Utilize the integrated 10-bit ADC in Max5970/Max5978 to enable voltage
and current monitoring. This feature is seamlessly integrated through
the hwmon subsystem.
Signed-off-by: Naresh Solanki <naresh.solanki@xxxxxxxxxxxxx>
---
Change in V6:
- Remove unrelated change
- Add necessary return value check
- Remove unneeded NULL check
Changes in V5:
- Simplify memory allocation for rdevs
Changes in V4:
- Use IS_REACHABLE
- Use rdevs array for hwmon ops.
- Remove duplicate i2c_set_clientdata
Changes in V3:
- Update signed-off
- Add break
- Update hwmon dev register name to max5970
- Remove changes in Kconfig.
Changes in V2:
- default case added for switch statement
- Add dependency on HWMON
---
drivers/regulator/max5970-regulator.c | 144 +++++++++++++++++++++++++-
1 file changed, 143 insertions(+), 1 deletion(-)
diff --git a/drivers/regulator/max5970-regulator.c b/drivers/regulator/max5970-regulator.c
index b56a174cde3d..56cc56ae63b7 100644
--- a/drivers/regulator/max5970-regulator.c
+++ b/drivers/regulator/max5970-regulator.c
@@ -10,6 +10,7 @@
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/err.h>
+#include <linux/hwmon.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/of.h>
@@ -32,6 +33,132 @@ enum max597x_regulator_id {
MAX597X_SW1,
};
+static int max5970_read_adc(struct regmap *regmap, int reg, long *val)
+{
+ u8 reg_data[2];
+ int ret;
+
+ ret = regmap_bulk_read(regmap, reg, ®_data[0], 2);
+ if (ret < 0)
+ return ret;
+
+ *val = (reg_data[0] << 2) | (reg_data[1] & 3);
+
+ return 0;
+}
+
+static int max5970_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct regulator_dev **rdevs = dev_get_drvdata(dev);
+ struct max5970_regulator *ddata = rdev_get_drvdata(rdevs[channel]);
+ struct regmap *regmap = ddata->regmap;
+ int ret;
+
+ switch (type) {
+ case hwmon_curr:
+ switch (attr) {
+ case hwmon_curr_input:
+ ret = max5970_read_adc(regmap, MAX5970_REG_CURRENT_H(channel), val);
+ if (ret < 0)
+ return ret;
+ /*
+ * Calculate current from ADC value, IRNG range & shunt resistor value.
+ * ddata->irng holds the voltage corresponding to the maximum value the
+ * 10-bit ADC can measure.
+ * To obtain the output, multiply the ADC value by the IRNG range (in
+ * millivolts) and then divide it by the maximum value of the 10-bit ADC.
+ */
+ *val = (*val * ddata->irng) >> 10;
+ /* Convert the voltage meansurement across shunt resistor to current */
+ *val = (*val * 1000) / ddata->shunt_micro_ohms;
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ case hwmon_in:
+ switch (attr) {
+ case hwmon_in_input:
+ ret = max5970_read_adc(regmap, MAX5970_REG_VOLTAGE_H(channel), val);
+ if (ret < 0)
+ return ret;
+ /*
+ * Calculate voltage from ADC value and MON range.
+ * ddata->mon_rng holds the voltage corresponding to the maximum value the
+ * 10-bit ADC can measure.
+ * To obtain the output, multiply the ADC value by the MON range (in
+ * microvolts) and then divide it by the maximum value of the 10-bit ADC.
+ */
+ *val = mul_u64_u32_shr(*val, ddata->mon_rng, 10);
+ /* uV to mV */
+ *val = *val / 1000;
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static umode_t max5970_is_visible(const void *data,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ struct regulator_dev **rdevs = (struct regulator_dev **)data;
+ struct max5970_regulator *ddata;
+
+ if (channel >= MAX5970_NUM_SWITCHES || !rdevs[channel])
+ return 0;
+
+ ddata = rdev_get_drvdata(rdevs[channel]);
+
+ if (channel >= ddata->num_switches)
+ return 0;
+
+ switch (type) {
+ case hwmon_in:
+ switch (attr) {
+ case hwmon_in_input:
+ return 0444;
+ default:
+ break;
+ }
+ break;
+ case hwmon_curr:
+ switch (attr) {
+ case hwmon_curr_input:
+ /* Current measurement requires knowledge of the shunt resistor value. */
+ if (ddata->shunt_micro_ohms)
+ return 0444;
+ break;
+ default:
+ break;
+ }
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+
+static const struct hwmon_ops max5970_hwmon_ops = {
+ .is_visible = max5970_is_visible,
+ .read = max5970_read,
+};
+
+static const struct hwmon_channel_info *max5970_info[] = {
+ HWMON_CHANNEL_INFO(in, HWMON_I_INPUT, HWMON_I_INPUT),
+ HWMON_CHANNEL_INFO(curr, HWMON_C_INPUT, HWMON_C_INPUT),
+ NULL
+};
+
+static const struct hwmon_chip_info max5970_chip_info = {
+ .ops = &max5970_hwmon_ops,
+ .info = max5970_info,
+};
+
static int max597x_uvp_ovp_check_mode(struct regulator_dev *rdev, int severity)
{
int ret, reg;
@@ -431,7 +558,8 @@ static int max597x_regulator_probe(struct platform_device *pdev)
struct i2c_client *i2c = to_i2c_client(pdev->dev.parent);
struct regulator_config config = { };
struct regulator_dev *rdev;
- struct regulator_dev *rdevs[MAX5970_NUM_SWITCHES];
+ struct regulator_dev **rdevs = NULL;
+ struct device *hwmon_dev;
int num_switches;
int ret, i;
@@ -442,6 +570,11 @@ static int max597x_regulator_probe(struct platform_device *pdev)
if (!max597x)
return -ENOMEM;
+ rdevs = devm_kcalloc(&i2c->dev, MAX5970_NUM_SWITCHES, sizeof(struct regulator_dev *),
+ GFP_KERNEL);
+ if (!rdevs)
+ return -ENOMEM;
+
i2c_set_clientdata(i2c, max597x);
if (of_device_is_compatible(i2c->dev.of_node, "maxim,max5978"))
@@ -485,6 +618,15 @@ static int max597x_regulator_probe(struct platform_device *pdev)
max597x->shunt_micro_ohms[i] = data->shunt_micro_ohms;
}
+ if (IS_REACHABLE(CONFIG_HWMON)) {
+ hwmon_dev = devm_hwmon_device_register_with_info(&i2c->dev, "max5970", rdevs,
+ &max5970_chip_info, NULL);
+ if (IS_ERR(hwmon_dev)) {
+ return dev_err_probe(&i2c->dev, PTR_ERR(hwmon_dev),
+ "Unable to register hwmon device\n");
+ }
+ }
+
if (i2c->irq) {
ret =
max597x_setup_irq(&i2c->dev, i2c->irq, rdevs, num_switches,
base-commit: e95d9ba0eb4ef2f9f7fa0451c3ad4f77c685538d
--
2.41.0
