Re: [PATCH v4 3/3] iio: adc: mt6360: Add ADC driver for MT6360

From: Gene Chen
Date: Fri Sep 18 2020 - 04:04:58 EST

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Jonathan Cameron <jic23@xxxxxxxxxx> 於 2020年9月18日週五上午1:53寫道：
>
> On Wed, 16 Sep 2020 01:36:09 +0800
> Gene Chen <gene.chen.richtek@xxxxxxxxx> wrote:
>
> > From: Gene Chen <gene_chen@xxxxxxxxxxx>
> >
> > Add MT6360 ADC driver include Charger Current, Voltage, and
> > Temperature.
> >
> > Signed-off-by: Gene Chen <gene_chen@xxxxxxxxxxx>
> Comments inline.
>
> > ---
> > drivers/iio/adc/Kconfig | 11 ++
> > drivers/iio/adc/Makefile | 1 +
> > drivers/iio/adc/mt6360-adc.c | 357 +++++++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 369 insertions(+)
> > create mode 100644 drivers/iio/adc/mt6360-adc.c
> >
> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > index 66d9cc0..8d36b66 100644
> > --- a/drivers/iio/adc/Kconfig
> > +++ b/drivers/iio/adc/Kconfig
> > @@ -703,6 +703,17 @@ config MCP3911
> > This driver can also be built as a module. If so, the module will be
> > called mcp3911.
> >
> > +config MEDIATEK_MT6360_ADC
> > + tristate "Mediatek MT6360 ADC driver"
> > + depends on MFD_MT6360
> > + select IIO_BUFFER
> > + select IIO_TRIGGERED_BUFFER
> > + help
> > + Say Y here to enable MT6360 ADC support.
> > + Integrated for System Monitoring includes
> > + is used in smartphones and tablets and supports a 11 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 90f94ad..5fca90a 100644
> > --- a/drivers/iio/adc/Makefile
> > +++ b/drivers/iio/adc/Makefile
> > @@ -65,6 +65,7 @@ obj-$(CONFIG_MAX9611) += max9611.o
> > obj-$(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_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/mt6360-adc.c b/drivers/iio/adc/mt6360-adc.c
> > new file mode 100644
> > index 0000000..b256d0a
> > --- /dev/null
> > +++ b/drivers/iio/adc/mt6360-adc.c
> > @@ -0,0 +1,357 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +#include <linux/delay.h>
> > +#include <linux/irq.h>
> > +#include <linux/kernel.h>
> > +#include <linux/ktime.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +
> > +#include <linux/iio/buffer.h>
> > +#include <linux/iio/iio.h>
> > +#include <linux/iio/trigger_consumer.h>
> > +#include <linux/iio/triggered_buffer.h>
> > +
> > +#define MT6360_REG_PMUCHGCTRL3 0x313
> > +#define MT6360_REG_PMUADCCFG 0x356
> > +#define MT6360_REG_PMUADCIDLET 0x358
> > +#define MT6360_REG_PMUADCRPT1 0x35A
> > +
> > +/* PMUCHGCTRL3 0x313 */
> > +#define MT6360_AICR_MASK GENMASK(7, 2)
> > +#define MT6360_AICR_SHFT 2
> > +#define MT6360_AICR_400MA 0x6
> > +/* PMUADCCFG 0x356 */
> > +#define MT6360_ADCEN_MASK 0x8000
> > +/* PMUADCRPT1 0x35A */
> > +#define MT6360_PREFERCH_MASK GENMASK(7, 4)
> > +#define MT6360_PREFERCH_SHFT 4
> > +#define MT6360_RPTCH_MASK GENMASK(3, 0)
> > +#define MT6360_NO_PREFER 15
> > +
> > +/* Time in ms */
> > +#define ADC_WAIT_TIME_MS 25
> > +
> > +enum {
> > + MT6360_CHAN_USBID = 0,
> > + MT6360_CHAN_VBUSDIV5,
> > + MT6360_CHAN_VBUSDIV2,
> > + MT6360_CHAN_VSYS,
> > + MT6360_CHAN_VBAT,
> > + MT6360_CHAN_IBUS,
> > + MT6360_CHAN_IBAT,
> > + MT6360_CHAN_CHG_VDDP,
> > + MT6360_CHAN_TEMP_JC,
> > + MT6360_CHAN_VREF_TS,
> > + MT6360_CHAN_TS,
> > + MT6360_CHAN_MAX
> > +};
> > +
> > +struct mt6360_adc_data {
> > + struct device *dev;
> > + struct regmap *regmap;
> > + struct mutex adc_lock;
>
> Please add a comment to document what the scope of the lock is.
>

ACK

> > + ktime_t last_off_timestamps[MT6360_CHAN_MAX];
> > +};
> > +
> > +static int mt6360_adc_read_channel(struct mt6360_adc_data *mad, int channel, int *val)
> > +{
> > + __be16 adc_enable;
> > + u8 rpt[3];
> > + ktime_t start_t, predict_end_t;
> > + unsigned int pre_wait_time;
> > + int ret;
> > +
> > + mutex_lock(&mad->adc_lock);
> > +
> > + /* Select the preferred ADC channel */
> > + ret = regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
> > + channel << MT6360_PREFERCH_SHFT);
> > + if (ret)
> > + goto out_adc_lock;
> > +
> > + adc_enable = cpu_to_be16(MT6360_ADCEN_MASK | BIT(channel));
> > + ret = regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable,
>
> Shouldn't be any need to cast a pointer explicitly to void *
>

ACK

> > + sizeof(__be16));
>
> sizeof(adc_enable) preferred.
>

ACK

> > + if (ret)
> > + goto out_adc_lock;
> > +
> > + start_t = ktime_get();
> > + predict_end_t = ktime_add_ms(mad->last_off_timestamps[channel], 2 * ADC_WAIT_TIME_MS);
> > +
> > + if (ktime_after(start_t, predict_end_t))
> > + pre_wait_time = ADC_WAIT_TIME_MS;
> > + else
> > + pre_wait_time = 3 * ADC_WAIT_TIME_MS;
> > +
> > + msleep(pre_wait_time);
> > +
> > + while (true) {
> > + ret = regmap_raw_read(mad->regmap, MT6360_REG_PMUADCRPT1, rpt, sizeof(rpt));
> > + if (ret)
> > + goto out_adc_conv;
> > +
> > + /*
> > + * There are two functions, ZCV and TypeC OTP, running ADC VBAT and TS in
> > + * background, and ADC samples are taken on a fixed frequency no matter read the
> > + * previous one or not.
> > + * To avoid conflict, We set minimum time threshold after enable ADC and
> > + * check report channel is the same.
> > + * The worst case is run the same ADC twice and background function is also running,
> > + * ADC conversion sequence is desire channel before start ADC, background ADC,
> > + * desire channel after start ADC.
> > + * So the minimum correct data is three times of typical conversion time.
> > + */
> > + if ((rpt[0] & MT6360_RPTCH_MASK) == channel)
> > + break;
> > +
> > + msleep(ADC_WAIT_TIME_MS);
> > + }
> > +
> > + /* rpt[1]: ADC_HI_BYTE, rpt[2]: ADC_LOW_BYTE */
> > + *val = be16_to_cpup((__be16 *)(rpt + 1));
>
> To be entirely safe, probably need that to be an unaligned read?
>

Maybe I can change to "*val = rpt[1] << 8 | rpt[2];".
It's more abvious.

> > + ret = IIO_VAL_INT;
> > +
> > +out_adc_conv:
> > + /* Only keep ADC enable */
> > + adc_enable = cpu_to_be16(MT6360_ADCEN_MASK);
> > + regmap_raw_write(mad->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable, sizeof(__be16));
>
> sizeof(adc_enable)
>

ACK

> > + mad->last_off_timestamps[channel] = ktime_get();
> > + /* Config prefer channel to NO_PREFER */
> > + regmap_update_bits(mad->regmap, MT6360_REG_PMUADCRPT1, MT6360_PREFERCH_MASK,
> > + MT6360_NO_PREFER << MT6360_PREFERCH_SHFT);
> > +out_adc_lock:
> > + mutex_unlock(&mad->adc_lock);
> > +
> > + return ret;
> > +}
> > +
> > +static int mt6360_adc_read_scale(struct mt6360_adc_data *mad, int channel, int *val, int *val2)
> > +{
> > + unsigned int regval;
> > + int ret;
> > +
> > + switch (channel) {
> > + case MT6360_CHAN_USBID:
> > + fallthrough;
>
> I don't think we need fallthrough for cases
> with nothing in them.
>

Every channel needs set " *val = 2500" for scale.
Do you mean change as below?

switch (channel) {
case MT6360_CHAN_USBID:
case MT6360_CHAN_VSYS:
case MT6360_CHAN_VBAT:
case MT6360_CHAN_CHG_VDDP:
case MT6360_CHAN_VREF_TS:
fallthrough;
case MT6360_CHAN_TS:
*val = 1250;
return IIO_VAL_INT;

> > + case MT6360_CHAN_USBID:

> > + case MT6360_CHAN_VSYS:
> > + fallthrough;
> > + case MT6360_CHAN_VBAT:
> > + fallthrough;
> > + case MT6360_CHAN_CHG_VDDP:
> > + fallthrough;
> > + case MT6360_CHAN_VREF_TS:
> > + fallthrough;
> > + case MT6360_CHAN_TS:
> > + *val = 1250;
> > + return IIO_VAL_INT;
> > + case MT6360_CHAN_VBUSDIV5:
> > + *val = 6250;
> > + return IIO_VAL_INT;
> > + case MT6360_CHAN_VBUSDIV2:
> > + fallthrough;
> > + case MT6360_CHAN_IBUS:
> > + fallthrough;
> > + case MT6360_CHAN_IBAT:
> > + *val = 2500;
> > +
> > + if (channel == MT6360_CHAN_IBUS) {
> > + /* IBUS will be affected by input current limit for the different Ron */
> > + /* Check whether the config is <400mA or not */
> > + ret = regmap_read(mad->regmap, MT6360_REG_PMUCHGCTRL3, &regval);
> > + if (ret)
> > + return ret;
> > +
> > + regval = (regval & MT6360_AICR_MASK) >> MT6360_AICR_SHFT;
> > + if (regval < MT6360_AICR_400MA)
> > + *val = 1900;
> > + }
> > +
> > + return IIO_VAL_INT;
> > + case MT6360_CHAN_TEMP_JC:
> > + *val = 105;
> > + *val2 = 100;
> > + return IIO_VAL_FRACTIONAL;
> > + }
> > +
> > + return -EINVAL;
> > +}
> > +
> > +static int mt6360_adc_read_offset(struct mt6360_adc_data *mad, int channel, int *val)
> > +{
> > + *val = (channel == MT6360_CHAN_TEMP_JC) ? -80 : 0;
> > + return IIO_VAL_INT;
> > +
> > +}
> > +
> > +static int mt6360_adc_read_raw(struct iio_dev *iio_dev, const struct iio_chan_spec *chan,
> > + int *val, int *val2, long mask)
> > +{
> > + struct mt6360_adc_data *mad = iio_priv(iio_dev);
> > +
> > + switch (mask) {
> > + case IIO_CHAN_INFO_RAW:
> > + return mt6360_adc_read_channel(mad, chan->channel, val);
> > + case IIO_CHAN_INFO_SCALE:
> > + return mt6360_adc_read_scale(mad, chan->channel, val, val2);
> > + case IIO_CHAN_INFO_OFFSET:
> > + return mt6360_adc_read_offset(mad, chan->channel, val);
> > + }
> > +
> > + return -EINVAL;
> > +}
> > +
> > +static const struct iio_info mt6360_adc_iio_info = {
> > + .read_raw = mt6360_adc_read_raw,
> > +};
> > +
> > +#define MT6360_ADC_CHAN(_idx, _type) { \
> > + .type = _type, \
> > + .channel = MT6360_CHAN_##_idx, \
> > + .scan_index = MT6360_CHAN_##_idx, \
> > + .extend_name = #_idx, \
> > + .datasheet_name = #_idx, \
> > + .scan_type = { \
> > + .sign = 'u', \
> > + .realbits = 16, \
> > + .storagebits = 16, \
> > + .endianness = IIO_CPU, \
> > + }, \
> > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
>
> Docs in patch 1 need to reflect this change. Currently they have
> processed channels.
>

ACK

> > + BIT(IIO_CHAN_INFO_SCALE) | \
> > + BIT(IIO_CHAN_INFO_OFFSET), \
> > +}
> > +
> > +static const struct iio_chan_spec mt6360_adc_channels[] = {
> > + MT6360_ADC_CHAN(USBID, IIO_VOLTAGE),
> > + MT6360_ADC_CHAN(VBUSDIV5, IIO_VOLTAGE),
> > + MT6360_ADC_CHAN(VBUSDIV2, IIO_VOLTAGE),
> > + MT6360_ADC_CHAN(VSYS, IIO_VOLTAGE),
> > + MT6360_ADC_CHAN(VBAT, IIO_VOLTAGE),
> > + MT6360_ADC_CHAN(IBUS, IIO_CURRENT),
> > + MT6360_ADC_CHAN(IBAT, IIO_CURRENT),
> > + MT6360_ADC_CHAN(CHG_VDDP, IIO_VOLTAGE),
> > + MT6360_ADC_CHAN(TEMP_JC, IIO_TEMP),
> > + MT6360_ADC_CHAN(VREF_TS, IIO_VOLTAGE),
> > + MT6360_ADC_CHAN(TS, IIO_VOLTAGE),
> > + IIO_CHAN_SOFT_TIMESTAMP(MT6360_CHAN_MAX),
> > +};
> > +
> > +static irqreturn_t mt6360_adc_trigger_handler(int irq, void *p)
> > +{
> > + struct iio_poll_func *pf = p;
> > + struct iio_dev *indio_dev = pf->indio_dev;
> > + struct mt6360_adc_data *mad = iio_priv(indio_dev);
> > + struct {
> > + u16 values[MT6360_CHAN_MAX];
>
> There is a hole in here I think? (MT6360_CHAN_MAX is 11?)
> If so we need to explicitly memset the structure to avoid any
> risk of kernel data leakage to userspace.
>
> > + int64_t timestamp;
> > + } data;
>
> I guess we know this is on a platform with 64bit alignment for int64_t's
> (unlike x86_64 for example)
>

Do you mean change as below?
struct {
u16 values[MT6360_CHAN_MAX];
int64_t timestamp; __aligned(8)
} data;

> > + int i = 0, bit, val, ret;
> > +
> > + for_each_set_bit(bit, indio_dev->active_scan_mask, indio_dev->masklength) {
> > + ret = mt6360_adc_read_channel(mad, bit, &val);
> > + if (ret < 0) {
> > + dev_warn(&indio_dev->dev, "Failed to get channel %d conversion val\n", bit);
> > + goto out;
> > + }
> > +
> > + data.values[i++] = val;
> > + }
> > + iio_push_to_buffers_with_timestamp(indio_dev, &data, iio_get_time_ns(indio_dev));
> > +out:
> > + iio_trigger_notify_done(indio_dev->trig);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static inline int mt6360_adc_reset(struct mt6360_adc_data *info)
> > +{
> > + __be16 adc_enable;
> > + ktime_t all_off_time;
> > + int i, ret;
> > +
> > + /* Clear ADC idle wait time to 0 */
> > + ret = regmap_write(info->regmap, MT6360_REG_PMUADCIDLET, 0);
> > + if (ret)
> > + return ret;
> > +
> > + /* Only keep ADC enable, but keep all channels off */
> > + adc_enable = cpu_to_be16(MT6360_ADCEN_MASK);
> > + ret = regmap_raw_write(info->regmap, MT6360_REG_PMUADCCFG, (void *)&adc_enable,
> > + sizeof(__be16));
> > + if (ret)
> > + return ret;
> > +
> > + /* Reset all channel off time to the current one */
> > + all_off_time = ktime_get();
> > + for (i = 0; i < MT6360_CHAN_MAX; i++)
> > + info->last_off_timestamps[i] = all_off_time;
> > +
> > + return 0;
> > +}
> > +
> > +static int mt6360_adc_probe(struct platform_device *pdev)
> > +{
> > + struct mt6360_adc_data *mad;
> > + struct regmap *regmap;
> > + struct iio_dev *indio_dev;
> > + int ret;
> > +
> > + regmap = dev_get_regmap(pdev->dev.parent, NULL);
> > + if (!regmap) {
> > + dev_err(&pdev->dev, "Failed to get parent regmap\n");
> > + return -ENODEV;
> > + }
> > +
> > + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*mad));
> > + if (!indio_dev)
> > + return -ENOMEM;
> > +
> > + mad = iio_priv(indio_dev);
> > + mad->dev = &pdev->dev;
> > + mad->regmap = regmap;
> > + mutex_init(&mad->adc_lock);
> > +
> > + ret = mt6360_adc_reset(mad);
> > + if (ret < 0) {
> > + dev_err(&pdev->dev, "Failed to reset adc\n");
> > + return ret;
> > + }
> > +
> > + indio_dev->name = dev_name(&pdev->dev);
> > + indio_dev->dev.parent = &pdev->dev;
> > + indio_dev->info = &mt6360_adc_iio_info;
> > + indio_dev->modes = INDIO_DIRECT_MODE;
> > + indio_dev->channels = mt6360_adc_channels;
> > + indio_dev->num_channels = ARRAY_SIZE(mt6360_adc_channels);
> > +
> > + ret = devm_iio_triggered_buffer_setup(&pdev->dev, indio_dev, NULL,
> > + mt6360_adc_trigger_handler, NULL);
> > + if (ret) {
> > + dev_err(&pdev->dev, "Failed to allocate iio trigger buffer\n");
> > + return ret;
> > + }
> > +
> > + return devm_iio_device_register(&pdev->dev, indio_dev);
> > +}
> > +
> > +static const struct of_device_id __maybe_unused mt6360_adc_of_id[] = {
> > + { .compatible = "mediatek,mt6360-adc", },
> > + {}
> > +};
> > +MODULE_DEVICE_TABLE(of, mt6360_adc_of_id);
> > +
> > +static struct platform_driver mt6360_adc_driver = {
> > + .driver = {
> > + .name = "mt6360-adc",
> > + .of_match_table = mt6360_adc_of_id,
> > + },
> > + .probe = mt6360_adc_probe,
> > +};
> > +module_platform_driver(mt6360_adc_driver);
> > +
> > +MODULE_AUTHOR("Gene Chen <gene_chen@xxxxxxxxxxx>");
> > +MODULE_DESCRIPTION("MT6360 ADC Driver");
> > +MODULE_LICENSE("GPL v2");
>

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