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linux/drivers/iio/adc/at91-sama5d2_adc.c

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/*
* Atmel ADC driver for SAMA5D2 devices and compatible.
*
* Copyright (C) 2015 Atmel,
* 2015 Ludovic Desroches <ludovic.desroches@atmel.com>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/regulator/consumer.h>
/* Control Register */
#define AT91_SAMA5D2_CR 0x00
/* Software Reset */
#define AT91_SAMA5D2_CR_SWRST BIT(0)
/* Start Conversion */
#define AT91_SAMA5D2_CR_START BIT(1)
/* Touchscreen Calibration */
#define AT91_SAMA5D2_CR_TSCALIB BIT(2)
/* Comparison Restart */
#define AT91_SAMA5D2_CR_CMPRST BIT(4)
/* Mode Register */
#define AT91_SAMA5D2_MR 0x04
/* Trigger Selection */
#define AT91_SAMA5D2_MR_TRGSEL(v) ((v) << 1)
/* ADTRG */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG0 0
/* TIOA0 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG1 1
/* TIOA1 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG2 2
/* TIOA2 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG3 3
/* PWM event line 0 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG4 4
/* PWM event line 1 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG5 5
/* TIOA3 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG6 6
/* RTCOUT0 */
#define AT91_SAMA5D2_MR_TRGSEL_TRIG7 7
/* Sleep Mode */
#define AT91_SAMA5D2_MR_SLEEP BIT(5)
/* Fast Wake Up */
#define AT91_SAMA5D2_MR_FWUP BIT(6)
/* Prescaler Rate Selection */
#define AT91_SAMA5D2_MR_PRESCAL(v) ((v) << AT91_SAMA5D2_MR_PRESCAL_OFFSET)
#define AT91_SAMA5D2_MR_PRESCAL_OFFSET 8
#define AT91_SAMA5D2_MR_PRESCAL_MAX 0xff
#define AT91_SAMA5D2_MR_PRESCAL_MASK GENMASK(15, 8)
/* Startup Time */
#define AT91_SAMA5D2_MR_STARTUP(v) ((v) << 16)
#define AT91_SAMA5D2_MR_STARTUP_MASK GENMASK(19, 16)
/* Analog Change */
#define AT91_SAMA5D2_MR_ANACH BIT(23)
/* Tracking Time */
#define AT91_SAMA5D2_MR_TRACKTIM(v) ((v) << 24)
#define AT91_SAMA5D2_MR_TRACKTIM_MAX 0xff
/* Transfer Time */
#define AT91_SAMA5D2_MR_TRANSFER(v) ((v) << 28)
#define AT91_SAMA5D2_MR_TRANSFER_MAX 0x3
/* Use Sequence Enable */
#define AT91_SAMA5D2_MR_USEQ BIT(31)
/* Channel Sequence Register 1 */
#define AT91_SAMA5D2_SEQR1 0x08
/* Channel Sequence Register 2 */
#define AT91_SAMA5D2_SEQR2 0x0c
/* Channel Enable Register */
#define AT91_SAMA5D2_CHER 0x10
/* Channel Disable Register */
#define AT91_SAMA5D2_CHDR 0x14
/* Channel Status Register */
#define AT91_SAMA5D2_CHSR 0x18
/* Last Converted Data Register */
#define AT91_SAMA5D2_LCDR 0x20
/* Interrupt Enable Register */
#define AT91_SAMA5D2_IER 0x24
/* Interrupt Disable Register */
#define AT91_SAMA5D2_IDR 0x28
/* Interrupt Mask Register */
#define AT91_SAMA5D2_IMR 0x2c
/* Interrupt Status Register */
#define AT91_SAMA5D2_ISR 0x30
/* Last Channel Trigger Mode Register */
#define AT91_SAMA5D2_LCTMR 0x34
/* Last Channel Compare Window Register */
#define AT91_SAMA5D2_LCCWR 0x38
/* Overrun Status Register */
#define AT91_SAMA5D2_OVER 0x3c
/* Extended Mode Register */
#define AT91_SAMA5D2_EMR 0x40
/* Compare Window Register */
#define AT91_SAMA5D2_CWR 0x44
/* Channel Gain Register */
#define AT91_SAMA5D2_CGR 0x48
/* Channel Offset Register */
#define AT91_SAMA5D2_COR 0x4c
#define AT91_SAMA5D2_COR_DIFF_OFFSET 16
/* Channel Data Register 0 */
#define AT91_SAMA5D2_CDR0 0x50
/* Analog Control Register */
#define AT91_SAMA5D2_ACR 0x94
/* Touchscreen Mode Register */
#define AT91_SAMA5D2_TSMR 0xb0
/* Touchscreen X Position Register */
#define AT91_SAMA5D2_XPOSR 0xb4
/* Touchscreen Y Position Register */
#define AT91_SAMA5D2_YPOSR 0xb8
/* Touchscreen Pressure Register */
#define AT91_SAMA5D2_PRESSR 0xbc
/* Trigger Register */
#define AT91_SAMA5D2_TRGR 0xc0
/* Correction Select Register */
#define AT91_SAMA5D2_COSR 0xd0
/* Correction Value Register */
#define AT91_SAMA5D2_CVR 0xd4
/* Channel Error Correction Register */
#define AT91_SAMA5D2_CECR 0xd8
/* Write Protection Mode Register */
#define AT91_SAMA5D2_WPMR 0xe4
/* Write Protection Status Register */
#define AT91_SAMA5D2_WPSR 0xe8
/* Version Register */
#define AT91_SAMA5D2_VERSION 0xfc
#define AT91_SAMA5D2_CHAN_SINGLE(num, addr) \
{ \
.type = IIO_VOLTAGE, \
.channel = num, \
.address = addr, \
.scan_type = { \
.sign = 'u', \
.realbits = 12, \
}, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
.datasheet_name = "CH"#num, \
.indexed = 1, \
}
#define AT91_SAMA5D2_CHAN_DIFF(num, num2, addr) \
{ \
.type = IIO_VOLTAGE, \
.differential = 1, \
.channel = num, \
.channel2 = num2, \
.address = addr, \
.scan_type = { \
.sign = 's', \
.realbits = 12, \
}, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
.datasheet_name = "CH"#num"-CH"#num2, \
.indexed = 1, \
}
#define at91_adc_readl(st, reg) readl_relaxed(st->base + reg)
#define at91_adc_writel(st, reg, val) writel_relaxed(val, st->base + reg)
struct at91_adc_soc_info {
unsigned startup_time;
unsigned min_sample_rate;
unsigned max_sample_rate;
};
struct at91_adc_state {
void __iomem *base;
int irq;
struct clk *per_clk;
struct regulator *reg;
struct regulator *vref;
int vref_uv;
const struct iio_chan_spec *chan;
bool conversion_done;
u32 conversion_value;
struct at91_adc_soc_info soc_info;
wait_queue_head_t wq_data_available;
/*
* lock to prevent concurrent 'single conversion' requests through
* sysfs.
*/
struct mutex lock;
};
static const struct iio_chan_spec at91_adc_channels[] = {
AT91_SAMA5D2_CHAN_SINGLE(0, 0x50),
AT91_SAMA5D2_CHAN_SINGLE(1, 0x54),
AT91_SAMA5D2_CHAN_SINGLE(2, 0x58),
AT91_SAMA5D2_CHAN_SINGLE(3, 0x5c),
AT91_SAMA5D2_CHAN_SINGLE(4, 0x60),
AT91_SAMA5D2_CHAN_SINGLE(5, 0x64),
AT91_SAMA5D2_CHAN_SINGLE(6, 0x68),
AT91_SAMA5D2_CHAN_SINGLE(7, 0x6c),
AT91_SAMA5D2_CHAN_SINGLE(8, 0x70),
AT91_SAMA5D2_CHAN_SINGLE(9, 0x74),
AT91_SAMA5D2_CHAN_SINGLE(10, 0x78),
AT91_SAMA5D2_CHAN_SINGLE(11, 0x7c),
AT91_SAMA5D2_CHAN_DIFF(0, 1, 0x50),
AT91_SAMA5D2_CHAN_DIFF(2, 3, 0x58),
AT91_SAMA5D2_CHAN_DIFF(4, 5, 0x60),
AT91_SAMA5D2_CHAN_DIFF(6, 7, 0x68),
AT91_SAMA5D2_CHAN_DIFF(8, 9, 0x70),
AT91_SAMA5D2_CHAN_DIFF(10, 11, 0x78),
};
static unsigned at91_adc_startup_time(unsigned startup_time_min,
unsigned adc_clk_khz)
{
const unsigned startup_lookup[] = {
0, 8, 16, 24,
64, 80, 96, 112,
512, 576, 640, 704,
768, 832, 896, 960
};
unsigned ticks_min, i;
/*
* Since the adc frequency is checked before, there is no reason
* to not meet the startup time constraint.
*/
ticks_min = startup_time_min * adc_clk_khz / 1000;
for (i = 0; i < ARRAY_SIZE(startup_lookup); i++)
if (startup_lookup[i] > ticks_min)
break;
return i;
}
static void at91_adc_setup_samp_freq(struct at91_adc_state *st, unsigned freq)
{
struct iio_dev *indio_dev = iio_priv_to_dev(st);
unsigned f_per, prescal, startup, mr;
f_per = clk_get_rate(st->per_clk);
prescal = (f_per / (2 * freq)) - 1;
startup = at91_adc_startup_time(st->soc_info.startup_time,
freq / 1000);
mr = at91_adc_readl(st, AT91_SAMA5D2_MR);
mr &= ~(AT91_SAMA5D2_MR_STARTUP_MASK | AT91_SAMA5D2_MR_PRESCAL_MASK);
mr |= AT91_SAMA5D2_MR_STARTUP(startup);
mr |= AT91_SAMA5D2_MR_PRESCAL(prescal);
at91_adc_writel(st, AT91_SAMA5D2_MR, mr);
dev_dbg(&indio_dev->dev, "freq: %u, startup: %u, prescal: %u\n",
freq, startup, prescal);
}
static unsigned at91_adc_get_sample_freq(struct at91_adc_state *st)
{
unsigned f_adc, f_per = clk_get_rate(st->per_clk);
unsigned mr, prescal;
mr = at91_adc_readl(st, AT91_SAMA5D2_MR);
prescal = (mr >> AT91_SAMA5D2_MR_PRESCAL_OFFSET)
& AT91_SAMA5D2_MR_PRESCAL_MAX;
f_adc = f_per / (2 * (prescal + 1));
return f_adc;
}
static irqreturn_t at91_adc_interrupt(int irq, void *private)
{
struct iio_dev *indio = private;
struct at91_adc_state *st = iio_priv(indio);
u32 status = at91_adc_readl(st, AT91_SAMA5D2_ISR);
u32 imr = at91_adc_readl(st, AT91_SAMA5D2_IMR);
if (status & imr) {
st->conversion_value = at91_adc_readl(st, st->chan->address);
st->conversion_done = true;
wake_up_interruptible(&st->wq_data_available);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
static int at91_adc_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct at91_adc_state *st = iio_priv(indio_dev);
u32 cor = 0;
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&st->lock);
st->chan = chan;
if (chan->differential)
cor = (BIT(chan->channel) | BIT(chan->channel2)) <<
AT91_SAMA5D2_COR_DIFF_OFFSET;
at91_adc_writel(st, AT91_SAMA5D2_COR, cor);
at91_adc_writel(st, AT91_SAMA5D2_CHER, BIT(chan->channel));
at91_adc_writel(st, AT91_SAMA5D2_IER, BIT(chan->channel));
at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_START);
ret = wait_event_interruptible_timeout(st->wq_data_available,
st->conversion_done,
msecs_to_jiffies(1000));
if (ret == 0)
ret = -ETIMEDOUT;
if (ret > 0) {
*val = st->conversion_value;
if (chan->scan_type.sign == 's')
*val = sign_extend32(*val, 11);
ret = IIO_VAL_INT;
st->conversion_done = false;
}
at91_adc_writel(st, AT91_SAMA5D2_IDR, BIT(chan->channel));
at91_adc_writel(st, AT91_SAMA5D2_CHDR, BIT(chan->channel));
mutex_unlock(&st->lock);
return ret;
case IIO_CHAN_INFO_SCALE:
*val = st->vref_uv / 1000;
if (chan->differential)
*val *= 2;
*val2 = chan->scan_type.realbits;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_SAMP_FREQ:
*val = at91_adc_get_sample_freq(st);
return IIO_VAL_INT;
default:
return -EINVAL;
}
}
static int at91_adc_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct at91_adc_state *st = iio_priv(indio_dev);
if (mask != IIO_CHAN_INFO_SAMP_FREQ)
return -EINVAL;
if (val < st->soc_info.min_sample_rate ||
val > st->soc_info.max_sample_rate)
return -EINVAL;
at91_adc_setup_samp_freq(st, val);
return 0;
}
static const struct iio_info at91_adc_info = {
.read_raw = &at91_adc_read_raw,
.write_raw = &at91_adc_write_raw,
.driver_module = THIS_MODULE,
};
static int at91_adc_probe(struct platform_device *pdev)
{
struct iio_dev *indio_dev;
struct at91_adc_state *st;
struct resource *res;
int ret;
indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
indio_dev->dev.parent = &pdev->dev;
indio_dev->name = dev_name(&pdev->dev);
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &at91_adc_info;
indio_dev->channels = at91_adc_channels;
indio_dev->num_channels = ARRAY_SIZE(at91_adc_channels);
st = iio_priv(indio_dev);
ret = of_property_read_u32(pdev->dev.of_node,
"atmel,min-sample-rate-hz",
&st->soc_info.min_sample_rate);
if (ret) {
dev_err(&pdev->dev,
"invalid or missing value for atmel,min-sample-rate-hz\n");
return ret;
}
ret = of_property_read_u32(pdev->dev.of_node,
"atmel,max-sample-rate-hz",
&st->soc_info.max_sample_rate);
if (ret) {
dev_err(&pdev->dev,
"invalid or missing value for atmel,max-sample-rate-hz\n");
return ret;
}
ret = of_property_read_u32(pdev->dev.of_node, "atmel,startup-time-ms",
&st->soc_info.startup_time);
if (ret) {
dev_err(&pdev->dev,
"invalid or missing value for atmel,startup-time-ms\n");
return ret;
}
init_waitqueue_head(&st->wq_data_available);
mutex_init(&st->lock);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -EINVAL;
st->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(st->base))
return PTR_ERR(st->base);
st->irq = platform_get_irq(pdev, 0);
if (st->irq <= 0) {
if (!st->irq)
st->irq = -ENXIO;
return st->irq;
}
st->per_clk = devm_clk_get(&pdev->dev, "adc_clk");
if (IS_ERR(st->per_clk))
return PTR_ERR(st->per_clk);
st->reg = devm_regulator_get(&pdev->dev, "vddana");
if (IS_ERR(st->reg))
return PTR_ERR(st->reg);
st->vref = devm_regulator_get(&pdev->dev, "vref");
if (IS_ERR(st->vref))
return PTR_ERR(st->vref);
ret = devm_request_irq(&pdev->dev, st->irq, at91_adc_interrupt, 0,
pdev->dev.driver->name, indio_dev);
if (ret)
return ret;
ret = regulator_enable(st->reg);
if (ret)
return ret;
ret = regulator_enable(st->vref);
if (ret)
goto reg_disable;
st->vref_uv = regulator_get_voltage(st->vref);
if (st->vref_uv <= 0) {
ret = -EINVAL;
goto vref_disable;
}
at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST);
at91_adc_writel(st, AT91_SAMA5D2_IDR, 0xffffffff);
/*
* Transfer field must be set to 2 according to the datasheet and
* allows different analog settings for each channel.
*/
at91_adc_writel(st, AT91_SAMA5D2_MR,
AT91_SAMA5D2_MR_TRANSFER(2) | AT91_SAMA5D2_MR_ANACH);
at91_adc_setup_samp_freq(st, st->soc_info.min_sample_rate);
ret = clk_prepare_enable(st->per_clk);
if (ret)
goto vref_disable;
platform_set_drvdata(pdev, indio_dev);
ret = iio_device_register(indio_dev);
if (ret < 0)
goto per_clk_disable_unprepare;
dev_info(&pdev->dev, "version: %x\n",
readl_relaxed(st->base + AT91_SAMA5D2_VERSION));
return 0;
per_clk_disable_unprepare:
clk_disable_unprepare(st->per_clk);
vref_disable:
regulator_disable(st->vref);
reg_disable:
regulator_disable(st->reg);
return ret;
}
static int at91_adc_remove(struct platform_device *pdev)
{
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
struct at91_adc_state *st = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
clk_disable_unprepare(st->per_clk);
regulator_disable(st->vref);
regulator_disable(st->reg);
return 0;
}
static const struct of_device_id at91_adc_dt_match[] = {
{
.compatible = "atmel,sama5d2-adc",
}, {
/* sentinel */
}
};
MODULE_DEVICE_TABLE(of, at91_adc_dt_match);
static struct platform_driver at91_adc_driver = {
.probe = at91_adc_probe,
.remove = at91_adc_remove,
.driver = {
.name = "at91-sama5d2_adc",
.of_match_table = at91_adc_dt_match,
},
};
module_platform_driver(at91_adc_driver)
MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@atmel.com>");
MODULE_DESCRIPTION("Atmel AT91 SAMA5D2 ADC");
MODULE_LICENSE("GPL v2");
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