hwmon: (w83795) Add support for dynamic in0-2 limits

The W83795G can be configured to set the in0, in1 and/or in2 voltage
limits dynamically based on VID input pins. Switch the respective
sysfs attributes to read-only.

Signed-off-by: Jean Delvare <khali@linux-fr.org>

diff --git a/drivers/hwmon/w83795.c b/drivers/hwmon/w83795.c
index 24e4424..458fb29 100644 (file)
--- a/drivers/hwmon/w83795.c
+++ b/drivers/hwmon/w83795.c
@@ -316,6 +316,7 @@ struct w83795_data {
        u8 bank;
 
        u32 has_in;             /* Enable monitor VIN or not */
+       u8 has_dyn_in;          /* Only in2-0 can have this */
        u16 in[21][3];          /* Register value, read/high/low */
        u8 in_lsb[10][3];       /* LSB Register value, high/low */
        u8 has_gain;            /* has gain: in17-20 * 8 */
@@ -450,6 +451,23 @@ static struct w83795_data *w83795_update_device(struct device *dev)
                data->in[i][IN_READ] = tmp;
        }
 
+       /* in0-2 can have dynamic limits (W83795G only) */
+       if (data->has_dyn_in) {
+               u8 lsb_max = w83795_read(client, IN_LSB_REG(0, IN_MAX));
+               u8 lsb_low = w83795_read(client, IN_LSB_REG(0, IN_LOW));
+
+               for (i = 0; i < 3; i++) {
+                       if (!(data->has_dyn_in & (1 << i)))
+                               continue;
+                       data->in[i][IN_MAX] =
+                               w83795_read(client, W83795_REG_IN[i][IN_MAX]);
+                       data->in[i][IN_LOW] =
+                               w83795_read(client, W83795_REG_IN[i][IN_LOW]);
+                       data->in_lsb[i][IN_MAX] = (lsb_max >> (2 * i)) & 0x03;
+                       data->in_lsb[i][IN_LOW] = (lsb_low >> (2 * i)) & 0x03;
+               }
+       }
+
        /* Update fan */
        for (i = 0; i < ARRAY_SIZE(data->fan); i++) {
                if (!(data->has_fan & (1 << i)))
@@ -1450,6 +1468,8 @@ store_sf_setup(struct device *dev, struct device_attribute *attr,
 
 #define NOT_USED                       -1
 
+/* Don't change the attribute order, _max and _min are accessed by index
+ * somewhere else in the code */
 #define SENSOR_ATTR_IN(index) {                                                \
        SENSOR_ATTR_2(in##index##_input, S_IRUGO, show_in, NULL,        \
                IN_READ, index), \
@@ -1844,6 +1864,39 @@ static int device_remove_file_wrapper(struct device *dev,
        return 0;
 }
 
+static void w83795_check_dynamic_in_limits(struct i2c_client *client)
+{
+       struct w83795_data *data = i2c_get_clientdata(client);
+       u8 vid_ctl;
+       int i, err_max, err_min;
+
+       vid_ctl = w83795_read(client, W83795_REG_VID_CTRL);
+
+       /* Return immediately if VRM isn't configured */
+       if ((vid_ctl & 0x07) == 0x00 || (vid_ctl & 0x07) == 0x07)
+               return;
+
+       data->has_dyn_in = (vid_ctl >> 3) & 0x07;
+       for (i = 0; i < 2; i++) {
+               if (!(data->has_dyn_in & (1 << i)))
+                       continue;
+
+               /* Voltage limits in dynamic mode, switch to read-only */
+               err_max = sysfs_chmod_file(&client->dev.kobj,
+                                          &w83795_in[i][2].dev_attr.attr,
+                                          S_IRUGO);
+               err_min = sysfs_chmod_file(&client->dev.kobj,
+                                          &w83795_in[i][3].dev_attr.attr,
+                                          S_IRUGO);
+               if (err_max || err_min)
+                       dev_warn(&client->dev, "Failed to set in%d limits "
+                                "read-only (%d, %d)\n", i, err_max, err_min);
+               else
+                       dev_info(&client->dev, "in%d limits set dynamically "
+                                "from VID\n", i);
+       }
+}
+
 /* Check pins that can be used for either temperature or voltage monitoring */
 static void w83795_apply_temp_config(struct w83795_data *data, u8 config,
                                     int temp_chan, int in_chan)
@@ -2049,6 +2102,9 @@ static int w83795_probe(struct i2c_client *client,
        if (err)
                goto exit_remove;
 
+       if (data->chip_type == w83795g)
+               w83795_check_dynamic_in_limits(client);
+
        data->hwmon_dev = hwmon_device_register(dev);
        if (IS_ERR(data->hwmon_dev)) {
                err = PTR_ERR(data->hwmon_dev);