iio: adc: add NXP LPC18xx ADC driver
Add base support for the 10-bit SAR ADC peripheral found on NXP LPC18xx/43xx SoCs. This is a minimal driver that does not support burst mode, interrupts, DMA or hardware triggers. User manual with register description can be found on: LPC18xx: www.nxp.com/documents/user_manual/UM10430.pdf LPC43xx: www.nxp.com/documents/user_manual/UM10503.pdf Signed-off-by: Joachim Eastwood <manabian@gmail.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Joachim Eastwood
Jonathan Cameron
parent
1c118b7230
commit
a583c24dee
|
|
@ -235,6 +235,16 @@ config LP8788_ADC
|
|||
To compile this driver as a module, choose M here: the module will be
|
||||
called lp8788_adc.
|
||||
|
||||
config LPC18XX_ADC
|
||||
tristate "NXP LPC18xx ADC driver"
|
||||
depends on ARCH_LPC18XX || COMPILE_TEST
|
||||
depends on OF && HAS_IOMEM
|
||||
help
|
||||
Say yes here to build support for NXP LPC18XX ADC.
|
||||
|
||||
To compile this driver as a module, choose M here: the module will be
|
||||
called lpc18xx_adc.
|
||||
|
||||
config MAX1027
|
||||
tristate "Maxim max1027 ADC driver"
|
||||
depends on SPI
|
||||
|
|
|
|||
|
|
@ -24,6 +24,7 @@ obj-$(CONFIG_HI8435) += hi8435.o
|
|||
obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
|
||||
obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
|
||||
obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
|
||||
obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o
|
||||
obj-$(CONFIG_MAX1027) += max1027.o
|
||||
obj-$(CONFIG_MAX1363) += max1363.o
|
||||
obj-$(CONFIG_MCP320X) += mcp320x.o
|
||||
|
|
|
|||
|
|
@ -0,0 +1,231 @@
|
|||
/*
|
||||
* IIO ADC driver for NXP LPC18xx ADC
|
||||
*
|
||||
* 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:
|
||||
* - 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,
|
||||
.driver_module = THIS_MODULE,
|
||||
};
|
||||
|
||||
static int lpc18xx_adc_probe(struct platform_device *pdev)
|
||||
{
|
||||
struct iio_dev *indio_dev;
|
||||
struct lpc18xx_adc *adc;
|
||||
struct resource *res;
|
||||
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);
|
||||
|
||||
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
||||
adc->base = devm_ioremap_resource(&pdev->dev, res);
|
||||
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->dev.parent = &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");
|
||||
Loading…
Reference in New Issue