Re: [PATCH v9 5/9] iio: adc: qcom-spmi-rradc: introduce round robin adc

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

On Thu, Mar 03, 2022 at 04:00:31AM +0000, Caleb Connolly wrote:
> The Round Robin ADC is responsible for reading data about the rate of
> charge from the USB or DC input ports, it can also read the battery
> ID (resistence), skin temperature and the die temperature of the pmic.
> It is found on the PMI8998 and PM660 Qualcomm PMICs.
> 
> Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
> ---
>  drivers/iio/adc/Kconfig           |   12 +
>  drivers/iio/adc/Makefile          |    1 +
>  drivers/iio/adc/qcom-spmi-rradc.c | 1020 +++++++++++++++++++++++++++++
>  3 files changed, 1033 insertions(+)
>  create mode 100644 drivers/iio/adc/qcom-spmi-rradc.c
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 4fdc8bfbb407..66557b434fa8 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -812,6 +812,18 @@ config QCOM_PM8XXX_XOADC
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called qcom-pm8xxx-xoadc.
>  
> +config QCOM_SPMI_RRADC
> +	tristate "Qualcomm SPMI RRADC"
> +	depends on MFD_SPMI_PMIC
> +	help
> +	  This is for the PMIC Round Robin ADC driver.
> +
> +	  This driver exposes the battery ID resistor, battery thermal, PMIC die
> +	  temperature, charger USB in and DC in voltage and current.
> +
> +	  To compile this driver as a module, choose M here: the module will
> +	  be called qcom-qpmi-rradc.
> +
>  config QCOM_SPMI_IADC
>  	tristate "Qualcomm SPMI PMIC current ADC"
>  	depends on SPMI
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 4a8f1833993b..b0dd7f142abd 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -77,6 +77,7 @@ obj-$(CONFIG_NPCM_ADC) += npcm_adc.o
>  obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
>  obj-$(CONFIG_QCOM_SPMI_ADC5) += qcom-spmi-adc5.o
>  obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
> +obj-$(CONFIG_QCOM_SPMI_RRADC) += qcom-spmi-rradc.o
>  obj-$(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
> diff --git a/drivers/iio/adc/qcom-spmi-rradc.c b/drivers/iio/adc/qcom-spmi-rradc.c
> new file mode 100644
> index 000000000000..84a6b007ab8e
> --- /dev/null
> +++ b/drivers/iio/adc/qcom-spmi-rradc.c
> @@ -0,0 +1,1020 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022 Linaro Limited.
> + *  Author: Caleb Connolly <caleb.connolly@linaro.org>

Just curious: Did you write this driver from scratch or inherited from
Qcom downstream? If it is the later, you should share the copyright with
Qcom/LF.

Thanks,
Mani

> + *
> + * This driver is for the Round Robin ADC found in the pmi8998 and pm660 PMICs.
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/delay.h>
> +#include <linux/kernel.h>
> +#include <linux/math64.h>
> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/spmi.h>
> +#include <linux/types.h>
> +#include <linux/units.h>
> +
> +#include <asm/unaligned.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/types.h>
> +
> +#include <soc/qcom/qcom-spmi-pmic.h>
> +
> +#define DRIVER_NAME "qcom-spmi-rradc"
> +
> +#define RR_ADC_EN_CTL 0x46
> +#define RR_ADC_SKIN_TEMP_LSB 0x50
> +#define RR_ADC_SKIN_TEMP_MSB 0x51
> +#define RR_ADC_CTL 0x52
> +#define RR_ADC_CTL_CONTINUOUS_SEL BIT(3)
> +#define RR_ADC_LOG 0x53
> +#define RR_ADC_LOG_CLR_CTRL BIT(0)
> +
> +#define RR_ADC_FAKE_BATT_LOW_LSB 0x58
> +#define RR_ADC_FAKE_BATT_LOW_MSB 0x59
> +#define RR_ADC_FAKE_BATT_HIGH_LSB 0x5A
> +#define RR_ADC_FAKE_BATT_HIGH_MSB 0x5B
> +
> +#define RR_ADC_BATT_ID_CTRL 0x60
> +#define RR_ADC_BATT_ID_CTRL_CHANNEL_CONV BIT(0)
> +#define RR_ADC_BATT_ID_TRIGGER 0x61
> +#define RR_ADC_BATT_ID_STS 0x62
> +#define RR_ADC_BATT_ID_CFG 0x63
> +#define BATT_ID_SETTLE_MASK GENMASK(7, 5)
> +#define RR_ADC_BATT_ID_5_LSB 0x66
> +#define RR_ADC_BATT_ID_5_MSB 0x67
> +#define RR_ADC_BATT_ID_15_LSB 0x68
> +#define RR_ADC_BATT_ID_15_MSB 0x69
> +#define RR_ADC_BATT_ID_150_LSB 0x6A
> +#define RR_ADC_BATT_ID_150_MSB 0x6B
> +
> +#define RR_ADC_BATT_THERM_CTRL 0x70
> +#define RR_ADC_BATT_THERM_TRIGGER 0x71
> +#define RR_ADC_BATT_THERM_STS 0x72
> +#define RR_ADC_BATT_THERM_CFG 0x73
> +#define RR_ADC_BATT_THERM_LSB 0x74
> +#define RR_ADC_BATT_THERM_MSB 0x75
> +#define RR_ADC_BATT_THERM_FREQ 0x76
> +
> +#define RR_ADC_AUX_THERM_CTRL 0x80
> +#define RR_ADC_AUX_THERM_TRIGGER 0x81
> +#define RR_ADC_AUX_THERM_STS 0x82
> +#define RR_ADC_AUX_THERM_CFG 0x83
> +#define RR_ADC_AUX_THERM_LSB 0x84
> +#define RR_ADC_AUX_THERM_MSB 0x85
> +
> +#define RR_ADC_SKIN_HOT 0x86
> +#define RR_ADC_SKIN_TOO_HOT 0x87
> +
> +#define RR_ADC_AUX_THERM_C1 0x88
> +#define RR_ADC_AUX_THERM_C2 0x89
> +#define RR_ADC_AUX_THERM_C3 0x8A
> +#define RR_ADC_AUX_THERM_HALF_RANGE 0x8B
> +
> +#define RR_ADC_USB_IN_V_CTRL 0x90
> +#define RR_ADC_USB_IN_V_TRIGGER 0x91
> +#define RR_ADC_USB_IN_V_STS 0x92
> +#define RR_ADC_USB_IN_V_LSB 0x94
> +#define RR_ADC_USB_IN_V_MSB 0x95
> +#define RR_ADC_USB_IN_I_CTRL 0x98
> +#define RR_ADC_USB_IN_I_TRIGGER 0x99
> +#define RR_ADC_USB_IN_I_STS 0x9A
> +#define RR_ADC_USB_IN_I_LSB 0x9C
> +#define RR_ADC_USB_IN_I_MSB 0x9D
> +
> +#define RR_ADC_DC_IN_V_CTRL 0xA0
> +#define RR_ADC_DC_IN_V_TRIGGER 0xA1
> +#define RR_ADC_DC_IN_V_STS 0xA2
> +#define RR_ADC_DC_IN_V_LSB 0xA4
> +#define RR_ADC_DC_IN_V_MSB 0xA5
> +#define RR_ADC_DC_IN_I_CTRL 0xA8
> +#define RR_ADC_DC_IN_I_TRIGGER 0xA9
> +#define RR_ADC_DC_IN_I_STS 0xAA
> +#define RR_ADC_DC_IN_I_LSB 0xAC
> +#define RR_ADC_DC_IN_I_MSB 0xAD
> +
> +#define RR_ADC_PMI_DIE_TEMP_CTRL 0xB0
> +#define RR_ADC_PMI_DIE_TEMP_TRIGGER 0xB1
> +#define RR_ADC_PMI_DIE_TEMP_STS 0xB2
> +#define RR_ADC_PMI_DIE_TEMP_CFG 0xB3
> +#define RR_ADC_PMI_DIE_TEMP_LSB 0xB4
> +#define RR_ADC_PMI_DIE_TEMP_MSB 0xB5
> +
> +#define RR_ADC_CHARGER_TEMP_CTRL 0xB8
> +#define RR_ADC_CHARGER_TEMP_TRIGGER 0xB9
> +#define RR_ADC_CHARGER_TEMP_STS 0xBA
> +#define RR_ADC_CHARGER_TEMP_CFG 0xBB
> +#define RR_ADC_CHARGER_TEMP_LSB 0xBC
> +#define RR_ADC_CHARGER_TEMP_MSB 0xBD
> +#define RR_ADC_CHARGER_HOT 0xBE
> +#define RR_ADC_CHARGER_TOO_HOT 0xBF
> +
> +#define RR_ADC_GPIO_CTRL 0xC0
> +#define RR_ADC_GPIO_TRIGGER 0xC1
> +#define RR_ADC_GPIO_STS 0xC2
> +#define RR_ADC_GPIO_LSB 0xC4
> +#define RR_ADC_GPIO_MSB 0xC5
> +
> +#define RR_ADC_ATEST_CTRL 0xC8
> +#define RR_ADC_ATEST_TRIGGER 0xC9
> +#define RR_ADC_ATEST_STS 0xCA
> +#define RR_ADC_ATEST_LSB 0xCC
> +#define RR_ADC_ATEST_MSB 0xCD
> +#define RR_ADC_SEC_ACCESS 0xD0
> +
> +#define RR_ADC_PERPH_RESET_CTL2 0xD9
> +#define RR_ADC_PERPH_RESET_CTL3 0xDA
> +#define RR_ADC_PERPH_RESET_CTL4 0xDB
> +#define RR_ADC_INT_TEST1 0xE0
> +#define RR_ADC_INT_TEST_VAL 0xE1
> +
> +#define RR_ADC_TM_TRIGGER_CTRLS 0xE2
> +#define RR_ADC_TM_ADC_CTRLS 0xE3
> +#define RR_ADC_TM_CNL_CTRL 0xE4
> +#define RR_ADC_TM_BATT_ID_CTRL 0xE5
> +#define RR_ADC_TM_THERM_CTRL 0xE6
> +#define RR_ADC_TM_CONV_STS 0xE7
> +#define RR_ADC_TM_ADC_READ_LSB 0xE8
> +#define RR_ADC_TM_ADC_READ_MSB 0xE9
> +#define RR_ADC_TM_ATEST_MUX_1 0xEA
> +#define RR_ADC_TM_ATEST_MUX_2 0xEB
> +#define RR_ADC_TM_REFERENCES 0xED
> +#define RR_ADC_TM_MISC_CTL 0xEE
> +#define RR_ADC_TM_RR_CTRL 0xEF
> +
> +#define RR_ADC_TRIGGER_EVERY_CYCLE BIT(7)
> +#define RR_ADC_TRIGGER_CTL BIT(0)
> +
> +#define RR_ADC_BATT_ID_RANGE 820
> +
> +#define RR_ADC_BITS 10
> +#define RR_ADC_CHAN_MSB (1 << RR_ADC_BITS)
> +#define RR_ADC_FS_VOLTAGE_MV 2500
> +
> +/* BATT_THERM 0.25K/LSB */
> +#define RR_ADC_BATT_THERM_LSB_K 4
> +
> +#define RR_ADC_TEMP_FS_VOLTAGE_NUM 5000000
> +#define RR_ADC_TEMP_FS_VOLTAGE_DEN 3
> +#define RR_ADC_DIE_TEMP_OFFSET 601400
> +#define RR_ADC_DIE_TEMP_SLOPE 2
> +#define RR_ADC_DIE_TEMP_OFFSET_MILLI_DEGC 25000
> +
> +#define RR_ADC_CHG_TEMP_GF_OFFSET_UV 1303168
> +#define RR_ADC_CHG_TEMP_GF_SLOPE_UV_PER_C 3784
> +#define RR_ADC_CHG_TEMP_SMIC_OFFSET_UV 1338433
> +#define RR_ADC_CHG_TEMP_SMIC_SLOPE_UV_PER_C 3655
> +#define RR_ADC_CHG_TEMP_660_GF_OFFSET_UV 1309001
> +#define RR_ADC_CHG_TEMP_660_GF_SLOPE_UV_PER_C 3403
> +#define RR_ADC_CHG_TEMP_660_SMIC_OFFSET_UV 1295898
> +#define RR_ADC_CHG_TEMP_660_SMIC_SLOPE_UV_PER_C 3596
> +#define RR_ADC_CHG_TEMP_660_MGNA_OFFSET_UV 1314779
> +#define RR_ADC_CHG_TEMP_660_MGNA_SLOPE_UV_PER_C 3496
> +#define RR_ADC_CHG_TEMP_OFFSET_MILLI_DEGC 25000
> +#define RR_ADC_CHG_THRESHOLD_SCALE 4
> +
> +#define RR_ADC_VOLT_INPUT_FACTOR 8
> +#define RR_ADC_CURR_INPUT_FACTOR 2000
> +#define RR_ADC_CURR_USBIN_INPUT_FACTOR_MIL 1886
> +#define RR_ADC_CURR_USBIN_660_FACTOR_MIL 9
> +#define RR_ADC_CURR_USBIN_660_UV_VAL 579500
> +
> +#define RR_ADC_GPIO_FS_RANGE 5000
> +#define RR_ADC_COHERENT_CHECK_RETRY 5
> +#define RR_ADC_CHAN_MAX_CONTINUOUS_BUFFER_LEN 16
> +
> +#define RR_ADC_STS_CHANNEL_READING_MASK GENMASK(1, 0)
> +#define RR_ADC_STS_CHANNEL_STS BIT(1)
> +
> +#define RR_ADC_TP_REV_VERSION1 21
> +#define RR_ADC_TP_REV_VERSION2 29
> +#define RR_ADC_TP_REV_VERSION3 32
> +
> +#define RRADC_BATT_ID_DELAY_MAX 8
> +
> +enum rradc_channel_id {
> +	RR_ADC_BATT_ID = 0,
> +	RR_ADC_BATT_THERM,
> +	RR_ADC_SKIN_TEMP,
> +	RR_ADC_USBIN_I,
> +	RR_ADC_USBIN_V,
> +	RR_ADC_DCIN_I,
> +	RR_ADC_DCIN_V,
> +	RR_ADC_DIE_TEMP,
> +	RR_ADC_CHG_TEMP,
> +	RR_ADC_GPIO,
> +	RR_ADC_CHAN_MAX
> +};
> +
> +struct rradc_chip;
> +
> +/**
> + * struct rradc_channel - rradc channel data
> + * @label:		channel label
> + * @lsb:		Channel least significant byte
> + * @status:		Channel status address
> + * @size:		number of bytes to read
> + * @trigger_addr:	Trigger address, trigger is only used on some channels
> + * @trigger_mask:	Trigger mask
> + * @scale_fn:		Post process callback for channels which can't be exposed
> + *			as offset + scale.
> + */
> +struct rradc_channel {
> +	const char *label;
> +	u8 lsb;
> +	u8 status;
> +	int size;
> +	int trigger_addr;
> +	int trigger_mask;
> +	int (*scale_fn)(struct rradc_chip *chip, u16 adc_code, int *result);
> +};
> +
> +struct rradc_chip {
> +	struct device *dev;
> +	const struct qcom_spmi_pmic *pmic;
> +	/*
> +	 * Lock held while doing channel conversion
> +	 * involving multiple register read/writes
> +	 */
> +	struct mutex conversion_lock;
> +	struct regmap *regmap;
> +	u32 base;
> +	int batt_id_delay;
> +	u16 batt_id_data;
> +};
> +
> +static const int batt_id_delays[] = { 0, 1, 4, 12, 20, 40, 60, 80 };
> +static const struct rradc_channel rradc_chans[RR_ADC_CHAN_MAX];
> +static const struct iio_chan_spec rradc_iio_chans[RR_ADC_CHAN_MAX];
> +
> +static int rradc_read(struct rradc_chip *chip, u16 addr, __le16 *buf, int len)
> +{
> +	int ret, retry_cnt = 0;
> +	__le16 data_check[RR_ADC_CHAN_MAX_CONTINUOUS_BUFFER_LEN / 2];
> +
> +	if (len > RR_ADC_CHAN_MAX_CONTINUOUS_BUFFER_LEN) {
> +		dev_err(chip->dev,
> +			"Can't read more than %d bytes, but asked to read %d bytes.\n",
> +			RR_ADC_CHAN_MAX_CONTINUOUS_BUFFER_LEN, len);
> +		return -EINVAL;
> +	}
> +
> +	while (retry_cnt < RR_ADC_COHERENT_CHECK_RETRY) {
> +		ret = regmap_bulk_read(chip->regmap, chip->base + addr, buf,
> +				       len);
> +		if (ret < 0) {
> +			dev_err(chip->dev, "rr_adc reg 0x%x failed :%d\n", addr,
> +				ret);
> +			return ret;
> +		}
> +
> +		ret = regmap_bulk_read(chip->regmap, chip->base + addr,
> +				       data_check, len);
> +		if (ret < 0) {
> +			dev_err(chip->dev, "rr_adc reg 0x%x failed :%d\n", addr,
> +				ret);
> +			return ret;
> +		}
> +
> +		if (memcmp(buf, data_check, len) != 0) {
> +			retry_cnt++;
> +			dev_dbg(chip->dev,
> +				"coherent read error, retry_cnt:%d\n",
> +				retry_cnt);
> +			continue;
> +		}
> +
> +		break;
> +	}
> +
> +	if (retry_cnt == RR_ADC_COHERENT_CHECK_RETRY)
> +		dev_err(chip->dev, "Retry exceeded for coherrency check\n");
> +
> +	return ret;
> +}
> +
> +static int rradc_get_fab_coeff(struct rradc_chip *chip, int64_t *offset,
> +			       int64_t *slope)
> +{
> +	if (chip->pmic->subtype == PM660_SUBTYPE) {
> +		switch (chip->pmic->fab_id) {
> +		case PM660_FAB_ID_GF:
> +			*offset = RR_ADC_CHG_TEMP_660_GF_OFFSET_UV;
> +			*slope = RR_ADC_CHG_TEMP_660_GF_SLOPE_UV_PER_C;
> +			return 0;
> +		case PM660_FAB_ID_TSMC:
> +			*offset = RR_ADC_CHG_TEMP_660_SMIC_OFFSET_UV;
> +			*slope = RR_ADC_CHG_TEMP_660_SMIC_SLOPE_UV_PER_C;
> +			return 0;
> +		default:
> +			*offset = RR_ADC_CHG_TEMP_660_MGNA_OFFSET_UV;
> +			*slope = RR_ADC_CHG_TEMP_660_MGNA_SLOPE_UV_PER_C;
> +		}
> +	} else if (chip->pmic->subtype == PMI8998_SUBTYPE) {
> +		switch (chip->pmic->fab_id) {
> +		case PMI8998_FAB_ID_GF:
> +			*offset = RR_ADC_CHG_TEMP_GF_OFFSET_UV;
> +			*slope = RR_ADC_CHG_TEMP_GF_SLOPE_UV_PER_C;
> +			return 0;
> +		case PMI8998_FAB_ID_SMIC:
> +			*offset = RR_ADC_CHG_TEMP_SMIC_OFFSET_UV;
> +			*slope = RR_ADC_CHG_TEMP_SMIC_SLOPE_UV_PER_C;
> +			return 0;
> +		default:
> +			return -EINVAL;
> +		}
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +/*
> + * These functions explicitly cast int64_t to int.
> + * They will never overflow, as the values are small enough.
> + */
> +static int rradc_post_process_batt_id(struct rradc_chip *chip, u16 adc_code,
> +				      int *result_ohms)
> +{
> +	uint32_t current_value;
> +	int64_t r_id;
> +
> +	current_value = chip->batt_id_data;
> +	r_id = ((int64_t)adc_code * RR_ADC_FS_VOLTAGE_MV);
> +	r_id = div64_s64(r_id, (RR_ADC_CHAN_MSB * current_value));
> +	*result_ohms = (int)(r_id * MILLI);
> +
> +	return 0;
> +}
> +
> +static int rradc_enable_continuous_mode(struct rradc_chip *chip)
> +{
> +	int ret;
> +
> +	/* Clear channel log */
> +	ret = regmap_update_bits(chip->regmap, chip->base + RR_ADC_LOG,
> +				 RR_ADC_LOG_CLR_CTRL, RR_ADC_LOG_CLR_CTRL);
> +	if (ret < 0) {
> +		dev_err(chip->dev, "log ctrl update to clear failed:%d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = regmap_update_bits(chip->regmap, chip->base + RR_ADC_LOG,
> +				 RR_ADC_LOG_CLR_CTRL, 0);
> +	if (ret < 0) {
> +		dev_err(chip->dev, "log ctrl update to not clear failed:%d\n",
> +			ret);
> +		return ret;
> +	}
> +
> +	/* Switch to continuous mode */
> +	ret = regmap_update_bits(chip->regmap, chip->base + RR_ADC_CTL,
> +				 RR_ADC_CTL_CONTINUOUS_SEL,
> +				 RR_ADC_CTL_CONTINUOUS_SEL);
> +	if (ret < 0)
> +		dev_err(chip->dev, "Update to continuous mode failed:%d\n",
> +			ret);
> +
> +	return ret;
> +}
> +
> +static int rradc_disable_continuous_mode(struct rradc_chip *chip)
> +{
> +	int ret;
> +
> +	/* Switch to non continuous mode */
> +	ret = regmap_update_bits(chip->regmap, chip->base + RR_ADC_CTL,
> +				 RR_ADC_CTL_CONTINUOUS_SEL, 0);
> +	if (ret < 0)
> +		dev_err(chip->dev, "Update to non-continuous mode failed:%d\n",
> +			ret);
> +
> +	return ret;
> +}
> +
> +static bool rradc_is_ready(struct rradc_chip *chip,
> +			   enum rradc_channel_id chan_address)
> +{
> +	const struct rradc_channel *chan = &rradc_chans[chan_address];
> +	int ret;
> +	unsigned int status, mask;
> +
> +	/* BATT_ID STS bit does not get set initially */
> +	switch (chan_address) {
> +	case RR_ADC_BATT_ID:
> +		mask = RR_ADC_STS_CHANNEL_STS;
> +		break;
> +	default:
> +		mask = RR_ADC_STS_CHANNEL_READING_MASK;
> +		break;
> +	}
> +
> +	ret = regmap_read(chip->regmap, chip->base + chan->status, &status);
> +	if (ret < 0 || !(status & mask))
> +		return false;
> +
> +	return true;
> +}
> +
> +static int rradc_read_status_in_cont_mode(struct rradc_chip *chip,
> +					  enum rradc_channel_id chan_address)
> +{
> +	const struct rradc_channel *chan = &rradc_chans[chan_address];
> +	const struct iio_chan_spec *iio_chan = &rradc_iio_chans[chan_address];
> +	int ret, i;
> +
> +	if (chan->trigger_mask == 0) {
> +		dev_err(chip->dev, "Channel doesn't have a trigger mask\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = regmap_update_bits(chip->regmap, chip->base + chan->trigger_addr,
> +				 chan->trigger_mask, chan->trigger_mask);
> +	if (ret < 0) {
> +		dev_err(chip->dev,
> +			"Failed to apply trigger for channel '%s' ret=%d\n",
> +			iio_chan->extend_name, ret);
> +		return ret;
> +	}
> +
> +	ret = rradc_enable_continuous_mode(chip);
> +	if (ret < 0) {
> +		dev_err(chip->dev, "Failed to switch to continuous mode\n");
> +		goto disable_trigger;
> +	}
> +
> +	/*
> +	 * The wait/sleep values were found through trial and error,
> +	 * this is mostly for the battery ID channel which takes some
> +	 * time to settle.
> +	 */
> +	for (i = 0; i < 5; i++) {
> +		if (rradc_is_ready(chip, chan_address))
> +			break;
> +		usleep_range(50000, 50000 + 500);
> +	}
> +
> +	if (i == 5) {
> +		dev_err(chip->dev, "Channel '%s' is not ready\n",
> +			iio_chan->extend_name);
> +		ret = -ETIMEDOUT;
> +	}
> +
> +	rradc_disable_continuous_mode(chip);
> +
> +disable_trigger:
> +	regmap_update_bits(chip->regmap, chip->base + chan->trigger_addr,
> +			   chan->trigger_mask, 0);
> +
> +	return ret;
> +}
> +
> +static int rradc_prepare_batt_id_conversion(struct rradc_chip *chip,
> +					    enum rradc_channel_id chan_address,
> +					    u16 *data)
> +{
> +	int ret;
> +
> +	ret = regmap_update_bits(chip->regmap, chip->base + RR_ADC_BATT_ID_CTRL,
> +				 RR_ADC_BATT_ID_CTRL_CHANNEL_CONV,
> +				 RR_ADC_BATT_ID_CTRL_CHANNEL_CONV);
> +	if (ret < 0) {
> +		dev_err(chip->dev, "Enabling BATT ID channel failed:%d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = regmap_update_bits(chip->regmap,
> +				 chip->base + RR_ADC_BATT_ID_TRIGGER,
> +				 RR_ADC_TRIGGER_CTL, RR_ADC_TRIGGER_CTL);
> +	if (ret < 0) {
> +		dev_err(chip->dev, "BATT_ID trigger set failed:%d\n", ret);
> +		goto out_disable_batt_id;
> +	}
> +
> +	ret = rradc_read_status_in_cont_mode(chip, chan_address);
> +
> +	/* Reset registers back to default values */
> +	regmap_update_bits(chip->regmap, chip->base + RR_ADC_BATT_ID_TRIGGER,
> +			   RR_ADC_TRIGGER_CTL, 0);
> +
> +out_disable_batt_id:
> +	regmap_update_bits(chip->regmap, chip->base + RR_ADC_BATT_ID_CTRL,
> +			   RR_ADC_BATT_ID_CTRL_CHANNEL_CONV, 0);
> +
> +	return ret;
> +}
> +
> +static int rradc_do_conversion(struct rradc_chip *chip,
> +			       enum rradc_channel_id chan_address, u16 *data)
> +{
> +	const struct rradc_channel *chan = &rradc_chans[chan_address];
> +	const struct iio_chan_spec *iio_chan = &rradc_iio_chans[chan_address];
> +	int ret;
> +	__le16 buf[3];
> +
> +	mutex_lock(&chip->conversion_lock);
> +
> +	switch (chan_address) {
> +	case RR_ADC_BATT_ID:
> +		ret = rradc_prepare_batt_id_conversion(chip, chan_address, data);
> +		if (ret < 0) {
> +			dev_err(chip->dev, "Battery ID conversion failed:%d\n",
> +				ret);
> +			goto unlock_out;
> +		}
> +		break;
> +
> +	case RR_ADC_USBIN_V:
> +	case RR_ADC_DIE_TEMP:
> +		ret = rradc_read_status_in_cont_mode(chip, chan_address);
> +		if (ret < 0) {
> +			dev_err(chip->dev,
> +				"Error reading in continuous mode:%d\n", ret);
> +			goto unlock_out;
> +		}
> +		break;
> +	default:
> +		if (!rradc_is_ready(chip, chan_address)) {
> +			/*
> +			 * Usually this means the channel isn't attached, for example
> +			 * the in_voltage_usbin_v_input channel will not be ready if
> +			 * no USB cable is attached
> +			 */
> +			dev_dbg(chip->dev, "channel '%s' is not ready\n",
> +				iio_chan->extend_name);
> +			ret = -ENODATA;
> +			goto unlock_out;
> +		}
> +		break;
> +	}
> +
> +	ret = rradc_read(chip, chan->lsb, buf, chan->size);
> +	if (ret) {
> +		dev_err(chip->dev, "read data failed\n");
> +		goto unlock_out;
> +	}
> +
> +	/*
> +	 * For the battery ID we read the register for every ID ADC and then
> +	 * see which one is actually connected.
> +	 */
> +	if (chan_address == RR_ADC_BATT_ID) {
> +		u16 batt_id_150 = le16_to_cpu(buf[2]);
> +		u16 batt_id_15 = le16_to_cpu(buf[1]);
> +		u16 batt_id_5 = le16_to_cpu(buf[0]);
> +
> +		if (!batt_id_150 && !batt_id_15 && !batt_id_5) {
> +			dev_err(chip->dev,
> +				"Invalid batt_id values with all zeros\n");
> +			ret = -EINVAL;
> +			goto unlock_out;
> +		}
> +
> +		if (batt_id_150 <= RR_ADC_BATT_ID_RANGE) {
> +			*data = batt_id_150;
> +			chip->batt_id_data = 150;
> +		} else if (batt_id_15 <= RR_ADC_BATT_ID_RANGE) {
> +			*data = batt_id_15;
> +			chip->batt_id_data = 15;
> +		} else {
> +			*data = batt_id_5;
> +			chip->batt_id_data = 5;
> +		}
> +	} else {
> +		/*
> +		 * All of the other channels are either 1 or 2 bytes.
> +		 * We can rely on the second byte being 0 for 1-byte channels.
> +		 */
> +		*data = le16_to_cpu(buf[0]);
> +	}
> +
> +unlock_out:
> +	mutex_unlock(&chip->conversion_lock);
> +
> +	return ret;
> +}
> +
> +static int rradc_read_scale(struct rradc_chip *chip, int chan_address, int *val,
> +			    int *val2)
> +{
> +	int64_t fab_offset, fab_slope;
> +	int ret;
> +
> +	ret = rradc_get_fab_coeff(chip, &fab_offset, &fab_slope);
> +	if (ret < 0) {
> +		dev_err(chip->dev, "Unable to get fab id coefficients\n");
> +		return -EINVAL;
> +	}
> +
> +	switch (chan_address) {
> +	case RR_ADC_SKIN_TEMP:
> +		*val = MILLI;
> +		*val2 = RR_ADC_BATT_THERM_LSB_K;
> +		return IIO_VAL_FRACTIONAL;
> +	case RR_ADC_USBIN_I:
> +		*val = RR_ADC_CURR_USBIN_INPUT_FACTOR_MIL *
> +		       RR_ADC_FS_VOLTAGE_MV;
> +		*val2 = RR_ADC_CHAN_MSB;
> +		return IIO_VAL_FRACTIONAL;
> +	case RR_ADC_DCIN_I:
> +		*val = RR_ADC_CURR_INPUT_FACTOR * RR_ADC_FS_VOLTAGE_MV;
> +		*val2 = RR_ADC_CHAN_MSB;
> +		return IIO_VAL_FRACTIONAL;
> +	case RR_ADC_USBIN_V:
> +	case RR_ADC_DCIN_V:
> +		*val = RR_ADC_VOLT_INPUT_FACTOR * RR_ADC_FS_VOLTAGE_MV * MILLI;
> +		*val2 = RR_ADC_CHAN_MSB;
> +		return IIO_VAL_FRACTIONAL;
> +	case RR_ADC_GPIO:
> +		*val = RR_ADC_GPIO_FS_RANGE;
> +		*val2 = RR_ADC_CHAN_MSB;
> +		return IIO_VAL_FRACTIONAL;
> +	case RR_ADC_CHG_TEMP:
> +		/*
> +		 * We divide val2 by MILLI instead of multiplying val
> +		 * to avoid an integer overflow.
> +		 */
> +		*val = -RR_ADC_TEMP_FS_VOLTAGE_NUM;
> +		*val2 = div64_s64(RR_ADC_TEMP_FS_VOLTAGE_DEN * RR_ADC_CHAN_MSB *
> +					  fab_slope,
> +				  MILLI);
> +
> +		return IIO_VAL_FRACTIONAL;
> +	case RR_ADC_DIE_TEMP:
> +		*val = RR_ADC_TEMP_FS_VOLTAGE_NUM;
> +		*val2 = RR_ADC_TEMP_FS_VOLTAGE_DEN * RR_ADC_CHAN_MSB *
> +			RR_ADC_DIE_TEMP_SLOPE;
> +
> +		return IIO_VAL_FRACTIONAL;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int rradc_read_offset(struct rradc_chip *chip, int chan_address, int *val)
> +{
> +	int64_t fab_offset, fab_slope;
> +	int64_t offset1, offset2;
> +	int ret;
> +
> +	switch (chan_address) {
> +	case RR_ADC_SKIN_TEMP:
> +		/*
> +		 * Offset from kelvin to degC, divided by the
> +		 * scale factor (250). We lose some precision here.
> +		 * 273150 / 250 = 1092.6
> +		 */
> +		*val = div64_s64(ABSOLUTE_ZERO_MILLICELSIUS,
> +				 (MILLI / RR_ADC_BATT_THERM_LSB_K));
> +		return IIO_VAL_INT;
> +	case RR_ADC_CHG_TEMP:
> +		ret = rradc_get_fab_coeff(chip, &fab_offset, &fab_slope);
> +		if (ret < 0) {
> +			dev_err(chip->dev,
> +				"Unable to get fab id coefficients\n");
> +			return -EINVAL;
> +		}
> +		offset1 = -(fab_offset * RR_ADC_TEMP_FS_VOLTAGE_DEN *
> +			    RR_ADC_CHAN_MSB);
> +		offset1 += (int64_t)RR_ADC_TEMP_FS_VOLTAGE_NUM / 2ULL;
> +		offset1 = div64_s64(offset1,
> +				    (int64_t)(RR_ADC_TEMP_FS_VOLTAGE_NUM));
> +
> +		offset2 = (int64_t)RR_ADC_CHG_TEMP_OFFSET_MILLI_DEGC *
> +			  RR_ADC_TEMP_FS_VOLTAGE_DEN * RR_ADC_CHAN_MSB *
> +			  (int64_t)fab_slope;
> +		offset2 += ((int64_t)MILLI * RR_ADC_TEMP_FS_VOLTAGE_NUM) / 2;
> +		offset2 = div64_s64(
> +			offset2, ((int64_t)MILLI * RR_ADC_TEMP_FS_VOLTAGE_NUM));
> +
> +		/*
> +		 * The -1 is to compensate for lost precision.
> +		 * It should actually be -0.7906976744186046.
> +		 * This works out to every value being off
> +		 * by about +0.091 degrees C after applying offset and scale.
> +		 */
> +		*val = (int)(offset1 - offset2 - 1);
> +		return IIO_VAL_INT;
> +	case RR_ADC_DIE_TEMP:
> +		offset1 = -RR_ADC_DIE_TEMP_OFFSET *
> +			  (int64_t)RR_ADC_TEMP_FS_VOLTAGE_DEN *
> +			  (int64_t)RR_ADC_CHAN_MSB;
> +		offset1 = div64_s64(offset1, RR_ADC_TEMP_FS_VOLTAGE_NUM);
> +
> +		offset2 = -(int64_t)RR_ADC_CHG_TEMP_OFFSET_MILLI_DEGC *
> +			  RR_ADC_TEMP_FS_VOLTAGE_DEN * RR_ADC_CHAN_MSB *
> +			  RR_ADC_DIE_TEMP_SLOPE;
> +		offset2 = div64_s64(offset2,
> +				    ((int64_t)RR_ADC_TEMP_FS_VOLTAGE_NUM));
> +
> +		/*
> +		 * The result is -339, it should be -338.69789, this results
> +		 * in the calculated die temp being off by
> +		 * -0.004 - -0.0175 degrees C
> +		 */
> +		*val = (int)(offset1 - offset2);
> +		return IIO_VAL_INT;
> +	default:
> +		break;
> +	}
> +	return -EINVAL;
> +}
> +
> +static int rradc_read_raw(struct iio_dev *indio_dev,
> +			  struct iio_chan_spec const *chan_spec, int *val,
> +			  int *val2, long mask)
> +{
> +	struct rradc_chip *chip = iio_priv(indio_dev);
> +	const struct rradc_channel *chan;
> +	int ret;
> +	u16 adc_code;
> +
> +	if (chan_spec->address >= RR_ADC_CHAN_MAX) {
> +		dev_err(chip->dev, "Invalid channel index:%lu\n",
> +			chan_spec->address);
> +		return -EINVAL;
> +	}
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_SCALE:
> +		return rradc_read_scale(chip, chan_spec->address, val, val2);
> +	case IIO_CHAN_INFO_OFFSET:
> +		return rradc_read_offset(chip, chan_spec->address, val);
> +	case IIO_CHAN_INFO_RAW:
> +		ret = rradc_do_conversion(chip, chan_spec->address, &adc_code);
> +		if (ret < 0)
> +			return ret;
> +
> +		*val = adc_code;
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_PROCESSED:
> +		chan = &rradc_chans[chan_spec->address];
> +		if (!chan->scale_fn)
> +			return -EINVAL;
> +		ret = rradc_do_conversion(chip, chan_spec->address, &adc_code);
> +		if (ret < 0)
> +			return ret;
> +
> +		*val = chan->scale_fn(chip, adc_code, val);
> +		return IIO_VAL_INT;
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int rradc_read_label(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan, char *label)
> +{
> +	return snprintf(label, PAGE_SIZE, "%s\n",
> +			rradc_chans[chan->address].label);
> +}
> +
> +static const struct iio_info rradc_info = {
> +	.read_raw = rradc_read_raw,
> +	.read_label = rradc_read_label,
> +};
> +
> +static const struct rradc_channel rradc_chans[RR_ADC_CHAN_MAX] = {
> +	{
> +		.label = "batt_id",
> +		.scale_fn = rradc_post_process_batt_id,
> +		.lsb = RR_ADC_BATT_ID_5_LSB,
> +		.status = RR_ADC_BATT_ID_STS,
> +		.size = 6,
> +		.trigger_addr = RR_ADC_BATT_ID_TRIGGER,
> +		.trigger_mask = BIT(0),
> +	}, {
> +		.label = "batt",
> +		.lsb = RR_ADC_BATT_THERM_LSB,
> +		.status = RR_ADC_BATT_THERM_STS,
> +		.size = 2,
> +		.trigger_addr = RR_ADC_BATT_THERM_TRIGGER,
> +	}, {
> +		.label = "pmi8998_skin",
> +		.lsb = RR_ADC_SKIN_TEMP_LSB,
> +		.status = RR_ADC_AUX_THERM_STS,
> +		.size = 2,
> +		.trigger_addr = RR_ADC_AUX_THERM_TRIGGER,
> +	}, {
> +		.label = "usbin_i",
> +		.lsb = RR_ADC_USB_IN_I_LSB,
> +		.status = RR_ADC_USB_IN_I_STS,
> +		.size = 2,
> +		.trigger_addr = RR_ADC_USB_IN_I_TRIGGER,
> +	}, {
> +		.label = "usbin_v",
> +		.lsb = RR_ADC_USB_IN_V_LSB,
> +		.status = RR_ADC_USB_IN_V_STS,
> +		.size = 2,
> +		.trigger_addr = RR_ADC_USB_IN_V_TRIGGER,
> +		.trigger_mask = BIT(7),
> +	}, {
> +		.label = "dcin_i",
> +		.lsb = RR_ADC_DC_IN_I_LSB,
> +		.status = RR_ADC_DC_IN_I_STS,
> +		.size = 2,
> +		.trigger_addr = RR_ADC_DC_IN_I_TRIGGER,
> +	}, {
> +		.label = "dcin_v",
> +		.lsb = RR_ADC_DC_IN_V_LSB,
> +		.status = RR_ADC_DC_IN_V_STS,
> +		.size = 2,
> +		.trigger_addr = RR_ADC_DC_IN_V_TRIGGER,
> +	}, {
> +		.label = "pmi8998_die",
> +		.lsb = RR_ADC_PMI_DIE_TEMP_LSB,
> +		.status = RR_ADC_PMI_DIE_TEMP_STS,
> +		.size = 2,
> +		.trigger_addr = RR_ADC_PMI_DIE_TEMP_TRIGGER,
> +		.trigger_mask = RR_ADC_TRIGGER_EVERY_CYCLE,
> +	}, {
> +		.label = "chg",
> +		.lsb = RR_ADC_CHARGER_TEMP_LSB,
> +		.status = RR_ADC_CHARGER_TEMP_STS,
> +		.size = 2,
> +		.trigger_addr = RR_ADC_CHARGER_TEMP_TRIGGER,
> +	}, {
> +		.label = "gpio",
> +		.lsb = RR_ADC_GPIO_LSB,
> +		.status = RR_ADC_GPIO_STS,
> +		.size = 2,
> +		.trigger_addr = RR_ADC_GPIO_TRIGGER,
> +	},
> +};
> +
> +static const struct iio_chan_spec rradc_iio_chans[RR_ADC_CHAN_MAX] = {
> +	{
> +		.type = IIO_RESISTANCE,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> +		.address = RR_ADC_BATT_ID,
> +		.channel = 0,
> +		.indexed = 1,
> +	}, {
> +		.type = IIO_TEMP,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> +		.address = RR_ADC_BATT_THERM,
> +		.channel = 0,
> +		.indexed = 1,
> +	}, {
> +		.type = IIO_TEMP,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +				      BIT(IIO_CHAN_INFO_SCALE) |
> +				      BIT(IIO_CHAN_INFO_OFFSET),
> +		.address = RR_ADC_SKIN_TEMP,
> +		.channel = 1,
> +		.indexed = 1,
> +	}, {
> +		.type = IIO_CURRENT,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +				      BIT(IIO_CHAN_INFO_SCALE),
> +		.address = RR_ADC_USBIN_I,
> +		.channel = 0,
> +		.indexed = 1,
> +	}, {
> +		.type = IIO_VOLTAGE,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +				      BIT(IIO_CHAN_INFO_SCALE),
> +		.address = RR_ADC_USBIN_V,
> +		.channel = 0,
> +		.indexed = 1,
> +	}, {
> +		.type = IIO_CURRENT,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +				      BIT(IIO_CHAN_INFO_SCALE),
> +		.address = RR_ADC_DCIN_I,
> +		.channel = 1,
> +		.indexed = 1,
> +	}, {
> +		.type = IIO_VOLTAGE,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +				      BIT(IIO_CHAN_INFO_SCALE),
> +		.address = RR_ADC_DCIN_V,
> +		.channel = 1,
> +		.indexed = 1,
> +	}, {
> +		.type = IIO_TEMP,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +				      BIT(IIO_CHAN_INFO_SCALE) |
> +				      BIT(IIO_CHAN_INFO_OFFSET),
> +		.address = RR_ADC_DIE_TEMP,
> +		.channel = 2,
> +		.indexed = 1,
> +	}, {
> +		.type = IIO_TEMP,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +				      BIT(IIO_CHAN_INFO_OFFSET) |
> +				      BIT(IIO_CHAN_INFO_SCALE),
> +		.address = RR_ADC_CHG_TEMP,
> +		.channel = 3,
> +		.indexed = 1,
> +	}, {
> +		.type = IIO_VOLTAGE,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +				      BIT(IIO_CHAN_INFO_SCALE),
> +		.address = RR_ADC_GPIO,
> +		.channel = 2,
> +		.indexed = 1,
> +	},
> +};
> +
> +static int rradc_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct iio_dev *indio_dev;
> +	struct rradc_chip *chip;
> +	int ret, i, batt_id_delay;
> +
> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*chip));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	chip = iio_priv(indio_dev);
> +	chip->regmap = dev_get_regmap(pdev->dev.parent, NULL);
> +	if (!chip->regmap) {
> +		dev_err(dev, "Couldn't get parent's regmap\n");
> +		return -EINVAL;
> +	}
> +
> +	chip->dev = dev;
> +	mutex_init(&chip->conversion_lock);
> +
> +	ret = device_property_read_u32(dev, "reg", &chip->base);
> +	if (ret < 0) {
> +		dev_err(chip->dev, "Couldn't find reg address, ret = %d\n",
> +			ret);
> +		return ret;
> +	}
> +
> +	batt_id_delay = -1;
> +	ret = device_property_read_u32(dev, "qcom,batt-id-delay-ms",
> +				       &batt_id_delay);
> +	if (!ret) {
> +		for (i = 0; i < RRADC_BATT_ID_DELAY_MAX; i++) {
> +			if (batt_id_delay == batt_id_delays[i])
> +				break;
> +		}
> +		if (i == RRADC_BATT_ID_DELAY_MAX)
> +			batt_id_delay = -1;
> +	}
> +
> +	if (batt_id_delay >= 0) {
> +		batt_id_delay = FIELD_PREP(BATT_ID_SETTLE_MASK, batt_id_delay);
> +		ret = regmap_update_bits(chip->regmap,
> +					 chip->base + RR_ADC_BATT_ID_CFG,
> +					 batt_id_delay, batt_id_delay);
> +		if (ret < 0) {
> +			dev_err(chip->dev,
> +				"BATT_ID settling time config failed:%d\n",
> +				ret);
> +		}
> +	}
> +
> +	/* Get the PMIC revision, we need it to handle some varying coefficients */
> +	chip->pmic = qcom_pmic_get(chip->dev);
> +	if (IS_ERR(chip->pmic)) {
> +		dev_err(chip->dev, "Unable to get reference to PMIC device\n");
> +		return PTR_ERR(chip->pmic);
> +	}
> +
> +	switch (chip->pmic->subtype) {
> +	case PMI8998_SUBTYPE:
> +		indio_dev->name = "pmi8998-rradc";
> +		break;
> +	case PM660_SUBTYPE:
> +		indio_dev->name = "pm660-rradc";
> +		break;
> +	default:
> +		indio_dev->name = DRIVER_NAME;
> +		break;
> +	}
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->info = &rradc_info;
> +	indio_dev->channels = rradc_iio_chans;
> +	indio_dev->num_channels = ARRAY_SIZE(rradc_iio_chans);
> +
> +	return devm_iio_device_register(dev, indio_dev);
> +}
> +
> +static const struct of_device_id rradc_match_table[] = {
> +	{ .compatible = "qcom,pm660-rradc" },
> +	{ .compatible = "qcom,pmi8998-rradc" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, rradc_match_table);
> +
> +static struct platform_driver rradc_driver = {
> +	.driver		= {
> +		.name		= DRIVER_NAME,
> +		.of_match_table	= rradc_match_table,
> +	},
> +	.probe = rradc_probe,
> +};
> +module_platform_driver(rradc_driver);
> +
> +MODULE_DESCRIPTION("QCOM SPMI PMIC RR ADC driver");
> +MODULE_AUTHOR("Caleb Connolly <caleb.connolly@linaro.org>");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.35.1
>