Re: [PATCH v3 2/3] drivers: hwmon: Add W83773G driver

From: Guenter Roeck
Date: Fri Nov 10 2017 - 09:49:36 EST

On 11/08/2017 11:09 PM, Lei YU wrote:
Nuvoton W83773G is a hardware monitor IC providing one local
temperature and two remote temperature sensors.

Signed-off-by: Lei YU <mine260309@xxxxxxxxx>

Nicely done. Couple of nitpicks left.

Thanks!
Guenter

---
v2:
- Rewrite the driver using regmap
- Add offset and update_interval
v3:
- Use devm_hwmon_device_register_with_info() with is_visible/read/write
functions.
---
drivers/hwmon/Kconfig | 10 ++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/w83773g.c | 348 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 359 insertions(+)
create mode 100644 drivers/hwmon/w83773g.c

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index d654314..11c6248 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1710,6 +1710,16 @@ config SENSORS_VT8231
This driver can also be built as a module. If so, the module
will be called vt8231.
+config SENSORS_W83773G
+ tristate "Nuvoton W83773G"
+ depends on I2C
+ help
+ If you say yes here you get support for the Nuvoton W83773G hardware
+ monitoring chip.
+
+ This driver can also be built as a module. If so, the module
+ will be called w83773g.
+
config SENSORS_W83781D
tristate "Winbond W83781D, W83782D, W83783S, Asus AS99127F"
depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index c84d978..0649ad8 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_SENSORS_ATK0110) += asus_atk0110.o
# asb100, then w83781d go first, as they can override other drivers' addresses.
obj-$(CONFIG_SENSORS_ASB100) += asb100.o
obj-$(CONFIG_SENSORS_W83627HF) += w83627hf.o
+obj-$(CONFIG_SENSORS_W83773G) += w83773g.o
obj-$(CONFIG_SENSORS_W83792D) += w83792d.o
obj-$(CONFIG_SENSORS_W83793) += w83793.o
obj-$(CONFIG_SENSORS_W83795) += w83795.o
diff --git a/drivers/hwmon/w83773g.c b/drivers/hwmon/w83773g.c
new file mode 100644
index 0000000..58ac45b
--- /dev/null
+++ b/drivers/hwmon/w83773g.c
@@ -0,0 +1,348 @@
+/*
+ * Copyright (C) 2017 IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Driver for the Nuvoton W83773G SMBus temperature sensor IC.
+ * Supported models: W83773G
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/err.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+
+/* Addresses to scan */
+static const unsigned short normal_i2c[] = { 0x4c, 0x4d, I2C_CLIENT_END };
+
+/* W83773 has 3 channels */
+#define W83773_CHANNELS 3
+
+/* The W83773 registers */
+#define W83773_CONVERSION_RATE_REG_READ 0x04
+#define W83773_CONVERSION_RATE_REG_WRITE 0x0A
+#define W83773_MANUFACTURER_ID_REG 0xFE
+#define W83773_LOCAL_TEMP 0x00
+
+static const u8 W83773_STATUS[2] = { 0x02, 0x17 };
+
+static const u8 W83773_TEMP_LSB[2] = { 0x10, 0x25 };
+static const u8 W83773_TEMP_MSB[2] = { 0x01, 0x24 };
+
+static const u8 W83773_OFFSET_LSB[2] = { 0x12, 0x16 };
+static const u8 W83773_OFFSET_MSB[2] = { 0x11, 0x15 };
+
+/* this is the number of sensors in the device */
+static const struct i2c_device_id w83773_id[] = {
+ { "w83773g" },
+ { }
+};
+
+MODULE_DEVICE_TABLE(i2c, w83773_id);
+
+static const struct of_device_id w83773_of_match[] = {
+ {
+ .compatible = "nuvoton,w83773g"
+ },
+ { },
+};
+MODULE_DEVICE_TABLE(of, w83773_of_match);
+
+static inline long temp_of_local(s8 reg)
+{
+ return reg * 1000;
+}
+
+static inline long temp_of_remote(s8 hb, u8 lb)
+{
+ return (hb << 3 | lb >> 5) * 125;
+}
+
+static int get_local_temp(struct regmap *regmap, long *val)
+{
+ unsigned int regval;
+ int ret;
+
+ ret = regmap_read(regmap, W83773_LOCAL_TEMP, &regval);
+ if (ret < 0)
+ return ret;
+
+ *val = temp_of_local(regval);
+ return 0;
+}
+
+static int get_remote_temp(struct regmap *regmap, int index, long *val)
+{
+ unsigned int regval_high;
+ unsigned int regval_low;
+ int ret;
+
+ ret = regmap_read(regmap, W83773_TEMP_MSB[index], &regval_high);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_read(regmap, W83773_TEMP_LSB[index], &regval_low);
+ if (ret < 0)
+ return ret;
+
+ *val = temp_of_remote(regval_high, regval_low);
+ return 0;
+}
+
+static int get_fault(struct regmap *regmap, int index, long *val)
+{
+ unsigned int regval;
+ int ret;
+
+ ret = regmap_read(regmap, W83773_STATUS[index], &regval);
+
Drop the empty line please.

+ if (ret < 0)
+ return ret;
+
+ *val = (u8)regval & 0x04 >> 2;
+ return 0;
+}
+
+static int get_offset(struct regmap *regmap, int index, long *val)
+{
+ unsigned int regval_high;
+ unsigned int regval_low;
+ int ret;
+
+ ret = regmap_read(regmap, W83773_OFFSET_MSB[index], &regval_high);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_read(regmap, W83773_OFFSET_LSB[index], &regval_low);
+ if (ret < 0)
+ return ret;
+
+ *val = temp_of_remote(regval_high, regval_low);
+ return 0;
+}
+
+static int set_offset(struct regmap *regmap, int index, long val)
+{
+ int ret;
+ u8 high_byte;
+ u8 low_byte;
+
+ val = clamp_val(val, -127825, 127825);
+ /* offset value equals to (high_byte << 3 | low_byte >> 5) * 125 */
+ val /= 125;
+ high_byte = val >> 3;
+ low_byte = (val & 0x07) << 5;
+
+ ret = regmap_write(regmap, W83773_OFFSET_MSB[index], high_byte);
+ if (ret < 0)
+ return ret;
+
+ ret = regmap_write(regmap, W83773_OFFSET_LSB[index], low_byte);
+ if (ret < 0)
+ return ret;
+
+ return 0;

For the second call,

return regmap_write(regmap, W83773_OFFSET_LSB[index], low_byte);

+}
+
+static int get_update_interval(struct regmap *regmap, long *val)
+{
+ unsigned int regval;
+ int ret;
+
+ ret = regmap_read(regmap, W83773_CONVERSION_RATE_REG_READ, &regval);
+ if (ret < 0)
+ return ret;
+
+ *val = 16000 >> regval;
+ return 0;
+}
+
+static int set_update_interval(struct regmap *regmap, long val)
+{
+ int ret;
+ int rate;
+
+ if (val <= 0)
+ return -EINVAL;
+
Not really needed since you are clamping below. For consistency I would suggest
to drop it (otherwise 0 returns -EINVAL, 1 translates to 62).

+ /*
+ * For valid rates, interval can be calculated as
+ * interval = (1 << (8 - rate)) * 62.5;
+ * Rounded rate is therefore
+ * rate = 8 - __fls(interval * 8 / (62.5 * 7));
+ * Use clamp_val() to avoid overflows, and to ensure valid input
+ * for __fls.
+ */
+ val = clamp_val(val, 62, 16000) * 10;
+ rate = 8 - __fls((val * 8 / (625 * 7)));
+ ret = regmap_write(regmap, W83773_CONVERSION_RATE_REG_WRITE, rate);
+ if (ret < 0)
+ return ret;
+ return 0;

just
return regmap_write(regmap, W83773_CONVERSION_RATE_REG_WRITE, rate);

+}
+
+static int w83773_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct regmap *regmap = dev_get_drvdata(dev);
+
+ if (type == hwmon_chip) {
+ if (attr == hwmon_chip_update_interval)
+ return get_update_interval(regmap, val);
+ else

else not needed after return

+ return -EOPNOTSUPP;
+ }
+
+ switch (attr) {
+ case hwmon_temp_input:
+ if (channel == 0)
+ return get_local_temp(regmap, val);
+ else

else not needed after return

+ return get_remote_temp(regmap, channel - 1, val);
+ case hwmon_temp_fault:
+ return get_fault(regmap, channel - 1, val);
+ case hwmon_temp_offset:
+ return get_offset(regmap, channel - 1, val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int w83773_write(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long val)
+{
+ struct regmap *regmap = dev_get_drvdata(dev);
+
+ if (type == hwmon_chip && attr == hwmon_chip_update_interval)
+ return set_update_interval(regmap, val);
+
+ if (type == hwmon_temp && attr == hwmon_temp_offset)
+ return set_offset(regmap, channel - 1, val);
+
+ return -EOPNOTSUPP;
+}
+
+static umode_t w83773_is_visible(const void *data, enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ switch (type) {
+ case hwmon_chip:
+ switch (attr) {
+ case hwmon_chip_update_interval:
+ return 0644;
+ }
+ break;
+ case hwmon_temp:
+ switch (attr) {
+ case hwmon_temp_input:
+ return 0444;
+ case hwmon_temp_fault:

The above case statements can be combined.

+ return 0444;
+ case hwmon_temp_offset:
+ return 0644;

Wonder if static analyzers complain here and above because
of the missing default: case. Any idea ?

+ }
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+
+static const u32 w83773_chip_config[] = {
+ HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL,
+ 0
+};
+
+static const struct hwmon_channel_info w83773_chip = {
+ .type = hwmon_chip,
+ .config = w83773_chip_config,
+};
+
+static const u32 w83773_temp_config[] = {
+ HWMON_T_INPUT,
+ HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_OFFSET,
+ HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_OFFSET,
+ 0
+};
+
+static const struct hwmon_channel_info w83773_temp = {
+ .type = hwmon_temp,
+ .config = w83773_temp_config,
+};
+
+static const struct hwmon_channel_info *w83773_info[] = {
+ &w83773_chip,
+ &w83773_temp,
+ NULL
+};
+
+static const struct hwmon_ops w83773_ops = {
+ .is_visible = w83773_is_visible,
+ .read = w83773_read,
+ .write = w83773_write,
+};
+
+static const struct hwmon_chip_info w83773_chip_info = {
+ .ops = &w83773_ops,
+ .info = w83773_info,
+};
+
+static const struct regmap_config w83773_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+};
+
+static int w83773_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct device *dev = &client->dev;
+ struct device *hwmon_dev;
+ struct regmap *regmap;
+ int ret;
+
+ regmap = devm_regmap_init_i2c(client, &w83773_regmap_config);
+ if (IS_ERR(regmap)) {
+ dev_err(dev, "failed to allocate register map\n");
+ return PTR_ERR(regmap);
+ }
+
+ /* Set the conversion rate to 2 Hz */
+ ret = regmap_write(regmap, W83773_CONVERSION_RATE_REG_WRITE, 0x05);
+ if (ret < 0) {
+ dev_err(&client->dev, "error writing config rate register\n");
+ return ret;
+ }
+
+ i2c_set_clientdata(client, regmap);
+
+ hwmon_dev = devm_hwmon_device_register_with_info(dev,
+ client->name,
+ regmap,
+ &w83773_chip_info,
+ NULL);
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static struct i2c_driver w83773_driver = {
+ .class = I2C_CLASS_HWMON,
+ .driver = {
+ .name = "w83773g",
+ .of_match_table = of_match_ptr(w83773_of_match),
+ },
+ .probe = w83773_probe,
+ .id_table = w83773_id,
+ .address_list = normal_i2c,

address_list is only used if there is a detect function, so you can drop it.

+};
+
+module_i2c_driver(w83773_driver);
+
+MODULE_AUTHOR("Lei YU <mine260309@xxxxxxxxx>");
+MODULE_DESCRIPTION("W83773G temperature sensor driver");
+MODULE_LICENSE("GPL");