--- /dev/null
+/*
+ * mcp3422.c - driver for the Microchip mcp3422/3/4 chip family
+ *
+ * Copyright (C) 2013, Angelo Compagnucci
+ * Author: Angelo Compagnucci <angelo.compagnucci@gmail.com>
+ *
+ * Datasheet: http://ww1.microchip.com/downloads/en/devicedoc/22088b.pdf
+ *
+ * This driver exports the value of analog input voltage to sysfs, the
+ * voltage unit is nV.
+ *
+ * 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/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/sysfs.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+/* Masks */
+#define MCP3422_CHANNEL_MASK 0x60
+#define MCP3422_PGA_MASK 0x03
+#define MCP3422_SRATE_MASK 0x0C
+#define MCP3422_SRATE_240 0x0
+#define MCP3422_SRATE_60 0x1
+#define MCP3422_SRATE_15 0x2
+#define MCP3422_SRATE_3 0x3
+#define MCP3422_PGA_1 0
+#define MCP3422_PGA_2 1
+#define MCP3422_PGA_4 2
+#define MCP3422_PGA_8 3
+#define MCP3422_CONT_SAMPLING 0x10
+
+#define MCP3422_CHANNEL(config) (((config) & MCP3422_CHANNEL_MASK) >> 5)
+#define MCP3422_PGA(config) ((config) & MCP3422_PGA_MASK)
+#define MCP3422_SAMPLE_RATE(config) (((config) & MCP3422_SRATE_MASK) >> 2)
+
+#define MCP3422_CHANNEL_VALUE(value) (((value) << 5) & MCP3422_CHANNEL_MASK)
+#define MCP3422_PGA_VALUE(value) ((value) & MCP3422_PGA_MASK)
+#define MCP3422_SAMPLE_RATE_VALUE(value) ((value << 2) & MCP3422_SRATE_MASK)
+
+#define MCP3422_CHAN(_index) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = _index, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \
+ | BIT(IIO_CHAN_INFO_SCALE), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
+ }
+
+/* LSB is in nV to eliminate floating point */
+static const u32 rates_to_lsb[] = {1000000, 250000, 62500, 15625};
+
+/*
+ * scales calculated as:
+ * rates_to_lsb[sample_rate] / (1 << pga);
+ * pga is 1 for 0, 2
+ */
+
+static const int mcp3422_scales[4][4] = {
+ { 1000000, 250000, 62500, 15625 },
+ { 500000 , 125000, 31250, 7812 },
+ { 250000 , 62500 , 15625, 3906 },
+ { 125000 , 31250 , 7812 , 1953 } };
+
+/* Constant msleep times for data acquisitions */
+static const int mcp3422_read_times[4] = {
+ [MCP3422_SRATE_240] = 1000 / 240,
+ [MCP3422_SRATE_60] = 1000 / 60,
+ [MCP3422_SRATE_15] = 1000 / 15,
+ [MCP3422_SRATE_3] = 1000 / 3 };
+
+/* sample rates to integer conversion table */
+static const int mcp3422_sample_rates[4] = {
+ [MCP3422_SRATE_240] = 240,
+ [MCP3422_SRATE_60] = 60,
+ [MCP3422_SRATE_15] = 15,
+ [MCP3422_SRATE_3] = 3 };
+
+/* sample rates to sign extension table */
+static const int mcp3422_sign_extend[4] = {
+ [MCP3422_SRATE_240] = 12,
+ [MCP3422_SRATE_60] = 14,
+ [MCP3422_SRATE_15] = 16,
+ [MCP3422_SRATE_3] = 18 };
+
+/* Client data (each client gets its own) */
+struct mcp3422 {
+ struct i2c_client *i2c;
+ u8 config;
+ u8 pga[4];
+ struct mutex lock;
+};
+
+static int mcp3422_update_config(struct mcp3422 *adc, u8 newconfig)
+{
+ int ret;
+
+ mutex_lock(&adc->lock);
+
+ ret = i2c_master_send(adc->i2c, &newconfig, 1);
+ if (ret > 0) {
+ adc->config = newconfig;
+ ret = 0;
+ }
+
+ mutex_unlock(&adc->lock);
+
+ return ret;
+}
+
+static int mcp3422_read(struct mcp3422 *adc, int *value, u8 *config)
+{
+ int ret = 0;
+ u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
+ u8 buf[4] = {0, 0, 0, 0};
+ u32 temp;
+
+ if (sample_rate == MCP3422_SRATE_3) {
+ ret = i2c_master_recv(adc->i2c, buf, 4);
+ temp = buf[0] << 16 | buf[1] << 8 | buf[2];
+ *config = buf[3];
+ } else {
+ ret = i2c_master_recv(adc->i2c, buf, 3);
+ temp = buf[0] << 8 | buf[1];
+ *config = buf[2];
+ }
+
+ *value = sign_extend32(temp, mcp3422_sign_extend[sample_rate]);
+
+ return ret;
+}
+
+static int mcp3422_read_channel(struct mcp3422 *adc,
+ struct iio_chan_spec const *channel, int *value)
+{
+ int ret;
+ u8 config;
+ u8 req_channel = channel->channel;
+
+ if (req_channel != MCP3422_CHANNEL(adc->config)) {
+ config = adc->config;
+ config &= ~MCP3422_CHANNEL_MASK;
+ config |= MCP3422_CHANNEL_VALUE(req_channel);
+ config &= ~MCP3422_PGA_MASK;
+ config |= MCP3422_PGA_VALUE(adc->pga[req_channel]);
+ ret = mcp3422_update_config(adc, config);
+ if (ret < 0)
+ return ret;
+ msleep(mcp3422_read_times[MCP3422_SAMPLE_RATE(adc->config)]);
+ }
+
+ return mcp3422_read(adc, value, &config);
+}
+
+static int mcp3422_read_raw(struct iio_dev *iio,
+ struct iio_chan_spec const *channel, int *val1,
+ int *val2, long mask)
+{
+ struct mcp3422 *adc = iio_priv(iio);
+ int err;
+
+ u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
+ u8 pga = MCP3422_PGA(adc->config);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ err = mcp3422_read_channel(adc, channel, val1);
+ if (err < 0)
+ return -EINVAL;
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_SCALE:
+
+ *val1 = 0;
+ *val2 = mcp3422_scales[sample_rate][pga];
+ return IIO_VAL_INT_PLUS_NANO;
+
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ *val1 = mcp3422_sample_rates[MCP3422_SAMPLE_RATE(adc->config)];
+ return IIO_VAL_INT;
+
+ default:
+ break;
+ }
+
+ return -EINVAL;
+}
+
+static int mcp3422_write_raw(struct iio_dev *iio,
+ struct iio_chan_spec const *channel, int val1,
+ int val2, long mask)
+{
+ struct mcp3422 *adc = iio_priv(iio);
+ u8 temp;
+ u8 config = adc->config;
+ u8 req_channel = channel->channel;
+ u8 sample_rate = MCP3422_SAMPLE_RATE(config);
+ u8 i;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_SCALE:
+ if (val1 != 0)
+ return -EINVAL;
+
+ for (i = 0; i < ARRAY_SIZE(mcp3422_scales[0]); i++) {
+ if (val2 == mcp3422_scales[sample_rate][i]) {
+ adc->pga[req_channel] = i;
+
+ config &= ~MCP3422_CHANNEL_MASK;
+ config |= MCP3422_CHANNEL_VALUE(req_channel);
+ config &= ~MCP3422_PGA_MASK;
+ config |= MCP3422_PGA_VALUE(adc->pga[req_channel]);
+
+ return mcp3422_update_config(adc, config);
+ }
+ }
+ return -EINVAL;
+
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ switch (val1) {
+ case 240:
+ temp = MCP3422_SRATE_240;
+ break;
+ case 60:
+ temp = MCP3422_SRATE_60;
+ break;
+ case 15:
+ temp = MCP3422_SRATE_15;
+ break;
+ case 3:
+ temp = MCP3422_SRATE_3;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ config &= ~MCP3422_CHANNEL_MASK;
+ config |= MCP3422_CHANNEL_VALUE(req_channel);
+ config &= ~MCP3422_SRATE_MASK;
+ config |= MCP3422_SAMPLE_RATE_VALUE(temp);
+
+ return mcp3422_update_config(adc, config);
+
+ default:
+ break;
+ }
+
+ return -EINVAL;
+}
+
+static int mcp3422_write_raw_get_fmt(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, long mask)
+{
+ switch (mask) {
+ case IIO_CHAN_INFO_SCALE:
+ return IIO_VAL_INT_PLUS_NANO;
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ return IIO_VAL_INT_PLUS_MICRO;
+ default:
+ return -EINVAL;
+ }
+}
+
+static ssize_t mcp3422_show_scales(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct mcp3422 *adc = iio_priv(dev_to_iio_dev(dev));
+ u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
+
+ return sprintf(buf, "0.%09u 0.%09u 0.%09u 0.%09u\n",
+ mcp3422_scales[sample_rate][0],
+ mcp3422_scales[sample_rate][1],
+ mcp3422_scales[sample_rate][2],
+ mcp3422_scales[sample_rate][3]);
+}
+
+static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("240 60 15 3");
+static IIO_DEVICE_ATTR(in_voltage_scale_available, S_IRUGO,
+ mcp3422_show_scales, NULL, 0);
+
+static struct attribute *mcp3422_attributes[] = {
+ &iio_const_attr_sampling_frequency_available.dev_attr.attr,
+ &iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group mcp3422_attribute_group = {
+ .attrs = mcp3422_attributes,
+};
+
+static const struct iio_chan_spec mcp3422_channels[] = {
+ MCP3422_CHAN(0),
+ MCP3422_CHAN(1),
+};
+
+static const struct iio_chan_spec mcp3424_channels[] = {
+ MCP3422_CHAN(0),
+ MCP3422_CHAN(1),
+ MCP3422_CHAN(2),
+ MCP3422_CHAN(3),
+};
+
+static const struct iio_info mcp3422_info = {
+ .read_raw = mcp3422_read_raw,
+ .write_raw = mcp3422_write_raw,
+ .write_raw_get_fmt = mcp3422_write_raw_get_fmt,
+ .attrs = &mcp3422_attribute_group,
+ .driver_module = THIS_MODULE,
+};
+
+static int mcp3422_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct iio_dev *indio_dev;
+ struct mcp3422 *adc;
+ int err;
+ u8 config;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+ return -ENODEV;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*adc));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ adc = iio_priv(indio_dev);
+ adc->i2c = client;
+
+ mutex_init(&adc->lock);
+
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->name = dev_name(&client->dev);
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->info = &mcp3422_info;
+
+ switch ((unsigned int)(id->driver_data)) {
+ case 2:
+ case 3:
+ indio_dev->channels = mcp3422_channels;
+ indio_dev->num_channels = ARRAY_SIZE(mcp3422_channels);
+ break;
+ case 4:
+ indio_dev->channels = mcp3424_channels;
+ indio_dev->num_channels = ARRAY_SIZE(mcp3424_channels);
+ break;
+ }
+
+ /* meaningful default configuration */
+ config = (MCP3422_CONT_SAMPLING
+ | MCP3422_CHANNEL_VALUE(1)
+ | MCP3422_PGA_VALUE(MCP3422_PGA_1)
+ | MCP3422_SAMPLE_RATE_VALUE(MCP3422_SRATE_240));
+ mcp3422_update_config(adc, config);
+
+ err = iio_device_register(indio_dev);
+ if (err < 0)
+ return err;
+
+ i2c_set_clientdata(client, indio_dev);
+
+ return 0;
+}
+
+static int mcp3422_remove(struct i2c_client *client)
+{
+ iio_device_unregister(i2c_get_clientdata(client));
+ return 0;
+}
+
+static const struct i2c_device_id mcp3422_id[] = {
+ { "mcp3422", 2 },
+ { "mcp3423", 3 },
+ { "mcp3424", 4 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, mcp3422_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id mcp3422_of_match[] = {
+ { .compatible = "mcp3422" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, mcp3422_of_match);
+#endif
+
+static struct i2c_driver mcp3422_driver = {
+ .driver = {
+ .name = "mcp3422",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(mcp3422_of_match),
+ },
+ .probe = mcp3422_probe,
+ .remove = mcp3422_remove,
+ .id_table = mcp3422_id,
+};
+module_i2c_driver(mcp3422_driver);
+
+MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
+MODULE_DESCRIPTION("Microchip mcp3422/3/4 driver");
+MODULE_LICENSE("GPL v2");
projects / platform / kernel / linux-starfive.git / commitdiff