339 lines
8.1 KiB
C
339 lines
8.1 KiB
C
/*
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* TI ADC MFD driver
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*
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* Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation version 2.
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*
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* This program is distributed "as is" WITHOUT ANY WARRANTY of any
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* kind, whether express or implied; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/interrupt.h>
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#include <linux/platform_device.h>
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#include <linux/io.h>
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#include <linux/iio/iio.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/iio/machine.h>
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#include <linux/iio/driver.h>
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#include <linux/mfd/ti_am335x_tscadc.h>
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struct tiadc_device {
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struct ti_tscadc_dev *mfd_tscadc;
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int channels;
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u8 channel_line[8];
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u8 channel_step[8];
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};
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static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
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{
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return readl(adc->mfd_tscadc->tscadc_base + reg);
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}
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static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
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unsigned int val)
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{
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writel(val, adc->mfd_tscadc->tscadc_base + reg);
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}
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static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
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{
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u32 step_en;
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step_en = ((1 << adc_dev->channels) - 1);
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step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
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return step_en;
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}
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static void tiadc_step_config(struct tiadc_device *adc_dev)
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{
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unsigned int stepconfig;
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int i, steps;
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/*
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* There are 16 configurable steps and 8 analog input
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* lines available which are shared between Touchscreen and ADC.
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*
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* Steps backwards i.e. from 16 towards 0 are used by ADC
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* depending on number of input lines needed.
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* Channel would represent which analog input
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* needs to be given to ADC to digitalize data.
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*/
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steps = TOTAL_STEPS - adc_dev->channels;
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stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
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for (i = 0; i < adc_dev->channels; i++) {
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int chan;
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chan = adc_dev->channel_line[i];
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tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
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stepconfig | STEPCONFIG_INP(chan));
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tiadc_writel(adc_dev, REG_STEPDELAY(steps),
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STEPCONFIG_OPENDLY);
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adc_dev->channel_step[i] = steps;
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steps++;
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}
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}
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static const char * const chan_name_ain[] = {
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"AIN0",
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"AIN1",
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"AIN2",
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"AIN3",
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"AIN4",
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"AIN5",
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"AIN6",
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"AIN7",
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};
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static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
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{
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struct tiadc_device *adc_dev = iio_priv(indio_dev);
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struct iio_chan_spec *chan_array;
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struct iio_chan_spec *chan;
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int i;
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indio_dev->num_channels = channels;
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chan_array = kcalloc(channels,
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sizeof(struct iio_chan_spec), GFP_KERNEL);
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if (chan_array == NULL)
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return -ENOMEM;
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chan = chan_array;
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for (i = 0; i < channels; i++, chan++) {
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chan->type = IIO_VOLTAGE;
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chan->indexed = 1;
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chan->channel = adc_dev->channel_line[i];
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chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
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chan->datasheet_name = chan_name_ain[chan->channel];
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chan->scan_type.sign = 'u';
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chan->scan_type.realbits = 12;
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chan->scan_type.storagebits = 32;
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}
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indio_dev->channels = chan_array;
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return 0;
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}
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static void tiadc_channels_remove(struct iio_dev *indio_dev)
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{
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kfree(indio_dev->channels);
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}
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static int tiadc_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 tiadc_device *adc_dev = iio_priv(indio_dev);
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int i, map_val;
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unsigned int fifo1count, read, stepid;
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u32 step = UINT_MAX;
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bool found = false;
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u32 step_en;
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unsigned long timeout = jiffies + usecs_to_jiffies
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(IDLE_TIMEOUT * adc_dev->channels);
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step_en = get_adc_step_mask(adc_dev);
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am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en);
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/* Wait for ADC sequencer to complete sampling */
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while (tiadc_readl(adc_dev, REG_ADCFSM) & SEQ_STATUS) {
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if (time_after(jiffies, timeout))
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return -EAGAIN;
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}
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map_val = chan->channel + TOTAL_CHANNELS;
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/*
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* When the sub-system is first enabled,
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* the sequencer will always start with the
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* lowest step (1) and continue until step (16).
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* For ex: If we have enabled 4 ADC channels and
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* currently use only 1 out of them, the
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* sequencer still configures all the 4 steps,
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* leading to 3 unwanted data.
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* Hence we need to flush out this data.
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*/
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for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
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if (chan->channel == adc_dev->channel_line[i]) {
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step = adc_dev->channel_step[i];
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break;
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}
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}
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if (WARN_ON_ONCE(step == UINT_MAX))
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return -EINVAL;
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fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
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for (i = 0; i < fifo1count; i++) {
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read = tiadc_readl(adc_dev, REG_FIFO1);
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stepid = read & FIFOREAD_CHNLID_MASK;
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stepid = stepid >> 0x10;
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if (stepid == map_val) {
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read = read & FIFOREAD_DATA_MASK;
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found = true;
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*val = read;
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}
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}
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if (found == false)
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return -EBUSY;
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return IIO_VAL_INT;
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}
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static const struct iio_info tiadc_info = {
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.read_raw = &tiadc_read_raw,
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.driver_module = THIS_MODULE,
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};
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static int tiadc_probe(struct platform_device *pdev)
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{
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struct iio_dev *indio_dev;
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struct tiadc_device *adc_dev;
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struct device_node *node = pdev->dev.of_node;
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struct property *prop;
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const __be32 *cur;
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int err;
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u32 val;
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int channels = 0;
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if (!node) {
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dev_err(&pdev->dev, "Could not find valid DT data.\n");
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return -EINVAL;
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}
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indio_dev = devm_iio_device_alloc(&pdev->dev,
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sizeof(struct tiadc_device));
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if (indio_dev == NULL) {
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dev_err(&pdev->dev, "failed to allocate iio device\n");
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return -ENOMEM;
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}
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adc_dev = iio_priv(indio_dev);
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adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
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of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
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adc_dev->channel_line[channels] = val;
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channels++;
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}
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adc_dev->channels = channels;
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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->modes = INDIO_DIRECT_MODE;
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indio_dev->info = &tiadc_info;
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tiadc_step_config(adc_dev);
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err = tiadc_channel_init(indio_dev, adc_dev->channels);
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if (err < 0)
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return err;
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err = iio_device_register(indio_dev);
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if (err)
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goto err_free_channels;
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platform_set_drvdata(pdev, indio_dev);
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return 0;
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err_free_channels:
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tiadc_channels_remove(indio_dev);
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return err;
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}
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static int tiadc_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 tiadc_device *adc_dev = iio_priv(indio_dev);
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u32 step_en;
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iio_device_unregister(indio_dev);
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tiadc_channels_remove(indio_dev);
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step_en = get_adc_step_mask(adc_dev);
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am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
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return 0;
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}
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#ifdef CONFIG_PM
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static int tiadc_suspend(struct device *dev)
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{
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct tiadc_device *adc_dev = iio_priv(indio_dev);
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struct ti_tscadc_dev *tscadc_dev;
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unsigned int idle;
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tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
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if (!device_may_wakeup(tscadc_dev->dev)) {
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idle = tiadc_readl(adc_dev, REG_CTRL);
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idle &= ~(CNTRLREG_TSCSSENB);
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tiadc_writel(adc_dev, REG_CTRL, (idle |
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CNTRLREG_POWERDOWN));
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}
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return 0;
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}
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static int tiadc_resume(struct device *dev)
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{
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struct iio_dev *indio_dev = dev_get_drvdata(dev);
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struct tiadc_device *adc_dev = iio_priv(indio_dev);
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unsigned int restore;
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/* Make sure ADC is powered up */
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restore = tiadc_readl(adc_dev, REG_CTRL);
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restore &= ~(CNTRLREG_POWERDOWN);
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tiadc_writel(adc_dev, REG_CTRL, restore);
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tiadc_step_config(adc_dev);
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return 0;
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}
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static const struct dev_pm_ops tiadc_pm_ops = {
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.suspend = tiadc_suspend,
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.resume = tiadc_resume,
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};
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#define TIADC_PM_OPS (&tiadc_pm_ops)
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#else
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#define TIADC_PM_OPS NULL
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#endif
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static const struct of_device_id ti_adc_dt_ids[] = {
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{ .compatible = "ti,am3359-adc", },
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{ }
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};
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MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
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static struct platform_driver tiadc_driver = {
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.driver = {
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.name = "TI-am335x-adc",
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.owner = THIS_MODULE,
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.pm = TIADC_PM_OPS,
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.of_match_table = of_match_ptr(ti_adc_dt_ids),
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},
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.probe = tiadc_probe,
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.remove = tiadc_remove,
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};
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module_platform_driver(tiadc_driver);
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MODULE_DESCRIPTION("TI ADC controller driver");
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MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
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MODULE_LICENSE("GPL");
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