Re: [PATCH v7 2/2] hwmon: (nct7802) Make temperature/voltage sensors configurable

Guenter Roeck <linux@xxxxxxxxxxxx> · Sun, 10 Oct 2021 21:08:57 -0700

On 10/10/21 6:53 PM, Oskar Senft wrote:
I wasn't sure if submitting JUST a v7 of nuvoton,nct7802.yaml (i.e.
the 1/2 in this series) would be the right thing to do and thought it
would be easier to follow if I dropped both. I couldn't find
documentation on what's the right thing to do in that case. Would it
have been better to only submit nuvoton,nct7802.yaml as "PATCH v7" ?


First, please don't top-post.

Second, no, submitting both patches was the right thing to do, but
you should not drop a Reviewed-by: tag if there was no change to
the patch.

Guenter

Oskar.

On Sun, Oct 10, 2021 at 9:49 PM Guenter Roeck <linux@xxxxxxxxxxxx> wrote:

On 10/10/21 6:22 PM, Oskar Senft wrote:
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@xxxxxxxxxx>

I sent a Reviewed-by: for v6 of this patch.

---
Changes from PATCH v6:
- None (resubmitted due to changes in nuvoton,nct7802.yaml).


Why did you drop it if there was no change ?

Guenter

Changes from PATCH v5:
- Removed unused "found_channel_config" variable.
- Initialize mode_mask and mode_val to defaults.
---
   drivers/hwmon/nct7802.c | 129 ++++++++++++++++++++++++++++++++++++++--
   1 file 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
@@ -51,6 +51,23 @@ static const u8 REG_VOLTAGE_LIMIT_MSB_SHIFT[2][5] = {
   #define REG_CHIP_ID         0xfe
   #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;










