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path: root/drivers/hwmon/ltc2945.c
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Diffstat (limited to 'drivers/hwmon/ltc2945.c')
-rw-r--r--drivers/hwmon/ltc2945.c132
1 files changed, 87 insertions, 45 deletions
diff --git a/drivers/hwmon/ltc2945.c b/drivers/hwmon/ltc2945.c
index 9adebb59f604..3494f7261ebf 100644
--- a/drivers/hwmon/ltc2945.c
+++ b/drivers/hwmon/ltc2945.c
@@ -58,6 +58,22 @@
#define CONTROL_MULT_SELECT (1 << 0)
#define CONTROL_TEST_MODE (1 << 4)
+static const struct of_device_id __maybe_unused ltc2945_of_match[] = {
+ { .compatible = "adi,ltc2945" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ltc2945_of_match);
+
+/**
+ * struct ltc2945_data - LTC2945 device data
+ * @regmap: regmap device
+ * @shunt_resistor: shunt resistor value in micro ohms (1000 by default)
+ */
+struct ltc2945_data {
+ struct regmap *regmap;
+ u32 shunt_resistor;
+};
+
static inline bool is_power_reg(u8 reg)
{
return reg < LTC2945_SENSE_H;
@@ -66,7 +82,9 @@ static inline bool is_power_reg(u8 reg)
/* Return the value from the given register in uW, mV, or mA */
static long long ltc2945_reg_to_val(struct device *dev, u8 reg)
{
- struct regmap *regmap = dev_get_drvdata(dev);
+ struct ltc2945_data *data = dev_get_drvdata(dev);
+ struct regmap *regmap = data->regmap;
+ u32 shunt_resistor = data->shunt_resistor;
unsigned int control;
u8 buf[3];
long long val;
@@ -78,10 +96,10 @@ static long long ltc2945_reg_to_val(struct device *dev, u8 reg)
return ret;
if (is_power_reg(reg)) {
- /* power */
+ /* 24-bit power */
val = (buf[0] << 16) + (buf[1] << 8) + buf[2];
} else {
- /* current, voltage */
+ /* 12-bit current, voltage */
val = (buf[0] << 4) + (buf[1] >> 4);
}
@@ -92,9 +110,7 @@ static long long ltc2945_reg_to_val(struct device *dev, u8 reg)
case LTC2945_MAX_POWER_THRES_H:
case LTC2945_MIN_POWER_THRES_H:
/*
- * Convert to uW by assuming current is measured with
- * an 1mOhm sense resistor, similar to current
- * measurements.
+ * Convert to uW
* Control register bit 0 selects if voltage at SENSE+/VDD
* or voltage at ADIN is used to measure power.
*/
@@ -108,6 +124,14 @@ static long long ltc2945_reg_to_val(struct device *dev, u8 reg)
/* 0.5 mV * 25 uV = 0.0125 uV resolution. */
val = (val * 25LL) >> 1;
}
+ val *= 1000;
+ /* Overflow check: Assuming max 24-bit power, val is at most 53 bits right now. */
+ val = DIV_ROUND_CLOSEST_ULL(val, shunt_resistor);
+ /*
+ * Overflow check: After division, depending on shunt resistor,
+ * val can still be > 32 bits so returning long long makes sense
+ */
+
break;
case LTC2945_VIN_H:
case LTC2945_MAX_VIN_H:
@@ -130,14 +154,11 @@ static long long ltc2945_reg_to_val(struct device *dev, u8 reg)
case LTC2945_MIN_SENSE_H:
case LTC2945_MAX_SENSE_THRES_H:
case LTC2945_MIN_SENSE_THRES_H:
- /*
- * 25 uV resolution. Convert to current as measured with
- * an 1 mOhm sense resistor, in mA. If a different sense
- * resistor is installed, calculate the actual current by
- * dividing the reported current by the sense resistor value
- * in mOhm.
- */
- val *= 25;
+ /* 25 uV resolution. Convert to mA. */
+ val *= 25 * 1000;
+ /* Overflow check: Assuming max 12-bit sense, val is at most 27 bits right now */
+ val = DIV_ROUND_CLOSEST_ULL(val, shunt_resistor);
+ /* Overflow check: After division, <= 27 bits */
break;
default:
return -EINVAL;
@@ -145,13 +166,18 @@ static long long ltc2945_reg_to_val(struct device *dev, u8 reg)
return val;
}
-static int ltc2945_val_to_reg(struct device *dev, u8 reg,
- unsigned long val)
+static long long ltc2945_val_to_reg(struct device *dev, u8 reg,
+ unsigned long long val)
{
- struct regmap *regmap = dev_get_drvdata(dev);
+ struct ltc2945_data *data = dev_get_drvdata(dev);
+ struct regmap *regmap = data->regmap;
+ u32 shunt_resistor = data->shunt_resistor;
unsigned int control;
int ret;
+ /* Ensure we don't overflow */
+ val = clamp_val(val, 0, U32_MAX);
+
switch (reg) {
case LTC2945_POWER_H:
case LTC2945_MAX_POWER_H:
@@ -159,9 +185,6 @@ static int ltc2945_val_to_reg(struct device *dev, u8 reg,
case LTC2945_MAX_POWER_THRES_H:
case LTC2945_MIN_POWER_THRES_H:
/*
- * Convert to register value by assuming current is measured
- * with an 1mOhm sense resistor, similar to current
- * measurements.
* Control register bit 0 selects if voltage at SENSE+/VDD
* or voltage at ADIN is used to measure power, which in turn
* determines register calculations.
@@ -171,14 +194,16 @@ static int ltc2945_val_to_reg(struct device *dev, u8 reg,
return ret;
if (control & CONTROL_MULT_SELECT) {
/* 25 mV * 25 uV = 0.625 uV resolution. */
- val = DIV_ROUND_CLOSEST(val, 625);
+ val *= shunt_resistor;
+ /* Overflow check: Assuming 32-bit val and shunt resistor, val <= 64bits */
+ val = DIV_ROUND_CLOSEST_ULL(val, 625 * 1000);
+ /* Overflow check: val is now <= 44 bits */
} else {
- /*
- * 0.5 mV * 25 uV = 0.0125 uV resolution.
- * Divide first to avoid overflow;
- * accept loss of accuracy.
- */
- val = DIV_ROUND_CLOSEST(val, 25) * 2;
+ /* 0.5 mV * 25 uV = 0.0125 uV resolution. */
+ val *= shunt_resistor;
+ /* Overflow check: Assuming 32-bit val and shunt resistor, val <= 64bits */
+ val = DIV_ROUND_CLOSEST_ULL(val, 25 * 1000) * 2;
+ /* Overflow check: val is now <= 51 bits */
}
break;
case LTC2945_VIN_H:
@@ -187,7 +212,7 @@ static int ltc2945_val_to_reg(struct device *dev, u8 reg,
case LTC2945_MAX_VIN_THRES_H:
case LTC2945_MIN_VIN_THRES_H:
/* 25 mV resolution. */
- val /= 25;
+ val = DIV_ROUND_CLOSEST_ULL(val, 25);
break;
case LTC2945_ADIN_H:
case LTC2945_MAX_ADIN_H:
@@ -202,14 +227,11 @@ static int ltc2945_val_to_reg(struct device *dev, u8 reg,
case LTC2945_MIN_SENSE_H:
case LTC2945_MAX_SENSE_THRES_H:
case LTC2945_MIN_SENSE_THRES_H:
- /*
- * 25 uV resolution. Convert to current as measured with
- * an 1 mOhm sense resistor, in mA. If a different sense
- * resistor is installed, calculate the actual current by
- * dividing the reported current by the sense resistor value
- * in mOhm.
- */
- val = DIV_ROUND_CLOSEST(val, 25);
+ /* 25 uV resolution. Convert to mA. */
+ val *= shunt_resistor;
+ /* Overflow check: Assuming 32-bit val and 32-bit shunt resistor, val is 64bits */
+ val = DIV_ROUND_CLOSEST_ULL(val, 25 * 1000);
+ /* Overflow check: val is now <= 50 bits */
break;
default:
return -EINVAL;
@@ -234,20 +256,23 @@ static ssize_t ltc2945_value_store(struct device *dev,
const char *buf, size_t count)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
- struct regmap *regmap = dev_get_drvdata(dev);
+ struct ltc2945_data *data = dev_get_drvdata(dev);
+ struct regmap *regmap = data->regmap;
u8 reg = attr->index;
- unsigned long val;
+ unsigned int val;
u8 regbuf[3];
int num_regs;
- int regval;
+ long long regval;
int ret;
- ret = kstrtoul(buf, 10, &val);
+ ret = kstrtouint(buf, 10, &val);
if (ret)
return ret;
/* convert to register value, then clamp and write result */
regval = ltc2945_val_to_reg(dev, reg, val);
+ if (regval < 0)
+ return regval;
if (is_power_reg(reg)) {
regval = clamp_val(regval, 0, 0xffffff);
regbuf[0] = regval >> 16;
@@ -269,7 +294,8 @@ static ssize_t ltc2945_history_store(struct device *dev,
const char *buf, size_t count)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
- struct regmap *regmap = dev_get_drvdata(dev);
+ struct ltc2945_data *data = dev_get_drvdata(dev);
+ struct regmap *regmap = data->regmap;
u8 reg = attr->index;
int num_regs = is_power_reg(reg) ? 3 : 2;
u8 buf_min[3] = { 0xff, 0xff, 0xff };
@@ -321,7 +347,8 @@ static ssize_t ltc2945_bool_show(struct device *dev,
struct device_attribute *da, char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
- struct regmap *regmap = dev_get_drvdata(dev);
+ struct ltc2945_data *data = dev_get_drvdata(dev);
+ struct regmap *regmap = data->regmap;
unsigned int fault;
int ret;
@@ -450,6 +477,12 @@ static int ltc2945_probe(struct i2c_client *client)
struct device *dev = &client->dev;
struct device *hwmon_dev;
struct regmap *regmap;
+ struct ltc2945_data *data;
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+ dev_set_drvdata(dev, data);
regmap = devm_regmap_init_i2c(client, &ltc2945_regmap_config);
if (IS_ERR(regmap)) {
@@ -457,11 +490,19 @@ static int ltc2945_probe(struct i2c_client *client)
return PTR_ERR(regmap);
}
+ data->regmap = regmap;
+ if (device_property_read_u32(dev, "shunt-resistor-micro-ohms",
+ &data->shunt_resistor))
+ data->shunt_resistor = 1000;
+
+ if (data->shunt_resistor == 0)
+ return -EINVAL;
+
/* Clear faults */
regmap_write(regmap, LTC2945_FAULT, 0x00);
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
- regmap,
+ data,
ltc2945_groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
@@ -475,8 +516,9 @@ MODULE_DEVICE_TABLE(i2c, ltc2945_id);
static struct i2c_driver ltc2945_driver = {
.driver = {
- .name = "ltc2945",
- },
+ .name = "ltc2945",
+ .of_match_table = of_match_ptr(ltc2945_of_match),
+ },
.probe_new = ltc2945_probe,
.id_table = ltc2945_id,
};
generated by cgit v1.2.3-70-g09d2 (git 2.48.1) at 2025-02-28 18:05:33 +0000