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linux-sg2042/drivers/iio/adc/ti_am335x_adc.c

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/*
* TI ADC MFD driver
*
* Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation version 2.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/iio/iio.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/iio/machine.h>
#include <linux/iio/driver.h>
#include <linux/mfd/ti_am335x_tscadc.h>
#include <linux/iio/buffer.h>
#include <linux/iio/kfifo_buf.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#define DMA_BUFFER_SIZE SZ_2K
struct tiadc_dma {
struct dma_slave_config conf;
struct dma_chan *chan;
dma_addr_t addr;
dma_cookie_t cookie;
u8 *buf;
int current_period;
int period_size;
u8 fifo_thresh;
};
struct tiadc_device {
struct ti_tscadc_dev *mfd_tscadc;
struct tiadc_dma dma;
struct mutex fifo1_lock; /* to protect fifo access */
int channels;
int total_ch_enabled;
u8 channel_line[8];
u8 channel_step[8];
int buffer_en_ch_steps;
u16 data[8];
u32 open_delay[8], sample_delay[8], step_avg[8];
};
static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
{
return readl(adc->mfd_tscadc->tscadc_base + reg);
}
static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
unsigned int val)
{
writel(val, adc->mfd_tscadc->tscadc_base + reg);
}
static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
{
u32 step_en;
step_en = ((1 << adc_dev->channels) - 1);
step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
return step_en;
}
static u32 get_adc_chan_step_mask(struct tiadc_device *adc_dev,
struct iio_chan_spec const *chan)
{
int i;
for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
if (chan->channel == adc_dev->channel_line[i]) {
u32 step;
step = adc_dev->channel_step[i];
/* +1 for the charger */
return 1 << (step + 1);
}
}
WARN_ON(1);
return 0;
}
static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
{
return 1 << adc_dev->channel_step[chan];
}
static void tiadc_step_config(struct iio_dev *indio_dev)
{
struct tiadc_device *adc_dev = iio_priv(indio_dev);
struct device *dev = adc_dev->mfd_tscadc->dev;
unsigned int stepconfig;
int i, steps = 0;
/*
* There are 16 configurable steps and 8 analog input
* lines available which are shared between Touchscreen and ADC.
*
* Steps forwards i.e. from 0 towards 16 are used by ADC
* depending on number of input lines needed.
* Channel would represent which analog input
* needs to be given to ADC to digitalize data.
*/
for (i = 0; i < adc_dev->channels; i++) {
int chan;
chan = adc_dev->channel_line[i];
if (adc_dev->step_avg[i] > STEPCONFIG_AVG_16) {
dev_warn(dev, "chan %d step_avg truncating to %d\n",
chan, STEPCONFIG_AVG_16);
adc_dev->step_avg[i] = STEPCONFIG_AVG_16;
}
if (adc_dev->step_avg[i])
stepconfig =
STEPCONFIG_AVG(ffs(adc_dev->step_avg[i]) - 1) |
STEPCONFIG_FIFO1;
else
stepconfig = STEPCONFIG_FIFO1;
if (iio_buffer_enabled(indio_dev))
stepconfig |= STEPCONFIG_MODE_SWCNT;
tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
stepconfig | STEPCONFIG_INP(chan));
if (adc_dev->open_delay[i] > STEPDELAY_OPEN_MASK) {
dev_warn(dev, "chan %d open delay truncating to 0x3FFFF\n",
chan);
adc_dev->open_delay[i] = STEPDELAY_OPEN_MASK;
}
if (adc_dev->sample_delay[i] > 0xFF) {
dev_warn(dev, "chan %d sample delay truncating to 0xFF\n",
chan);
adc_dev->sample_delay[i] = 0xFF;
}
tiadc_writel(adc_dev, REG_STEPDELAY(steps),
STEPDELAY_OPEN(adc_dev->open_delay[i]) |
STEPDELAY_SAMPLE(adc_dev->sample_delay[i]));
adc_dev->channel_step[i] = steps;
steps++;
}
}
static irqreturn_t tiadc_irq_h(int irq, void *private)
{
struct iio_dev *indio_dev = private;
struct tiadc_device *adc_dev = iio_priv(indio_dev);
unsigned int status, config;
status = tiadc_readl(adc_dev, REG_IRQSTATUS);
/*
* ADC and touchscreen share the IRQ line.
* FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only
*/
if (status & IRQENB_FIFO1OVRRUN) {
/* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */
config = tiadc_readl(adc_dev, REG_CTRL);
config &= ~(CNTRLREG_TSCSSENB);
tiadc_writel(adc_dev, REG_CTRL, config);
tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1OVRRUN
| IRQENB_FIFO1UNDRFLW | IRQENB_FIFO1THRES);
tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_TSCSSENB));
return IRQ_HANDLED;
} else if (status & IRQENB_FIFO1THRES) {
/* Disable irq and wake worker thread */
tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES);
return IRQ_WAKE_THREAD;
}
return IRQ_NONE;
}
static irqreturn_t tiadc_worker_h(int irq, void *private)
{
struct iio_dev *indio_dev = private;
struct tiadc_device *adc_dev = iio_priv(indio_dev);
int i, k, fifo1count, read;
u16 *data = adc_dev->data;
fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
for (k = 0; k < fifo1count; k = k + i) {
for (i = 0; i < (indio_dev->scan_bytes)/2; i++) {
read = tiadc_readl(adc_dev, REG_FIFO1);
data[i] = read & FIFOREAD_DATA_MASK;
}
iio_push_to_buffers(indio_dev, (u8 *) data);
}
tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES);
tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES);
return IRQ_HANDLED;
}
static void tiadc_dma_rx_complete(void *param)
{
struct iio_dev *indio_dev = param;
struct tiadc_device *adc_dev = iio_priv(indio_dev);
struct tiadc_dma *dma = &adc_dev->dma;
u8 *data;
int i;
data = dma->buf + dma->current_period * dma->period_size;
dma->current_period = 1 - dma->current_period; /* swap the buffer ID */
for (i = 0; i < dma->period_size; i += indio_dev->scan_bytes) {
iio_push_to_buffers(indio_dev, data);
data += indio_dev->scan_bytes;
}
}
static int tiadc_start_dma(struct iio_dev *indio_dev)
{
struct tiadc_device *adc_dev = iio_priv(indio_dev);
struct tiadc_dma *dma = &adc_dev->dma;
struct dma_async_tx_descriptor *desc;
dma->current_period = 0; /* We start to fill period 0 */
/*
* Make the fifo thresh as the multiple of total number of
* channels enabled, so make sure that cyclic DMA period
* length is also a multiple of total number of channels
* enabled. This ensures that no invalid data is reported
* to the stack via iio_push_to_buffers().
*/
dma->fifo_thresh = rounddown(FIFO1_THRESHOLD + 1,
adc_dev->total_ch_enabled) - 1;
/* Make sure that period length is multiple of fifo thresh level */
dma->period_size = rounddown(DMA_BUFFER_SIZE / 2,
(dma->fifo_thresh + 1) * sizeof(u16));
dma->conf.src_maxburst = dma->fifo_thresh + 1;
dmaengine_slave_config(dma->chan, &dma->conf);
desc = dmaengine_prep_dma_cyclic(dma->chan, dma->addr,
dma->period_size * 2,
dma->period_size, DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT);
if (!desc)
return -EBUSY;
desc->callback = tiadc_dma_rx_complete;
desc->callback_param = indio_dev;
dma->cookie = dmaengine_submit(desc);
dma_async_issue_pending(dma->chan);
tiadc_writel(adc_dev, REG_FIFO1THR, dma->fifo_thresh);
tiadc_writel(adc_dev, REG_DMA1REQ, dma->fifo_thresh);
tiadc_writel(adc_dev, REG_DMAENABLE_SET, DMA_FIFO1);
return 0;
}
static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
{
struct tiadc_device *adc_dev = iio_priv(indio_dev);
int i, fifo1count, read;
tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
IRQENB_FIFO1OVRRUN |
IRQENB_FIFO1UNDRFLW));
/* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */
fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
for (i = 0; i < fifo1count; i++)
read = tiadc_readl(adc_dev, REG_FIFO1);
return 0;
}
static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
{
struct tiadc_device *adc_dev = iio_priv(indio_dev);
struct tiadc_dma *dma = &adc_dev->dma;
unsigned int irq_enable;
unsigned int enb = 0;
u8 bit;
tiadc_step_config(indio_dev);
for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels) {
enb |= (get_adc_step_bit(adc_dev, bit) << 1);
adc_dev->total_ch_enabled++;
}
adc_dev->buffer_en_ch_steps = enb;
if (dma->chan)
tiadc_start_dma(indio_dev);
am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb);
tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES
| IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW);
irq_enable = IRQENB_FIFO1OVRRUN;
if (!dma->chan)
irq_enable |= IRQENB_FIFO1THRES;
tiadc_writel(adc_dev, REG_IRQENABLE, irq_enable);
return 0;
}
static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
{
struct tiadc_device *adc_dev = iio_priv(indio_dev);
struct tiadc_dma *dma = &adc_dev->dma;
int fifo1count, i, read;
tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW));
am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
adc_dev->buffer_en_ch_steps = 0;
adc_dev->total_ch_enabled = 0;
if (dma->chan) {
tiadc_writel(adc_dev, REG_DMAENABLE_CLEAR, 0x2);
dmaengine_terminate_async(dma->chan);
}
/* Flush FIFO of leftover data in the time it takes to disable adc */
fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
for (i = 0; i < fifo1count; i++)
read = tiadc_readl(adc_dev, REG_FIFO1);
return 0;
}
static int tiadc_buffer_postdisable(struct iio_dev *indio_dev)
{
tiadc_step_config(indio_dev);
return 0;
}
static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = {
.preenable = &tiadc_buffer_preenable,
.postenable = &tiadc_buffer_postenable,
.predisable = &tiadc_buffer_predisable,
.postdisable = &tiadc_buffer_postdisable,
};
static int tiadc_iio_buffered_hardware_setup(struct iio_dev *indio_dev,
irqreturn_t (*pollfunc_bh)(int irq, void *p),
irqreturn_t (*pollfunc_th)(int irq, void *p),
int irq,
unsigned long flags,
const struct iio_buffer_setup_ops *setup_ops)
{
struct iio_buffer *buffer;
int ret;
buffer = iio_kfifo_allocate();
if (!buffer)
return -ENOMEM;
iio_device_attach_buffer(indio_dev, buffer);
ret = request_threaded_irq(irq, pollfunc_th, pollfunc_bh,
flags, indio_dev->name, indio_dev);
if (ret)
goto error_kfifo_free;
indio_dev->setup_ops = setup_ops;
indio_dev->modes |= INDIO_BUFFER_SOFTWARE;
return 0;
error_kfifo_free:
iio_kfifo_free(indio_dev->buffer);
return ret;
}
static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev)
{
struct tiadc_device *adc_dev = iio_priv(indio_dev);
free_irq(adc_dev->mfd_tscadc->irq, indio_dev);
iio_kfifo_free(indio_dev->buffer);
}
static const char * const chan_name_ain[] = {
"AIN0",
"AIN1",
"AIN2",
"AIN3",
"AIN4",
"AIN5",
"AIN6",
"AIN7",
};
static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
{
struct tiadc_device *adc_dev = iio_priv(indio_dev);
struct iio_chan_spec *chan_array;
struct iio_chan_spec *chan;
int i;
indio_dev->num_channels = channels;
chan_array = kcalloc(channels, sizeof(*chan_array), GFP_KERNEL);
if (chan_array == NULL)
return -ENOMEM;
chan = chan_array;
for (i = 0; i < channels; i++, chan++) {
chan->type = IIO_VOLTAGE;
chan->indexed = 1;
chan->channel = adc_dev->channel_line[i];
chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
chan->datasheet_name = chan_name_ain[chan->channel];
chan->scan_index = i;
chan->scan_type.sign = 'u';
chan->scan_type.realbits = 12;
chan->scan_type.storagebits = 16;
}
indio_dev->channels = chan_array;
return 0;
}
static void tiadc_channels_remove(struct iio_dev *indio_dev)
{
kfree(indio_dev->channels);
}
static int tiadc_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct tiadc_device *adc_dev = iio_priv(indio_dev);
int ret = IIO_VAL_INT;
int i, map_val;
unsigned int fifo1count, read, stepid;
bool found = false;
u32 step_en;
unsigned long timeout;
if (iio_buffer_enabled(indio_dev))
return -EBUSY;
step_en = get_adc_chan_step_mask(adc_dev, chan);
if (!step_en)
return -EINVAL;
mutex_lock(&adc_dev->fifo1_lock);
fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
while (fifo1count--)
tiadc_readl(adc_dev, REG_FIFO1);
am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en);
timeout = jiffies + msecs_to_jiffies
(IDLE_TIMEOUT * adc_dev->channels);
/* Wait for Fifo threshold interrupt */
while (1) {
fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
if (fifo1count)
break;
if (time_after(jiffies, timeout)) {
am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
ret = -EAGAIN;
goto err_unlock;
}
}
map_val = adc_dev->channel_step[chan->scan_index];
/*
* We check the complete FIFO. We programmed just one entry but in case
* something went wrong we left empty handed (-EAGAIN previously) and
* then the value apeared somehow in the FIFO we would have two entries.
* Therefore we read every item and keep only the latest version of the
* requested channel.
*/
for (i = 0; i < fifo1count; i++) {
read = tiadc_readl(adc_dev, REG_FIFO1);
stepid = read & FIFOREAD_CHNLID_MASK;
stepid = stepid >> 0x10;
if (stepid == map_val) {
read = read & FIFOREAD_DATA_MASK;
found = true;
*val = (u16) read;
}
}
am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
if (found == false)
ret = -EBUSY;
err_unlock:
mutex_unlock(&adc_dev->fifo1_lock);
return ret;
}
static const struct iio_info tiadc_info = {
.read_raw = &tiadc_read_raw,
.driver_module = THIS_MODULE,
};
static int tiadc_request_dma(struct platform_device *pdev,
struct tiadc_device *adc_dev)
{
struct tiadc_dma *dma = &adc_dev->dma;
dma_cap_mask_t mask;
/* Default slave configuration parameters */
dma->conf.direction = DMA_DEV_TO_MEM;
dma->conf.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
dma->conf.src_addr = adc_dev->mfd_tscadc->tscadc_phys_base + REG_FIFO1;
dma_cap_zero(mask);
dma_cap_set(DMA_CYCLIC, mask);
/* Get a channel for RX */
dma->chan = dma_request_chan(adc_dev->mfd_tscadc->dev, "fifo1");
if (IS_ERR(dma->chan)) {
int ret = PTR_ERR(dma->chan);
dma->chan = NULL;
return ret;
}
/* RX buffer */
dma->buf = dma_alloc_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
&dma->addr, GFP_KERNEL);
if (!dma->buf)
goto err;
return 0;
err:
dma_release_channel(dma->chan);
return -ENOMEM;
}
static int tiadc_parse_dt(struct platform_device *pdev,
struct tiadc_device *adc_dev)
{
struct device_node *node = pdev->dev.of_node;
struct property *prop;
const __be32 *cur;
int channels = 0;
u32 val;
of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
adc_dev->channel_line[channels] = val;
/* Set Default values for optional DT parameters */
adc_dev->open_delay[channels] = STEPCONFIG_OPENDLY;
adc_dev->sample_delay[channels] = STEPCONFIG_SAMPLEDLY;
adc_dev->step_avg[channels] = 16;
channels++;
}
of_property_read_u32_array(node, "ti,chan-step-avg",
adc_dev->step_avg, channels);
of_property_read_u32_array(node, "ti,chan-step-opendelay",
adc_dev->open_delay, channels);
of_property_read_u32_array(node, "ti,chan-step-sampledelay",
adc_dev->sample_delay, channels);
adc_dev->channels = channels;
return 0;
}
static int tiadc_probe(struct platform_device *pdev)
{
struct iio_dev *indio_dev;
struct tiadc_device *adc_dev;
struct device_node *node = pdev->dev.of_node;
int err;
if (!node) {
dev_err(&pdev->dev, "Could not find valid DT data.\n");
return -EINVAL;
}
indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*indio_dev));
if (indio_dev == NULL) {
dev_err(&pdev->dev, "failed to allocate iio device\n");
return -ENOMEM;
}
adc_dev = iio_priv(indio_dev);
adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
tiadc_parse_dt(pdev, adc_dev);
indio_dev->dev.parent = &pdev->dev;
indio_dev->name = dev_name(&pdev->dev);
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &tiadc_info;
tiadc_step_config(indio_dev);
tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);
mutex_init(&adc_dev->fifo1_lock);
err = tiadc_channel_init(indio_dev, adc_dev->channels);
if (err < 0)
return err;
err = tiadc_iio_buffered_hardware_setup(indio_dev,
&tiadc_worker_h,
&tiadc_irq_h,
adc_dev->mfd_tscadc->irq,
IRQF_SHARED,
&tiadc_buffer_setup_ops);
if (err)
goto err_free_channels;
err = iio_device_register(indio_dev);
if (err)
goto err_buffer_unregister;
platform_set_drvdata(pdev, indio_dev);
err = tiadc_request_dma(pdev, adc_dev);
if (err && err == -EPROBE_DEFER)
goto err_dma;
return 0;
err_dma:
iio_device_unregister(indio_dev);
err_buffer_unregister:
tiadc_iio_buffered_hardware_remove(indio_dev);
err_free_channels:
tiadc_channels_remove(indio_dev);
return err;
}
static int tiadc_remove(struct platform_device *pdev)
{
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
struct tiadc_device *adc_dev = iio_priv(indio_dev);
struct tiadc_dma *dma = &adc_dev->dma;
u32 step_en;
if (dma->chan) {
dma_free_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
dma->buf, dma->addr);
dma_release_channel(dma->chan);
}
iio_device_unregister(indio_dev);
tiadc_iio_buffered_hardware_remove(indio_dev);
tiadc_channels_remove(indio_dev);
step_en = get_adc_step_mask(adc_dev);
am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
return 0;
}
static int __maybe_unused tiadc_suspend(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct tiadc_device *adc_dev = iio_priv(indio_dev);
struct ti_tscadc_dev *tscadc_dev;
unsigned int idle;
tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
if (!device_may_wakeup(tscadc_dev->dev)) {
idle = tiadc_readl(adc_dev, REG_CTRL);
idle &= ~(CNTRLREG_TSCSSENB);
tiadc_writel(adc_dev, REG_CTRL, (idle |
CNTRLREG_POWERDOWN));
}
return 0;
}
static int __maybe_unused tiadc_resume(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct tiadc_device *adc_dev = iio_priv(indio_dev);
unsigned int restore;
/* Make sure ADC is powered up */
restore = tiadc_readl(adc_dev, REG_CTRL);
restore &= ~(CNTRLREG_POWERDOWN);
tiadc_writel(adc_dev, REG_CTRL, restore);
tiadc_step_config(indio_dev);
am335x_tsc_se_set_cache(adc_dev->mfd_tscadc,
adc_dev->buffer_en_ch_steps);
return 0;
}
static SIMPLE_DEV_PM_OPS(tiadc_pm_ops, tiadc_suspend, tiadc_resume);
static const struct of_device_id ti_adc_dt_ids[] = {
{ .compatible = "ti,am3359-adc", },
{ }
};
MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
static struct platform_driver tiadc_driver = {
.driver = {
.name = "TI-am335x-adc",
.pm = &tiadc_pm_ops,
.of_match_table = ti_adc_dt_ids,
},
.probe = tiadc_probe,
.remove = tiadc_remove,
};
module_platform_driver(tiadc_driver);
MODULE_DESCRIPTION("TI ADC controller driver");
MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
MODULE_LICENSE("GPL");
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