hwmon: Add MCP3021 ADC driver

Add I2C driver for MCP3021 that is an ADC chip from Microchip. The MCP3021 is a successive approximation A/D converter (ADC) with 10-bit resolution. The driver export the value of Vin to sysfs, the voltage unit is mV. Through the sysfs interface, lm-sensors tool can also display Vin voltage. Signed-off-by: Mingkai Hu <Mingkai.hu@freescale.com> Signed-off-by: Xie Xiaobo <X.Xie@freescale.com> Signed-off-by: Jean Delvare <khali@linux-fr.org>

hwmon: Add MCP3021 ADC driver
Add I2C driver for MCP3021 that is an ADC chip from Microchip. The MCP3021 is a successive approximation A/D converter (ADC) with 10-bit resolution. The driver export the value of Vin to sysfs, the voltage unit is mV. Through the sysfs interface, lm-sensors tool can also display Vin voltage. Signed-off-by: Mingkai Hu <Mingkai.hu@freescale.com> Signed-off-by: Xie Xiaobo <X.Xie@freescale.com> Signed-off-by: Jean Delvare <khali@linux-fr.org>
Xie Xiaobo · Jean Delvare
1 parent 0c2732152a
Showing 4 changed files with 204 additions and 0 deletions Side-by-side Diff
Documentation/hwmon/mcp3021
drivers/hwmon/Kconfig
drivers/hwmon/Makefile
drivers/hwmon/mcp3021.c
+Kernel driver MCP3021
+======================
+
+Supported chips:
+  * Microchip Technology MCP3021
+    Prefix: 'mcp3021'
+    Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/21805a.pdf
+
+Author: Mingkai Hu
+
+Description
+-----------
+
+This driver implements support for the Microchip Technology MCP3021 chip.
+
+The Microchip Technology Inc. MCP3021 is a successive approximation A/D
+converter (ADC) with 10-bit resolution.
+This device provides one single-ended input with very low power consumption.
+Communication to the MCP3021 is performed using a 2-wire I2C compatible
+interface. Standard (100 kHz) and Fast (400 kHz) I2C modes are available.
+The default I2C device address is 0x4d (contact the Microchip factory for
+additional address options).
@@ -813,6 +813,16 @@
 	  This driver can also be built as a module.  If so, the module
 	  will be called max6650.
  
+config SENSORS_MCP3021
+	tristate "Microchip MCP3021"
+	depends on I2C && EXPERIMENTAL
+	help
+	  If you say yes here you get support for the MCP3021 chip
+	  that is a A/D converter (ADC) with 10-bit resolution.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called mcp3021.
+
 config SENSORS_NTC_THERMISTOR
 	tristate "NTC thermistor support"
 	depends on EXPERIMENTAL
@@ -95,6 +95,7 @@
 obj-$(CONFIG_SENSORS_MAX6642)	+= max6642.o
 obj-$(CONFIG_SENSORS_MAX6650)	+= max6650.o
 obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o
+obj-$(CONFIG_SENSORS_MCP3021)	+= mcp3021.o
 obj-$(CONFIG_SENSORS_NTC_THERMISTOR)	+= ntc_thermistor.o
 obj-$(CONFIG_SENSORS_PC87360)	+= pc87360.o
 obj-$(CONFIG_SENSORS_PC87427)	+= pc87427.o
+/*
+ * mcp3021.c - driver for the Microchip MCP3021 chip
+ *
+ * Copyright (C) 2008-2009, 2012 Freescale Semiconductor, Inc.
+ * Author: Mingkai Hu <Mingkai.hu@freescale.com>
+ *
+ * This driver export the value of analog input voltage to sysfs, the
+ * voltage unit is mV. Through the sysfs interface, lm-sensors tool
+ * can also display the input voltage.
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/hwmon.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/device.h>
+
+/* Vdd info */
+#define MCP3021_VDD_MAX		5500
+#define MCP3021_VDD_MIN		2700
+#define MCP3021_VDD_REF		3300
+
+/* output format */
+#define MCP3021_SAR_SHIFT	2
+#define MCP3021_SAR_MASK	0x3ff
+
+#define MCP3021_OUTPUT_RES	10	/* 10-bit resolution */
+#define MCP3021_OUTPUT_SCALE	4
+
+/*
+ * Client data (each client gets its own)
+ */
+struct mcp3021_data {
+	struct device *hwmon_dev;
+	u32 vdd;	/* device power supply */
+};
+
+static int mcp3021_read16(struct i2c_client *client)
+{
+	int ret;
+	u16 reg;
+	__be16 buf;
+
+	ret = i2c_master_recv(client, (char *)&buf, 2);
+	if (ret < 0)
+		return ret;
+	if (ret != 2)
+		return -EIO;
+
+	/* The output code of the MCP3021 is transmitted with MSB first. */
+	reg = be16_to_cpu(buf);
+
+	/*
+	 * The ten-bit output code is composed of the lower 4-bit of the
+	 * first byte and the upper 6-bit of the second byte.
+	 */
+	reg = (reg >> MCP3021_SAR_SHIFT) & MCP3021_SAR_MASK;
+
+	return reg;
+}
+
+static inline u16 volts_from_reg(u16 vdd, u16 val)
+{
+	if (val == 0)
+		return 0;
+
+	val = val * MCP3021_OUTPUT_SCALE - MCP3021_OUTPUT_SCALE / 2;
+
+	return val * DIV_ROUND_CLOSEST(vdd,
+			(1 << MCP3021_OUTPUT_RES) * MCP3021_OUTPUT_SCALE);
+}
+
+static ssize_t show_in_input(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct mcp3021_data *data = i2c_get_clientdata(client);
+	int reg, in_input;
+
+	reg = mcp3021_read16(client);
+	if (reg < 0)
+		return reg;
+
+	in_input = volts_from_reg(data->vdd, reg);
+	return sprintf(buf, "%d\n", in_input);
+}
+
+static DEVICE_ATTR(in0_input, S_IRUGO, show_in_input, NULL);
+
+static int mcp3021_probe(struct i2c_client *client,
+				const struct i2c_device_id *id)
+{
+	int err;
+	struct mcp3021_data *data = NULL;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+		return -ENODEV;
+
+	data = kzalloc(sizeof(struct mcp3021_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, data);
+
+	if (client->dev.platform_data) {
+		data->vdd = *(u32 *)client->dev.platform_data;
+		if (data->vdd > MCP3021_VDD_MAX ||
+				data->vdd < MCP3021_VDD_MIN) {
+			err = -EINVAL;
+			goto exit_free;
+		}
+	} else
+		data->vdd = MCP3021_VDD_REF;
+
+	err = sysfs_create_file(&client->dev.kobj, &dev_attr_in0_input.attr);
+	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_file(&client->dev.kobj, &dev_attr_in0_input.attr);
+exit_free:
+	kfree(data);
+	return err;
+}
+
+static int mcp3021_remove(struct i2c_client *client)
+{
+	struct mcp3021_data *data = i2c_get_clientdata(client);
+
+	hwmon_device_unregister(data->hwmon_dev);
+	sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr);
+	kfree(data);
+
+	return 0;
+}
+
+static const struct i2c_device_id mcp3021_id[] = {
+	{ "mcp3021", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, mcp3021_id);
+
+static struct i2c_driver mcp3021_driver = {
+	.driver = {
+		.name = "mcp3021",
+	},
+	.probe = mcp3021_probe,
+	.remove = mcp3021_remove,
+	.id_table = mcp3021_id,
+};
+
+module_i2c_driver(mcp3021_driver);
+
+MODULE_AUTHOR("Mingkai Hu <Mingkai.hu@freescale.com>");
+MODULE_DESCRIPTION("Microchip MCP3021 driver");
+MODULE_LICENSE("GPL");
	1	+Kernel driver MCP3021
	2	+======================
	3	+
	4	+Supported chips:
	5	+ * Microchip Technology MCP3021
	6	+ Prefix: 'mcp3021'
	7	+ Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/21805a.pdf
	8	+
	9	+Author: Mingkai Hu
	10	+
	11	+Description
	12	+-----------
	13	+
	14	+This driver implements support for the Microchip Technology MCP3021 chip.
	15	+
	16	+The Microchip Technology Inc. MCP3021 is a successive approximation A/D
	17	+converter (ADC) with 10-bit resolution.
	18	+This device provides one single-ended input with very low power consumption.
	19	+Communication to the MCP3021 is performed using a 2-wire I2C compatible
	20	+interface. Standard (100 kHz) and Fast (400 kHz) I2C modes are available.
	21	+The default I2C device address is 0x4d (contact the Microchip factory for
	22	+additional address options).
...	...	@@ -813,6 +813,16 @@
813	813	This driver can also be built as a module. If so, the module
814	814	will be called max6650.
815	815
	816	+config SENSORS_MCP3021
	817	+ tristate "Microchip MCP3021"
	818	+ depends on I2C && EXPERIMENTAL
	819	+ help
	820	+ If you say yes here you get support for the MCP3021 chip
	821	+ that is a A/D converter (ADC) with 10-bit resolution.
	822	+
	823	+ This driver can also be built as a module. If so, the module
	824	+ will be called mcp3021.
	825	+
816	826	config SENSORS_NTC_THERMISTOR
817	827	tristate "NTC thermistor support"
818	828	depends on EXPERIMENTAL
...	...	@@ -95,6 +95,7 @@
95	95	obj-$(CONFIG_SENSORS_MAX6642) += max6642.o
96	96	obj-$(CONFIG_SENSORS_MAX6650) += max6650.o
97	97	obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o
	98	+obj-$(CONFIG_SENSORS_MCP3021) += mcp3021.o
98	99	obj-$(CONFIG_SENSORS_NTC_THERMISTOR) += ntc_thermistor.o
99	100	obj-$(CONFIG_SENSORS_PC87360) += pc87360.o
100	101	obj-$(CONFIG_SENSORS_PC87427) += pc87427.o
	1	+/*
	2	+ * mcp3021.c - driver for the Microchip MCP3021 chip
	3	+ *
	4	+ * Copyright (C) 2008-2009, 2012 Freescale Semiconductor, Inc.
	5	+ * Author: Mingkai Hu <Mingkai.hu@freescale.com>
	6	+ *
	7	+ * This driver export the value of analog input voltage to sysfs, the
	8	+ * voltage unit is mV. Through the sysfs interface, lm-sensors tool
	9	+ * can also display the input voltage.
	10	+ *
	11	+ * This program is free software; you can redistribute it and/or modify
	12	+ * it under the terms of the GNU General Public License as published by
	13	+ * the Free Software Foundation; either version 2 of the License, or
	14	+ * (at your option) any later version.
	15	+ */
	16	+
	17	+#include <linux/kernel.h>
	18	+#include <linux/module.h>
	19	+#include <linux/hwmon.h>
	20	+#include <linux/slab.h>
	21	+#include <linux/i2c.h>
	22	+#include <linux/err.h>
	23	+#include <linux/device.h>
	24	+
	25	+/* Vdd info */
	26	+#define MCP3021_VDD_MAX 5500
	27	+#define MCP3021_VDD_MIN 2700
	28	+#define MCP3021_VDD_REF 3300
	29	+
	30	+/* output format */
	31	+#define MCP3021_SAR_SHIFT 2
	32	+#define MCP3021_SAR_MASK 0x3ff
	33	+
	34	+#define MCP3021_OUTPUT_RES 10 /* 10-bit resolution */
	35	+#define MCP3021_OUTPUT_SCALE 4
	36	+
	37	+/*
	38	+ * Client data (each client gets its own)
	39	+ */
	40	+struct mcp3021_data {
	41	+ struct device *hwmon_dev;
	42	+ u32 vdd; /* device power supply */
	43	+};
	44	+
	45	+static int mcp3021_read16(struct i2c_client *client)
	46	+{
	47	+ int ret;
	48	+ u16 reg;
	49	+ __be16 buf;
	50	+
	51	+ ret = i2c_master_recv(client, (char *)&buf, 2);
	52	+ if (ret < 0)
	53	+ return ret;
	54	+ if (ret != 2)
	55	+ return -EIO;
	56	+
	57	+ /* The output code of the MCP3021 is transmitted with MSB first. */
	58	+ reg = be16_to_cpu(buf);
	59	+
	60	+ /*
	61	+ * The ten-bit output code is composed of the lower 4-bit of the
	62	+ * first byte and the upper 6-bit of the second byte.
	63	+ */
	64	+ reg = (reg >> MCP3021_SAR_SHIFT) & MCP3021_SAR_MASK;
	65	+
	66	+ return reg;
	67	+}
	68	+
	69	+static inline u16 volts_from_reg(u16 vdd, u16 val)
	70	+{
	71	+ if (val == 0)
	72	+ return 0;
	73	+
	74	+ val = val * MCP3021_OUTPUT_SCALE - MCP3021_OUTPUT_SCALE / 2;
	75	+
	76	+ return val * DIV_ROUND_CLOSEST(vdd,
	77	+ (1 << MCP3021_OUTPUT_RES) * MCP3021_OUTPUT_SCALE);
	78	+}
	79	+
	80	+static ssize_t show_in_input(struct device dev, struct device_attribute attr,
	81	+ char *buf)
	82	+{
	83	+ struct i2c_client *client = to_i2c_client(dev);
	84	+ struct mcp3021_data *data = i2c_get_clientdata(client);
	85	+ int reg, in_input;
	86	+
	87	+ reg = mcp3021_read16(client);
	88	+ if (reg < 0)
	89	+ return reg;
	90	+
	91	+ in_input = volts_from_reg(data->vdd, reg);
	92	+ return sprintf(buf, "%d\n", in_input);
	93	+}
	94	+
	95	+static DEVICE_ATTR(in0_input, S_IRUGO, show_in_input, NULL);
	96	+
	97	+static int mcp3021_probe(struct i2c_client *client,
	98	+ const struct i2c_device_id *id)
	99	+{
	100	+ int err;
	101	+ struct mcp3021_data *data = NULL;
	102	+
	103	+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
	104	+ return -ENODEV;
	105	+
	106	+ data = kzalloc(sizeof(struct mcp3021_data), GFP_KERNEL);
	107	+ if (!data)
	108	+ return -ENOMEM;
	109	+
	110	+ i2c_set_clientdata(client, data);
	111	+
	112	+ if (client->dev.platform_data) {
	113	+ data->vdd = (u32 )client->dev.platform_data;
	114	+ if (data->vdd > MCP3021_VDD_MAX \|\|
	115	+ data->vdd < MCP3021_VDD_MIN) {
	116	+ err = -EINVAL;
	117	+ goto exit_free;
	118	+ }
	119	+ } else
	120	+ data->vdd = MCP3021_VDD_REF;
	121	+
	122	+ err = sysfs_create_file(&client->dev.kobj, &dev_attr_in0_input.attr);
	123	+ if (err)
	124	+ goto exit_free;
	125	+
	126	+ data->hwmon_dev = hwmon_device_register(&client->dev);
	127	+ if (IS_ERR(data->hwmon_dev)) {
	128	+ err = PTR_ERR(data->hwmon_dev);
	129	+ goto exit_remove;
	130	+ }
	131	+
	132	+ return 0;
	133	+
	134	+exit_remove:
	135	+ sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr);
	136	+exit_free:
	137	+ kfree(data);
	138	+ return err;
	139	+}
	140	+
	141	+static int mcp3021_remove(struct i2c_client *client)
	142	+{
	143	+ struct mcp3021_data *data = i2c_get_clientdata(client);
	144	+
	145	+ hwmon_device_unregister(data->hwmon_dev);
	146	+ sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr);
	147	+ kfree(data);
	148	+
	149	+ return 0;
	150	+}
	151	+
	152	+static const struct i2c_device_id mcp3021_id[] = {
	153	+ { "mcp3021", 0 },
	154	+ { }
	155	+};
	156	+MODULE_DEVICE_TABLE(i2c, mcp3021_id);
	157	+
	158	+static struct i2c_driver mcp3021_driver = {
	159	+ .driver = {
	160	+ .name = "mcp3021",
	161	+ },
	162	+ .probe = mcp3021_probe,
	163	+ .remove = mcp3021_remove,
	164	+ .id_table = mcp3021_id,
	165	+};
	166	+
	167	+module_i2c_driver(mcp3021_driver);
	168	+
	169	+MODULE_AUTHOR("Mingkai Hu <Mingkai.hu@freescale.com>");
	170	+MODULE_DESCRIPTION("Microchip MCP3021 driver");
	171	+MODULE_LICENSE("GPL");