520 lines
13 KiB
C
520 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2013 Oskar Andero <oskar.andero@gmail.com>
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* Copyright (C) 2014 Rose Technology
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* Allan Bendorff Jensen <abj@rosetechnology.dk>
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* Soren Andersen <san@rosetechnology.dk>
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*
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* Driver for following ADC chips from Microchip Technology's:
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* 10 Bit converter
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* MCP3001
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* MCP3002
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* MCP3004
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* MCP3008
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* ------------
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* 12 bit converter
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* MCP3201
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* MCP3202
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* MCP3204
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* MCP3208
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* ------------
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* 13 bit converter
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* MCP3301
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* ------------
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* 22 bit converter
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* MCP3550
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* MCP3551
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* MCP3553
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*
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* Datasheet can be found here:
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* https://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf mcp3001
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* https://ww1.microchip.com/downloads/en/DeviceDoc/21294E.pdf mcp3002
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* https://ww1.microchip.com/downloads/en/DeviceDoc/21295d.pdf mcp3004/08
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* http://ww1.microchip.com/downloads/en/DeviceDoc/21290D.pdf mcp3201
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* http://ww1.microchip.com/downloads/en/DeviceDoc/21034D.pdf mcp3202
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* http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf mcp3204/08
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* https://ww1.microchip.com/downloads/en/DeviceDoc/21700E.pdf mcp3301
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* http://ww1.microchip.com/downloads/en/DeviceDoc/21950D.pdf mcp3550/1/3
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*/
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#include <linux/err.h>
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#include <linux/delay.h>
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#include <linux/spi/spi.h>
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#include <linux/module.h>
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#include <linux/mod_devicetable.h>
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#include <linux/iio/iio.h>
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#include <linux/regulator/consumer.h>
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enum {
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mcp3001,
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mcp3002,
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mcp3004,
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mcp3008,
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mcp3201,
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mcp3202,
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mcp3204,
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mcp3208,
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mcp3301,
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mcp3550_50,
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mcp3550_60,
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mcp3551,
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mcp3553,
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};
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struct mcp320x_chip_info {
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const struct iio_chan_spec *channels;
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unsigned int num_channels;
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unsigned int resolution;
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unsigned int conv_time; /* usec */
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};
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/**
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* struct mcp320x - Microchip SPI ADC instance
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* @spi: SPI slave (parent of the IIO device)
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* @msg: SPI message to select a channel and receive a value from the ADC
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* @transfer: SPI transfers used by @msg
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* @start_conv_msg: SPI message to start a conversion by briefly asserting CS
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* @start_conv_transfer: SPI transfer used by @start_conv_msg
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* @reg: regulator generating Vref
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* @lock: protects read sequences
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* @chip_info: ADC properties
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* @tx_buf: buffer for @transfer[0] (not used on single-channel converters)
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* @rx_buf: buffer for @transfer[1]
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*/
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struct mcp320x {
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struct spi_device *spi;
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struct spi_message msg;
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struct spi_transfer transfer[2];
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struct spi_message start_conv_msg;
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struct spi_transfer start_conv_transfer;
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struct regulator *reg;
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struct mutex lock;
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const struct mcp320x_chip_info *chip_info;
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u8 tx_buf __aligned(IIO_DMA_MINALIGN);
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u8 rx_buf[4];
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};
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static int mcp320x_channel_to_tx_data(int device_index,
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const unsigned int channel, bool differential)
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{
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int start_bit = 1;
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switch (device_index) {
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case mcp3002:
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case mcp3202:
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return ((start_bit << 4) | (!differential << 3) |
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(channel << 2));
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case mcp3004:
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case mcp3204:
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case mcp3008:
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case mcp3208:
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return ((start_bit << 6) | (!differential << 5) |
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(channel << 2));
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default:
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return -EINVAL;
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}
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}
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static int mcp320x_adc_conversion(struct mcp320x *adc, u8 channel,
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bool differential, int device_index, int *val)
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{
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int ret;
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if (adc->chip_info->conv_time) {
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ret = spi_sync(adc->spi, &adc->start_conv_msg);
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if (ret < 0)
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return ret;
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usleep_range(adc->chip_info->conv_time,
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adc->chip_info->conv_time + 100);
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}
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memset(&adc->rx_buf, 0, sizeof(adc->rx_buf));
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if (adc->chip_info->num_channels > 1)
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adc->tx_buf = mcp320x_channel_to_tx_data(device_index, channel,
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differential);
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ret = spi_sync(adc->spi, &adc->msg);
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if (ret < 0)
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return ret;
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switch (device_index) {
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case mcp3001:
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*val = (adc->rx_buf[0] << 5 | adc->rx_buf[1] >> 3);
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return 0;
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case mcp3002:
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case mcp3004:
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case mcp3008:
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*val = (adc->rx_buf[0] << 2 | adc->rx_buf[1] >> 6);
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return 0;
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case mcp3201:
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*val = (adc->rx_buf[0] << 7 | adc->rx_buf[1] >> 1);
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return 0;
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case mcp3202:
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case mcp3204:
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case mcp3208:
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*val = (adc->rx_buf[0] << 4 | adc->rx_buf[1] >> 4);
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return 0;
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case mcp3301:
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*val = sign_extend32((adc->rx_buf[0] & 0x1f) << 8
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| adc->rx_buf[1], 12);
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return 0;
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case mcp3550_50:
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case mcp3550_60:
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case mcp3551:
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case mcp3553: {
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u32 raw = be32_to_cpup((__be32 *)adc->rx_buf);
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if (!(adc->spi->mode & SPI_CPOL))
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raw <<= 1; /* strip Data Ready bit in SPI mode 0,0 */
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/*
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* If the input is within -vref and vref, bit 21 is the sign.
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* Up to 12% overrange or underrange are allowed, in which case
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* bit 23 is the sign and bit 0 to 21 is the value.
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*/
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raw >>= 8;
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if (raw & BIT(22) && raw & BIT(23))
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return -EIO; /* cannot have overrange AND underrange */
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else if (raw & BIT(22))
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raw &= ~BIT(22); /* overrange */
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else if (raw & BIT(23) || raw & BIT(21))
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raw |= GENMASK(31, 22); /* underrange or negative */
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*val = (s32)raw;
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return 0;
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}
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default:
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return -EINVAL;
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}
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}
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static int mcp320x_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *channel, int *val,
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int *val2, long mask)
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{
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struct mcp320x *adc = iio_priv(indio_dev);
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int ret = -EINVAL;
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int device_index = 0;
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mutex_lock(&adc->lock);
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device_index = spi_get_device_id(adc->spi)->driver_data;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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ret = mcp320x_adc_conversion(adc, channel->address,
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channel->differential, device_index, val);
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if (ret < 0)
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goto out;
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ret = IIO_VAL_INT;
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break;
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case IIO_CHAN_INFO_SCALE:
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ret = regulator_get_voltage(adc->reg);
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if (ret < 0)
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goto out;
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/* convert regulator output voltage to mV */
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*val = ret / 1000;
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*val2 = adc->chip_info->resolution;
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ret = IIO_VAL_FRACTIONAL_LOG2;
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break;
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}
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out:
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mutex_unlock(&adc->lock);
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return ret;
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}
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#define MCP320X_VOLTAGE_CHANNEL(num) \
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{ \
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.type = IIO_VOLTAGE, \
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.indexed = 1, \
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.channel = (num), \
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.address = (num), \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
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}
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#define MCP320X_VOLTAGE_CHANNEL_DIFF(chan1, chan2) \
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{ \
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.type = IIO_VOLTAGE, \
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.indexed = 1, \
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.channel = (chan1), \
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.channel2 = (chan2), \
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.address = (chan1), \
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.differential = 1, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
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}
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static const struct iio_chan_spec mcp3201_channels[] = {
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MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
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};
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static const struct iio_chan_spec mcp3202_channels[] = {
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MCP320X_VOLTAGE_CHANNEL(0),
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MCP320X_VOLTAGE_CHANNEL(1),
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MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
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MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
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};
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static const struct iio_chan_spec mcp3204_channels[] = {
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MCP320X_VOLTAGE_CHANNEL(0),
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MCP320X_VOLTAGE_CHANNEL(1),
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MCP320X_VOLTAGE_CHANNEL(2),
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MCP320X_VOLTAGE_CHANNEL(3),
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MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
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MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
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MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
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MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
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};
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static const struct iio_chan_spec mcp3208_channels[] = {
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MCP320X_VOLTAGE_CHANNEL(0),
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MCP320X_VOLTAGE_CHANNEL(1),
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MCP320X_VOLTAGE_CHANNEL(2),
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MCP320X_VOLTAGE_CHANNEL(3),
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MCP320X_VOLTAGE_CHANNEL(4),
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MCP320X_VOLTAGE_CHANNEL(5),
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MCP320X_VOLTAGE_CHANNEL(6),
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MCP320X_VOLTAGE_CHANNEL(7),
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MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
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MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
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MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
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MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
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MCP320X_VOLTAGE_CHANNEL_DIFF(4, 5),
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MCP320X_VOLTAGE_CHANNEL_DIFF(5, 4),
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MCP320X_VOLTAGE_CHANNEL_DIFF(6, 7),
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MCP320X_VOLTAGE_CHANNEL_DIFF(7, 6),
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};
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static const struct iio_info mcp320x_info = {
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.read_raw = mcp320x_read_raw,
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};
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static const struct mcp320x_chip_info mcp320x_chip_infos[] = {
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[mcp3001] = {
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.channels = mcp3201_channels,
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.num_channels = ARRAY_SIZE(mcp3201_channels),
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.resolution = 10
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},
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[mcp3002] = {
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.channels = mcp3202_channels,
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.num_channels = ARRAY_SIZE(mcp3202_channels),
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.resolution = 10
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},
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[mcp3004] = {
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.channels = mcp3204_channels,
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.num_channels = ARRAY_SIZE(mcp3204_channels),
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.resolution = 10
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},
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[mcp3008] = {
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.channels = mcp3208_channels,
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.num_channels = ARRAY_SIZE(mcp3208_channels),
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.resolution = 10
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},
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[mcp3201] = {
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.channels = mcp3201_channels,
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.num_channels = ARRAY_SIZE(mcp3201_channels),
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.resolution = 12
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},
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[mcp3202] = {
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.channels = mcp3202_channels,
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.num_channels = ARRAY_SIZE(mcp3202_channels),
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.resolution = 12
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},
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[mcp3204] = {
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.channels = mcp3204_channels,
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.num_channels = ARRAY_SIZE(mcp3204_channels),
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.resolution = 12
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},
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[mcp3208] = {
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.channels = mcp3208_channels,
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.num_channels = ARRAY_SIZE(mcp3208_channels),
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.resolution = 12
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},
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[mcp3301] = {
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.channels = mcp3201_channels,
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.num_channels = ARRAY_SIZE(mcp3201_channels),
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.resolution = 13
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},
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[mcp3550_50] = {
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.channels = mcp3201_channels,
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.num_channels = ARRAY_SIZE(mcp3201_channels),
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.resolution = 21,
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/* 2% max deviation + 144 clock periods to exit shutdown */
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.conv_time = 80000 * 1.02 + 144000 / 102.4,
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},
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[mcp3550_60] = {
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.channels = mcp3201_channels,
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.num_channels = ARRAY_SIZE(mcp3201_channels),
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.resolution = 21,
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.conv_time = 66670 * 1.02 + 144000 / 122.88,
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},
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[mcp3551] = {
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.channels = mcp3201_channels,
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.num_channels = ARRAY_SIZE(mcp3201_channels),
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.resolution = 21,
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.conv_time = 73100 * 1.02 + 144000 / 112.64,
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},
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[mcp3553] = {
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.channels = mcp3201_channels,
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.num_channels = ARRAY_SIZE(mcp3201_channels),
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.resolution = 21,
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.conv_time = 16670 * 1.02 + 144000 / 122.88,
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},
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};
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static void mcp320x_regulator_disable(void *reg)
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{
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regulator_disable(reg);
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}
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static int mcp320x_probe(struct spi_device *spi)
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{
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struct iio_dev *indio_dev;
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struct mcp320x *adc;
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const struct mcp320x_chip_info *chip_info;
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int ret, device_index;
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indio_dev = devm_iio_device_alloc(&spi->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->spi = spi;
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indio_dev->name = spi_get_device_id(spi)->name;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->info = &mcp320x_info;
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device_index = spi_get_device_id(spi)->driver_data;
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chip_info = &mcp320x_chip_infos[device_index];
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indio_dev->channels = chip_info->channels;
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indio_dev->num_channels = chip_info->num_channels;
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adc->chip_info = chip_info;
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adc->transfer[0].tx_buf = &adc->tx_buf;
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adc->transfer[0].len = sizeof(adc->tx_buf);
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adc->transfer[1].rx_buf = adc->rx_buf;
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adc->transfer[1].len = DIV_ROUND_UP(chip_info->resolution, 8);
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if (chip_info->num_channels == 1)
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/* single-channel converters are rx only (no MOSI pin) */
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spi_message_init_with_transfers(&adc->msg,
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&adc->transfer[1], 1);
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else
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spi_message_init_with_transfers(&adc->msg, adc->transfer,
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ARRAY_SIZE(adc->transfer));
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switch (device_index) {
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case mcp3550_50:
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case mcp3550_60:
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case mcp3551:
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case mcp3553:
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/* rx len increases from 24 to 25 bit in SPI mode 0,0 */
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if (!(spi->mode & SPI_CPOL))
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adc->transfer[1].len++;
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/* conversions are started by asserting CS pin for 8 usec */
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adc->start_conv_transfer.delay.value = 8;
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adc->start_conv_transfer.delay.unit = SPI_DELAY_UNIT_USECS;
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spi_message_init_with_transfers(&adc->start_conv_msg,
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&adc->start_conv_transfer, 1);
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/*
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* If CS was previously kept low (continuous conversion mode)
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* and then changed to high, the chip is in shutdown.
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* Sometimes it fails to wake from shutdown and clocks out
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* only 0xffffff. The magic sequence of performing two
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* conversions without delay between them resets the chip
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* and ensures all subsequent conversions succeed.
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*/
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mcp320x_adc_conversion(adc, 0, 1, device_index, &ret);
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mcp320x_adc_conversion(adc, 0, 1, device_index, &ret);
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}
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adc->reg = devm_regulator_get(&spi->dev, "vref");
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if (IS_ERR(adc->reg))
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return PTR_ERR(adc->reg);
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ret = regulator_enable(adc->reg);
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if (ret < 0)
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return ret;
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ret = devm_add_action_or_reset(&spi->dev, mcp320x_regulator_disable, adc->reg);
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if (ret < 0)
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return ret;
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mutex_init(&adc->lock);
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return devm_iio_device_register(&spi->dev, indio_dev);
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}
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static const struct of_device_id mcp320x_dt_ids[] = {
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/* NOTE: The use of compatibles with no vendor prefix is deprecated. */
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{ .compatible = "mcp3001" },
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{ .compatible = "mcp3002" },
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{ .compatible = "mcp3004" },
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{ .compatible = "mcp3008" },
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{ .compatible = "mcp3201" },
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{ .compatible = "mcp3202" },
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{ .compatible = "mcp3204" },
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{ .compatible = "mcp3208" },
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{ .compatible = "mcp3301" },
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{ .compatible = "microchip,mcp3001" },
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{ .compatible = "microchip,mcp3002" },
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{ .compatible = "microchip,mcp3004" },
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{ .compatible = "microchip,mcp3008" },
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{ .compatible = "microchip,mcp3201" },
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{ .compatible = "microchip,mcp3202" },
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{ .compatible = "microchip,mcp3204" },
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{ .compatible = "microchip,mcp3208" },
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{ .compatible = "microchip,mcp3301" },
|
|
{ .compatible = "microchip,mcp3550-50" },
|
|
{ .compatible = "microchip,mcp3550-60" },
|
|
{ .compatible = "microchip,mcp3551" },
|
|
{ .compatible = "microchip,mcp3553" },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(of, mcp320x_dt_ids);
|
|
|
|
static const struct spi_device_id mcp320x_id[] = {
|
|
{ "mcp3001", mcp3001 },
|
|
{ "mcp3002", mcp3002 },
|
|
{ "mcp3004", mcp3004 },
|
|
{ "mcp3008", mcp3008 },
|
|
{ "mcp3201", mcp3201 },
|
|
{ "mcp3202", mcp3202 },
|
|
{ "mcp3204", mcp3204 },
|
|
{ "mcp3208", mcp3208 },
|
|
{ "mcp3301", mcp3301 },
|
|
{ "mcp3550-50", mcp3550_50 },
|
|
{ "mcp3550-60", mcp3550_60 },
|
|
{ "mcp3551", mcp3551 },
|
|
{ "mcp3553", mcp3553 },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(spi, mcp320x_id);
|
|
|
|
static struct spi_driver mcp320x_driver = {
|
|
.driver = {
|
|
.name = "mcp320x",
|
|
.of_match_table = mcp320x_dt_ids,
|
|
},
|
|
.probe = mcp320x_probe,
|
|
.id_table = mcp320x_id,
|
|
};
|
|
module_spi_driver(mcp320x_driver);
|
|
|
|
MODULE_AUTHOR("Oskar Andero <oskar.andero@gmail.com>");
|
|
MODULE_DESCRIPTION("Microchip Technology MCP3x01/02/04/08 and MCP3550/1/3");
|
|
MODULE_LICENSE("GPL v2");
|