Re: [lm-sensors] [PATCH] hwmon: add driver for Microchip TC74
From: Maciej S. Szmigiero
Date: Sun Jun 21 2015 - 10:06:16 EST
Hello Guenter,
Thanks for your review.
Best regards,
Maciej Szmigiero
W dniu 21.06.2015 15:19, Guenter Roeck pisze:
> On 06/21/2015 05:38 AM, Maciej S. Szmigiero wrote:
>> Add hwmon driver for the Microchip TC74.
>>
>> The TC74 is a single-input 8-bit I2C temperature sensor,
>> with +-2 degrees centigrade accuracy.
>>
>> Signed-off-by: Maciej Szmigiero <mail@xxxxxxxxxxxxxxxxxxxxx>
>>
>> diff --git a/Documentation/hwmon/tc74 b/Documentation/hwmon/tc74
>> new file mode 100644
>> index 0000000..caecb1f
>> --- /dev/null
>> +++ b/Documentation/hwmon/tc74
>> @@ -0,0 +1,20 @@
>> +Kernel driver tc74
>> +====================
>> +
>> +Supported chips:
>> + * Microchip TC74
>> + Prefix: 'tc74'
>> + Datasheet: Publicly available at Microchip website.
>> +
>> +Description
>> +-----------
>> +
>> +Driver supports the above part.
>> +
>> +The tc74 has an 8-bit sensor, with 1 degree centigrade resolution
>> +and +- 2 degrees centigrade accuracy.
>> +
>> +Notes
>> +-----
>> +
>> +Currently entering low power standby mode is not supported.
>> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
>> index 25d9e72..bbaaa2e 100644
>> --- a/drivers/hwmon/Kconfig
>> +++ b/drivers/hwmon/Kconfig
>> @@ -1452,6 +1452,16 @@ config SENSORS_INA2XX
>> This driver can also be built as a module. If so, the module
>> will be called ina2xx.
>>
>> +config SENSORS_TC74
>> + tristate "Microchip TC74"
>> + depends on I2C
>> + help
>> + If you say yes here you get support for Microchip TC74 single
>> + input temperature sensor chips.
>> +
>> + This driver can also be built as a module. If so, the module
>> + will be called tc74.
>> +
>> config SENSORS_THMC50
>> tristate "Texas Instruments THMC50 / Analog Devices ADM1022"
>> depends on I2C
>> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
>> index b4a40f1..ab90402 100644
>> --- a/drivers/hwmon/Makefile
>> +++ b/drivers/hwmon/Makefile
>> @@ -140,6 +140,7 @@ obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o
>> obj-$(CONFIG_SENSORS_SMSC47M1) += smsc47m1.o
>> obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
>> obj-$(CONFIG_SENSORS_AMC6821) += amc6821.o
>> +obj-$(CONFIG_SENSORS_TC74) += tc74.o
>> obj-$(CONFIG_SENSORS_THMC50) += thmc50.o
>> obj-$(CONFIG_SENSORS_TMP102) += tmp102.o
>> obj-$(CONFIG_SENSORS_TMP103) += tmp103.o
>> diff --git a/drivers/hwmon/tc74.c b/drivers/hwmon/tc74.c
>> new file mode 100644
>> index 0000000..5000c58
>> --- /dev/null
>> +++ b/drivers/hwmon/tc74.c
>> @@ -0,0 +1,191 @@
>> +/*
>> + * An hwmon driver for the Microchip TC74
>> + *
>> + * Copyright 2015 Maciej Szmigiero <mail@xxxxxxxxxxxxxxxxxxxxx>
>> + *
>> + * Based on ad7414.c:
>> + * Copyright 2006 Stefan Roese, DENX Software Engineering
>> + * Copyright 2008 Sean MacLennan, PIKA Technologies
>> + * Copyright 2008 Frank Edelhaeuser, Spansion Inc.
>> + *
>> + * 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.
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/jiffies.h>
>> +#include <linux/i2c.h>
>> +#include <linux/hwmon.h>
>> +#include <linux/hwmon-sysfs.h>
>> +#include <linux/err.h>
>> +#include <linux/mutex.h>
>> +#include <linux/sysfs.h>
>> +#include <linux/slab.h>
>> +
> Include files in alphabetic order, please.
>
>> +/* TC74 registers */
>> +#define TC74_REG_TEMP 0x00
>> +#define TC74_REG_CONFIG 0x01
>> +
>> +struct tc74_data {
>> + struct i2c_client *client;
>> + struct mutex lock; /* atomic read data updates */
>> + char valid; /* !=0 if following fields are valid */
>
> bool, please, and use true/false.
>
>> + unsigned long next_update; /* In jiffies */
>> + s8 temp_input; /* Temp value in dC */
>> +};
>> +
>> +static inline s8 tc74_temp_from_reg(s32 reg)
>> +{
>> + u8 v8 = reg & 0xff;
>> +
>> + return (s8)v8;
>> +}
>> +
>> +static inline s32 tc74_read(struct i2c_client *client, u8 reg)
>> +{
>> + return i2c_smbus_read_byte_data(client, reg);
>> +}
>> +
>> +static inline s32 tc74_write(struct i2c_client *client, u8 reg, u8 value)
>> +{
>> + return i2c_smbus_write_byte_data(client, reg, value);
>> +}
>> +
> Those three functions are unnecessary; please drop.
>
>> +static int tc74_update_device(struct device *dev)
>> +{
>> + struct tc74_data *data = dev_get_drvdata(dev);
>> + struct i2c_client *client = data->client;
>> + int ret;
>> +
>> + ret = mutex_lock_interruptible(&data->lock);
>> + if (ret)
>> + return ret;
>> +
>> + if (time_after(jiffies, data->next_update) || !data->valid) {
>> + s32 value;
>> +
>> + value = tc74_read(client, TC74_REG_CONFIG);
>> + if (value < 0) {
>> + dev_dbg(&client->dev, "TC74_REG_CONFIG read err %d\n",
>> + (int)value);
>> +
>> + ret = value;
>> + goto ret_unlock;
>> + }
>> +
>> + if (!(value & 1 << 6)) {
>
> Please use BIT().
>
>> + /* not ready yet */
>> +
>> + ret = -EAGAIN;
>> + goto ret_unlock;
>> + }
>> +
>> + value = tc74_read(client, TC74_REG_TEMP);
>> + if (value < 0) {
>> + dev_dbg(&client->dev, "TC74_REG_TEMP read err %d\n",
>> + (int)value);
>> +
>> + ret = value;
>> + goto ret_unlock;
>> + }
>> +
>> + data->temp_input = tc74_temp_from_reg(value);
>
> C handles type conversion automatically, so just assign the value.
>
>> + data->next_update = jiffies + HZ / 4;
>> + data->valid = 1;
>> + }
>> +
>> +ret_unlock:
>> + mutex_unlock(&data->lock);
>> +
>> + return ret;
>> +}
>> +
>> +static ssize_t show_temp_input(struct device *dev,
>> + struct device_attribute *attr, char *buf)
>> +{
>> + struct tc74_data *data = dev_get_drvdata(dev);
>> + int ret;linux-kernel@xxxxxxxxxxxxxxx
>> +
> ???? does this compile ???
>
>> + ret = tc74_update_device(dev);
>> + if (ret)
>> + return ret;
>> +
>> + return sprintf(buf, "%d\n", (int)(data->temp_input) * 1000);
>
> Unnecessary typecast.
>
>> +}
>> +static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0);
>> +
>> +static struct attribute *tc74_attrs[] = {
>> + &sensor_dev_attr_temp1_input.dev_attr.attr,
>> + NULL
>> +};
>> +
>> +ATTRIBUTE_GROUPS(tc74);
>> +
>> +static int tc74_probe(struct i2c_client *client,
>> + const struct i2c_device_id *dev_id)
>> +{
>> + struct device *dev = &client->dev;
>> + struct tc74_data *data;
>> + struct device *hwmon_dev;
>> + s32 conf;
>> +
>> + if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
>> + return -EOPNOTSUPP;
>> +
>> + data = devm_kzalloc(dev, sizeof(struct tc74_data), GFP_KERNEL);
>> + if (!data)
>> + return -ENOMEM;
>> +
>> + data->client = client;
>> + mutex_init(&data->lock);
>> +
>> + /* Make sure the chip is powered up. */
>> + conf = tc74_read(client, TC74_REG_CONFIG);
>> + if (conf < 0) {
>> + dev_err(dev, "unable to read config register\n");
>> +
>> + return conf;
>> + } else if (conf & 0x3f) {
>> + dev_err(dev, "invalid config register value\n");
>> +
>> + return -ENODEV;
>> + } else if (conf & 1 << 7) {
>
> Please use BIT().
>
> The else cases are all not needed.
>
>> + s32 ret;
>> +
>> + conf &= ~(1 << 7);
>
> Please use BIT.
>
>> +
>> + ret = tc74_write(client, TC74_REG_CONFIG, conf);
>> + if (ret)
>> + dev_warn(dev, "unable to disable STANDBY\n");
>> + }
>> +
>> + dev_info(&client->dev, "chip found\n");
>> +
>
> Unnecessary noise; please drop.
>
> Thanks,
> Guenter
>
>> + hwmon_dev = devm_hwmon_device_register_with_groups(dev,
>> + client->name,
>> + data, tc74_groups);
>> + return PTR_ERR_OR_ZERO(hwmon_dev);
>> +}
>> +
>> +static const struct i2c_device_id tc74_id[] = {
>> + { "tc74", 0 },
>> + {}
>> +};
>> +MODULE_DEVICE_TABLE(i2c, tc74_id);
>> +
>> +static struct i2c_driver tc74_driver = {
>> + .driver = {
>> + .name = "tc74",
>> + },
>> + .probe = tc74_probe,
>> + .id_table = tc74_id,
>> +};
>> +
>> +module_i2c_driver(tc74_driver);
>> +
>> +MODULE_AUTHOR("Maciej Szmigiero <mail@xxxxxxxxxxxxxxxxxxxxx>");
>> +
>> +MODULE_DESCRIPTION("TC74 driver");
>> +MODULE_LICENSE("GPL");
>>
>
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