qpnp-fg-gen3: Read debug battery id thresholds from RR_ADC registers

Currently, GEN3 FG driver uses a debug battery id threshold of
7 KOhms. However, depending on the battery id chosen by the user
this threshold can be modified in the bootloader. Hence, add
support to read the debug battery id thresholds directly from
RR_ADC peripheral registers. This can be used to decide whether
a fake battery SOC (67) can be displayed to the user.

Change-Id: I22ab702e10c310e4f847c6c81a48a8f0f3188429
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>

3 files changed, 68 insertions, 11 deletions

diff --git a/drivers/power/qcom-charger/fg-core.h b/drivers/power/qcom-charger/fg-core.h
index 9ddd18800f9d..e284de8bdff1 100644
--- a/drivers/power/qcom-charger/fg-core.h
+++ b/drivers/power/qcom-charger/fg-core.h
@@ -39,6 +39,12 @@
 			pr_debug(fmt, ##__VA_ARGS__);	\
 	} while (0)
 
+#define is_between(left, right, value) \
+		(((left) >= (right) && (left) >= (value) \
+			&& (value) >= (right)) \
+		|| ((left) <= (right) && (left) <= (value) \
+			&& (value) <= (right)))
+
 /* Awake votable reasons */
 #define SRAM_READ	"fg_sram_read"
 #define SRAM_WRITE	"fg_sram_write"
@@ -310,8 +316,9 @@ struct fg_chip {
 	u32			batt_soc_base;
 	u32			batt_info_base;
 	u32			mem_if_base;
+	u32			rradc_base;
 	u32			wa_flags;
-	int			batt_id_kohms;
+	int			batt_id_ohms;
 	int			charge_status;
 	int			prev_charge_status;
 	int			charge_done;
diff --git a/drivers/power/qcom-charger/fg-reg.h b/drivers/power/qcom-charger/fg-reg.h
index ffc46f328f91..7ad26215e469 100644
--- a/drivers/power/qcom-charger/fg-reg.h
+++ b/drivers/power/qcom-charger/fg-reg.h
@@ -13,6 +13,10 @@
 #ifndef __FG_REG_H__
 #define __FG_REG_H__
 
+/* FG_ADC_RR register definitions used only for READ */
+#define ADC_RR_FAKE_BATT_LOW_LSB(chip)		(chip->rradc_base + 0x58)
+#define ADC_RR_FAKE_BATT_HIGH_LSB(chip)		(chip->rradc_base + 0x5A)
+
 /* FG_BATT_SOC register definitions */
 #define BATT_SOC_FG_ALG_STS(chip)		(chip->batt_soc_base + 0x06)
 #define BATT_SOC_FG_ALG_AUX_STS0(chip)		(chip->batt_soc_base + 0x07)
diff --git a/drivers/power/qcom-charger/qpnp-fg-gen3.c b/drivers/power/qcom-charger/qpnp-fg-gen3.c
index 84204163f076..f1dc6d8ab2fb 100644
--- a/drivers/power/qcom-charger/qpnp-fg-gen3.c
+++ b/drivers/power/qcom-charger/qpnp-fg-gen3.c
@@ -693,18 +693,57 @@ static bool is_batt_empty(struct fg_chip *chip)
 	return ((vbatt_uv < chip->dt.cutoff_volt_mv * 1000) ? true : false);
 }
 
-#define DEBUG_BATT_ID_KOHMS	7
+static int fg_get_debug_batt_id(struct fg_chip *chip, int *batt_id)
+{
+	int rc;
+	u64 temp;
+	u8 buf[2];
+
+	rc = fg_read(chip, ADC_RR_FAKE_BATT_LOW_LSB(chip), buf, 2);
+	if (rc < 0) {
+		pr_err("failed to read addr=0x%04x, rc=%d\n",
+			ADC_RR_FAKE_BATT_LOW_LSB(chip), rc);
+		return rc;
+	}
+
+	/*
+	 * Fake battery threshold is encoded in the following format.
+	 * Threshold (code) = (battery_id in Ohms) * 0.00015 * 2^10 / 2.5
+	 */
+	temp = (buf[1] << 8 | buf[0]) * 2500000;
+	do_div(temp, 150 * 1024);
+	batt_id[0] = temp;
+	rc = fg_read(chip, ADC_RR_FAKE_BATT_HIGH_LSB(chip), buf, 2);
+	if (rc < 0) {
+		pr_err("failed to read addr=0x%04x, rc=%d\n",
+			ADC_RR_FAKE_BATT_HIGH_LSB(chip), rc);
+		return rc;
+	}
+
+	temp = (buf[1] << 8 | buf[0]) * 2500000;
+	do_div(temp, 150 * 1024);
+	batt_id[1] = temp;
+	pr_debug("debug batt_id range: [%d %d]\n", batt_id[0], batt_id[1]);
+	return 0;
+}
+
 static bool is_debug_batt_id(struct fg_chip *chip)
 {
-	int batt_id_delta = 0;
+	int debug_batt_id[2], rc;
 
-	if (!chip->batt_id_kohms)
+	if (!chip->batt_id_ohms)
 		return false;
 
-	batt_id_delta = abs(chip->batt_id_kohms - DEBUG_BATT_ID_KOHMS);
-	if (batt_id_delta <= 1) {
-		fg_dbg(chip, FG_POWER_SUPPLY, "Debug battery id: %dKohms\n",
-			chip->batt_id_kohms);
+	rc = fg_get_debug_batt_id(chip, debug_batt_id);
+	if (rc < 0) {
+		pr_err("Failed to get debug batt_id, rc=%d\n", rc);
+		return false;
+	}
+
+	if (is_between(debug_batt_id[0], debug_batt_id[1],
+		chip->batt_id_ohms)) {
+		fg_dbg(chip, FG_POWER_SUPPLY, "Debug battery id: %dohms\n",
+			chip->batt_id_ohms);
 		return true;
 	}
 
@@ -792,8 +831,8 @@ static int fg_get_batt_profile(struct fg_chip *chip)
 		return rc;
 	}
 
+	chip->batt_id_ohms = batt_id;
 	batt_id /= 1000;
-	chip->batt_id_kohms = batt_id;
 	batt_node = of_find_node_by_name(node, "qcom,battery-data");
 	if (!batt_node) {
 		pr_err("Batterydata not available\n");
@@ -3076,10 +3115,17 @@ static int fg_parse_dt(struct fg_chip *chip)
 		}
 	}
 
+	rc = of_property_read_u32(node, "qcom,rradc-base", &base);
+	if (rc < 0) {
+		dev_err(chip->dev, "rradc-base not specified, rc=%d\n", rc);
+		return rc;
+	}
+	chip->rradc_base = base;
+
 	rc = fg_get_batt_profile(chip);
 	if (rc < 0)
 		pr_warn("profile for batt_id=%dKOhms not found..using OTP, rc:%d\n",
-			chip->batt_id_kohms, rc);
+			chip->batt_id_ohms / 1000, rc);
 
 	/* Read all the optional properties below */
 	rc = of_property_read_u32(node, "qcom,fg-cutoff-voltage", &temp);
@@ -3362,7 +3408,7 @@ static int fg_gen3_probe(struct platform_device *pdev)
 
 	if (!rc)
 		pr_info("battery SOC:%d voltage: %duV temp: %d id: %dKOhms\n",
-			msoc, volt_uv, batt_temp, chip->batt_id_kohms);
+			msoc, volt_uv, batt_temp, chip->batt_id_ohms / 1000);
 
 	device_init_wakeup(chip->dev, true);
 	if (chip->profile_available)