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regulator/max1586: support increased V3 voltage range
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The V3 regulator can be configured with an external resistor
connected to the feedback pin (R24 in the data sheet) to
increase the voltage range.

For example, hx4700 has R24 = 3.32 kOhm to achieve a maximum
V3 voltage of 1.55 V which is needed for 624 MHz CPU frequency.

Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
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Philipp Zabel authored and Liam Girdwood committed Jun 15, 2009
1 parent 6113c3a commit b110a8f
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Showing 2 changed files with 63 additions and 19 deletions.
71 changes: 52 additions & 19 deletions drivers/regulator/max1586.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,51 +29,71 @@

#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

#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);
}

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);
}

/*
Expand Down Expand Up @@ -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)
Expand All @@ -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",
Expand All @@ -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;
}

Expand Down
11 changes: 11 additions & 0 deletions include/linux/regulator/max1586.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand All @@ -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

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