This is a note to let you know that I've just added the patch titled

iio: adc: axp288: Fix TS-pin handling

to my staging git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git in the staging-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 9bcf15f75cac3c6a00d8f8083a635de9c8537799 Mon Sep 17 00:00:00 2001

From: Hans de Goede hdegoede@redhat.com Date: Sat, 5 Jan 2019 19:36:18 +0100 Subject: iio: adc: axp288: Fix TS-pin handling MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

Prior to this commit there were 3 issues with our handling of the TS-pin:

1) There are 2 ways how the firmware can disable monitoring of the TS-pin for designs which do not have a temperature-sensor for the battery: a) Clearing bit 0 of the AXP20X_ADC_EN1 register b) Setting bit 2 of the AXP288_ADC_TS_PIN_CTRL monitoring

Prior to this commit we were unconditionally setting both bits to the value used on devices with a TS. This causes the temperature protection to kick in on devices without a TS, such as the Jumper ezbook v2, causing them to not charge under Linux.

This commit fixes this by using regmap_update_bits when updating these 2 registers, leaving the 2 mentioned bits alone.

The next 2 problems are related to our handling of the current-source for the TS-pin. The current-source used for the battery temp-sensor (TS) is shared with the GPADC. For proper fuel-gauge and charger operation the TS current-source needs to be permanently on. But to read the GPADC we need to temporary switch the TS current-source to ondemand, so that the GPADC can use it, otherwise we will always read an all 0 value.

2) Problem 2 is we were writing hardcoded values to the ADC TS pin-ctrl register, overwriting various other unrelated bits. Specifically we were overwriting the current-source setting for the TS and GPIO0 pins, forcing it to 80ųA independent of its original setting. On a Chuwi Vi10 tablet this was causing us to get a too high adc value (due to a too high current-source) resulting in the following errors being logged:

ACPI Error: AE_ERROR, Returned by Handler for [UserDefinedRegion] ACPI Error: Method parse/execution failed _SB.SXP1._TMP, AE_ERROR

This commit fixes this by using regmap_update_bits to change only the relevant bits.

3) After reading the GPADC channel we were unconditionally enabling the TS current-source even on devices where the TS-pin is not used and the current-source thus was off before axp288_adc_read_raw call.

This commit fixes this by making axp288_adc_set_ts a nop on devices where the ADC is not enabled for the TS-pin.

BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1610545 Fixes: 3091141d7803 ("iio: adc: axp288: Fix the GPADC pin ...") Signed-off-by: Hans de Goede hdegoede@redhat.com Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com --- drivers/iio/adc/axp288_adc.c | 76 ++++++++++++++++++++++++++++-------- 1 file changed, 60 insertions(+), 16 deletions(-)

diff --git a/drivers/iio/adc/axp288_adc.c b/drivers/iio/adc/axp288_adc.c index 031d568b4972..4e339cfd0c54 100644 --- a/drivers/iio/adc/axp288_adc.c +++ b/drivers/iio/adc/axp288_adc.c @@ -27,9 +27,18 @@ #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 +/* + * This mask enables all ADCs except for the battery temp-sensor (TS), that is + * left as-is to avoid breaking charging on devices without a temp-sensor. + */ +#define AXP288_ADC_EN_MASK 0xF0 +#define AXP288_ADC_TS_ENABLE 0x01 + +#define AXP288_ADC_TS_CURRENT_ON_OFF_MASK GENMASK(1, 0) +#define AXP288_ADC_TS_CURRENT_OFF (0 << 0) +#define AXP288_ADC_TS_CURRENT_ON_WHEN_CHARGING (1 << 0) +#define AXP288_ADC_TS_CURRENT_ON_ONDEMAND (2 << 0) +#define AXP288_ADC_TS_CURRENT_ON (3 << 0)

enum axp288_adc_id { AXP288_ADC_TS, @@ -44,6 +53,7 @@ enum axp288_adc_id { struct axp288_adc_info { int irq; struct regmap *regmap; + bool ts_enabled; };

static const struct iio_chan_spec axp288_adc_channels[] = { @@ -115,21 +125,33 @@ static int axp288_adc_read_channel(int *val, unsigned long address, return IIO_VAL_INT; }

-static int axp288_adc_set_ts(struct regmap *regmap, unsigned int mode, - unsigned long address) +/* + * The current-source used for the battery temp-sensor (TS) is shared + * with the GPADC. For proper fuel-gauge and charger operation the TS + * current-source needs to be permanently on. But to read the GPADC we + * need to temporary switch the TS current-source to ondemand, so that + * the GPADC can use it, otherwise we will always read an all 0 value. + */ +static int axp288_adc_set_ts(struct axp288_adc_info *info, + unsigned int mode, unsigned long address) { int ret;

- /* channels other than GPADC do not need to switch TS pin */ + /* No need to switch the current-source if the TS pin is disabled */ + if (!info->ts_enabled) + return 0; + + /* Channels other than GPADC do not need the current source */ if (address != AXP288_GP_ADC_H) return 0;

- ret = regmap_write(regmap, AXP288_ADC_TS_PIN_CTRL, mode); + ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL, + AXP288_ADC_TS_CURRENT_ON_OFF_MASK, mode); if (ret) return ret;

/* When switching to the GPADC pin give things some time to settle */ - if (mode == AXP288_ADC_TS_PIN_GPADC) + if (mode == AXP288_ADC_TS_CURRENT_ON_ONDEMAND) usleep_range(6000, 10000);

return 0; @@ -145,14 +167,14 @@ static int axp288_adc_read_raw(struct iio_dev *indio_dev, mutex_lock(&indio_dev->mlock); switch (mask) { case IIO_CHAN_INFO_RAW: - if (axp288_adc_set_ts(info->regmap, AXP288_ADC_TS_PIN_GPADC, + if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON_ONDEMAND, chan->address)) { dev_err(&indio_dev->dev, "GPADC mode\n"); ret = -EINVAL; break; } ret = axp288_adc_read_channel(val, chan->address, info->regmap); - if (axp288_adc_set_ts(info->regmap, AXP288_ADC_TS_PIN_ON, + if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON, chan->address)) dev_err(&indio_dev->dev, "TS pin restore\n"); break; @@ -164,13 +186,35 @@ static int axp288_adc_read_raw(struct iio_dev *indio_dev, return ret; }

-static int axp288_adc_set_state(struct regmap *regmap) +static int axp288_adc_initialize(struct axp288_adc_info *info) { - /* ADC should be always enabled for internal FG to function */ - if (regmap_write(regmap, AXP288_ADC_TS_PIN_CTRL, AXP288_ADC_TS_PIN_ON)) - return -EIO; + int ret, adc_enable_val; + + /* + * Determine if the TS pin is enabled and set the TS current-source + * accordingly. + */ + ret = regmap_read(info->regmap, AXP20X_ADC_EN1, &adc_enable_val); + if (ret) + return ret; + + if (adc_enable_val & AXP288_ADC_TS_ENABLE) { + info->ts_enabled = true; + ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL, + AXP288_ADC_TS_CURRENT_ON_OFF_MASK, + AXP288_ADC_TS_CURRENT_ON); + } else { + info->ts_enabled = false; + ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL, + AXP288_ADC_TS_CURRENT_ON_OFF_MASK, + AXP288_ADC_TS_CURRENT_OFF); + } + if (ret) + return ret;

- return regmap_write(regmap, AXP20X_ADC_EN1, AXP288_ADC_EN_MASK); + /* Turn on the ADC for all channels except TS, leave TS as is */ + return regmap_update_bits(info->regmap, AXP20X_ADC_EN1, + AXP288_ADC_EN_MASK, AXP288_ADC_EN_MASK); }

static const struct iio_info axp288_adc_iio_info = { @@ -200,7 +244,7 @@ static int axp288_adc_probe(struct platform_device *pdev) * Set ADC to enabled state at all time, including system suspend. * otherwise internal fuel gauge functionality may be affected. */ - ret = axp288_adc_set_state(axp20x->regmap); + ret = axp288_adc_initialize(info); if (ret) { dev_err(&pdev->dev, "unable to enable ADC device\n"); return ret;