2 files changed, 63 insertions, 19 deletions

diff --git a/drivers/regulator/max1586.c b/drivers/regulator/max1586.c
index bbbb55fcfe8c..92799f40c864 100644
--- a/drivers/regulator/max1586.c
+++ b/drivers/regulator/max1586.c
@@ -29,7 +29,6 @@
 
 #define MAX1586_V3_MIN_UV   700000
 #define MAX1586_V3_MAX_UV  1475000
-#define MAX1586_V3_STEP_UV   25000
 
 #define MAX1586_V6_MIN_UV        0
 #define MAX1586_V6_MAX_UV  3000000
@@ -37,33 +36,52 @@
 #define I2C_V3_SELECT (0 << 5)
 #define I2C_V6_SELECT (1 << 5)
 
+struct max1586_data {
+        struct i2c_client *client;
+
+        /* min/max V3 voltage */
+        int min_uV;
+        int max_uV;
+
+        struct regulator_dev *rdev[0];
+};
+
 /*
  * V3 voltage
  * On I2C bus, sending a "x" byte to the max1586 means :
  *   set V3 to 0.700V + (x & 0x1f) * 0.025V
+ * This voltage can be increased by external resistors
+ * R24 and R25=100kOhm as described in the data sheet.
+ * The gain is approximately: 1 + R24/R25 + R24/185.5kOhm
  */
-static int max1586_v3_calc_voltage(unsigned selector)
+static int max1586_v3_calc_voltage(struct max1586_data *max1586,
+        unsigned selector)
 {
-        return MAX1586_V3_MIN_UV + (MAX1586_V3_STEP_UV * selector);
+        unsigned range_uV = max1586->max_uV - max1586->min_uV;
+
+        return max1586->min_uV + (selector * range_uV / MAX1586_V3_MAX_VSEL);
 }
 
 static int max1586_v3_set(struct regulator_dev *rdev, int min_uV, int max_uV)
 {
-        struct i2c_client *client = rdev_get_drvdata(rdev);
+        struct max1586_data *max1586 = rdev_get_drvdata(rdev);
+        struct i2c_client *client = max1586->client;
+        unsigned range_uV = max1586->max_uV - max1586->min_uV;
         unsigned selector;
         u8 v3_prog;
 
-        if (min_uV < MAX1586_V3_MIN_UV || min_uV > MAX1586_V3_MAX_UV)
-                return -EINVAL;
-        if (max_uV < MAX1586_V3_MIN_UV || max_uV > MAX1586_V3_MAX_UV)
+        if (min_uV > max1586->max_uV || max_uV < max1586->min_uV)
                 return -EINVAL;
+        if (min_uV < max1586->min_uV)
+                min_uV = max1586->min_uV;
 
-        selector = (min_uV - MAX1586_V3_MIN_UV) / MAX1586_V3_STEP_UV;
-        if (max1586_v3_calc_voltage(selector) > max_uV)
+        selector = ((min_uV - max1586->min_uV) * MAX1586_V3_MAX_VSEL +
+                        range_uV - 1) / range_uV;
+        if (max1586_v3_calc_voltage(max1586, selector) > max_uV)
                 return -EINVAL;
 
         dev_dbg(&client->dev, "changing voltage v3 to %dmv\n",
-                max1586_v3_calc_voltage(selector) / 1000);
+                max1586_v3_calc_voltage(max1586, selector) / 1000);
 
         v3_prog = I2C_V3_SELECT | (u8) selector;
         return i2c_smbus_write_byte(client, v3_prog);
@@ -71,9 +89,11 @@ static int max1586_v3_set(struct regulator_dev *rdev, int min_uV, int max_uV)
 
 static int max1586_v3_list(struct regulator_dev *rdev, unsigned selector)
 {
+        struct max1586_data *max1586 = rdev_get_drvdata(rdev);
+
         if (selector > MAX1586_V3_MAX_VSEL)
                 return -EINVAL;
-        return max1586_v3_calc_voltage(selector);
+        return max1586_v3_calc_voltage(max1586, selector);
 }
 
 /*
@@ -164,14 +184,25 @@ static int max1586_pmic_probe(struct i2c_client *client,
 {
         struct regulator_dev **rdev;
         struct max1586_platform_data *pdata = client->dev.platform_data;
-        int i, id, ret = 0;
+        struct max1586_data *max1586;
+        int i, id, ret = -ENOMEM;
+
+        max1586 = kzalloc(sizeof(struct max1586_data) +
+                        sizeof(struct regulator_dev *) * (MAX1586_V6 + 1),
+                        GFP_KERNEL);
+        if (!max1586)
+                goto out;
 
-        rdev = kzalloc(sizeof(struct regulator_dev *) * (MAX1586_V6 + 1),
-                       GFP_KERNEL);
-        if (!rdev)
-                return -ENOMEM;
+        max1586->client = client;
 
-        ret = -EINVAL;
+        if (!pdata->v3_gain) {
+                ret = -EINVAL;
+                goto out_unmap;
+        }
+        max1586->min_uV = MAX1586_V3_MIN_UV * pdata->v3_gain / 1000000;
+        max1586->max_uV = MAX1586_V3_MAX_UV * pdata->v3_gain / 1000000;
+
+        rdev = max1586->rdev;
         for (i = 0; i < pdata->num_subdevs && i <= MAX1586_V6; i++) {
                 id = pdata->subdevs[i].id;
                 if (!pdata->subdevs[i].platform_data)
@@ -182,7 +213,7 @@ static int max1586_pmic_probe(struct i2c_client *client,
                 }
                 rdev[i] = regulator_register(&max1586_reg[id], &client->dev,
                                              pdata->subdevs[i].platform_data,
-                                             client);
+                                             max1586);
                 if (IS_ERR(rdev[i])) {
                         ret = PTR_ERR(rdev[i]);
                         dev_err(&client->dev, "failed to register %s\n",
@@ -198,7 +229,9 @@ static int max1586_pmic_probe(struct i2c_client *client,
 err:
         while (--i >= 0)
                 regulator_unregister(rdev[i]);
-        kfree(rdev);
+out_unmap:
+        kfree(max1586);
+out:
         return ret;
 }
 
diff --git a/include/linux/regulator/max1586.h b/include/linux/regulator/max1586.h
index 2056973396b6..44563192bf16 100644
--- a/include/linux/regulator/max1586.h
+++ b/include/linux/regulator/max1586.h
@@ -26,6 +26,12 @@
 #define MAX1586_V3 0
 #define MAX1586_V6 1
 
+/* precalculated values for v3_gain */
+#define MAX1586_GAIN_NO_R24   1000000  /* 700000 .. 1475000 mV */
+#define MAX1586_GAIN_R24_3k32 1051098  /* 735768 .. 1550369 mV */
+#define MAX1586_GAIN_R24_5k11 1078648  /* 755053 .. 1591005 mV */
+#define MAX1586_GAIN_R24_7k5  1115432  /* 780802 .. 1645262 mV */
+
 /**
  * max1586_subdev_data - regulator data
  * @id: regulator Id (either MAX1586_V3 or MAX1586_V6)
@@ -43,10 +49,15 @@ struct max1586_subdev_data {
  * @num_subdevs: number of regultors used (may be 1 or 2)
  * @subdevs: regulator used
  *           At most, there will be a regulator for V3 and one for V6 voltages.
+ * @v3_gain: gain on the V3 voltage output multiplied by 1e6.
+ *           This can be calculated as ((1 + R24/R25 + R24/185.5kOhm) * 1e6)
+ *           for an external resistor configuration as described in the
+ *           data sheet (R25=100kOhm).
  */
 struct max1586_platform_data {
         int num_subdevs;
         struct max1586_subdev_data *subdevs;
+        int v3_gain;
 };
 
 #endif