![Gregor Boirie](/assets/img/avatar_default.png)
Adds a new per-device sysfs attribute "current_timestamp_clock" to allow userspace to select a particular POSIX clock for buffered samples and events timestamping. Following clocks, as listed in clock_gettime(2), are supported: CLOCK_REALTIME, CLOCK_MONOTONIC, CLOCK_MONOTONIC_RAW, CLOCK_REALTIME_COARSE, CLOCK_MONOTONIC_COARSE, CLOCK_BOOTTIME and CLOCK_TAI. Signed-off-by: Gregor Boirie <gregor.boirie@parrot.com> Acked-by: Sanchayan Maity <maitysanchayan@gmail.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
448 lines
11 KiB
C
448 lines
11 KiB
C
/*
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* Copyright (c) 2014-2015 Imagination Technologies Ltd.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*
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*/
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#include <linux/clk.h>
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/regulator/consumer.h>
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#include <linux/slab.h>
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#include <linux/iio/buffer.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/sysfs.h>
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#include <linux/iio/trigger.h>
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#include <linux/iio/trigger_consumer.h>
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#include <linux/iio/triggered_buffer.h>
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/* Registers */
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#define CC10001_ADC_CONFIG 0x00
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#define CC10001_ADC_START_CONV BIT(4)
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#define CC10001_ADC_MODE_SINGLE_CONV BIT(5)
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#define CC10001_ADC_DDATA_OUT 0x04
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#define CC10001_ADC_EOC 0x08
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#define CC10001_ADC_EOC_SET BIT(0)
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#define CC10001_ADC_CHSEL_SAMPLED 0x0c
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#define CC10001_ADC_POWER_DOWN 0x10
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#define CC10001_ADC_POWER_DOWN_SET BIT(0)
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#define CC10001_ADC_DEBUG 0x14
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#define CC10001_ADC_DATA_COUNT 0x20
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#define CC10001_ADC_DATA_MASK GENMASK(9, 0)
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#define CC10001_ADC_NUM_CHANNELS 8
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#define CC10001_ADC_CH_MASK GENMASK(2, 0)
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#define CC10001_INVALID_SAMPLED 0xffff
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#define CC10001_MAX_POLL_COUNT 20
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/*
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* As per device specification, wait six clock cycles after power-up to
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* activate START. Since adding two more clock cycles delay does not
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* impact the performance too much, we are adding two additional cycles delay
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* intentionally here.
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*/
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#define CC10001_WAIT_CYCLES 8
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struct cc10001_adc_device {
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void __iomem *reg_base;
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struct clk *adc_clk;
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struct regulator *reg;
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u16 *buf;
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bool shared;
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struct mutex lock;
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unsigned int start_delay_ns;
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unsigned int eoc_delay_ns;
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};
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static inline void cc10001_adc_write_reg(struct cc10001_adc_device *adc_dev,
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u32 reg, u32 val)
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{
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writel(val, adc_dev->reg_base + reg);
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}
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static inline u32 cc10001_adc_read_reg(struct cc10001_adc_device *adc_dev,
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u32 reg)
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{
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return readl(adc_dev->reg_base + reg);
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}
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static void cc10001_adc_power_up(struct cc10001_adc_device *adc_dev)
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{
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cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_DOWN, 0);
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ndelay(adc_dev->start_delay_ns);
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}
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static void cc10001_adc_power_down(struct cc10001_adc_device *adc_dev)
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{
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cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_DOWN,
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CC10001_ADC_POWER_DOWN_SET);
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}
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static void cc10001_adc_start(struct cc10001_adc_device *adc_dev,
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unsigned int channel)
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{
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u32 val;
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/* Channel selection and mode of operation */
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val = (channel & CC10001_ADC_CH_MASK) | CC10001_ADC_MODE_SINGLE_CONV;
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cc10001_adc_write_reg(adc_dev, CC10001_ADC_CONFIG, val);
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udelay(1);
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val = cc10001_adc_read_reg(adc_dev, CC10001_ADC_CONFIG);
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val = val | CC10001_ADC_START_CONV;
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cc10001_adc_write_reg(adc_dev, CC10001_ADC_CONFIG, val);
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}
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static u16 cc10001_adc_poll_done(struct iio_dev *indio_dev,
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unsigned int channel,
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unsigned int delay)
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{
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struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
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unsigned int poll_count = 0;
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while (!(cc10001_adc_read_reg(adc_dev, CC10001_ADC_EOC) &
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CC10001_ADC_EOC_SET)) {
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ndelay(delay);
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if (poll_count++ == CC10001_MAX_POLL_COUNT)
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return CC10001_INVALID_SAMPLED;
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}
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poll_count = 0;
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while ((cc10001_adc_read_reg(adc_dev, CC10001_ADC_CHSEL_SAMPLED) &
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CC10001_ADC_CH_MASK) != channel) {
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ndelay(delay);
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if (poll_count++ == CC10001_MAX_POLL_COUNT)
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return CC10001_INVALID_SAMPLED;
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}
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/* Read the 10 bit output register */
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return cc10001_adc_read_reg(adc_dev, CC10001_ADC_DDATA_OUT) &
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CC10001_ADC_DATA_MASK;
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}
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static irqreturn_t cc10001_adc_trigger_h(int irq, void *p)
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{
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struct cc10001_adc_device *adc_dev;
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struct iio_poll_func *pf = p;
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struct iio_dev *indio_dev;
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unsigned int delay_ns;
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unsigned int channel;
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unsigned int scan_idx;
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bool sample_invalid;
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u16 *data;
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int i;
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indio_dev = pf->indio_dev;
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adc_dev = iio_priv(indio_dev);
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data = adc_dev->buf;
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mutex_lock(&adc_dev->lock);
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if (!adc_dev->shared)
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cc10001_adc_power_up(adc_dev);
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/* Calculate delay step for eoc and sampled data */
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delay_ns = adc_dev->eoc_delay_ns / CC10001_MAX_POLL_COUNT;
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i = 0;
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sample_invalid = false;
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for_each_set_bit(scan_idx, indio_dev->active_scan_mask,
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indio_dev->masklength) {
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channel = indio_dev->channels[scan_idx].channel;
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cc10001_adc_start(adc_dev, channel);
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data[i] = cc10001_adc_poll_done(indio_dev, channel, delay_ns);
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if (data[i] == CC10001_INVALID_SAMPLED) {
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dev_warn(&indio_dev->dev,
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"invalid sample on channel %d\n", channel);
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sample_invalid = true;
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goto done;
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}
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i++;
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}
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done:
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if (!adc_dev->shared)
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cc10001_adc_power_down(adc_dev);
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mutex_unlock(&adc_dev->lock);
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if (!sample_invalid)
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iio_push_to_buffers_with_timestamp(indio_dev, data,
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iio_get_time_ns(indio_dev));
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iio_trigger_notify_done(indio_dev->trig);
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return IRQ_HANDLED;
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}
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static u16 cc10001_adc_read_raw_voltage(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan)
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{
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struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
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unsigned int delay_ns;
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u16 val;
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if (!adc_dev->shared)
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cc10001_adc_power_up(adc_dev);
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/* Calculate delay step for eoc and sampled data */
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delay_ns = adc_dev->eoc_delay_ns / CC10001_MAX_POLL_COUNT;
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cc10001_adc_start(adc_dev, chan->channel);
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val = cc10001_adc_poll_done(indio_dev, chan->channel, delay_ns);
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if (!adc_dev->shared)
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cc10001_adc_power_down(adc_dev);
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return val;
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}
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static int cc10001_adc_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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if (iio_buffer_enabled(indio_dev))
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return -EBUSY;
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mutex_lock(&adc_dev->lock);
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*val = cc10001_adc_read_raw_voltage(indio_dev, chan);
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mutex_unlock(&adc_dev->lock);
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if (*val == CC10001_INVALID_SAMPLED)
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return -EIO;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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ret = regulator_get_voltage(adc_dev->reg);
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if (ret < 0)
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return ret;
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*val = ret / 1000;
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*val2 = chan->scan_type.realbits;
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return IIO_VAL_FRACTIONAL_LOG2;
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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 cc10001_update_scan_mode(struct iio_dev *indio_dev,
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const unsigned long *scan_mask)
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{
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struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
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kfree(adc_dev->buf);
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adc_dev->buf = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
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if (!adc_dev->buf)
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return -ENOMEM;
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return 0;
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}
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static const struct iio_info cc10001_adc_info = {
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.driver_module = THIS_MODULE,
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.read_raw = &cc10001_adc_read_raw,
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.update_scan_mode = &cc10001_update_scan_mode,
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};
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static int cc10001_adc_channel_init(struct iio_dev *indio_dev,
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unsigned long channel_map)
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{
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struct iio_chan_spec *chan_array, *timestamp;
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unsigned int bit, idx = 0;
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indio_dev->num_channels = bitmap_weight(&channel_map,
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CC10001_ADC_NUM_CHANNELS) + 1;
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chan_array = devm_kcalloc(&indio_dev->dev, indio_dev->num_channels,
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sizeof(struct iio_chan_spec),
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GFP_KERNEL);
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if (!chan_array)
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return -ENOMEM;
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for_each_set_bit(bit, &channel_map, CC10001_ADC_NUM_CHANNELS) {
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struct iio_chan_spec *chan = &chan_array[idx];
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chan->type = IIO_VOLTAGE;
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chan->indexed = 1;
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chan->channel = bit;
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chan->scan_index = idx;
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chan->scan_type.sign = 'u';
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chan->scan_type.realbits = 10;
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chan->scan_type.storagebits = 16;
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chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
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chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
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idx++;
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}
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timestamp = &chan_array[idx];
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timestamp->type = IIO_TIMESTAMP;
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timestamp->channel = -1;
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timestamp->scan_index = idx;
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timestamp->scan_type.sign = 's';
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timestamp->scan_type.realbits = 64;
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timestamp->scan_type.storagebits = 64;
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indio_dev->channels = chan_array;
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return 0;
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}
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static int cc10001_adc_probe(struct platform_device *pdev)
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{
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struct device_node *node = pdev->dev.of_node;
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struct cc10001_adc_device *adc_dev;
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unsigned long adc_clk_rate;
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struct resource *res;
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struct iio_dev *indio_dev;
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unsigned long channel_map;
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int ret;
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indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc_dev));
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if (indio_dev == NULL)
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return -ENOMEM;
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adc_dev = iio_priv(indio_dev);
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channel_map = GENMASK(CC10001_ADC_NUM_CHANNELS - 1, 0);
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if (!of_property_read_u32(node, "adc-reserved-channels", &ret)) {
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adc_dev->shared = true;
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channel_map &= ~ret;
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}
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adc_dev->reg = devm_regulator_get(&pdev->dev, "vref");
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if (IS_ERR(adc_dev->reg))
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return PTR_ERR(adc_dev->reg);
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ret = regulator_enable(adc_dev->reg);
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if (ret)
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return ret;
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indio_dev->dev.parent = &pdev->dev;
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indio_dev->name = dev_name(&pdev->dev);
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indio_dev->info = &cc10001_adc_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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adc_dev->reg_base = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(adc_dev->reg_base)) {
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ret = PTR_ERR(adc_dev->reg_base);
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goto err_disable_reg;
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}
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adc_dev->adc_clk = devm_clk_get(&pdev->dev, "adc");
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if (IS_ERR(adc_dev->adc_clk)) {
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dev_err(&pdev->dev, "failed to get the clock\n");
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ret = PTR_ERR(adc_dev->adc_clk);
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goto err_disable_reg;
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}
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ret = clk_prepare_enable(adc_dev->adc_clk);
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if (ret) {
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dev_err(&pdev->dev, "failed to enable the clock\n");
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goto err_disable_reg;
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}
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adc_clk_rate = clk_get_rate(adc_dev->adc_clk);
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if (!adc_clk_rate) {
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ret = -EINVAL;
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dev_err(&pdev->dev, "null clock rate!\n");
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goto err_disable_clk;
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}
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adc_dev->eoc_delay_ns = NSEC_PER_SEC / adc_clk_rate;
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adc_dev->start_delay_ns = adc_dev->eoc_delay_ns * CC10001_WAIT_CYCLES;
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/*
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* There is only one register to power-up/power-down the AUX ADC.
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* If the ADC is shared among multiple CPUs, always power it up here.
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* If the ADC is used only by the MIPS, power-up/power-down at runtime.
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*/
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if (adc_dev->shared)
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cc10001_adc_power_up(adc_dev);
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/* Setup the ADC channels available on the device */
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ret = cc10001_adc_channel_init(indio_dev, channel_map);
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if (ret < 0)
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goto err_disable_clk;
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mutex_init(&adc_dev->lock);
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ret = iio_triggered_buffer_setup(indio_dev, NULL,
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&cc10001_adc_trigger_h, NULL);
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if (ret < 0)
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goto err_disable_clk;
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ret = iio_device_register(indio_dev);
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if (ret < 0)
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goto err_cleanup_buffer;
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platform_set_drvdata(pdev, indio_dev);
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return 0;
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err_cleanup_buffer:
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iio_triggered_buffer_cleanup(indio_dev);
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err_disable_clk:
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clk_disable_unprepare(adc_dev->adc_clk);
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err_disable_reg:
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regulator_disable(adc_dev->reg);
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return ret;
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}
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static int cc10001_adc_remove(struct platform_device *pdev)
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{
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struct iio_dev *indio_dev = platform_get_drvdata(pdev);
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struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
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cc10001_adc_power_down(adc_dev);
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iio_device_unregister(indio_dev);
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iio_triggered_buffer_cleanup(indio_dev);
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clk_disable_unprepare(adc_dev->adc_clk);
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regulator_disable(adc_dev->reg);
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return 0;
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}
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static const struct of_device_id cc10001_adc_dt_ids[] = {
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{ .compatible = "cosmic,10001-adc", },
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{ }
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};
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MODULE_DEVICE_TABLE(of, cc10001_adc_dt_ids);
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static struct platform_driver cc10001_adc_driver = {
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.driver = {
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.name = "cc10001-adc",
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.of_match_table = cc10001_adc_dt_ids,
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},
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.probe = cc10001_adc_probe,
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.remove = cc10001_adc_remove,
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};
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module_platform_driver(cc10001_adc_driver);
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MODULE_AUTHOR("Phani Movva <Phani.Movva@imgtec.com>");
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MODULE_DESCRIPTION("Cosmic Circuits ADC driver");
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MODULE_LICENSE("GPL v2");
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