hwmon: (lm90) Add support for 2nd remote channel's offset register

The ADT7481 have LM90_HAVE_TEMP3 and LM90_HAVE_OFFSET flags, but the
support of second remote channel's offset is missing. Add that
implementation.

Signed-off-by: Slawomir Stepien <slawomir.stepien@nokia.com>
Link: https://lore.kernel.org/r/20220607063504.1287855-2-sst@poczta.fm
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
index a18aed5..ec885cb 100644 (file)
--- a/drivers/hwmon/lm90.c
+++ b/drivers/hwmon/lm90.c
@@ -672,6 +672,7 @@ enum lm90_temp_reg_index {
        REMOTE2_TEMP,   /* max6695/96 only */
        REMOTE2_LOW,    /* max6695/96 only */
        REMOTE2_HIGH,   /* max6695/96 only */
+       REMOTE2_OFFSET,
 
        TEMP_REG_NUM
 };
@@ -1028,6 +1029,14 @@ static int lm90_update_limits(struct device *dev)
                        return val;
                data->temp[REMOTE2_HIGH] = val << 8;
 
+               if (data->flags & LM90_HAVE_OFFSET) {
+                       val = lm90_read16(client, LM90_REG_REMOTE_OFFSH,
+                                         LM90_REG_REMOTE_OFFSL, false);
+                       if (val < 0)
+                               return val;
+                       data->temp[REMOTE2_OFFSET] = val;
+               }
+
                lm90_select_remote_channel(data, false);
        }
 
@@ -1298,6 +1307,7 @@ static int lm90_temp_get_resolution(struct lm90_data *data, int index)
                        return data->resolution;
                return 8;
        case REMOTE_OFFSET:
+       case REMOTE2_OFFSET:
        case REMOTE2_TEMP:
                return data->resolution;
        case LOCAL_TEMP:
@@ -1428,6 +1438,36 @@ static int lm90_set_temphyst(struct lm90_data *data, long val)
        return lm90_write_reg(data->client, LM90_REG_TCRIT_HYST, data->temp_hyst);
 }
 
+static int lm90_get_temp_offset(struct lm90_data *data, int index)
+{
+       int res = lm90_temp_get_resolution(data, index);
+
+       return lm90_temp_from_reg(0, data->temp[index], res);
+}
+
+static int lm90_set_temp_offset(struct lm90_data *data, int index, int channel, long val)
+{
+       int err;
+
+       val = lm90_temp_to_reg(0, val, lm90_temp_get_resolution(data, index));
+
+       /* For ADT7481 we can use the same registers for remote channel 1 and 2 */
+       if (channel > 1)
+               lm90_select_remote_channel(data, true);
+
+       err = lm90_write16(data->client, LM90_REG_REMOTE_OFFSH, LM90_REG_REMOTE_OFFSL, val);
+
+       if (channel > 1)
+               lm90_select_remote_channel(data, false);
+
+       if (err)
+               return err;
+
+       data->temp[index] = val;
+
+       return 0;
+}
+
 static const u8 lm90_temp_index[MAX_CHANNELS] = {
        LOCAL_TEMP, REMOTE_TEMP, REMOTE2_TEMP
 };
@@ -1448,6 +1488,10 @@ static const u8 lm90_temp_emerg_index[MAX_CHANNELS] = {
        LOCAL_EMERG, REMOTE_EMERG, REMOTE2_EMERG
 };
 
+static const s8 lm90_temp_offset_index[MAX_CHANNELS] = {
+       -1, REMOTE_OFFSET, REMOTE2_OFFSET
+};
+
 static const u16 lm90_min_alarm_bits[MAX_CHANNELS] = { BIT(5), BIT(3), BIT(11) };
 static const u16 lm90_max_alarm_bits[MAX_CHANNELS] = { BIT(6), BIT(4), BIT(12) };
 static const u16 lm90_crit_alarm_bits[MAX_CHANNELS] = { BIT(0), BIT(1), BIT(9) };
@@ -1519,8 +1563,7 @@ static int lm90_temp_read(struct device *dev, u32 attr, int channel, long *val)
                *val = lm90_get_temphyst(data, lm90_temp_emerg_index[channel], channel);
                break;
        case hwmon_temp_offset:
-               *val = lm90_temp_from_reg(0, data->temp[REMOTE_OFFSET],
-                                         lm90_temp_get_resolution(data, REMOTE_OFFSET));
+               *val = lm90_get_temp_offset(data, lm90_temp_offset_index[channel]);
                break;
        default:
                return -EOPNOTSUPP;
@@ -1560,13 +1603,8 @@ static int lm90_temp_write(struct device *dev, u32 attr, int channel, long val)
                                    channel, val);
                break;
        case hwmon_temp_offset:
-               val = lm90_temp_to_reg(0, val,
-                                      lm90_temp_get_resolution(data, REMOTE_OFFSET));
-               err = lm90_write16(data->client, LM90_REG_REMOTE_OFFSH,
-                                  LM90_REG_REMOTE_OFFSL, val);
-               if (err)
-                       break;
-               data->temp[REMOTE_OFFSET] = val;
+               err = lm90_set_temp_offset(data, lm90_temp_offset_index[channel],
+                                          channel, val);
                break;
        default:
                err = -EOPNOTSUPP;
@@ -2803,6 +2841,8 @@ static int lm90_probe(struct i2c_client *client)
                }
                if (data->flags & LM90_HAVE_EMERGENCY_ALARM)
                        data->channel_config[2] |= HWMON_T_EMERGENCY_ALARM;
+               if (data->flags & LM90_HAVE_OFFSET)
+                       data->channel_config[2] |= HWMON_T_OFFSET;
        }
 
        data->faultqueue_mask = lm90_params[data->kind].faultqueue_mask;