static int ltc4215_get_voltage(struct device *dev, u8 reg)
{
struct ltc4215_data *data = ltc4215_update_device(dev);
const u8 regval = data->regs[reg];
u32 voltage = 0;
switch (reg) {
case LTC4215_SENSE:
voltage = regval * 151 / 1000;
break;
case LTC4215_SOURCE:
voltage = regval * 605 / 10;
break;
case LTC4215_ADIN:
voltage = regval * 482 * 125 / 1000;
break;
default:
WARN_ON_ONCE(1);
break;
}
return voltage;
}
/* Return the voltage from the given register in millivolts */
static int ltc4215_get_voltage(struct device *dev, u8 reg)
{
struct ltc4215_data *data = ltc4215_update_device(dev);
const u8 regval = data->regs[reg];
u32 voltage = 0;
switch (reg) {
case LTC4215_SENSE:
/* 151 uV per increment */
voltage = regval * 151 / 1000;
break;
case LTC4215_SOURCE:
/* 60.5 mV per increment */
voltage = regval * 605 / 10;
break;
case LTC4215_ADIN:
/* The ADIN input is divided by 12.5, and has 4.82 mV
* per increment, so we have the additional multiply */
voltage = regval * 482 * 125 / 1000;
break;
default:
/* If we get here, the developer messed up */
WARN_ON_ONCE(1);
break;
}
return voltage;
}
/* Return the current from the sense resistor in mA */
static unsigned int ltc4215_get_current(struct device *dev)
{
struct ltc4215_data *data = ltc4215_update_device(dev);
/* The strange looking conversions that follow are fixed-point
* math, since we cannot do floating point in the kernel.
*
* Step 1: convert sense register to microVolts
* Step 2: convert voltage to milliAmperes
*
* If you play around with the V=IR equation, you come up with
* the following: X uV / Y mOhm == Z mA
*
* With the resistors that are fractions of a milliOhm, we multiply
* the voltage and resistance by 10, to shift the decimal point.
* Now we can use the normal division operator again.
*/
/* Calculate voltage in microVolts (151 uV per increment) */
const unsigned int voltage = data->regs[LTC4215_SENSE] * 151;
/* Calculate current in milliAmperes (4 milliOhm sense resistor) */
const unsigned int curr = voltage / 4;
return curr;
}
static ssize_t ltc4215_show_alarm(struct device *dev,
struct device_attribute *da,
char *buf)
{
struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
struct ltc4215_data *data = ltc4215_update_device(dev);
const u8 reg = data->regs[attr->index];
const u32 mask = attr->nr;
return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0);
}
static unsigned int ltc4215_get_current(struct device *dev)
{
struct ltc4215_data *data = ltc4215_update_device(dev);
const unsigned int voltage = data->regs[LTC4215_SENSE] * 151;
const unsigned int curr = voltage / 4;
return curr;
}
