On Thu, 29 Jun 2017 06:34:22 -0700 Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > On 06/29/2017 03:45 AM, Mike Looijmans wrote: > > The LTC2741 and LTC2473 are single voltage monitoring chips. The LTC2473 > > is similar to the LTC2471 but outputs a signed differential value. > > > > Datasheet: > > http://cds.linear.com/docs/en/datasheet/24713fb.pdf > > > > Signed-off-by: Mike Looijmans <mike.looijmans@xxxxxxxx> > > Hi Mike, > > that looks like a perfect candidate for an iio driver, since its use is > not limited to hardware monitoring, it has a high sample rate, and it > doesn't have limit registers or actions. > > Jonathan, what do you think ? Late response given I just applied the IIO driver ;) Yes, fine for IIO. Whilst they list hwmon as one of the possible uses they list a whole load of others as well so IIO probably makes more sense for this one. Thanks, Jonathan > > Thanks, > Guenter > > > --- > > drivers/hwmon/Kconfig | 10 ++++ > > drivers/hwmon/Makefile | 1 + > > drivers/hwmon/ltc2471.c | 127 ++++++++++++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 138 insertions(+) > > create mode 100644 drivers/hwmon/ltc2471.c > > > > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > > index fbde226..c9a2a87 100644 > > --- a/drivers/hwmon/Kconfig > > +++ b/drivers/hwmon/Kconfig > > @@ -673,6 +673,16 @@ config SENSORS_LINEAGE > > This driver can also be built as a module. If so, the module > > will be called lineage-pem. > > > > +config SENSORS_LTC2471 > > + tristate "Linear Technology LTC2471 and LTC2473" > > + depends on I2C > > + help > > + If you say yes here you get support for Linear Technology LTC2471 > > + and LTC2473 voltage monitors. > > + > > + This driver can also be built as a module. If so, the module will > > + be called ltc2471. > > + > > config SENSORS_LTC2945 > > tristate "Linear Technology LTC2945" > > depends on I2C > > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile > > index 58cc3ac..6f60fe7 100644 > > --- a/drivers/hwmon/Makefile > > +++ b/drivers/hwmon/Makefile > > @@ -99,6 +99,7 @@ obj-$(CONFIG_SENSORS_LM93) += lm93.o > > obj-$(CONFIG_SENSORS_LM95234) += lm95234.o > > obj-$(CONFIG_SENSORS_LM95241) += lm95241.o > > obj-$(CONFIG_SENSORS_LM95245) += lm95245.o > > +obj-$(CONFIG_SENSORS_LTC2471) += ltc2471.o > > obj-$(CONFIG_SENSORS_LTC2945) += ltc2945.o > > obj-$(CONFIG_SENSORS_LTC2990) += ltc2990.o > > obj-$(CONFIG_SENSORS_LTC4151) += ltc4151.o > > diff --git a/drivers/hwmon/ltc2471.c b/drivers/hwmon/ltc2471.c > > new file mode 100644 > > index 0000000..17eaad8 > > --- /dev/null > > +++ b/drivers/hwmon/ltc2471.c > > @@ -0,0 +1,127 @@ > > +/* > > + * Driver for Linear Technology LTC2471 and LTC2473 voltage monitors > > + * The LTC2473 is identical to the 2471, but reports a differential signal. > > + * > > + * Copyright (C) 2017 Topic Embedded Products > > + * Author: Mike Looijmans <mike.looijmans@xxxxxxxx> > > + * > > + * License: GPLv2 > > + */ > > + > > +#include <linux/err.h> > > +#include <linux/hwmon.h> > > +#include <linux/hwmon-sysfs.h> > > +#include <linux/i2c.h> > > +#include <linux/kernel.h> > > +#include <linux/module.h> > > + > > +enum chips { > > + ltc2471, > > + ltc2473 > > +}; > > + > > +struct ltc2471_data { > > + struct i2c_client *i2c; > > + bool differential; > > +}; > > + > > +/* Reference voltage is 1.25V */ > > +#define LTC2471_VREF 1250 > > + > > +/* Read two bytes from the I2C bus to obtain the ADC result */ > > +static int ltc2471_get_value(struct i2c_client *i2c) > > +{ > > + int ret; > > + __be16 buf; > > + > > + ret = i2c_master_recv(i2c, (char *)&buf, 2); > > + if (ret < 0) > > + return ret; > > + if (ret != 2) > > + return -EIO; > > + > > + /* MSB first */ > > + return be16_to_cpu(buf); > > +} > > + > > +static ssize_t ltc2471_show_value(struct device *dev, > > + struct device_attribute *da, char *buf) > > +{ > > + struct ltc2471_data *data = dev_get_drvdata(dev); > > + int value; > > + > > + value = ltc2471_get_value(data->i2c); > > + if (unlikely(value < 0)) > > + return value; > > + > > + if (data->differential) > > + /* Ranges from -VREF to +VREF with "0" at 0x8000 */ > > + value = ((s32)LTC2471_VREF * (s32)(value - 0x8000)) >> 15; > > + else > > + /* Ranges from 0 to +VREF */ > > + value = ((u32)LTC2471_VREF * (u32)value) >> 16; > > + > > + return snprintf(buf, PAGE_SIZE, "%d\n", value); > > +} > > + > > +static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ltc2471_show_value, NULL, 0); > > + > > +static struct attribute *ltc2471_attrs[] = { > > + &sensor_dev_attr_in0_input.dev_attr.attr, > > + NULL > > +}; > > + > > +ATTRIBUTE_GROUPS(ltc2471); > > + > > +static int ltc2471_i2c_probe(struct i2c_client *i2c, > > + const struct i2c_device_id *id) > > +{ > > + int ret; > > + struct device *hwmon_dev; > > + struct ltc2471_data *data; > > + > > + if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_I2C)) > > + return -ENODEV; > > + > > + data = devm_kzalloc(&i2c->dev, sizeof(struct ltc2471_data), GFP_KERNEL); > > + if (unlikely(!data)) > > + return -ENOMEM; > > + > > + data->i2c = i2c; > > + data->differential = (id->driver_data == ltc2473); > > + > > + /* Trigger once to start conversion and check if chip is there */ > > + ret = ltc2471_get_value(i2c); > > + if (ret < 0) { > > + dev_err(&i2c->dev, "Cannot read from device.\n"); > > + return ret; > > + } > > + > > + hwmon_dev = devm_hwmon_device_register_with_groups(&i2c->dev, > > + i2c->name, > > + data, > > + ltc2471_groups); > > + > > + return PTR_ERR_OR_ZERO(hwmon_dev); > > +} > > + > > +static const struct i2c_device_id ltc2471_i2c_id[] = { > > + { "ltc2471", ltc2471 }, > > + { "ltc2473", ltc2473 }, > > + {} > > +}; > > +MODULE_DEVICE_TABLE(i2c, ltc2471_i2c_id); > > + > > +static struct i2c_driver ltc2471_i2c_driver = { > > + .driver = { > > + .name = "ltc2471", > > + }, > > + .probe = ltc2471_i2c_probe, > > + .id_table = ltc2471_i2c_id, > > +}; > > + > > +module_i2c_driver(ltc2471_i2c_driver); > > + > > +MODULE_DESCRIPTION("LTC2471/LTC2473 Sensor Driver"); > > +MODULE_AUTHOR("Topic Embedded Products"); > > +MODULE_LICENSE("GPL v2"); > > > -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
