428 lines
10 KiB
C
428 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* mcp3422.c - driver for the Microchip mcp3421/2/3/4/5/6/7/8 chip family
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*
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* Copyright (C) 2013, Angelo Compagnucci
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* Author: Angelo Compagnucci <angelo.compagnucci@gmail.com>
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*
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* Datasheet: http://ww1.microchip.com/downloads/en/devicedoc/22088b.pdf
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* https://ww1.microchip.com/downloads/en/DeviceDoc/22226a.pdf
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* https://ww1.microchip.com/downloads/en/DeviceDoc/22072b.pdf
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*
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* This driver exports the value of analog input voltage to sysfs, the
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* voltage unit is nV.
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*/
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#include <linux/err.h>
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#include <linux/i2c.h>
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#include <linux/module.h>
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#include <linux/mod_devicetable.h>
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#include <linux/delay.h>
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#include <linux/sysfs.h>
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#include <asm/unaligned.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/sysfs.h>
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/* Masks */
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#define MCP3422_CHANNEL_MASK 0x60
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#define MCP3422_PGA_MASK 0x03
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#define MCP3422_SRATE_MASK 0x0C
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#define MCP3422_SRATE_240 0x0
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#define MCP3422_SRATE_60 0x1
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#define MCP3422_SRATE_15 0x2
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#define MCP3422_SRATE_3 0x3
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#define MCP3422_PGA_1 0
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#define MCP3422_PGA_2 1
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#define MCP3422_PGA_4 2
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#define MCP3422_PGA_8 3
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#define MCP3422_CONT_SAMPLING 0x10
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#define MCP3422_CHANNEL(config) (((config) & MCP3422_CHANNEL_MASK) >> 5)
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#define MCP3422_PGA(config) ((config) & MCP3422_PGA_MASK)
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#define MCP3422_SAMPLE_RATE(config) (((config) & MCP3422_SRATE_MASK) >> 2)
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#define MCP3422_CHANNEL_VALUE(value) (((value) << 5) & MCP3422_CHANNEL_MASK)
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#define MCP3422_PGA_VALUE(value) ((value) & MCP3422_PGA_MASK)
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#define MCP3422_SAMPLE_RATE_VALUE(value) ((value << 2) & MCP3422_SRATE_MASK)
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#define MCP3422_CHAN(_index) \
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{ \
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.type = IIO_VOLTAGE, \
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.indexed = 1, \
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.channel = _index, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \
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| BIT(IIO_CHAN_INFO_SCALE), \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
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}
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static const int mcp3422_scales[4][4] = {
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{ 1000000, 500000, 250000, 125000 },
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{ 250000, 125000, 62500, 31250 },
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{ 62500, 31250, 15625, 7812 },
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{ 15625, 7812, 3906, 1953 } };
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/* Constant msleep times for data acquisitions */
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static const int mcp3422_read_times[4] = {
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[MCP3422_SRATE_240] = 1000 / 240,
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[MCP3422_SRATE_60] = 1000 / 60,
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[MCP3422_SRATE_15] = 1000 / 15,
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[MCP3422_SRATE_3] = 1000 / 3 };
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/* sample rates to integer conversion table */
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static const int mcp3422_sample_rates[4] = {
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[MCP3422_SRATE_240] = 240,
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[MCP3422_SRATE_60] = 60,
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[MCP3422_SRATE_15] = 15,
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[MCP3422_SRATE_3] = 3 };
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/* sample rates to sign extension table */
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static const int mcp3422_sign_extend[4] = {
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[MCP3422_SRATE_240] = 11,
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[MCP3422_SRATE_60] = 13,
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[MCP3422_SRATE_15] = 15,
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[MCP3422_SRATE_3] = 17 };
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/* Client data (each client gets its own) */
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struct mcp3422 {
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struct i2c_client *i2c;
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u8 id;
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u8 config;
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u8 pga[4];
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struct mutex lock;
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};
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static int mcp3422_update_config(struct mcp3422 *adc, u8 newconfig)
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{
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int ret;
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ret = i2c_master_send(adc->i2c, &newconfig, 1);
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if (ret > 0) {
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adc->config = newconfig;
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ret = 0;
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}
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return ret;
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}
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static int mcp3422_read(struct mcp3422 *adc, int *value, u8 *config)
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{
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int ret = 0;
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u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
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u8 buf[4] = {0, 0, 0, 0};
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u32 temp;
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if (sample_rate == MCP3422_SRATE_3) {
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ret = i2c_master_recv(adc->i2c, buf, 4);
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temp = get_unaligned_be24(&buf[0]);
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*config = buf[3];
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} else {
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ret = i2c_master_recv(adc->i2c, buf, 3);
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temp = get_unaligned_be16(&buf[0]);
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*config = buf[2];
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}
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*value = sign_extend32(temp, mcp3422_sign_extend[sample_rate]);
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return ret;
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}
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static int mcp3422_read_channel(struct mcp3422 *adc,
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struct iio_chan_spec const *channel, int *value)
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{
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int ret;
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u8 config;
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u8 req_channel = channel->channel;
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mutex_lock(&adc->lock);
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if (req_channel != MCP3422_CHANNEL(adc->config)) {
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config = adc->config;
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config &= ~MCP3422_CHANNEL_MASK;
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config |= MCP3422_CHANNEL_VALUE(req_channel);
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config &= ~MCP3422_PGA_MASK;
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config |= MCP3422_PGA_VALUE(adc->pga[req_channel]);
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ret = mcp3422_update_config(adc, config);
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if (ret < 0) {
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mutex_unlock(&adc->lock);
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return ret;
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}
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msleep(mcp3422_read_times[MCP3422_SAMPLE_RATE(adc->config)]);
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}
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ret = mcp3422_read(adc, value, &config);
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mutex_unlock(&adc->lock);
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return ret;
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}
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static int mcp3422_read_raw(struct iio_dev *iio,
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struct iio_chan_spec const *channel, int *val1,
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int *val2, long mask)
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{
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struct mcp3422 *adc = iio_priv(iio);
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int err;
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u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
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u8 pga = MCP3422_PGA(adc->config);
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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err = mcp3422_read_channel(adc, channel, val1);
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if (err < 0)
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return -EINVAL;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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*val1 = 0;
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*val2 = mcp3422_scales[sample_rate][pga];
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return IIO_VAL_INT_PLUS_NANO;
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case IIO_CHAN_INFO_SAMP_FREQ:
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*val1 = mcp3422_sample_rates[MCP3422_SAMPLE_RATE(adc->config)];
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return IIO_VAL_INT;
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default:
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break;
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}
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return -EINVAL;
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}
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static int mcp3422_write_raw(struct iio_dev *iio,
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struct iio_chan_spec const *channel, int val1,
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int val2, long mask)
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{
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struct mcp3422 *adc = iio_priv(iio);
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u8 temp;
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u8 config = adc->config;
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u8 req_channel = channel->channel;
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u8 sample_rate = MCP3422_SAMPLE_RATE(config);
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u8 i;
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switch (mask) {
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case IIO_CHAN_INFO_SCALE:
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if (val1 != 0)
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return -EINVAL;
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for (i = 0; i < ARRAY_SIZE(mcp3422_scales[0]); i++) {
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if (val2 == mcp3422_scales[sample_rate][i]) {
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adc->pga[req_channel] = i;
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config &= ~MCP3422_CHANNEL_MASK;
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config |= MCP3422_CHANNEL_VALUE(req_channel);
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config &= ~MCP3422_PGA_MASK;
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config |= MCP3422_PGA_VALUE(adc->pga[req_channel]);
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return mcp3422_update_config(adc, config);
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}
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}
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return -EINVAL;
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case IIO_CHAN_INFO_SAMP_FREQ:
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switch (val1) {
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case 240:
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temp = MCP3422_SRATE_240;
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break;
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case 60:
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temp = MCP3422_SRATE_60;
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break;
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case 15:
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temp = MCP3422_SRATE_15;
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break;
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case 3:
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if (adc->id > 4)
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return -EINVAL;
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temp = MCP3422_SRATE_3;
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break;
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default:
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return -EINVAL;
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}
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config &= ~MCP3422_CHANNEL_MASK;
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config |= MCP3422_CHANNEL_VALUE(req_channel);
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config &= ~MCP3422_SRATE_MASK;
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config |= MCP3422_SAMPLE_RATE_VALUE(temp);
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return mcp3422_update_config(adc, config);
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default:
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break;
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}
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return -EINVAL;
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}
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static int mcp3422_write_raw_get_fmt(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan, long mask)
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{
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switch (mask) {
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case IIO_CHAN_INFO_SCALE:
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return IIO_VAL_INT_PLUS_NANO;
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case IIO_CHAN_INFO_SAMP_FREQ:
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return IIO_VAL_INT_PLUS_MICRO;
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default:
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return -EINVAL;
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}
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}
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static ssize_t mcp3422_show_samp_freqs(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct mcp3422 *adc = iio_priv(dev_to_iio_dev(dev));
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if (adc->id > 4)
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return sprintf(buf, "240 60 15\n");
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return sprintf(buf, "240 60 15 3\n");
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}
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static ssize_t mcp3422_show_scales(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct mcp3422 *adc = iio_priv(dev_to_iio_dev(dev));
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u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config);
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return sprintf(buf, "0.%09u 0.%09u 0.%09u 0.%09u\n",
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mcp3422_scales[sample_rate][0],
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mcp3422_scales[sample_rate][1],
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mcp3422_scales[sample_rate][2],
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mcp3422_scales[sample_rate][3]);
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}
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static IIO_DEVICE_ATTR(sampling_frequency_available, S_IRUGO,
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mcp3422_show_samp_freqs, NULL, 0);
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static IIO_DEVICE_ATTR(in_voltage_scale_available, S_IRUGO,
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mcp3422_show_scales, NULL, 0);
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static struct attribute *mcp3422_attributes[] = {
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&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
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&iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group mcp3422_attribute_group = {
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.attrs = mcp3422_attributes,
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};
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static const struct iio_chan_spec mcp3421_channels[] = {
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MCP3422_CHAN(0),
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};
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static const struct iio_chan_spec mcp3422_channels[] = {
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MCP3422_CHAN(0),
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MCP3422_CHAN(1),
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};
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static const struct iio_chan_spec mcp3424_channels[] = {
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MCP3422_CHAN(0),
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MCP3422_CHAN(1),
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MCP3422_CHAN(2),
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MCP3422_CHAN(3),
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};
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static const struct iio_info mcp3422_info = {
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.read_raw = mcp3422_read_raw,
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.write_raw = mcp3422_write_raw,
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.write_raw_get_fmt = mcp3422_write_raw_get_fmt,
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.attrs = &mcp3422_attribute_group,
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};
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static int mcp3422_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct iio_dev *indio_dev;
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struct mcp3422 *adc;
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int err;
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u8 config;
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
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return -EOPNOTSUPP;
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indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*adc));
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if (!indio_dev)
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return -ENOMEM;
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adc = iio_priv(indio_dev);
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adc->i2c = client;
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adc->id = (u8)(id->driver_data);
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mutex_init(&adc->lock);
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indio_dev->name = dev_name(&client->dev);
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->info = &mcp3422_info;
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switch (adc->id) {
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case 1:
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case 5:
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indio_dev->channels = mcp3421_channels;
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indio_dev->num_channels = ARRAY_SIZE(mcp3421_channels);
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break;
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case 2:
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case 3:
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case 6:
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case 7:
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indio_dev->channels = mcp3422_channels;
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indio_dev->num_channels = ARRAY_SIZE(mcp3422_channels);
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break;
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case 4:
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case 8:
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indio_dev->channels = mcp3424_channels;
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indio_dev->num_channels = ARRAY_SIZE(mcp3424_channels);
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break;
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}
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/* meaningful default configuration */
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config = (MCP3422_CONT_SAMPLING
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| MCP3422_CHANNEL_VALUE(0)
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| MCP3422_PGA_VALUE(MCP3422_PGA_1)
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| MCP3422_SAMPLE_RATE_VALUE(MCP3422_SRATE_240));
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err = mcp3422_update_config(adc, config);
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if (err < 0)
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return err;
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err = devm_iio_device_register(&client->dev, indio_dev);
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if (err < 0)
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return err;
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i2c_set_clientdata(client, indio_dev);
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return 0;
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}
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static const struct i2c_device_id mcp3422_id[] = {
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{ "mcp3421", 1 },
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{ "mcp3422", 2 },
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{ "mcp3423", 3 },
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{ "mcp3424", 4 },
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{ "mcp3425", 5 },
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{ "mcp3426", 6 },
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{ "mcp3427", 7 },
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{ "mcp3428", 8 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, mcp3422_id);
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static const struct of_device_id mcp3422_of_match[] = {
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{ .compatible = "mcp3422" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, mcp3422_of_match);
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static struct i2c_driver mcp3422_driver = {
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.driver = {
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.name = "mcp3422",
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.of_match_table = mcp3422_of_match,
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},
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.probe = mcp3422_probe,
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.id_table = mcp3422_id,
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};
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module_i2c_driver(mcp3422_driver);
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MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
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MODULE_DESCRIPTION("Microchip mcp3421/2/3/4/5/6/7/8 driver");
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MODULE_LICENSE("GPL v2");
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