325 lines
8.6 KiB
C
325 lines
8.6 KiB
C
/*
|
|
* Aspeed AST2400/2500 ADC
|
|
*
|
|
* Copyright (C) 2017 Google, Inc.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms and conditions of the GNU General Public License,
|
|
* version 2, as published by the Free Software Foundation.
|
|
*
|
|
*/
|
|
|
|
#include <linux/clk.h>
|
|
#include <linux/clk-provider.h>
|
|
#include <linux/err.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/io.h>
|
|
#include <linux/module.h>
|
|
#include <linux/of_platform.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/types.h>
|
|
|
|
#include <linux/iio/iio.h>
|
|
#include <linux/iio/driver.h>
|
|
#include <linux/iopoll.h>
|
|
|
|
#define ASPEED_RESOLUTION_BITS 10
|
|
#define ASPEED_CLOCKS_PER_SAMPLE 12
|
|
|
|
#define ASPEED_REG_ENGINE_CONTROL 0x00
|
|
#define ASPEED_REG_INTERRUPT_CONTROL 0x04
|
|
#define ASPEED_REG_VGA_DETECT_CONTROL 0x08
|
|
#define ASPEED_REG_CLOCK_CONTROL 0x0C
|
|
#define ASPEED_REG_MAX 0xC0
|
|
|
|
#define ASPEED_OPERATION_MODE_POWER_DOWN (0x0 << 1)
|
|
#define ASPEED_OPERATION_MODE_STANDBY (0x1 << 1)
|
|
#define ASPEED_OPERATION_MODE_NORMAL (0x7 << 1)
|
|
|
|
#define ASPEED_ENGINE_ENABLE BIT(0)
|
|
|
|
#define ASPEED_ADC_CTRL_INIT_RDY BIT(8)
|
|
|
|
#define ASPEED_ADC_INIT_POLLING_TIME 500
|
|
#define ASPEED_ADC_INIT_TIMEOUT 500000
|
|
|
|
struct aspeed_adc_model_data {
|
|
const char *model_name;
|
|
unsigned int min_sampling_rate; // Hz
|
|
unsigned int max_sampling_rate; // Hz
|
|
unsigned int vref_voltage; // mV
|
|
bool wait_init_sequence;
|
|
};
|
|
|
|
struct aspeed_adc_data {
|
|
struct device *dev;
|
|
void __iomem *base;
|
|
spinlock_t clk_lock;
|
|
struct clk_hw *clk_prescaler;
|
|
struct clk_hw *clk_scaler;
|
|
};
|
|
|
|
#define ASPEED_CHAN(_idx, _data_reg_addr) { \
|
|
.type = IIO_VOLTAGE, \
|
|
.indexed = 1, \
|
|
.channel = (_idx), \
|
|
.address = (_data_reg_addr), \
|
|
.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 aspeed_adc_iio_channels[] = {
|
|
ASPEED_CHAN(0, 0x10),
|
|
ASPEED_CHAN(1, 0x12),
|
|
ASPEED_CHAN(2, 0x14),
|
|
ASPEED_CHAN(3, 0x16),
|
|
ASPEED_CHAN(4, 0x18),
|
|
ASPEED_CHAN(5, 0x1A),
|
|
ASPEED_CHAN(6, 0x1C),
|
|
ASPEED_CHAN(7, 0x1E),
|
|
ASPEED_CHAN(8, 0x20),
|
|
ASPEED_CHAN(9, 0x22),
|
|
ASPEED_CHAN(10, 0x24),
|
|
ASPEED_CHAN(11, 0x26),
|
|
ASPEED_CHAN(12, 0x28),
|
|
ASPEED_CHAN(13, 0x2A),
|
|
ASPEED_CHAN(14, 0x2C),
|
|
ASPEED_CHAN(15, 0x2E),
|
|
};
|
|
|
|
static int aspeed_adc_read_raw(struct iio_dev *indio_dev,
|
|
struct iio_chan_spec const *chan,
|
|
int *val, int *val2, long mask)
|
|
{
|
|
struct aspeed_adc_data *data = iio_priv(indio_dev);
|
|
const struct aspeed_adc_model_data *model_data =
|
|
of_device_get_match_data(data->dev);
|
|
|
|
switch (mask) {
|
|
case IIO_CHAN_INFO_RAW:
|
|
*val = readw(data->base + chan->address);
|
|
return IIO_VAL_INT;
|
|
|
|
case IIO_CHAN_INFO_SCALE:
|
|
*val = model_data->vref_voltage;
|
|
*val2 = ASPEED_RESOLUTION_BITS;
|
|
return IIO_VAL_FRACTIONAL_LOG2;
|
|
|
|
case IIO_CHAN_INFO_SAMP_FREQ:
|
|
*val = clk_get_rate(data->clk_scaler->clk) /
|
|
ASPEED_CLOCKS_PER_SAMPLE;
|
|
return IIO_VAL_INT;
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
static int aspeed_adc_write_raw(struct iio_dev *indio_dev,
|
|
struct iio_chan_spec const *chan,
|
|
int val, int val2, long mask)
|
|
{
|
|
struct aspeed_adc_data *data = iio_priv(indio_dev);
|
|
const struct aspeed_adc_model_data *model_data =
|
|
of_device_get_match_data(data->dev);
|
|
|
|
switch (mask) {
|
|
case IIO_CHAN_INFO_SAMP_FREQ:
|
|
if (val < model_data->min_sampling_rate ||
|
|
val > model_data->max_sampling_rate)
|
|
return -EINVAL;
|
|
|
|
clk_set_rate(data->clk_scaler->clk,
|
|
val * ASPEED_CLOCKS_PER_SAMPLE);
|
|
return 0;
|
|
|
|
case IIO_CHAN_INFO_SCALE:
|
|
case IIO_CHAN_INFO_RAW:
|
|
/*
|
|
* Technically, these could be written but the only reasons
|
|
* for doing so seem better handled in userspace. EPERM is
|
|
* returned to signal this is a policy choice rather than a
|
|
* hardware limitation.
|
|
*/
|
|
return -EPERM;
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
static int aspeed_adc_reg_access(struct iio_dev *indio_dev,
|
|
unsigned int reg, unsigned int writeval,
|
|
unsigned int *readval)
|
|
{
|
|
struct aspeed_adc_data *data = iio_priv(indio_dev);
|
|
|
|
if (!readval || reg % 4 || reg > ASPEED_REG_MAX)
|
|
return -EINVAL;
|
|
|
|
*readval = readl(data->base + reg);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct iio_info aspeed_adc_iio_info = {
|
|
.read_raw = aspeed_adc_read_raw,
|
|
.write_raw = aspeed_adc_write_raw,
|
|
.debugfs_reg_access = aspeed_adc_reg_access,
|
|
};
|
|
|
|
static int aspeed_adc_probe(struct platform_device *pdev)
|
|
{
|
|
struct iio_dev *indio_dev;
|
|
struct aspeed_adc_data *data;
|
|
const struct aspeed_adc_model_data *model_data;
|
|
struct resource *res;
|
|
const char *clk_parent_name;
|
|
int ret;
|
|
u32 adc_engine_control_reg_val;
|
|
|
|
indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*data));
|
|
if (!indio_dev)
|
|
return -ENOMEM;
|
|
|
|
data = iio_priv(indio_dev);
|
|
data->dev = &pdev->dev;
|
|
|
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
data->base = devm_ioremap_resource(&pdev->dev, res);
|
|
if (IS_ERR(data->base))
|
|
return PTR_ERR(data->base);
|
|
|
|
/* Register ADC clock prescaler with source specified by device tree. */
|
|
spin_lock_init(&data->clk_lock);
|
|
clk_parent_name = of_clk_get_parent_name(pdev->dev.of_node, 0);
|
|
|
|
data->clk_prescaler = clk_hw_register_divider(
|
|
&pdev->dev, "prescaler", clk_parent_name, 0,
|
|
data->base + ASPEED_REG_CLOCK_CONTROL,
|
|
17, 15, 0, &data->clk_lock);
|
|
if (IS_ERR(data->clk_prescaler))
|
|
return PTR_ERR(data->clk_prescaler);
|
|
|
|
/*
|
|
* Register ADC clock scaler downstream from the prescaler. Allow rate
|
|
* setting to adjust the prescaler as well.
|
|
*/
|
|
data->clk_scaler = clk_hw_register_divider(
|
|
&pdev->dev, "scaler", "prescaler",
|
|
CLK_SET_RATE_PARENT,
|
|
data->base + ASPEED_REG_CLOCK_CONTROL,
|
|
0, 10, 0, &data->clk_lock);
|
|
if (IS_ERR(data->clk_scaler)) {
|
|
ret = PTR_ERR(data->clk_scaler);
|
|
goto scaler_error;
|
|
}
|
|
|
|
model_data = of_device_get_match_data(&pdev->dev);
|
|
|
|
if (model_data->wait_init_sequence) {
|
|
/* Enable engine in normal mode. */
|
|
writel(ASPEED_OPERATION_MODE_NORMAL | ASPEED_ENGINE_ENABLE,
|
|
data->base + ASPEED_REG_ENGINE_CONTROL);
|
|
|
|
/* Wait for initial sequence complete. */
|
|
ret = readl_poll_timeout(data->base + ASPEED_REG_ENGINE_CONTROL,
|
|
adc_engine_control_reg_val,
|
|
adc_engine_control_reg_val &
|
|
ASPEED_ADC_CTRL_INIT_RDY,
|
|
ASPEED_ADC_INIT_POLLING_TIME,
|
|
ASPEED_ADC_INIT_TIMEOUT);
|
|
if (ret)
|
|
goto scaler_error;
|
|
}
|
|
|
|
/* Start all channels in normal mode. */
|
|
ret = clk_prepare_enable(data->clk_scaler->clk);
|
|
if (ret)
|
|
goto clk_enable_error;
|
|
|
|
adc_engine_control_reg_val = GENMASK(31, 16) |
|
|
ASPEED_OPERATION_MODE_NORMAL | ASPEED_ENGINE_ENABLE;
|
|
writel(adc_engine_control_reg_val,
|
|
data->base + ASPEED_REG_ENGINE_CONTROL);
|
|
|
|
model_data = of_device_get_match_data(&pdev->dev);
|
|
indio_dev->name = model_data->model_name;
|
|
indio_dev->dev.parent = &pdev->dev;
|
|
indio_dev->info = &aspeed_adc_iio_info;
|
|
indio_dev->modes = INDIO_DIRECT_MODE;
|
|
indio_dev->channels = aspeed_adc_iio_channels;
|
|
indio_dev->num_channels = ARRAY_SIZE(aspeed_adc_iio_channels);
|
|
|
|
ret = iio_device_register(indio_dev);
|
|
if (ret)
|
|
goto iio_register_error;
|
|
|
|
return 0;
|
|
|
|
iio_register_error:
|
|
writel(ASPEED_OPERATION_MODE_POWER_DOWN,
|
|
data->base + ASPEED_REG_ENGINE_CONTROL);
|
|
clk_disable_unprepare(data->clk_scaler->clk);
|
|
clk_enable_error:
|
|
clk_hw_unregister_divider(data->clk_scaler);
|
|
|
|
scaler_error:
|
|
clk_hw_unregister_divider(data->clk_prescaler);
|
|
return ret;
|
|
}
|
|
|
|
static int aspeed_adc_remove(struct platform_device *pdev)
|
|
{
|
|
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
|
|
struct aspeed_adc_data *data = iio_priv(indio_dev);
|
|
|
|
iio_device_unregister(indio_dev);
|
|
writel(ASPEED_OPERATION_MODE_POWER_DOWN,
|
|
data->base + ASPEED_REG_ENGINE_CONTROL);
|
|
clk_disable_unprepare(data->clk_scaler->clk);
|
|
clk_hw_unregister_divider(data->clk_scaler);
|
|
clk_hw_unregister_divider(data->clk_prescaler);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct aspeed_adc_model_data ast2400_model_data = {
|
|
.model_name = "ast2400-adc",
|
|
.vref_voltage = 2500, // mV
|
|
.min_sampling_rate = 10000,
|
|
.max_sampling_rate = 500000,
|
|
};
|
|
|
|
static const struct aspeed_adc_model_data ast2500_model_data = {
|
|
.model_name = "ast2500-adc",
|
|
.vref_voltage = 1800, // mV
|
|
.min_sampling_rate = 1,
|
|
.max_sampling_rate = 1000000,
|
|
.wait_init_sequence = true,
|
|
};
|
|
|
|
static const struct of_device_id aspeed_adc_matches[] = {
|
|
{ .compatible = "aspeed,ast2400-adc", .data = &ast2400_model_data },
|
|
{ .compatible = "aspeed,ast2500-adc", .data = &ast2500_model_data },
|
|
{},
|
|
};
|
|
MODULE_DEVICE_TABLE(of, aspeed_adc_matches);
|
|
|
|
static struct platform_driver aspeed_adc_driver = {
|
|
.probe = aspeed_adc_probe,
|
|
.remove = aspeed_adc_remove,
|
|
.driver = {
|
|
.name = KBUILD_MODNAME,
|
|
.of_match_table = aspeed_adc_matches,
|
|
}
|
|
};
|
|
|
|
module_platform_driver(aspeed_adc_driver);
|
|
|
|
MODULE_AUTHOR("Rick Altherr <raltherr@google.com>");
|
|
MODULE_DESCRIPTION("Aspeed AST2400/2500 ADC Driver");
|
|
MODULE_LICENSE("GPL");
|