Date:   Wed, 8 Nov 2017 14:03:34 +0800
From:   Lei YU <mine260309@...il.com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     Mark Rutland <mark.rutland@....com>,
        Jean Delvare <jdelvare@...e.com>,
        Jonathan Corbet <corbet@....net>,
        Jiri Kosina <trivial@...nel.org>, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-hwmon@...r.kernel.org,
        Joel Stanley <joel@....id.au>, Andrew Jeffery <andrew@...id.au>
Subject: Re: [PATCH v2 2/3] drivers: hwmon: Add W83773G driver

On Tue, Nov 7, 2017 at 10:33 PM, Guenter Roeck <linux@...ck-us.net> wrote:
> On 11/07/2017 12:27 AM, 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@...il.com>
>> ---
>> v2:
>>   - Rewrite the driver using regmap
>>   - Add offset and update_interval
>> ---
>>   drivers/hwmon/Kconfig   |  10 ++
>>   drivers/hwmon/Makefile  |   1 +
>>   drivers/hwmon/w83773g.c | 281
>> ++++++++++++++++++++++++++++++++++++++++++++++++
>>   3 files changed, 292 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..d352bac
>> --- /dev/null
>> +++ b/drivers/hwmon/w83773g.c
>> @@ -0,0 +1,281 @@
>> +/*
>> + * 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
>> };
>> +
>> +/* 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 int temp_of_local(s8 reg)
>> +{
>> +       return reg * 1000;
>> +}
>> +
>> +static inline int temp_of_remote(s8 hb, u8 lb)
>> +{
>> +       return (hb << 3 | lb >> 5) * 125;
>> +}
>> +
>> +static ssize_t show_local_temp(struct device *dev,
>> +                              struct device_attribute *attr,
>> +                              char *buf)
>> +{
>> +       struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
>> +       struct regmap *regmap = dev_get_drvdata(dev);
>> +       unsigned int regval;
>> +       int ret;
>> +
>> +       ret = regmap_read(regmap, sda->index, &regval);
>> +       if (ret < 0)
>> +               return ret;
>> +
>> +       return sprintf(buf, "%d\n", temp_of_local(regval));
>> +}
>> +
>> +static ssize_t show_remote_temp(struct device *dev,
>> +                               struct device_attribute *attr,
>> +                               char *buf)
>> +{
>> +       struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
>> +       struct regmap *regmap = dev_get_drvdata(dev);
>> +       unsigned int regval_high;
>> +       unsigned int regval_low;
>> +       int ret;
>> +
>> +       ret = regmap_read(regmap, W83773_TEMP_MSB[sda->index],
>> &regval_high);
>> +       ret |= regmap_read(regmap, W83773_TEMP_LSB[sda->index],
>> &regval_low);
>> +       if (ret < 0)
>> +               return ret;
>> +
>> +       return sprintf(buf, "%d\n", temp_of_remote(regval_high,
>> regval_low));
>> +}
>> +
>> +static ssize_t show_status(struct device *dev,
>> +                          struct device_attribute *attr,
>> +                          char *buf)
>> +{
>> +       struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
>> +       struct regmap *regmap = dev_get_drvdata(dev);
>> +       unsigned int regval;
>> +       int ret;
>> +
>> +       ret = regmap_read(regmap, W83773_STATUS[sda->index], &regval);
>> +
>> +       if (ret < 0)
>> +               return ret;
>> +
>> +       return sprintf(buf, "%d\n", (u8)regval & 0x04 >> 2);
>> +}
>> +
>> +static ssize_t show_offset(struct device *dev,
>> +                          struct device_attribute *attr,
>> +                          char *buf)
>> +{
>> +       struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
>> +       struct regmap *regmap = dev_get_drvdata(dev);
>> +       unsigned int regval_high;
>> +       unsigned int regval_low;
>> +       int ret;
>> +
>> +       ret = regmap_read(regmap, W83773_OFFSET_MSB[sda->index],
>> &regval_high);
>> +       ret |= regmap_read(regmap, W83773_OFFSET_LSB[sda->index],
>> &regval_low);
>> +       if (ret < 0)
>> +               return ret;
>> +
>> +       return sprintf(buf, "%d\n", temp_of_remote(regval_high,
>> regval_low));
>> +}
>> +
>> +static ssize_t set_offset(struct device *dev,
>> +                         struct device_attribute *attr,
>> +                         const char *buf, size_t count)
>> +{
>> +       struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
>> +       struct regmap *regmap = dev_get_drvdata(dev);
>> +       long val;
>> +       int ret;
>> +       int err;
>> +       u8 high_byte;
>> +       u8 low_byte;
>> +
>> +       err = kstrtol(buf, 10, &val);
>> +       if (err)
>> +               return err;
>> +
>> +       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[sda->index],
>> high_byte);
>> +       ret |= regmap_write(regmap, W83773_OFFSET_LSB[sda->index],
>> low_byte);
>
>
> Please don't do that. The errors, if any, might be different, messing up
> the error return.

OK, it will be fixed in v3.

>
>
>> +
>> +       if (ret < 0)
>> +               return ret;
>> +       return count;
>> +}
>> +
>> +static ssize_t show_update_interval(struct device *dev,
>> +                                   struct device_attribute *attr,
>> +                                   char *buf)
>> +{
>> +       struct regmap *regmap = dev_get_drvdata(dev);
>> +       unsigned int regval;
>> +       int ret;
>> +
>> +       ret = regmap_read(regmap, W83773_CONVERSION_RATE_REG_READ,
>> &regval);
>> +       if (ret < 0)
>> +               return ret;
>> +
>> +       return sprintf(buf, "%u\n", 16000 >> regval);
>> +}
>> +
>> +static ssize_t set_update_interval(struct device *dev,
>> +                                  struct device_attribute *attr,
>> +                                  const char *buf, size_t count)
>> +{
>> +       struct regmap *regmap = dev_get_drvdata(dev);
>> +       unsigned long val;
>> +       int ret;
>> +       int err, rate;
>> +
>> +       err = kstrtoul(buf, 10, &val);
>> +       if (err)
>> +               return err;
>> +
>> +       /*
>> +        * 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 count;
>> +}
>> +
>> +static SENSOR_DEVICE_ATTR(temp1_input, 0444, show_local_temp, NULL,
>> +                         W83773_LOCAL_TEMP);
>> +static SENSOR_DEVICE_ATTR(temp2_input, 0444, show_remote_temp, NULL, 0);
>> +static SENSOR_DEVICE_ATTR(temp2_fault, 0444, show_status, NULL, 0);
>> +static SENSOR_DEVICE_ATTR(temp2_offset, 0644, show_offset, set_offset,
>> 0);
>> +static SENSOR_DEVICE_ATTR(temp3_input, 0444, show_remote_temp, NULL, 1);
>> +static SENSOR_DEVICE_ATTR(temp3_fault, 0444, show_status, NULL, 1);
>> +static SENSOR_DEVICE_ATTR(temp3_offset, 0644, show_offset, set_offset,
>> 1);
>> +static DEVICE_ATTR(update_interval, 0644, show_update_interval,
>> +                  set_update_interval);
>> +
>> +static struct attribute *w83773g_attrs[] = {
>> +       &sensor_dev_attr_temp1_input.dev_attr.attr,
>> +       &sensor_dev_attr_temp2_input.dev_attr.attr,
>> +       &sensor_dev_attr_temp2_fault.dev_attr.attr,
>> +       &sensor_dev_attr_temp2_offset.dev_attr.attr,
>> +       &sensor_dev_attr_temp3_input.dev_attr.attr,
>> +       &sensor_dev_attr_temp3_fault.dev_attr.attr,
>> +       &sensor_dev_attr_temp3_offset.dev_attr.attr,
>> +       &dev_attr_update_interval.attr,
>> +       NULL
>> +};
>> +ATTRIBUTE_GROUPS(w83773g);
>> +
>> +static const struct regmap_config w83773g_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, &w83773g_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_groups(dev,
>> client->name,
>> +                                                     regmap,
>> w83773g_groups);
>
>
> You lost me here. Why did you stop using the new API ?

I was referencing some other hwmon driver (e.g. tmp401.c) and find out
the usage of SENSOR_DEVICE_ATTR, which I feel more clear and straightforward.

So what I know for know is:
1. In v1, devm_hwmon_device_register_with_info() with hwmon_chip_info providing
is_visible(), read/write() operations;
2. In v2, devm_hwmon_device_register_with_groups() with attribute_group.

So from your suggestion, it seems the hwmon_chip_info is more preferable, is it?
If yes, I will update this in v3 as well.

Thanks!
>
> Guenter
>
>
>> +       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,
>> +};
>> +
>> +module_i2c_driver(w83773_driver);
>> +
>> +MODULE_AUTHOR("Lei YU <mine260309@...il.com>");
>> +MODULE_DESCRIPTION("W83773G temperature sensor driver");
>> +MODULE_LICENSE("GPL");
>>
>

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