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Date: Sun, 21 Jun 2015 06:19:45 -0700 From: Guenter Roeck <linux@...ck-us.net> To: "Maciej S. Szmigiero" <mail@...iej.szmigiero.name>, lm-sensors@...sensors.org CC: Jean Delvare <jdelvare@...e.de>, Jonathan Corbet <corbet@....net>, linux-doc@...r.kernel.org, linux-kernel <linux-kernel@...r.kernel.org> Subject: Re: [lm-sensors] [PATCH] hwmon: add driver for Microchip TC74 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@...iej.szmigiero.name> > > 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@...iej.szmigiero.name> > + * > + * 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@...r.kernel.org > + ???? 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@...iej.szmigiero.name>"); > + > +MODULE_DESCRIPTION("TC74 driver"); > +MODULE_LICENSE("GPL"); > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/
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