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Subject[PATCH v4] hwmon: Add support for Texas Instruments ADS1015
Date
Signed-off-by: Dirk Eibach <eibach@gdsys.de>
---
Changes since v1:
- fixed/extended Documentation
- removed unused register definitions
- hardcoded PGA fullscale table size
- made sure patch applies against v2.6.38-rc4
- reordered functions to avoid forward declaration
- results from i2c_smbus_read_word_data() are handled correctly
- moved locking into ads1015_read_value()
- removed unnecessray clearing of bit
- proper error handling in ads1015_read_value()
- use DIV_ROUND_CLOSEST for scaling result
- removed detect()
Changes since v2:
- removed *all* leftovers from detect()
- fixed return with mutex held
- made sysfs representation configurable
(hope this will be the reference implementation for generations to come ;)

Changes since v3:
- included linux/of.h
- remove linux/types.h from header file
- sysfs is now configured with a bitmask
- assume big-endian of-properties

Documentation/hwmon/ads1015 | 67 ++++++++++
drivers/hwmon/Kconfig | 10 ++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/ads1015.c | 283 +++++++++++++++++++++++++++++++++++++++++++
include/linux/i2c/ads1015.h | 28 +++++
5 files changed, 389 insertions(+), 0 deletions(-)
create mode 100644 Documentation/hwmon/ads1015
create mode 100644 drivers/hwmon/ads1015.c
create mode 100644 include/linux/i2c/ads1015.h
diff --git a/Documentation/hwmon/ads1015 b/Documentation/hwmon/ads1015
new file mode 100644
index 0000000..56ee797
--- /dev/null
+++ b/Documentation/hwmon/ads1015
@@ -0,0 +1,67 @@
+Kernel driver ads1015
+=====================
+
+Supported chips:
+ * Texas Instruments ADS1015
+ Prefix: 'ads1015'
+ Datasheet: Publicly available at the Texas Instruments website :
+ http://focus.ti.com/lit/ds/symlink/ads1015.pdf
+
+Authors:
+ Dirk Eibach, Guntermann & Drunck GmbH <eibach@gdsys.de>
+
+Description
+-----------
+
+This driver implements support for the Texas Instruments ADS1015.
+
+This device is a 12-bit A-D converter with 4 inputs.
+
+The inputs can be used single ended or in certain differential combinations.
+
+The inputs can be exported to 8 sysfs input files in0_input - in7_input:
+in0: Voltage over AIN0 and AIN1.
+in1: Voltage over AIN0 and AIN3.
+in2: Voltage over AIN1 and AIN3.
+in3: Voltage over AIN2 and AIN3.
+in4: Voltage over AIN0 and GND.
+in5: Voltage over AIN1 and GND.
+in6: Voltage over AIN2 and GND.
+in7: Voltage over AIN3 and GND.
+
+Which inputs are exported can be configured using platform data or devicetree.
+
+By default all inputs are exported.
+
+Platform Data
+-------------
+
+In linux/i2c/ads1015.h platform data is defined as:
+
+struct ads1015_platform_data {
+ unsigned int exported_channels;
+};
+
+exported_channels is a bitmask that specifies which inputs should be exported.
+
+Example:
+struct ads1015_platform_data data = {
+ .exported_channels = (1 << 2) | (1 << 4)
+};
+
+In this case only in2_input and in4_input would be created.
+
+Devicetree
+----------
+
+The ads1015 node may have an "exported-channels" property.
+exported_channels is a bitmask that specifies which inputs should be exported.
+
+Example:
+ads1015@49 {
+ compatible = "ti,ads1015";
+ reg = <0x49>;
+ exported-channels = < 0x14 >;
+};
+
+In this case only in2_input and in4_input would be created.
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 773e484..7e247f7 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -871,6 +871,16 @@ config SENSORS_SMSC47B397
This driver can also be built as a module. If so, the module
will be called smsc47b397.

+config SENSORS_ADS1015
+ tristate "Texas Instruments ADS1015"
+ depends on I2C
+ help
+ If you say yes here you get support for Texas Instruments ADS1015
+ 12-bit 4-input ADC device.
+
+ This driver can also be built as a module. If so, the module
+ will be called ads1015.
+
config SENSORS_ADS7828
tristate "Texas Instruments ADS7828"
depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index dde02d9..aae4036 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_SENSORS_ADM1026) += adm1026.o
obj-$(CONFIG_SENSORS_ADM1029) += adm1029.o
obj-$(CONFIG_SENSORS_ADM1031) += adm1031.o
obj-$(CONFIG_SENSORS_ADM9240) += adm9240.o
+obj-$(CONFIG_SENSORS_ADS1015) += ads1015.o
obj-$(CONFIG_SENSORS_ADS7828) += ads7828.o
obj-$(CONFIG_SENSORS_ADS7871) += ads7871.o
obj-$(CONFIG_SENSORS_ADT7411) += adt7411.o
diff --git a/drivers/hwmon/ads1015.c b/drivers/hwmon/ads1015.c
new file mode 100644
index 0000000..7d593bb
--- /dev/null
+++ b/drivers/hwmon/ads1015.c
@@ -0,0 +1,283 @@
+/*
+ * ads1015.c - lm_sensors driver for ads1015 12-bit 4-input ADC
+ * (C) Copyright 2010
+ * Dirk Eibach, Guntermann & Drunck GmbH <eibach@gdsys.de>
+ *
+ * Based on the ads7828 driver by Steve Hardy.
+ *
+ * Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads1015.pdf
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.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/of.h>
+
+#include <linux/i2c/ads1015.h>
+
+/* ADS1015 registers */
+enum {
+ ADS1015_CONVERSION = 0,
+ ADS1015_CONFIG = 1,
+};
+
+/* PGA fullscale voltages in mV */
+static const unsigned int fullscale_table[8] = {
+ 6144, 4096, 2048, 1024, 512, 256, 256, 256 };
+
+#define ADS1015_CONFIG_CHANNELS 8
+#define ADS1015_DEFAULT_CHANNELS 0xff
+
+struct ads1015_data {
+ struct device *hwmon_dev;
+ struct mutex update_lock; /* mutex protect updates */
+ struct attribute *attr_table[ADS1015_CONFIG_CHANNELS + 1];
+ struct attribute_group attr_group;
+};
+
+static s32 ads1015_read_reg(struct i2c_client *client, unsigned int reg)
+{
+ s32 data = i2c_smbus_read_word_data(client, reg);
+
+ return (data < 0) ? data : swab16(data);
+}
+
+static s32 ads1015_write_reg(struct i2c_client *client, unsigned int reg,
+ u16 val)
+{
+ return i2c_smbus_write_word_data(client, reg, swab16(val));
+}
+
+static int ads1015_read_value(struct i2c_client *client, unsigned int channel,
+ int *value)
+{
+ u16 config;
+ s16 conversion;
+ unsigned int pga;
+ int fullscale;
+ unsigned int k;
+ struct ads1015_data *data = i2c_get_clientdata(client);
+ int res;
+
+ mutex_lock(&data->update_lock);
+
+ /* get fullscale voltage */
+ res = ads1015_read_reg(client, ADS1015_CONFIG);
+ if (res < 0)
+ goto err_unlock;
+ config = res;
+ pga = (config >> 9) & 0x0007;
+ fullscale = fullscale_table[pga];
+
+ /* set channel and start single conversion */
+ config &= ~(0x0007 << 12);
+ config |= (1 << 15) | (1 << 8) | (channel & 0x0007) << 12;
+
+ /* wait until conversion finished */
+ res = ads1015_write_reg(client, ADS1015_CONFIG, config);
+ if (res < 0)
+ goto err_unlock;
+ for (k = 0; k < 5; ++k) {
+ schedule_timeout(msecs_to_jiffies(1));
+ res = ads1015_read_reg(client, ADS1015_CONFIG);
+ if (res < 0)
+ goto err_unlock;
+ config = res;
+ if (config & (1 << 15))
+ break;
+ }
+ if (k == 5) {
+ res = -EIO;
+ goto err_unlock;
+ }
+
+ res = ads1015_read_reg(client, ADS1015_CONVERSION);
+ if (res < 0)
+ goto err_unlock;
+ conversion = res;
+
+ mutex_unlock(&data->update_lock);
+
+ *value = DIV_ROUND_CLOSEST(conversion * fullscale, 0x7ff0);
+
+ return 0;
+
+err_unlock:
+ mutex_unlock(&data->update_lock);
+ return res;
+}
+
+/* sysfs callback function */
+static ssize_t show_in(struct device *dev, struct device_attribute *da,
+ char *buf)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+ struct i2c_client *client = to_i2c_client(dev);
+ int in;
+ int res;
+
+ res = ads1015_read_value(client, attr->index, &in);
+
+ return (res < 0) ? res : sprintf(buf, "%d\n", in);
+}
+
+#define in_reg(offset)\
+static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO, show_in,\
+ NULL, offset)
+
+in_reg(0);
+in_reg(1);
+in_reg(2);
+in_reg(3);
+in_reg(4);
+in_reg(5);
+in_reg(6);
+in_reg(7);
+
+static struct attribute *all_attributes[] = {
+ &sensor_dev_attr_in0_input.dev_attr.attr,
+ &sensor_dev_attr_in1_input.dev_attr.attr,
+ &sensor_dev_attr_in2_input.dev_attr.attr,
+ &sensor_dev_attr_in3_input.dev_attr.attr,
+ &sensor_dev_attr_in4_input.dev_attr.attr,
+ &sensor_dev_attr_in5_input.dev_attr.attr,
+ &sensor_dev_attr_in6_input.dev_attr.attr,
+ &sensor_dev_attr_in7_input.dev_attr.attr,
+};
+
+/*
+ * Driver interface
+ */
+
+static int ads1015_remove(struct i2c_client *client)
+{
+ struct ads1015_data *data = i2c_get_clientdata(client);
+ hwmon_device_unregister(data->hwmon_dev);
+ sysfs_remove_group(&client->dev.kobj, &data->attr_group);
+ kfree(data);
+ return 0;
+}
+
+static unsigned int ads1015_get_exported_channels(struct i2c_client *client)
+{
+ struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev);
+#ifdef CONFIG_OF
+ struct device_node *np = client->dev.of_node;
+ const __be32 *of_channels;
+ int of_channels_size;
+#endif
+
+ /* prefer platform data */
+ if (pdata)
+ return pdata->exported_channels;
+
+#ifdef CONFIG_OF
+ /* fallback on OF */
+ of_channels = of_get_property(np, "exported-channels",
+ &of_channels_size);
+ if (of_channels && (of_channels_size == sizeof(*of_channels)))
+ return be32_to_cpup(of_channels);
+#endif
+
+ /* fallback on default configuration */
+ return ADS1015_DEFAULT_CHANNELS;
+}
+
+static int ads1015_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct ads1015_data *data;
+ int err;
+ unsigned int exported_channels;
+ unsigned int k;
+ unsigned int n = 0;
+
+ data = kzalloc(sizeof(struct ads1015_data), GFP_KERNEL);
+ if (!data) {
+ err = -ENOMEM;
+ goto exit;
+ }
+
+ i2c_set_clientdata(client, data);
+ mutex_init(&data->update_lock);
+
+ /* build sysfs attribute group */
+ data->attr_group.attrs = data->attr_table;
+ exported_channels = ads1015_get_exported_channels(client);
+ for (k = 0; k < ADS1015_CONFIG_CHANNELS; ++k) {
+ if (!(exported_channels & (1<<k)))
+ continue;
+ data->attr_table[n++] =
+ all_attributes[k];
+ }
+ err = sysfs_create_group(&client->dev.kobj, &data->attr_group);
+ if (err)
+ goto exit_free;
+
+ data->hwmon_dev = hwmon_device_register(&client->dev);
+ if (IS_ERR(data->hwmon_dev)) {
+ err = PTR_ERR(data->hwmon_dev);
+ goto exit_remove;
+ }
+
+ return 0;
+
+exit_remove:
+ sysfs_remove_group(&client->dev.kobj, &data->attr_group);
+exit_free:
+ kfree(data);
+exit:
+ return err;
+}
+
+static const struct i2c_device_id ads1015_id[] = {
+ { "ads1015", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ads1015_id);
+
+static struct i2c_driver ads1015_driver = {
+ .driver = {
+ .name = "ads1015",
+ },
+ .probe = ads1015_probe,
+ .remove = ads1015_remove,
+ .id_table = ads1015_id,
+};
+
+static int __init sensors_ads1015_init(void)
+{
+ return i2c_add_driver(&ads1015_driver);
+}
+
+static void __exit sensors_ads1015_exit(void)
+{
+ i2c_del_driver(&ads1015_driver);
+}
+
+MODULE_AUTHOR("Dirk Eibach <eibach@gdsys.de>");
+MODULE_DESCRIPTION("ADS1015 driver");
+MODULE_LICENSE("GPL");
+
+module_init(sensors_ads1015_init);
+module_exit(sensors_ads1015_exit);
diff --git a/include/linux/i2c/ads1015.h b/include/linux/i2c/ads1015.h
new file mode 100644
index 0000000..8541c6a
--- /dev/null
+++ b/include/linux/i2c/ads1015.h
@@ -0,0 +1,28 @@
+/*
+ * Platform Data for ADS1015 12-bit 4-input ADC
+ * (C) Copyright 2010
+ * Dirk Eibach, Guntermann & Drunck GmbH <eibach@gdsys.de>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef LINUX_ADS1015_H
+#define LINUX_ADS1015_H
+
+struct ads1015_platform_data {
+ unsigned int exported_channels;
+};
+
+#endif /* LINUX_ADS1015_H */
--
1.5.6.5


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