mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 03:10:12 +00:00
211 lines
4.9 KiB
C
211 lines
4.9 KiB
C
![]() |
/*
|
||
|
* IIO DAC driver for NXP LPC18xx DAC
|
||
|
*
|
||
|
* Copyright (C) 2016 Joachim Eastwood <manabian@gmail.com>
|
||
|
*
|
||
|
* This program is free software; you can redistribute it and/or modify
|
||
|
* it under the terms of the GNU General Public License version 2 as
|
||
|
* published by the Free Software Foundation.
|
||
|
*
|
||
|
* UNSUPPORTED hardware features:
|
||
|
* - 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 DAC registers and bits */
|
||
|
#define LPC18XX_DAC_CR 0x000
|
||
|
#define LPC18XX_DAC_CR_VALUE_SHIFT 6
|
||
|
#define LPC18XX_DAC_CR_VALUE_MASK 0x3ff
|
||
|
#define LPC18XX_DAC_CR_BIAS BIT(16)
|
||
|
#define LPC18XX_DAC_CTRL 0x004
|
||
|
#define LPC18XX_DAC_CTRL_DMA_ENA BIT(3)
|
||
|
|
||
|
struct lpc18xx_dac {
|
||
|
struct regulator *vref;
|
||
|
void __iomem *base;
|
||
|
struct mutex lock;
|
||
|
struct clk *clk;
|
||
|
};
|
||
|
|
||
|
static const struct iio_chan_spec lpc18xx_dac_iio_channels[] = {
|
||
|
{
|
||
|
.type = IIO_VOLTAGE,
|
||
|
.output = 1,
|
||
|
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
|
||
|
BIT(IIO_CHAN_INFO_SCALE),
|
||
|
},
|
||
|
};
|
||
|
|
||
|
static int lpc18xx_dac_read_raw(struct iio_dev *indio_dev,
|
||
|
struct iio_chan_spec const *chan,
|
||
|
int *val, int *val2, long mask)
|
||
|
{
|
||
|
struct lpc18xx_dac *dac = iio_priv(indio_dev);
|
||
|
u32 reg;
|
||
|
|
||
|
switch (mask) {
|
||
|
case IIO_CHAN_INFO_RAW:
|
||
|
reg = readl(dac->base + LPC18XX_DAC_CR);
|
||
|
*val = reg >> LPC18XX_DAC_CR_VALUE_SHIFT;
|
||
|
*val &= LPC18XX_DAC_CR_VALUE_MASK;
|
||
|
|
||
|
return IIO_VAL_INT;
|
||
|
|
||
|
case IIO_CHAN_INFO_SCALE:
|
||
|
*val = regulator_get_voltage(dac->vref) / 1000;
|
||
|
*val2 = 10;
|
||
|
|
||
|
return IIO_VAL_FRACTIONAL_LOG2;
|
||
|
}
|
||
|
|
||
|
return -EINVAL;
|
||
|
}
|
||
|
|
||
|
static int lpc18xx_dac_write_raw(struct iio_dev *indio_dev,
|
||
|
struct iio_chan_spec const *chan,
|
||
|
int val, int val2, long mask)
|
||
|
{
|
||
|
struct lpc18xx_dac *dac = iio_priv(indio_dev);
|
||
|
u32 reg;
|
||
|
|
||
|
switch (mask) {
|
||
|
case IIO_CHAN_INFO_RAW:
|
||
|
if (val < 0 || val > LPC18XX_DAC_CR_VALUE_MASK)
|
||
|
return -EINVAL;
|
||
|
|
||
|
reg = LPC18XX_DAC_CR_BIAS;
|
||
|
reg |= val << LPC18XX_DAC_CR_VALUE_SHIFT;
|
||
|
|
||
|
mutex_lock(&dac->lock);
|
||
|
writel(reg, dac->base + LPC18XX_DAC_CR);
|
||
|
writel(LPC18XX_DAC_CTRL_DMA_ENA, dac->base + LPC18XX_DAC_CTRL);
|
||
|
mutex_unlock(&dac->lock);
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
return -EINVAL;
|
||
|
}
|
||
|
|
||
|
static const struct iio_info lpc18xx_dac_info = {
|
||
|
.read_raw = lpc18xx_dac_read_raw,
|
||
|
.write_raw = lpc18xx_dac_write_raw,
|
||
|
.driver_module = THIS_MODULE,
|
||
|
};
|
||
|
|
||
|
static int lpc18xx_dac_probe(struct platform_device *pdev)
|
||
|
{
|
||
|
struct iio_dev *indio_dev;
|
||
|
struct lpc18xx_dac *dac;
|
||
|
struct resource *res;
|
||
|
int ret;
|
||
|
|
||
|
indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*dac));
|
||
|
if (!indio_dev)
|
||
|
return -ENOMEM;
|
||
|
|
||
|
platform_set_drvdata(pdev, indio_dev);
|
||
|
dac = iio_priv(indio_dev);
|
||
|
mutex_init(&dac->lock);
|
||
|
|
||
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
||
|
dac->base = devm_ioremap_resource(&pdev->dev, res);
|
||
|
if (IS_ERR(dac->base))
|
||
|
return PTR_ERR(dac->base);
|
||
|
|
||
|
dac->clk = devm_clk_get(&pdev->dev, NULL);
|
||
|
if (IS_ERR(dac->clk)) {
|
||
|
dev_err(&pdev->dev, "error getting clock\n");
|
||
|
return PTR_ERR(dac->clk);
|
||
|
}
|
||
|
|
||
|
dac->vref = devm_regulator_get(&pdev->dev, "vref");
|
||
|
if (IS_ERR(dac->vref)) {
|
||
|
dev_err(&pdev->dev, "error getting regulator\n");
|
||
|
return PTR_ERR(dac->vref);
|
||
|
}
|
||
|
|
||
|
indio_dev->name = dev_name(&pdev->dev);
|
||
|
indio_dev->dev.parent = &pdev->dev;
|
||
|
indio_dev->info = &lpc18xx_dac_info;
|
||
|
indio_dev->modes = INDIO_DIRECT_MODE;
|
||
|
indio_dev->channels = lpc18xx_dac_iio_channels;
|
||
|
indio_dev->num_channels = ARRAY_SIZE(lpc18xx_dac_iio_channels);
|
||
|
|
||
|
ret = regulator_enable(dac->vref);
|
||
|
if (ret) {
|
||
|
dev_err(&pdev->dev, "unable to enable regulator\n");
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
ret = clk_prepare_enable(dac->clk);
|
||
|
if (ret) {
|
||
|
dev_err(&pdev->dev, "unable to enable clock\n");
|
||
|
goto dis_reg;
|
||
|
}
|
||
|
|
||
|
writel(0, dac->base + LPC18XX_DAC_CTRL);
|
||
|
writel(0, dac->base + LPC18XX_DAC_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:
|
||
|
clk_disable_unprepare(dac->clk);
|
||
|
dis_reg:
|
||
|
regulator_disable(dac->vref);
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
static int lpc18xx_dac_remove(struct platform_device *pdev)
|
||
|
{
|
||
|
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
|
||
|
struct lpc18xx_dac *dac = iio_priv(indio_dev);
|
||
|
|
||
|
iio_device_unregister(indio_dev);
|
||
|
|
||
|
writel(0, dac->base + LPC18XX_DAC_CTRL);
|
||
|
clk_disable_unprepare(dac->clk);
|
||
|
regulator_disable(dac->vref);
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
static const struct of_device_id lpc18xx_dac_match[] = {
|
||
|
{ .compatible = "nxp,lpc1850-dac" },
|
||
|
{ /* sentinel */ }
|
||
|
};
|
||
|
MODULE_DEVICE_TABLE(of, lpc18xx_dac_match);
|
||
|
|
||
|
static struct platform_driver lpc18xx_dac_driver = {
|
||
|
.probe = lpc18xx_dac_probe,
|
||
|
.remove = lpc18xx_dac_remove,
|
||
|
.driver = {
|
||
|
.name = "lpc18xx-dac",
|
||
|
.of_match_table = lpc18xx_dac_match,
|
||
|
},
|
||
|
};
|
||
|
module_platform_driver(lpc18xx_dac_driver);
|
||
|
|
||
|
MODULE_DESCRIPTION("LPC18xx DAC driver");
|
||
|
MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
|
||
|
MODULE_LICENSE("GPL v2");
|