Initial import

1 files changed, 189 insertions, 0 deletions

diff --git a/drivers/hwmon/mcp3021.c b/drivers/hwmon/mcp3021.c
new file mode 100644
index 000000000..972444a14
--- /dev/null
+++ b/drivers/hwmon/mcp3021.c
@@ -0,0 +1,189 @@
+/*
+ * mcp3021.c - driver for Microchip MCP3021 and MCP3221
+ *
+ * Copyright (C) 2008-2009, 2012 Freescale Semiconductor, Inc.
+ * Author: Mingkai Hu <Mingkai.hu@freescale.com>
+ * Reworked by Sven Schuchmann <schuchmann@schleissheimer.de>
+ *
+ * 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 MCP3221_SAR_SHIFT	0
+#define MCP3221_SAR_MASK	0xfff
+#define MCP3221_OUTPUT_RES	12	/* 12-bit resolution */
+
+enum chips {
+	mcp3021,
+	mcp3221
+};
+
+/*
+ * Client data (each client gets its own)
+ */
+struct mcp3021_data {
+	struct device *hwmon_dev;
+	u32 vdd;	/* device power supply */
+	u16 sar_shift;
+	u16 sar_mask;
+	u8 output_res;
+};
+
+static int mcp3021_read16(struct i2c_client *client)
+{
+	struct mcp3021_data *data = i2c_get_clientdata(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 >> data->sar_shift) & data->sar_mask;
+
+	return reg;
+}
+
+static inline u16 volts_from_reg(struct mcp3021_data *data, u16 val)
+{
+	return DIV_ROUND_CLOSEST(data->vdd * val, 1 << data->output_res);
+}
+
+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, 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 = devm_kzalloc(&client->dev, sizeof(struct mcp3021_data),
+			    GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, data);
+
+	switch (id->driver_data) {
+	case mcp3021:
+		data->sar_shift = MCP3021_SAR_SHIFT;
+		data->sar_mask = MCP3021_SAR_MASK;
+		data->output_res = MCP3021_OUTPUT_RES;
+		break;
+
+	case mcp3221:
+		data->sar_shift = MCP3221_SAR_SHIFT;
+		data->sar_mask = MCP3221_SAR_MASK;
+		data->output_res = MCP3221_OUTPUT_RES;
+		break;
+	}
+
+	if (dev_get_platdata(&client->dev)) {
+		data->vdd = *(u32 *)dev_get_platdata(&client->dev);
+		if (data->vdd > MCP3021_VDD_MAX || data->vdd < MCP3021_VDD_MIN)
+			return -EINVAL;
+	} else {
+		data->vdd = MCP3021_VDD_REF;
+	}
+
+	err = sysfs_create_file(&client->dev.kobj, &dev_attr_in0_input.attr);
+	if (err)
+		return err;
+
+	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);
+	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);
+
+	return 0;
+}
+
+static const struct i2c_device_id mcp3021_id[] = {
+	{ "mcp3021", mcp3021 },
+	{ "mcp3221", mcp3221 },
+	{ }
+};
+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/MCP3221 driver");
+MODULE_LICENSE("GPL");