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authorOskar Senft <osk@google.com>2021-10-20 12:42:13 -0400
committerGuenter Roeck <linux@roeck-us.net>2021-10-27 10:42:49 -0700
commit0e346a86a51debe23755dae3b89957c1ba8ffbfd (patch)
treea66694eb18ea83f7bc578bed08cef6e4a140be0c /drivers/hwmon/nct7802.c
parent1bfaa49abf077864f11a8f3ae03d1a02550b95b7 (diff)
downloadlinux-0e346a86a51debe23755dae3b89957c1ba8ffbfd.tar.bz2
hwmon: (nct7802) Make temperature/voltage sensors configurable
This change allows LTD and RTD inputs to be configured via device tree bindings. If the DT bindings are not present or invalid, the input configuration is not modified and left at HW defaults. Signed-off-by: Oskar Senft <osk@google.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20211020164213.174597-2-osk@google.com Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon/nct7802.c')
-rw-r--r--drivers/hwmon/nct7802.c129
1 files changed, 125 insertions, 4 deletions
diff --git a/drivers/hwmon/nct7802.c b/drivers/hwmon/nct7802.c
index 604af2f6103a..d56f78327619 100644
--- a/drivers/hwmon/nct7802.c
+++ b/drivers/hwmon/nct7802.c
@@ -52,6 +52,23 @@ static const u8 REG_VOLTAGE_LIMIT_MSB_SHIFT[2][5] = {
#define REG_VERSION_ID 0xff
/*
+ * Resistance temperature detector (RTD) modes according to 7.2.32 Mode
+ * Selection Register
+ */
+#define RTD_MODE_CURRENT 0x1
+#define RTD_MODE_THERMISTOR 0x2
+#define RTD_MODE_VOLTAGE 0x3
+
+#define MODE_RTD_MASK 0x3
+#define MODE_LTD_EN 0x40
+
+/*
+ * Bit offset for sensors modes in REG_MODE.
+ * Valid for index 0..2, indicating RTD1..3.
+ */
+#define MODE_BIT_OFFSET_RTD(index) ((index) * 2)
+
+/*
* Data structures and manipulation thereof
*/
@@ -1038,7 +1055,112 @@ static const struct regmap_config nct7802_regmap_config = {
.volatile_reg = nct7802_regmap_is_volatile,
};
-static int nct7802_init_chip(struct nct7802_data *data)
+static int nct7802_get_channel_config(struct device *dev,
+ struct device_node *node, u8 *mode_mask,
+ u8 *mode_val)
+{
+ u32 reg;
+ const char *type_str, *md_str;
+ u8 md;
+
+ if (!node->name || of_node_cmp(node->name, "channel"))
+ return 0;
+
+ if (of_property_read_u32(node, "reg", &reg)) {
+ dev_err(dev, "Could not read reg value for '%s'\n",
+ node->full_name);
+ return -EINVAL;
+ }
+
+ if (reg > 3) {
+ dev_err(dev, "Invalid reg (%u) in '%s'\n", reg,
+ node->full_name);
+ return -EINVAL;
+ }
+
+ if (reg == 0) {
+ if (!of_device_is_available(node))
+ *mode_val &= ~MODE_LTD_EN;
+ else
+ *mode_val |= MODE_LTD_EN;
+ *mode_mask |= MODE_LTD_EN;
+ return 0;
+ }
+
+ /* At this point we have reg >= 1 && reg <= 3 */
+
+ if (!of_device_is_available(node)) {
+ *mode_val &= ~(MODE_RTD_MASK << MODE_BIT_OFFSET_RTD(reg - 1));
+ *mode_mask |= MODE_RTD_MASK << MODE_BIT_OFFSET_RTD(reg - 1);
+ return 0;
+ }
+
+ if (of_property_read_string(node, "sensor-type", &type_str)) {
+ dev_err(dev, "No type for '%s'\n", node->full_name);
+ return -EINVAL;
+ }
+
+ if (!strcmp(type_str, "voltage")) {
+ *mode_val |= (RTD_MODE_VOLTAGE & MODE_RTD_MASK)
+ << MODE_BIT_OFFSET_RTD(reg - 1);
+ *mode_mask |= MODE_RTD_MASK << MODE_BIT_OFFSET_RTD(reg - 1);
+ return 0;
+ }
+
+ if (strcmp(type_str, "temperature")) {
+ dev_err(dev, "Invalid type '%s' for '%s'\n", type_str,
+ node->full_name);
+ return -EINVAL;
+ }
+
+ if (reg == 3) {
+ /* RTD3 only supports thermistor mode */
+ md = RTD_MODE_THERMISTOR;
+ } else {
+ if (of_property_read_string(node, "temperature-mode",
+ &md_str)) {
+ dev_err(dev, "No mode for '%s'\n", node->full_name);
+ return -EINVAL;
+ }
+
+ if (!strcmp(md_str, "thermal-diode"))
+ md = RTD_MODE_CURRENT;
+ else if (!strcmp(md_str, "thermistor"))
+ md = RTD_MODE_THERMISTOR;
+ else {
+ dev_err(dev, "Invalid mode '%s' for '%s'\n", md_str,
+ node->full_name);
+ return -EINVAL;
+ }
+ }
+
+ *mode_val |= (md & MODE_RTD_MASK) << MODE_BIT_OFFSET_RTD(reg - 1);
+ *mode_mask |= MODE_RTD_MASK << MODE_BIT_OFFSET_RTD(reg - 1);
+
+ return 0;
+}
+
+static int nct7802_configure_channels(struct device *dev,
+ struct nct7802_data *data)
+{
+ /* Enable local temperature sensor by default */
+ u8 mode_mask = MODE_LTD_EN, mode_val = MODE_LTD_EN;
+ struct device_node *node;
+ int err;
+
+ if (dev->of_node) {
+ for_each_child_of_node(dev->of_node, node) {
+ err = nct7802_get_channel_config(dev, node, &mode_mask,
+ &mode_val);
+ if (err)
+ return err;
+ }
+ }
+
+ return regmap_update_bits(data->regmap, REG_MODE, mode_mask, mode_val);
+}
+
+static int nct7802_init_chip(struct device *dev, struct nct7802_data *data)
{
int err;
@@ -1047,8 +1169,7 @@ static int nct7802_init_chip(struct nct7802_data *data)
if (err)
return err;
- /* Enable local temperature sensor */
- err = regmap_update_bits(data->regmap, REG_MODE, 0x40, 0x40);
+ err = nct7802_configure_channels(dev, data);
if (err)
return err;
@@ -1074,7 +1195,7 @@ static int nct7802_probe(struct i2c_client *client)
mutex_init(&data->access_lock);
mutex_init(&data->in_alarm_lock);
- ret = nct7802_init_chip(data);
+ ret = nct7802_init_chip(dev, data);
if (ret < 0)
return ret;