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/*
* Rockchip Successive Approximation Register (SAR) A/D Converter
* Copyright (C) 2014 ROCKCHIP, Inc.
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* 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/module.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/regulator/consumer.h>
#include <linux/iio/iio.h>
#define SARADC_DATA 0x00
#define SARADC_DATA_MASK 0x3ff
#define SARADC_STAS 0x04
#define SARADC_STAS_BUSY BIT(0)
#define SARADC_CTRL 0x08
#define SARADC_CTRL_IRQ_STATUS BIT(6)
#define SARADC_CTRL_IRQ_ENABLE BIT(5)
#define SARADC_CTRL_POWER_CTRL BIT(3)
#define SARADC_CTRL_CHN_MASK 0x7
#define SARADC_DLY_PU_SOC 0x0c
#define SARADC_DLY_PU_SOC_MASK 0x3f
#define SARADC_BITS 10
#define SARADC_TIMEOUT msecs_to_jiffies(100)
struct rockchip_saradc {
void __iomem *regs;
struct clk *pclk;
struct clk *clk;
struct completion completion;
struct regulator *vref;
u16 last_val;
};
static int rockchip_saradc_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct rockchip_saradc *info = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&indio_dev->mlock);
reinit_completion(&info->completion);
/* 8 clock periods as delay between power up and start cmd */
writel_relaxed(8, info->regs + SARADC_DLY_PU_SOC);
/* Select the channel to be used and trigger conversion */
writel(SARADC_CTRL_POWER_CTRL
| (chan->channel & SARADC_CTRL_CHN_MASK)
| SARADC_CTRL_IRQ_ENABLE,
info->regs + SARADC_CTRL);
if (!wait_for_completion_timeout(&info->completion,
SARADC_TIMEOUT)) {
writel_relaxed(0, info->regs + SARADC_CTRL);
mutex_unlock(&indio_dev->mlock);
return -ETIMEDOUT;
}
*val = info->last_val;
mutex_unlock(&indio_dev->mlock);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
ret = regulator_get_voltage(info->vref);
if (ret < 0) {
dev_err(&indio_dev->dev, "failed to get voltage\n");
return ret;
}
*val = ret / 1000;
*val2 = SARADC_BITS;
return IIO_VAL_FRACTIONAL_LOG2;
default:
return -EINVAL;
}
}
static irqreturn_t rockchip_saradc_isr(int irq, void *dev_id)
{
struct rockchip_saradc *info = (struct rockchip_saradc *)dev_id;
/* Read value */
info->last_val = readl_relaxed(info->regs + SARADC_DATA);
info->last_val &= SARADC_DATA_MASK;
/* Clear irq & power down adc */
writel_relaxed(0, info->regs + SARADC_CTRL);
complete(&info->completion);
return IRQ_HANDLED;
}
static const struct iio_info rockchip_saradc_iio_info = {
.read_raw = rockchip_saradc_read_raw,
.driver_module = THIS_MODULE,
};
#define ADC_CHANNEL(_index, _id) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = _index, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.datasheet_name = _id, \
}
static const struct iio_chan_spec rockchip_saradc_iio_channels[] = {
ADC_CHANNEL(0, "adc0"),
ADC_CHANNEL(1, "adc1"),
ADC_CHANNEL(2, "adc2"),
};
static int rockchip_saradc_probe(struct platform_device *pdev)
{
struct rockchip_saradc *info = NULL;
struct device_node *np = pdev->dev.of_node;
struct iio_dev *indio_dev = NULL;
struct resource *mem;
int ret;
int irq;
if (!np)
return -ENODEV;
indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
if (!indio_dev) {
dev_err(&pdev->dev, "failed allocating iio device\n");
return -ENOMEM;
}
info = iio_priv(indio_dev);
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
info->regs = devm_ioremap_resource(&pdev->dev, mem);
if (IS_ERR(info->regs))
return PTR_ERR(info->regs);
init_completion(&info->completion);
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
dev_err(&pdev->dev, "no irq resource?\n");
return irq;
}
ret = devm_request_irq(&pdev->dev, irq, rockchip_saradc_isr,
0, dev_name(&pdev->dev), info);
if (ret < 0) {
dev_err(&pdev->dev, "failed requesting irq %d\n", irq);
return ret;
}
info->pclk = devm_clk_get(&pdev->dev, "apb_pclk");
if (IS_ERR(info->pclk)) {
dev_err(&pdev->dev, "failed to get pclk\n");
return PTR_ERR(info->pclk);
}
info->clk = devm_clk_get(&pdev->dev, "saradc");
if (IS_ERR(info->clk)) {
dev_err(&pdev->dev, "failed to get adc clock\n");
return PTR_ERR(info->clk);
}
info->vref = devm_regulator_get(&pdev->dev, "vref");
if (IS_ERR(info->vref)) {
dev_err(&pdev->dev, "failed to get regulator, %ld\n",
PTR_ERR(info->vref));
return PTR_ERR(info->vref);
}
/*
* Use a default of 1MHz for the converter clock.
* This may become user-configurable in the future.
*/
ret = clk_set_rate(info->clk, 1000000);
if (ret < 0) {
dev_err(&pdev->dev, "failed to set adc clk rate, %d\n", ret);
return ret;
}
ret = regulator_enable(info->vref);
if (ret < 0) {
dev_err(&pdev->dev, "failed to enable vref regulator\n");
return ret;
}
ret = clk_prepare_enable(info->pclk);
if (ret < 0) {
dev_err(&pdev->dev, "failed to enable pclk\n");
goto err_reg_voltage;
}
ret = clk_prepare_enable(info->clk);
if (ret < 0) {
dev_err(&pdev->dev, "failed to enable converter clock\n");
goto err_pclk;
}
platform_set_drvdata(pdev, indio_dev);
indio_dev->name = dev_name(&pdev->dev);
indio_dev->dev.parent = &pdev->dev;
indio_dev->dev.of_node = pdev->dev.of_node;
indio_dev->info = &rockchip_saradc_iio_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = rockchip_saradc_iio_channels;
indio_dev->num_channels = ARRAY_SIZE(rockchip_saradc_iio_channels);
ret = iio_device_register(indio_dev);
if (ret)
goto err_clk;
return 0;
err_clk:
clk_disable_unprepare(info->clk);
err_pclk:
clk_disable_unprepare(info->pclk);
err_reg_voltage:
regulator_disable(info->vref);
return ret;
}
static int rockchip_saradc_remove(struct platform_device *pdev)
{
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
struct rockchip_saradc *info = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
clk_disable_unprepare(info->clk);
clk_disable_unprepare(info->pclk);
regulator_disable(info->vref);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int rockchip_saradc_suspend(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct rockchip_saradc *info = iio_priv(indio_dev);
clk_disable_unprepare(info->clk);
clk_disable_unprepare(info->pclk);
regulator_disable(info->vref);
return 0;
}
static int rockchip_saradc_resume(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct rockchip_saradc *info = iio_priv(indio_dev);
int ret;
ret = regulator_enable(info->vref);
if (ret)
return ret;
ret = clk_prepare_enable(info->pclk);
if (ret)
return ret;
ret = clk_prepare_enable(info->clk);
if (ret)
return ret;
return ret;
}
#endif
static SIMPLE_DEV_PM_OPS(rockchip_saradc_pm_ops,
rockchip_saradc_suspend,
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