[PATCH v4] hwmon: Add support for Texas Instruments ADS1015

[PATCH v4] hwmon: Add support for Texas Instruments ADS1015

[Dirk Eibach]

Signed-off-by: Dirk Eibach <eibach-dJ+jgKLZIg4@public.gmane.org>
---
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-dJ+jgKLZIg4@public.gmane.org>
+
+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-dJ+jgKLZIg4@public.gmane.org>
+ *
+ * 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-dJ+jgKLZIg4@public.gmane.org>");
+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-dJ+jgKLZIg4@public.gmane.org>
+ *
+ * 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

Re: [PATCH v4] hwmon: Add support for Texas Instruments ADS1015

[Grant Likely]

[cc'ing Kay and Greg regarding sysfs stuff; please make sure my
comments are accurate.  :-) ]
On Thu, Mar 03, 2011 at 08:45:43AM +0100, Dirk Eibach wrote:
> Signed-off-by: Dirk Eibach <eibach-dJ+jgKLZIg4@public.gmane.org>

Patch is missing description.

> ---
> 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

I recommend putting the revision history *above* the '---' trim line.
It turns out to be useful to have the revision history in the commit
text that actually gets merged into mainline.

> 
> Documentation/hwmon/ads1015 |   67 ++++++++++
>  drivers/hwmon/Kconfig       |   10 ++
>  drivers/hwmon/Makefile      |    1 +
>  drivers/hwmon/ads1015.c     |  283 +++++++++++++++++++++++++++++++++++++++++++
>  include/linux/i2c/ads1015.h |   28 +++++

You can merge the Documentation/devicetree/bindings documentation
change into this patch.  No point in merging it separately.

>  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-dJ+jgKLZIg4@public.gmane.org>
> +
> +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.

The control file layout in sysfs *must* be documented.  And once it is
merged any changes must be backwards compatible since it is a
userspace interface.  Are you happy with the sysfs interface as it
stands?  From looking at the chip datasheet, there seem to be a lot of
possible configurations that aren't reflected by the sysfs interface.
Nor do I see any way for userspace to discover what the measurements
actually represent (but I'm not even remotely familiar with the
hwmon/sensors architecture, so I'm not an expert on how things should be
done here).

> 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-dJ+jgKLZIg4@public.gmane.org>
> + *
> + * 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)\

in_reg() is pretty generic.  Rename to something like
ads1015_input_attribute(offset)

> +static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO, show_in,\
> +	NULL, offset)

Indent 'static SENSOR_DEVICE_ATTR(...'

> +
> +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)

static int __devexit 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,

static int __devinit 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;

I suspect there are lifecycle issues here.  Attributes should not be
added to a device after the device is registered.  If adding
attributes, then a new struct device should be allocated, added to the
attribute group, and then registered as a child of the i2c_device.
Otherwise the attributes are not available at uevent time, which means
userspace (udev) may not be able to do the right things with the
device when the device appears.

Kay/GregKH, do I have this right?

> +
> +	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 },
> +	{ }

Should use initializers here:

	{ .name = "ads1015, },
	{}

The '0' can be omitted because by default it is initialized to zero.

> +};
> +MODULE_DEVICE_TABLE(i2c, ads1015_id);
> +
> +static struct i2c_driver ads1015_driver = {
> +	.driver = {
> +		.name = "ads1015",

		.owner = THIS_MODULE,
> +	},
> +	.probe = ads1015_probe,
> +	.remove = ads1015_remove,

.remove = __devexit_p(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-dJ+jgKLZIg4@public.gmane.org>");
> +MODULE_DESCRIPTION("ADS1015 driver");
> +MODULE_LICENSE("GPL");
> +
> +module_init(sensors_ads1015_init);
> +module_exit(sensors_ads1015_exit);

Move module_init and module_exit to directly below each functions they
are registering.


> 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-dJ+jgKLZIg4@public.gmane.org>
> + *
> + * 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
> 
> _______________________________________________
> devicetree-discuss mailing list
> devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
> https://lists.ozlabs.org/listinfo/devicetree-discuss

Re: [PATCH v4] hwmon: Add support for Texas Instruments ADS1015

[Greg KH]

On Thu, Mar 03, 2011 at 10:50:50AM -0700, Grant Likely wrote:
> > +	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;
> 
> I suspect there are lifecycle issues here.  Attributes should not be
> added to a device after the device is registered.  If adding
> attributes, then a new struct device should be allocated, added to the
> attribute group, and then registered as a child of the i2c_device.
> Otherwise the attributes are not available at uevent time, which means
> userspace (udev) may not be able to do the right things with the
> device when the device appears.
> 
> Kay/GregKH, do I have this right?

You have it right that the attributes need to be added earlier, yes.
But I don't recommend using a whole new struct device for this, each
subsystem should have a way to add groups of attributes for their
devices to properly show up before the uevent happens.

I don't recall what the hwmon subsystem does for this, I'm sure it is
somewhere in there...

thanks,

greg k-h

Re: [PATCH v4] hwmon: Add support for Texas Instruments ADS1015

[Wolfram Sang]

[-- Attachment #1.1: Type: text/plain, Size: 1436 bytes --]

> > ---
> > 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
> 
> I recommend putting the revision history *above* the '---' trim line.
> It turns out to be useful to have the revision history in the commit
> text that actually gets merged into mainline.

Is this common sense meanwhile? (That is quite many additional lines per
commit)

Regards,

   Wolfram

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

[-- Attachment #1.2: Digital signature --]
[-- Type: application/pgp-signature, Size: 197 bytes --]

[-- Attachment #2: Type: text/plain, Size: 192 bytes --]

_______________________________________________
devicetree-discuss mailing list
devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
https://lists.ozlabs.org/listinfo/devicetree-discuss

Re: [PATCH v4] hwmon: Add support for Texas Instruments ADS1015

[Grant Likely]

Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> wrote:

>> > ---
>> > 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
>> 
>> I recommend putting the revision history *above* the '---' trim line.
>> It turns out to be useful to have the revision history in the commit
>> text that actually gets merged into mainline.
>
>Is this common sense meanwhile? (That is quite many additional lines
>per
>commit)

Absolutely.  Commit text is cheap and useful.  I say the more detail the better.

g.


-- 
Sent from my Android phone with K-9 Mail. Please excuse my brevity.