regulator: as3722: detect SD0 low-voltage mode

SD0 may operate in low-voltage mode, with a minimum of 0.41V
and a maximum of 1.5V.  This is indicated by bit 4 of FUSE7.

Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Vince Hsu <vinceh@nvidia.com>
broonie.e6264@m.evernote.com
Signed-off-by: Mark Brown <broonie@linaro.org>

2 files changed, 30 insertions, 4 deletions

diff --git a/drivers/regulator/as3722-regulator.c b/drivers/regulator/as3722-regulator.c
index fdb31371a232..3d7fbc21181d 100644
--- a/drivers/regulator/as3722-regulator.c
+++ b/drivers/regulator/as3722-regulator.c
@@ -99,7 +99,6 @@ static const struct as3722_register_mapping as3722_reg_lookup[] = {
                 .sleep_ctrl_mask = AS3722_SD0_EXT_ENABLE_MASK,
                 .control_reg = AS3722_SD0_CONTROL_REG,
                 .mode_mask = AS3722_SD0_MODE_FAST,
-                .n_voltages = AS3722_SD0_VSEL_MAX + 1,
         },
         {
                 .regulator_id = AS3722_REGULATOR_ID_SD1,
@@ -112,7 +111,6 @@ static const struct as3722_register_mapping as3722_reg_lookup[] = {
                 .sleep_ctrl_mask = AS3722_SD1_EXT_ENABLE_MASK,
                 .control_reg = AS3722_SD1_CONTROL_REG,
                 .mode_mask = AS3722_SD1_MODE_FAST,
-                .n_voltages = AS3722_SD0_VSEL_MAX + 1,
         },
         {
                 .regulator_id = AS3722_REGULATOR_ID_SD2,
@@ -181,7 +179,6 @@ static const struct as3722_register_mapping as3722_reg_lookup[] = {
                 .sleep_ctrl_mask = AS3722_SD6_EXT_ENABLE_MASK,
                 .control_reg = AS3722_SD6_CONTROL_REG,
                 .mode_mask = AS3722_SD6_MODE_FAST,
-                .n_voltages = AS3722_SD0_VSEL_MAX + 1,
         },
         {
                 .regulator_id = AS3722_REGULATOR_ID_LDO0,
@@ -595,6 +592,22 @@ static int as3722_sd016_set_current_limit(struct regulator_dev *rdev,
         return as3722_update_bits(as3722, reg, mask, val);
 }
 
+static bool as3722_sd0_is_low_voltage(struct as3722_regulators *as3722_regs)
+{
+        int err;
+        unsigned val;
+
+        err = as3722_read(as3722_regs->as3722, AS3722_FUSE7_REG, &val);
+        if (err < 0) {
+                dev_err(as3722_regs->dev, "Reg 0x%02x read failed: %d\n",
+                        AS3722_FUSE7_REG, err);
+                return false;
+        }
+        if (val & AS3722_FUSE7_SD0_LOW_VOLTAGE)
+                return true;
+        return false;
+}
+
 static const struct regulator_linear_range as3722_sd2345_ranges[] = {
         REGULATOR_LINEAR_RANGE(612500, 0x01, 0x40, 12500),
         REGULATOR_LINEAR_RANGE(1425000, 0x41, 0x70, 25000),
@@ -820,7 +833,16 @@ static int as3722_regulator_probe(struct platform_device *pdev)
                                 ops = &as3722_sd016_extcntrl_ops;
                         else
                                 ops = &as3722_sd016_ops;
-                        as3722_regs->desc[id].min_uV = 610000;
+                        if (id == AS3722_REGULATOR_ID_SD0 &&
+                            as3722_sd0_is_low_voltage(as3722_regs)) {
+                                as3722_regs->desc[id].n_voltages =
+                                        AS3722_SD0_VSEL_LOW_VOL_MAX + 1;
+                                as3722_regs->desc[id].min_uV = 410000;
+                        } else {
+                                as3722_regs->desc[id].n_voltages =
+                                        AS3722_SD0_VSEL_MAX + 1,
+                                as3722_regs->desc[id].min_uV = 610000;
+                        }
                         as3722_regs->desc[id].uV_step = 10000;
                         as3722_regs->desc[id].linear_min_sel = 1;
                         break;
diff --git a/include/linux/mfd/as3722.h b/include/linux/mfd/as3722.h
index 16bf8a0dcd97..bb9616dc0efa 100644
--- a/include/linux/mfd/as3722.h
+++ b/include/linux/mfd/as3722.h
@@ -151,6 +151,7 @@
 #define AS3722_ASIC_ID1_REG                             0x90
 #define AS3722_ASIC_ID2_REG                             0x91
 #define AS3722_LOCK_REG                                 0x9E
+#define AS3722_FUSE7_REG                                0xA7
 #define AS3722_MAX_REGISTER                             0xF4
 
 #define AS3722_SD0_EXT_ENABLE_MASK                      0x03
@@ -224,6 +225,7 @@
 #define AS3722_SD_VSEL_MASK                             0x7F
 #define AS3722_SD0_VSEL_MIN                             0x01
 #define AS3722_SD0_VSEL_MAX                             0x5A
+#define AS3722_SD0_VSEL_LOW_VOL_MAX                     0x6E
 #define AS3722_SD2_VSEL_MIN                             0x01
 #define AS3722_SD2_VSEL_MAX                             0x7F
 
@@ -341,6 +343,8 @@
 #define AS3722_EXT_CONTROL_ENABLE2                      0x2
 #define AS3722_EXT_CONTROL_ENABLE3                      0x3
 
+#define AS3722_FUSE7_SD0_LOW_VOLTAGE                    BIT(4)
+
 /* Interrupt IDs */
 enum as3722_irq {
         AS3722_IRQ_LID,