--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2016-2017, 2019, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2022 Linaro Limited.
+ *  Author: Caleb Connolly <caleb.connolly@linaro.org>
+ *
+ * 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/property.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_PROCESSED) |
+                                     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");