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-rw-r--r--drivers/hwmon/mcp3021.c209
1 files changed, 209 insertions, 0 deletions
diff --git a/drivers/hwmon/mcp3021.c b/drivers/hwmon/mcp3021.c
new file mode 100644
index 000000000..e093b1998
--- /dev/null
+++ b/drivers/hwmon/mcp3021.c
@@ -0,0 +1,209 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * 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>
+ * DT support added by Clemens Gruber <clemens.gruber@pqgruber.com>
+ *
+ * This driver exports 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.
+ */
+
+#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>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+/* Vdd / reference voltage in millivolt */
+#define MCP3021_VDD_REF_MAX 5500
+#define MCP3021_VDD_REF_MIN 2700
+#define MCP3021_VDD_REF_DEFAULT 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 i2c_client *client;
+ u32 vdd; /* supply and reference voltage in millivolt */
+ u16 sar_shift;
+ u16 sar_mask;
+ u8 output_res;
+};
+
+static inline u16 volts_from_reg(struct mcp3021_data *data, u16 val)
+{
+ return DIV_ROUND_CLOSEST(data->vdd * val, 1 << data->output_res);
+}
+
+static int mcp3021_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct mcp3021_data *data = dev_get_drvdata(dev);
+ struct i2c_client *client = data->client;
+ __be16 buf;
+ u16 reg;
+ int ret;
+
+ if (type != hwmon_in)
+ return -EOPNOTSUPP;
+
+ 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;
+
+ *val = volts_from_reg(data, reg);
+
+ return 0;
+}
+
+static umode_t mcp3021_is_visible(const void *_data,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ if (type != hwmon_in)
+ return 0;
+
+ if (attr != hwmon_in_input)
+ return 0;
+
+ return 0444;
+}
+
+static const struct hwmon_channel_info *mcp3021_info[] = {
+ HWMON_CHANNEL_INFO(in, HWMON_I_INPUT),
+ NULL
+};
+
+static const struct hwmon_ops mcp3021_hwmon_ops = {
+ .is_visible = mcp3021_is_visible,
+ .read = mcp3021_read,
+};
+
+static const struct hwmon_chip_info mcp3021_chip_info = {
+ .ops = &mcp3021_hwmon_ops,
+ .info = mcp3021_info,
+};
+
+static const struct i2c_device_id mcp3021_id[];
+
+static int mcp3021_probe(struct i2c_client *client)
+{
+ struct mcp3021_data *data = NULL;
+ struct device_node *np = client->dev.of_node;
+ struct device *hwmon_dev;
+
+ 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);
+
+ if (np) {
+ if (!of_property_read_u32(np, "reference-voltage-microvolt",
+ &data->vdd))
+ data->vdd /= 1000;
+ else
+ data->vdd = MCP3021_VDD_REF_DEFAULT;
+ } else {
+ u32 *pdata = dev_get_platdata(&client->dev);
+
+ if (pdata)
+ data->vdd = *pdata;
+ else
+ data->vdd = MCP3021_VDD_REF_DEFAULT;
+ }
+
+ switch (i2c_match_id(mcp3021_id, client)->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;
+ }
+
+ data->client = client;
+
+ if (data->vdd > MCP3021_VDD_REF_MAX || data->vdd < MCP3021_VDD_REF_MIN)
+ return -EINVAL;
+
+ hwmon_dev = devm_hwmon_device_register_with_info(&client->dev,
+ client->name,
+ data,
+ &mcp3021_chip_info,
+ NULL);
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id mcp3021_id[] = {
+ { "mcp3021", mcp3021 },
+ { "mcp3221", mcp3221 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, mcp3021_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id of_mcp3021_match[] = {
+ { .compatible = "microchip,mcp3021", .data = (void *)mcp3021 },
+ { .compatible = "microchip,mcp3221", .data = (void *)mcp3221 },
+ { }
+};
+MODULE_DEVICE_TABLE(of, of_mcp3021_match);
+#endif
+
+static struct i2c_driver mcp3021_driver = {
+ .driver = {
+ .name = "mcp3021",
+ .of_match_table = of_match_ptr(of_mcp3021_match),
+ },
+ .probe_new = mcp3021_probe,
+ .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");