Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-only
/*
 * IIO ADC driver for NXP LPC18xx ADC
 *
 * Copyright (C) 2016 Joachim Eastwood <manabian@gmail.com>
 *
 * UNSUPPORTED hardware features:
 *  - Hardware triggers
 *  - Burst mode
 *  - Interrupts
 *  - DMA
 */
 
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/iio/iio.h>
#include <linux/iio/driver.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
 
/* LPC18XX ADC registers and bits */
#define LPC18XX_ADC_CR			0x000
#define  LPC18XX_ADC_CR_CLKDIV_SHIFT	8
#define  LPC18XX_ADC_CR_PDN		BIT(21)
#define  LPC18XX_ADC_CR_START_NOW	(0x1 << 24)
#define LPC18XX_ADC_GDR			0x004
 
/* Data register bits */
#define LPC18XX_ADC_SAMPLE_SHIFT	6
#define LPC18XX_ADC_SAMPLE_MASK		0x3ff
#define LPC18XX_ADC_CONV_DONE		BIT(31)
 
/* Clock should be 4.5 MHz or less */
#define LPC18XX_ADC_CLK_TARGET		4500000
 
struct lpc18xx_adc {
<------>struct regulator *vref;
<------>void __iomem *base;
<------>struct device *dev;
<------>struct mutex lock;
<------>struct clk *clk;
<------>u32 cr_reg;
};
 
#define LPC18XX_ADC_CHAN(_idx) {				\
<------>.type = IIO_VOLTAGE,					\
<------>.indexed = 1,						\
<------>.channel = _idx,					\
<------>.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
<------>.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
}
 
static const struct iio_chan_spec lpc18xx_adc_iio_channels[] = {
<------>LPC18XX_ADC_CHAN(0),
<------>LPC18XX_ADC_CHAN(1),
<------>LPC18XX_ADC_CHAN(2),
<------>LPC18XX_ADC_CHAN(3),
<------>LPC18XX_ADC_CHAN(4),
<------>LPC18XX_ADC_CHAN(5),
<------>LPC18XX_ADC_CHAN(6),
<------>LPC18XX_ADC_CHAN(7),
};
 
static int lpc18xx_adc_read_chan(struct lpc18xx_adc *adc, unsigned int ch)
{
<------>int ret;
<------>u32 reg;
 
<------>reg = adc->cr_reg | BIT(ch) | LPC18XX_ADC_CR_START_NOW;
<------>writel(reg, adc->base + LPC18XX_ADC_CR);
 
<------>ret = readl_poll_timeout(adc->base + LPC18XX_ADC_GDR, reg,
<------><------><------><------> reg & LPC18XX_ADC_CONV_DONE, 3, 9);
<------>if (ret) {
<------><------>dev_warn(adc->dev, "adc read timed out\n");
<------><------>return ret;
<------>}
 
<------>return (reg >> LPC18XX_ADC_SAMPLE_SHIFT) & LPC18XX_ADC_SAMPLE_MASK;
}
 
static int lpc18xx_adc_read_raw(struct iio_dev *indio_dev,
<------><------><------><------>struct iio_chan_spec const *chan,
<------><------><------><------>int *val, int *val2, long mask)
{
<------>struct lpc18xx_adc *adc = iio_priv(indio_dev);
 
<------>switch (mask) {
<------>case IIO_CHAN_INFO_RAW:
<------><------>mutex_lock(&adc->lock);
<------><------>*val = lpc18xx_adc_read_chan(adc, chan->channel);
<------><------>mutex_unlock(&adc->lock);
<------><------>if (*val < 0)
<------><------><------>return *val;
 
<------><------>return IIO_VAL_INT;
 
<------>case IIO_CHAN_INFO_SCALE:
<------><------>*val = regulator_get_voltage(adc->vref) / 1000;
<------><------>*val2 = 10;
 
<------><------>return IIO_VAL_FRACTIONAL_LOG2;
<------>}
 
<------>return -EINVAL;
}
 
static const struct iio_info lpc18xx_adc_info = {
<------>.read_raw = lpc18xx_adc_read_raw,
};
 
static int lpc18xx_adc_probe(struct platform_device *pdev)
{
<------>struct iio_dev *indio_dev;
<------>struct lpc18xx_adc *adc;
<------>unsigned int clkdiv;
<------>unsigned long rate;
<------>int ret;
 
<------>indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
<------>if (!indio_dev)
<------><------>return -ENOMEM;
 
<------>platform_set_drvdata(pdev, indio_dev);
<------>adc = iio_priv(indio_dev);
<------>adc->dev = &pdev->dev;
<------>mutex_init(&adc->lock);
 
<------>adc->base = devm_platform_ioremap_resource(pdev, 0);
<------>if (IS_ERR(adc->base))
<------><------>return PTR_ERR(adc->base);
 
<------>adc->clk = devm_clk_get(&pdev->dev, NULL);
<------>if (IS_ERR(adc->clk)) {
<------><------>dev_err(&pdev->dev, "error getting clock\n");
<------><------>return PTR_ERR(adc->clk);
<------>}
 
<------>rate = clk_get_rate(adc->clk);
<------>clkdiv = DIV_ROUND_UP(rate, LPC18XX_ADC_CLK_TARGET);
 
<------>adc->vref = devm_regulator_get(&pdev->dev, "vref");
<------>if (IS_ERR(adc->vref)) {
<------><------>dev_err(&pdev->dev, "error getting regulator\n");
<------><------>return PTR_ERR(adc->vref);
<------>}
 
<------>indio_dev->name = dev_name(&pdev->dev);
<------>indio_dev->info = &lpc18xx_adc_info;
<------>indio_dev->modes = INDIO_DIRECT_MODE;
<------>indio_dev->channels = lpc18xx_adc_iio_channels;
<------>indio_dev->num_channels = ARRAY_SIZE(lpc18xx_adc_iio_channels);
 
<------>ret = regulator_enable(adc->vref);
<------>if (ret) {
<------><------>dev_err(&pdev->dev, "unable to enable regulator\n");
<------><------>return ret;
<------>}
 
<------>ret = clk_prepare_enable(adc->clk);
<------>if (ret) {
<------><------>dev_err(&pdev->dev, "unable to enable clock\n");
<------><------>goto dis_reg;
<------>}
 
<------>adc->cr_reg = (clkdiv << LPC18XX_ADC_CR_CLKDIV_SHIFT) |
<------><------><------>LPC18XX_ADC_CR_PDN;
<------>writel(adc->cr_reg, adc->base + LPC18XX_ADC_CR);
 
<------>ret = iio_device_register(indio_dev);
<------>if (ret) {
<------><------>dev_err(&pdev->dev, "unable to register device\n");
<------><------>goto dis_clk;
<------>}
 
<------>return 0;
 
dis_clk:
<------>writel(0, adc->base + LPC18XX_ADC_CR);
<------>clk_disable_unprepare(adc->clk);
dis_reg:
<------>regulator_disable(adc->vref);
<------>return ret;
}
 
static int lpc18xx_adc_remove(struct platform_device *pdev)
{
<------>struct iio_dev *indio_dev = platform_get_drvdata(pdev);
<------>struct lpc18xx_adc *adc = iio_priv(indio_dev);
 
<------>iio_device_unregister(indio_dev);
 
<------>writel(0, adc->base + LPC18XX_ADC_CR);
<------>clk_disable_unprepare(adc->clk);
<------>regulator_disable(adc->vref);
 
<------>return 0;
}
 
static const struct of_device_id lpc18xx_adc_match[] = {
<------>{ .compatible = "nxp,lpc1850-adc" },
<------>{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, lpc18xx_adc_match);
 
static struct platform_driver lpc18xx_adc_driver = {
<------>.probe	= lpc18xx_adc_probe,
<------>.remove	= lpc18xx_adc_remove,
<------>.driver	= {
<------><------>.name = "lpc18xx-adc",
<------><------>.of_match_table = lpc18xx_adc_match,
<------>},
};
module_platform_driver(lpc18xx_adc_driver);
 
MODULE_DESCRIPTION("LPC18xx ADC driver");
MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
MODULE_LICENSE("GPL v2");