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linux/drivers/iio/adc/npcm_adc.c
Tomer Maimon 3ccb252400 iio: adc: npcm: Add NPCM8XX support 
Adding ADC NPCM8XX support to NPCM ADC driver.
ADC NPCM8XX uses a different resolution and voltage reference.

As part of adding NPCM8XX support:
- Add NPCM8XX specific compatible string.
- Add data to handle architecture-specific ADC parameters.

Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
Link: https://lore.kernel.org/r/20220713132640.215916-3-tmaimon77@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2022-07-18 18:29:29 +01:00

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// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2019 Nuvoton Technology corporation.
#include <linux/clk.h>
#include <linux/device.h>
#include <linux/mfd/syscon.h>
#include <linux/io.h>
#include <linux/iio/iio.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/reset.h>
struct npcm_adc_info {
u32 data_mask;
u32 internal_vref;
u32 res_bits;
};
struct npcm_adc {
bool int_status;
u32 adc_sample_hz;
struct device *dev;
void __iomem *regs;
struct clk *adc_clk;
wait_queue_head_t wq;
struct regulator *vref;
struct reset_control *reset;
/*
* Lock to protect the device state during a potential concurrent
* read access from userspace. Reading a raw value requires a sequence
* of register writes, then a wait for a event and finally a register
* read, during which userspace could issue another read request.
* This lock protects a read access from ocurring before another one
* has finished.
*/
struct mutex lock;
const struct npcm_adc_info *data;
};
/* ADC registers */
#define NPCM_ADCCON 0x00
#define NPCM_ADCDATA 0x04
/* ADCCON Register Bits */
#define NPCM_ADCCON_ADC_INT_EN BIT(21)
#define NPCM_ADCCON_REFSEL BIT(19)
#define NPCM_ADCCON_ADC_INT_ST BIT(18)
#define NPCM_ADCCON_ADC_EN BIT(17)
#define NPCM_ADCCON_ADC_RST BIT(16)
#define NPCM_ADCCON_ADC_CONV BIT(13)
#define NPCM_ADCCON_CH_MASK GENMASK(27, 24)
#define NPCM_ADCCON_CH(x) ((x) << 24)
#define NPCM_ADCCON_DIV_SHIFT 1
#define NPCM_ADCCON_DIV_MASK GENMASK(8, 1)
#define NPCM_ADC_ENABLE (NPCM_ADCCON_ADC_EN | NPCM_ADCCON_ADC_INT_EN)
/* ADC General Definition */
static const struct npcm_adc_info npxm7xx_adc_info = {
.data_mask = GENMASK(9, 0),
.internal_vref = 2048,
.res_bits = 10,
};
static const struct npcm_adc_info npxm8xx_adc_info = {
.data_mask = GENMASK(11, 0),
.internal_vref = 1229,
.res_bits = 12,
};
#define NPCM_ADC_CHAN(ch) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = ch, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
BIT(IIO_CHAN_INFO_SAMP_FREQ), \
}
static const struct iio_chan_spec npcm_adc_iio_channels[] = {
NPCM_ADC_CHAN(0),
NPCM_ADC_CHAN(1),
NPCM_ADC_CHAN(2),
NPCM_ADC_CHAN(3),
NPCM_ADC_CHAN(4),
NPCM_ADC_CHAN(5),
NPCM_ADC_CHAN(6),
NPCM_ADC_CHAN(7),
};
static irqreturn_t npcm_adc_isr(int irq, void *data)
{
u32 regtemp;
struct iio_dev *indio_dev = data;
struct npcm_adc *info = iio_priv(indio_dev);
regtemp = ioread32(info->regs + NPCM_ADCCON);
if (regtemp & NPCM_ADCCON_ADC_INT_ST) {
iowrite32(regtemp, info->regs + NPCM_ADCCON);
wake_up_interruptible(&info->wq);
info->int_status = true;
}
return IRQ_HANDLED;
}
static int npcm_adc_read(struct npcm_adc *info, int *val, u8 channel)
{
int ret;
u32 regtemp;
/* Select ADC channel */
regtemp = ioread32(info->regs + NPCM_ADCCON);
regtemp &= ~NPCM_ADCCON_CH_MASK;
info->int_status = false;
iowrite32(regtemp | NPCM_ADCCON_CH(channel) |
NPCM_ADCCON_ADC_CONV, info->regs + NPCM_ADCCON);
ret = wait_event_interruptible_timeout(info->wq, info->int_status,
msecs_to_jiffies(10));
if (ret == 0) {
regtemp = ioread32(info->regs + NPCM_ADCCON);
if (regtemp & NPCM_ADCCON_ADC_CONV) {
/* if conversion failed - reset ADC module */
reset_control_assert(info->reset);
msleep(100);
reset_control_deassert(info->reset);
msleep(100);
/* Enable ADC and start conversion module */
iowrite32(NPCM_ADC_ENABLE | NPCM_ADCCON_ADC_CONV,
info->regs + NPCM_ADCCON);
dev_err(info->dev, "RESET ADC Complete\n");
}
return -ETIMEDOUT;
}
if (ret < 0)
return ret;
*val = ioread32(info->regs + NPCM_ADCDATA);
*val &= info->data->data_mask;
return 0;
}
static int npcm_adc_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val,
int *val2, long mask)
{
int ret;
int vref_uv;
struct npcm_adc *info = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&info->lock);
ret = npcm_adc_read(info, val, chan->channel);
mutex_unlock(&info->lock);
if (ret) {
dev_err(info->dev, "NPCM ADC read failed\n");
return ret;
}
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
if (!IS_ERR(info->vref)) {
vref_uv = regulator_get_voltage(info->vref);
*val = vref_uv / 1000;
} else {
*val = info->data->internal_vref;
}
*val2 = info->data->res_bits;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_SAMP_FREQ:
*val = info->adc_sample_hz;
return IIO_VAL_INT;
default:
return -EINVAL;
}
return 0;
}
static const struct iio_info npcm_adc_iio_info = {
.read_raw = &npcm_adc_read_raw,
};
static const struct of_device_id npcm_adc_match[] = {
{ .compatible = "nuvoton,npcm750-adc", .data = &npxm7xx_adc_info},
{ .compatible = "nuvoton,npcm845-adc", .data = &npxm8xx_adc_info},
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, npcm_adc_match);
static int npcm_adc_probe(struct platform_device *pdev)
{
int ret;
int irq;
u32 div;
u32 reg_con;
struct npcm_adc *info;
struct iio_dev *indio_dev;
struct device *dev = &pdev->dev;
indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
if (!indio_dev)
return -ENOMEM;
info = iio_priv(indio_dev);
info->data = device_get_match_data(dev);
if (!info->data)
return -EINVAL;
mutex_init(&info->lock);
info->dev = &pdev->dev;
info->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(info->regs))
return PTR_ERR(info->regs);
info->reset = devm_reset_control_get(&pdev->dev, NULL);
if (IS_ERR(info->reset))
return PTR_ERR(info->reset);
info->adc_clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(info->adc_clk)) {
dev_warn(&pdev->dev, "ADC clock failed: can't read clk\n");
return PTR_ERR(info->adc_clk);
}
/* calculate ADC clock sample rate */
reg_con = ioread32(info->regs + NPCM_ADCCON);
div = reg_con & NPCM_ADCCON_DIV_MASK;
div = div >> NPCM_ADCCON_DIV_SHIFT;
info->adc_sample_hz = clk_get_rate(info->adc_clk) / ((div + 1) * 2);
irq = platform_get_irq(pdev, 0);
if (irq <= 0) {
ret = -EINVAL;
goto err_disable_clk;
}
ret = devm_request_irq(&pdev->dev, irq, npcm_adc_isr, 0,
"NPCM_ADC", indio_dev);
if (ret < 0) {
dev_err(dev, "failed requesting interrupt\n");
goto err_disable_clk;
}
reg_con = ioread32(info->regs + NPCM_ADCCON);
info->vref = devm_regulator_get_optional(&pdev->dev, "vref");
if (!IS_ERR(info->vref)) {
ret = regulator_enable(info->vref);
if (ret) {
dev_err(&pdev->dev, "Can't enable ADC reference voltage\n");
goto err_disable_clk;
}
iowrite32(reg_con & ~NPCM_ADCCON_REFSEL,
info->regs + NPCM_ADCCON);
} else {
/*
* Any error which is not ENODEV indicates the regulator
* has been specified and so is a failure case.
*/
if (PTR_ERR(info->vref) != -ENODEV) {
ret = PTR_ERR(info->vref);
goto err_disable_clk;
}
/* Use internal reference */
iowrite32(reg_con | NPCM_ADCCON_REFSEL,
info->regs + NPCM_ADCCON);
}
init_waitqueue_head(&info->wq);
reg_con = ioread32(info->regs + NPCM_ADCCON);
reg_con |= NPCM_ADC_ENABLE;
/* Enable the ADC Module */
iowrite32(reg_con, info->regs + NPCM_ADCCON);
/* Start ADC conversion */
iowrite32(reg_con | NPCM_ADCCON_ADC_CONV, info->regs + NPCM_ADCCON);
platform_set_drvdata(pdev, indio_dev);
indio_dev->name = dev_name(&pdev->dev);
indio_dev->info = &npcm_adc_iio_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = npcm_adc_iio_channels;
indio_dev->num_channels = ARRAY_SIZE(npcm_adc_iio_channels);
ret = iio_device_register(indio_dev);
if (ret) {
dev_err(&pdev->dev, "Couldn't register the device.\n");
goto err_iio_register;
}
pr_info("NPCM ADC driver probed\n");
return 0;
err_iio_register:
iowrite32(reg_con & ~NPCM_ADCCON_ADC_EN, info->regs + NPCM_ADCCON);
if (!IS_ERR(info->vref))
regulator_disable(info->vref);
err_disable_clk:
clk_disable_unprepare(info->adc_clk);
return ret;
}
static int npcm_adc_remove(struct platform_device *pdev)
{
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
struct npcm_adc *info = iio_priv(indio_dev);
u32 regtemp;
iio_device_unregister(indio_dev);
regtemp = ioread32(info->regs + NPCM_ADCCON);
iowrite32(regtemp & ~NPCM_ADCCON_ADC_EN, info->regs + NPCM_ADCCON);
if (!IS_ERR(info->vref))
regulator_disable(info->vref);
clk_disable_unprepare(info->adc_clk);
return 0;
}
static struct platform_driver npcm_adc_driver = {
.probe = npcm_adc_probe,
.remove = npcm_adc_remove,
.driver = {
.name = "npcm_adc",
.of_match_table = npcm_adc_match,
},
};
module_platform_driver(npcm_adc_driver);
MODULE_DESCRIPTION("Nuvoton NPCM ADC Driver");
MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>");
MODULE_LICENSE("GPL v2");
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