regulator: spm: check min/max voltages against HW configuration

Regulator HW has the programmable voltage upper and lower limit
registers and doesn't allow voltage set points outside the pre-
configured voltage limits. Add a check in driver that throws an
error if the SW specified voltage range is not within the pre-
configured limits in HW.

CRs-Fixed: 2044789
Change-Id: I3593ebf8e88824a0cfcb068686673a00051a11f0
Signed-off-by: Tirupathi Reddy <tirupath@codeaurora.org>

1 files changed, 106 insertions, 0 deletions

diff --git a/drivers/regulator/spm-regulator.c b/drivers/regulator/spm-regulator.c
index be59947ba6f2..d469463a0b00 100644
--- a/drivers/regulator/spm-regulator.c
+++ b/drivers/regulator/spm-regulator.c
@@ -95,6 +95,7 @@ static const struct voltage_range hf_range1 = {1550000, 1550000, 3125000,
 #define QPNP_SMPS_REG_VOLTAGE_SETPOINT	0x41
 #define QPNP_SMPS_REG_MODE		0x45
 #define QPNP_SMPS_REG_STEP_CTRL		0x61
+#define QPNP_SMPS_REG_UL_LL_CTRL	0x68
 
 /* FTS426 voltage control registers */
 #define QPNP_FTS426_REG_VOLTAGE_LB		0x40
@@ -102,6 +103,22 @@ static const struct voltage_range hf_range1 = {1550000, 1550000, 3125000,
 #define QPNP_FTS426_REG_VOLTAGE_VALID_LB	0x42
 #define QPNP_FTS426_REG_VOLTAGE_VALID_UB	0x43
 
+/* HF voltage limit registers */
+#define QPNP_HF_REG_VOLTAGE_ULS		0x69
+#define QPNP_HF_REG_VOLTAGE_LLS		0x6B
+
+/* FTS voltage limit registers */
+#define QPNP_FTS_REG_VOLTAGE_ULS_VALID	0x6A
+#define QPNP_FTS_REG_VOLTAGE_LLS_VALID	0x6C
+
+/* FTS426 voltage limit registers */
+#define QPNP_FTS426_REG_VOLTAGE_ULS_LB	0x68
+#define QPNP_FTS426_REG_VOLTAGE_ULS_UB	0x69
+
+/* Common regulator UL & LL limits control register layout */
+#define QPNP_COMMON_UL_EN_MASK		0x80
+#define QPNP_COMMON_LL_EN_MASK		0x40
+
 #define QPNP_SMPS_MODE_PWM		0x80
 #define QPNP_SMPS_MODE_AUTO		0x40
 #define QPNP_FTS426_MODE_PWM		0x07
@@ -924,6 +941,88 @@ static int qpnp_smps_init_step_rate(struct spm_vreg *vreg)
 	return rc;
 }
 
+static int qpnp_smps_check_constraints(struct spm_vreg *vreg,
+					struct regulator_init_data *init_data)
+{
+	int rc = 0, limit_min_uV, limit_max_uV;
+	u16 ul_reg, ll_reg;
+	u8 reg[2];
+
+	limit_min_uV = 0;
+	limit_max_uV = INT_MAX;
+
+	ul_reg = QPNP_FTS_REG_VOLTAGE_ULS_VALID;
+	ll_reg = QPNP_FTS_REG_VOLTAGE_LLS_VALID;
+
+	switch (vreg->regulator_type) {
+	case QPNP_TYPE_HF:
+		ul_reg = QPNP_HF_REG_VOLTAGE_ULS;
+		ll_reg = QPNP_HF_REG_VOLTAGE_LLS;
+	case QPNP_TYPE_FTS2:
+	case QPNP_TYPE_FTS2p5:
+		rc = regmap_bulk_read(vreg->regmap, vreg->spmi_base_addr
+					+ QPNP_SMPS_REG_UL_LL_CTRL, reg, 1);
+		if (rc) {
+			dev_err(&vreg->pdev->dev, "%s: UL_LL register read failed, rc=%d\n",
+				__func__, rc);
+			return rc;
+		}
+
+		if (reg[0] & QPNP_COMMON_UL_EN_MASK) {
+			rc = regmap_bulk_read(vreg->regmap, vreg->spmi_base_addr
+						+ ul_reg, &reg[1], 1);
+			if (rc) {
+				dev_err(&vreg->pdev->dev, "%s: ULS register read failed, rc=%d\n",
+					__func__, rc);
+				return rc;
+			}
+
+			limit_max_uV = spm_regulator_vlevel_to_uv(vreg, reg[1]);
+		}
+
+		if (reg[0] & QPNP_COMMON_LL_EN_MASK) {
+			rc = regmap_bulk_read(vreg->regmap, vreg->spmi_base_addr
+						+ ll_reg, &reg[1], 1);
+			if (rc) {
+				dev_err(&vreg->pdev->dev, "%s: LLS register read failed, rc=%d\n",
+					__func__, rc);
+				return rc;
+			}
+
+			limit_min_uV = spm_regulator_vlevel_to_uv(vreg, reg[1]);
+		}
+
+		break;
+	case QPNP_TYPE_FTS426:
+		rc = regmap_bulk_read(vreg->regmap, vreg->spmi_base_addr
+					+ QPNP_FTS426_REG_VOLTAGE_ULS_LB,
+					reg, 2);
+		if (rc) {
+			dev_err(&vreg->pdev->dev, "%s: could not read voltage limit registers, rc=%d\n",
+				__func__, rc);
+			return rc;
+		}
+
+		limit_max_uV = spm_regulator_vlevel_to_uv(vreg,
+					((unsigned)reg[1] << 8) | reg[0]);
+		break;
+	case QPNP_TYPE_ULT_HF:
+		/* no HW voltage limit configuration */
+		break;
+	}
+
+	if (init_data->constraints.min_uV < limit_min_uV
+	    || init_data->constraints.max_uV >  limit_max_uV) {
+		dev_err(&vreg->pdev->dev, "regulator min/max(%d/%d) constraints do not fit within HW configured min/max(%d/%d) constraints\n",
+			init_data->constraints.min_uV,
+			init_data->constraints.max_uV, limit_min_uV,
+			limit_max_uV);
+		return -EINVAL;
+	}
+
+	return rc;
+}
+
 static bool spm_regulator_using_range0(struct spm_vreg *vreg)
 {
 	return vreg->range == &fts2_range0 || vreg->range == &fts2p5_range0
@@ -1105,6 +1204,13 @@ static int spm_regulator_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
+	rc = qpnp_smps_check_constraints(vreg, init_data);
+	if (rc) {
+		dev_err(&pdev->dev, "%s: regulator constraints check failed, rc=%d\n",
+			__func__, rc);
+		return rc;
+	}
+
 	vreg->rdesc.name	= init_data->constraints.name;
 	vreg->rdesc.type	= REGULATOR_VOLTAGE;
 	vreg->rdesc.owner	= THIS_MODULE;