change meet your requirement?

>
> > +};
> > +
> > +static int mt6370_adc_read_channel(struct mt6370_adc_data *priv, int chan,
> > + unsigned long addr, int *val)
> > +{
> > + __be16 be_val;
> > + unsigned int reg_val;
> > + int ret;
> > +
> > + mutex_lock(&priv->lock);
> > +
> > + reg_val = MT6370_ADC_START_MASK | (addr << MT6370_ADC_CHAN_SHIFT);
>
> FIELD_PREP for that shift?

I got it! I'll refine it in the next patch.

>
> > + ret = regmap_write(priv->regmap, MT6370_REG_CHG_ADC, reg_val);
> > + if (ret)
> > + goto adc_unlock;
> > +
> > + msleep(ADC_CONV_TIME_US / 1000);
> > +
> > + ret = regmap_read_poll_timeout(priv->regmap,
> > + MT6370_REG_CHG_ADC, reg_val,
> > + !(reg_val & MT6370_ADC_START_MASK),
> > + ADC_CONV_POLLING_TIME,
> > + ADC_CONV_TIME_US * 3);
> > + if (ret) {
> > + if (ret == -ETIMEDOUT)
> > + dev_err(priv->dev, "Failed to wait adc conversion\n");
> > + goto adc_unlock;
> > + }
> > +
> > + ret = regmap_raw_read(priv->regmap, MT6370_REG_ADC_DATA_H,
> > + &be_val, sizeof(be_val));
> > + if (ret)
> > + goto adc_unlock;
> > +
> > + *val = be16_to_cpu(be_val);
> > + ret = IIO_VAL_INT;
> > +
> > +adc_unlock:
> > + mutex_unlock(&priv->lock);
> > +
> > + return ret;
> > +}
> > +
> > +static int mt6370_adc_read_scale(struct mt6370_adc_data *priv,
> > + int chan, int *val1, int *val2)
> > +{
> > + unsigned int reg_val;
> > + int ret;
> > +
> > + switch (chan) {
> > + case MT6370_CHAN_VBAT:
> > + case MT6370_CHAN_VSYS:
> > + case MT6370_CHAN_CHG_VDDP:
> > + *val1 = 5000;
>
> This seems very large. Voltages are in millivolts
> as per Documentation/ABI/testing/sysfs-bus-iio
> and this means each step is 5 volts.
>
> So value in mv is currently 5 * _raw
>

OK, I got it. Also, I will add the ABI file in the next version. Thanks!

>
>
> > + return IIO_VAL_INT;
> > + case MT6370_CHAN_IBUS:
> > + ret = regmap_read(priv->regmap, MT6370_REG_CHG_CTRL3, &reg_val);
> > + if (ret)
> > + return ret;
> > +
> > + reg_val = FIELD_GET(MT6370_AICR_ICHG_MASK, reg_val);
> > + if (reg_val < MT6370_AICR_400MA)
> > + *val1 = 33500;
> > + else
> > + *val1 = 50000;
> > +
> > + return IIO_VAL_INT;
> > + case MT6370_CHAN_IBAT:
> > + ret = regmap_read(priv->regmap, MT6370_REG_CHG_CTRL7, &reg_val);
> > + if (ret)
> > + return ret;
> > +
> > + reg_val = FIELD_GET(MT6370_AICR_ICHG_MASK, reg_val);
> > + if (reg_val < MT6370_ICHG_500MA)
> > + *val1 = 23750;
> > + else if (reg_val >= MT6370_ICHG_500MA &&
> > + reg_val < MT6370_ICHG_900MA)
> > + *val1 = 26800;
> > + else
> > + *val1 = 50000;
> > +
> > + return IIO_VAL_INT;
> > + case MT6370_CHAN_VBUSDIV5:
> > + *val1 = 25000;
> > + return IIO_VAL_INT;
> > + case MT6370_CHAN_VBUSDIV2:
> > + *val1 = 50000;
> > + return IIO_VAL_INT;
> > + case MT6370_CHAN_TS_BAT:
> > + *val1 = 25;
> > + *val2 = 10000;
> > + return IIO_VAL_FRACTIONAL;
> > + case MT6370_CHAN_TEMP_JC:
> > + *val1 = 2;
> > + return IIO_VAL_INT;
> > + }
> > +
> > + return -EINVAL;
> > +}
> > +
> > +static int mt6370_adc_read_offset(struct mt6370_adc_data *priv,
> > + int chan, int *val)
> > +{
> > + *val = (chan == MT6370_CHAN_TEMP_JC) ? -20 : 0;
>
> Offset default is 0, so for channels where it doesn't apply don't
> provide the offset attribute at all.
>

OK!

> > + return IIO_VAL_INT;
> > +}
> > +
> > +static int mt6370_adc_read_raw(struct iio_dev *iio_dev,
> > + const struct iio_chan_spec *chan,
> > + int *val, int *val2, long mask)
> > +{
> > + struct mt6370_adc_data *priv = iio_priv(iio_dev);
> > +
> > + switch (mask) {
> > + case IIO_CHAN_INFO_RAW:
> > + return mt6370_adc_read_channel(priv, chan->channel,
> > + chan->address, val);
> > + case IIO_CHAN_INFO_SCALE:
> > + return mt6370_adc_read_scale(priv, chan->channel, val, val2);
> > + case IIO_CHAN_INFO_OFFSET:
> > + return mt6370_adc_read_offset(priv, chan->channel, val);
> > + }
> > +
> > + return -EINVAL;
> > +}
> > +
> > +static const char * const mt6370_channel_labels[MT6370_CHAN_MAX] = {
>
> Perhaps define an enum with which to index this and the chan spec
> and hence ensure they end up matching.
> [vbusdiv5] = "vbusdiv5", etc
>

Do you mean that I can refine this const char array to the following array??

static const char * const mt6370_channel_labels[MT6370_CHAN_MAX] = {
[MT6370_CHAN_VBUSDIV5] = "vbusdiv5",
[MT6370_CHAN_VBUSDIV2] = "vbusdiv2",
...
...
[MT6370_CHAN_TEMP_JC] = "temp_jc",
};

> > + "vbusdiv5", "vbusdiv2", "vsys", "vbat",
> > + "ts_bat", "ibus", "ibat", "chg_vddp",
> > + "temp_jc",
> > +};
> > +
> > +static int mt6370_adc_read_label(struct iio_dev *iio_dev,
> > + struct iio_chan_spec const *chan, char *label)
> > +{
> > + return snprintf(label, PAGE_SIZE, "%s\n",
> > + mt6370_channel_labels[chan->channel]);
> > +}
> > +
> > +static const struct iio_info mt6370_adc_iio_info = {
> > + .read_raw = mt6370_adc_read_raw,
> > + .read_label = mt6370_adc_read_label,
> > +};
> > +
> > +#define MT6370_ADC_CHAN(_idx, _type, _addr) { \
> > + .type = _type, \
> > + .channel = MT6370_CHAN_##_idx, \
> > + .address = _addr, \
> > + .scan_index = MT6370_CHAN_##_idx, \
> > + .indexed = 1, \
> > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> > + BIT(IIO_CHAN_INFO_SCALE) | \
> > + BIT(IIO_CHAN_INFO_OFFSET), \
>
> See above. Only temp_jc channel should hav an offset.
>
OK!

> > +}
> > +
> > +static const struct iio_chan_spec mt6370_adc_channels[] = {
> > + MT6370_ADC_CHAN(VBUSDIV5, IIO_VOLTAGE, 1),
> > + MT6370_ADC_CHAN(VBUSDIV2, IIO_VOLTAGE, 2),
> > + MT6370_ADC_CHAN(VSYS, IIO_VOLTAGE, 3),
> > + MT6370_ADC_CHAN(VBAT, IIO_VOLTAGE, 4),
> > + MT6370_ADC_CHAN(TS_BAT, IIO_VOLTAGE, 6),
> > + MT6370_ADC_CHAN(IBUS, IIO_CURRENT, 8),
> > + MT6370_ADC_CHAN(IBAT, IIO_CURRENT, 9),
> > + MT6370_ADC_CHAN(CHG_VDDP, IIO_VOLTAGE, 11),
> > + MT6370_ADC_CHAN(TEMP_JC, IIO_TEMP, 12),
> > +};
> > +
> > +static int mt6370_adc_probe(struct platform_device *pdev)
> > +{
> > + int ret;
> > + struct mt6370_adc_data *priv;
> > + struct regmap *regmap;
> > + struct iio_dev *indio_dev;
> > +
> > + regmap = dev_get_regmap(pdev->dev.parent, NULL);
> > + if (!regmap) {
> > + dev_err(&pdev->dev, "Failed to get regmap\n");
> > + return -ENODEV;
> > + }
> > +
> > + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv));
> > + if (!indio_dev)
> > + return -ENOMEM;
> > +
> > + priv = iio_priv(indio_dev);
> > + priv->dev = &pdev->dev;
> > + priv->regmap = regmap;
> > + mutex_init(&priv->lock);
> > +
> > + ret = regmap_write(priv->regmap, MT6370_REG_CHG_ADC, 0);
> > + if (ret) {
> > + dev_err(&pdev->dev, "Failed to reset adc\n");
> > + return ret;
> > + }
> > +
> > + indio_dev->name = dev_name(&pdev->dev);
>
> What does this end up as? It's used for userspace ABI and should
> correspond to the part number, "mt6370-adc" probably
> appropriate in this case (I think it'll end up as simply "adc.x"
> currently?) Normally we just hard code this in the driver for
> whatever devices the driver supports.

I got it, I will change this name to "mt6370-adc" in the next version! Thanks!

>
> > + indio_dev->info = &mt6370_adc_iio_info;
> > + indio_dev->modes = INDIO_DIRECT_MODE;
> > + indio_dev->channels = mt6370_adc_channels;
> > + indio_dev->num_channels = ARRAY_SIZE(mt6370_adc_channels);
> > +
> > + return devm_iio_device_register(&pdev->dev, indio_dev);
> > +}
> > +
> > +static const struct of_device_id mt6370_adc_of_id[] = {
> > + { .compatible = "mediatek,mt6370-adc", },
> > + {}
> > +};
> > +MODULE_DEVICE_TABLE(of, mt6370_adc_of_id);
> > +
> > +static struct platform_driver mt6370_adc_driver = {
> > + .driver = {
> > + .name = "mt6370-adc",
> > + .of_match_table = mt6370_adc_of_id,
> > + },
> > + .probe = mt6370_adc_probe,
> > +};
> > +module_platform_driver(mt6370_adc_driver);
> > +
> > +MODULE_AUTHOR("ChiaEn Wu <chiaen_wu@xxxxxxxxxxx>");
> > +MODULE_DESCRIPTION("MT6370 ADC Drvier");
> > +MODULE_LICENSE("GPL v2");
>

Best regards,
ChiaEn Wu

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