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linux/drivers/iio/addac/stx104.c
William Breathitt Gray 66fe531268 iio: addac: stx104: Add 8254 Counter/Timer support 
The STX104 features an 8254 Counter/Timer chip providing three
counter/timers which can be used for frequency measurement, frequency
output, pulse width modulation, pulse width measurement, event count,
etc. The STX104 provides a register bank selection to bank select
between the 8254 Bank and the Indexed Register Array Bank; the Indexed
Register Array is not utilized by this driver, so the 8254 Bank is
selected unconditionally.

Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Link: https://lore.kernel.org/r/20230916112031.3634-1-william.gray@linaro.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2023-09-17 10:29:41 +01:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* IIO driver for the Apex Embedded Systems STX104
* Copyright (C) 2016 William Breathitt Gray
*/
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio/regmap.h>
#include <linux/i8254.h>
#include <linux/iio/iio.h>
#include <linux/iio/types.h>
#include <linux/isa.h>
#include <linux/kernel.h>
#include <linux/limits.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/mutex.h>
#include <linux/regmap.h>
#include <linux/types.h>
#define STX104_OUT_CHAN(chan) { \
.type = IIO_VOLTAGE, \
.channel = chan, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.indexed = 1, \
.output = 1 \
}
#define STX104_IN_CHAN(chan, diff) { \
.type = IIO_VOLTAGE, \
.channel = chan, \
.channel2 = chan, \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN) | \
BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.indexed = 1, \
.differential = diff \
}
#define STX104_NUM_OUT_CHAN 2
#define STX104_EXTENT 16
static unsigned int base[max_num_isa_dev(STX104_EXTENT)];
static unsigned int num_stx104;
module_param_hw_array(base, uint, ioport, &num_stx104, 0);
MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
#define STX104_AIO_BASE 0x0
#define STX104_SOFTWARE_STROBE STX104_AIO_BASE
#define STX104_ADC_DATA STX104_AIO_BASE
#define STX104_ADC_CHANNEL (STX104_AIO_BASE + 0x2)
#define STX104_DIO_REG (STX104_AIO_BASE + 0x3)
#define STX104_DAC_BASE (STX104_AIO_BASE + 0x4)
#define STX104_ADC_STATUS (STX104_AIO_BASE + 0x8)
#define STX104_ADC_CONTROL (STX104_AIO_BASE + 0x9)
#define STX104_ADC_CONFIGURATION (STX104_AIO_BASE + 0x11)
#define STX104_I8254_BASE (STX104_AIO_BASE + 0x12)
#define STX104_AIO_DATA_STRIDE 2
#define STX104_DAC_OFFSET(_channel) (STX104_DAC_BASE + STX104_AIO_DATA_STRIDE * (_channel))
/* ADC Channel */
#define STX104_FC GENMASK(3, 0)
#define STX104_LC GENMASK(7, 4)
#define STX104_SINGLE_CHANNEL(_channel) \
(u8_encode_bits(_channel, STX104_FC) | u8_encode_bits(_channel, STX104_LC))
/* ADC Status */
#define STX104_SD BIT(5)
#define STX104_CNV BIT(7)
#define STX104_DIFFERENTIAL 1
/* ADC Control */
#define STX104_ALSS GENMASK(1, 0)
#define STX104_SOFTWARE_TRIGGER u8_encode_bits(0x0, STX104_ALSS)
/* ADC Configuration */
#define STX104_GAIN GENMASK(1, 0)
#define STX104_ADBU BIT(2)
#define STX104_RBK GENMASK(7, 4)
#define STX104_BIPOLAR 0
#define STX104_GAIN_X1 0
#define STX104_GAIN_X2 1
#define STX104_GAIN_X4 2
#define STX104_GAIN_X8 3
/**
* struct stx104_iio - IIO device private data structure
* @lock: synchronization lock to prevent I/O race conditions
* @aio_data_map: Regmap for analog I/O data
* @aio_ctl_map: Regmap for analog I/O control
*/
struct stx104_iio {
struct mutex lock;
struct regmap *aio_data_map;
struct regmap *aio_ctl_map;
};
static const struct regmap_range aio_ctl_wr_ranges[] = {
regmap_reg_range(0x0, 0x0), regmap_reg_range(0x2, 0x2), regmap_reg_range(0x9, 0x9),
regmap_reg_range(0x11, 0x11),
};
static const struct regmap_range aio_ctl_rd_ranges[] = {
regmap_reg_range(0x2, 0x2), regmap_reg_range(0x8, 0x9), regmap_reg_range(0x11, 0x11),
};
static const struct regmap_range aio_ctl_volatile_ranges[] = {
regmap_reg_range(0x8, 0x8),
};
static const struct regmap_access_table aio_ctl_wr_table = {
.yes_ranges = aio_ctl_wr_ranges,
.n_yes_ranges = ARRAY_SIZE(aio_ctl_wr_ranges),
};
static const struct regmap_access_table aio_ctl_rd_table = {
.yes_ranges = aio_ctl_rd_ranges,
.n_yes_ranges = ARRAY_SIZE(aio_ctl_rd_ranges),
};
static const struct regmap_access_table aio_ctl_volatile_table = {
.yes_ranges = aio_ctl_volatile_ranges,
.n_yes_ranges = ARRAY_SIZE(aio_ctl_volatile_ranges),
};
static const struct regmap_config aio_ctl_regmap_config = {
.name = "aio_ctl",
.reg_bits = 8,
.reg_stride = 1,
.reg_base = STX104_AIO_BASE,
.val_bits = 8,
.io_port = true,
.wr_table = &aio_ctl_wr_table,
.rd_table = &aio_ctl_rd_table,
.volatile_table = &aio_ctl_volatile_table,
.cache_type = REGCACHE_FLAT,
};
static const struct regmap_range aio_data_wr_ranges[] = {
regmap_reg_range(0x4, 0x6),
};
static const struct regmap_range aio_data_rd_ranges[] = {
regmap_reg_range(0x0, 0x0),
};
static const struct regmap_access_table aio_data_wr_table = {
.yes_ranges = aio_data_wr_ranges,
.n_yes_ranges = ARRAY_SIZE(aio_data_wr_ranges),
};
static const struct regmap_access_table aio_data_rd_table = {
.yes_ranges = aio_data_rd_ranges,
.n_yes_ranges = ARRAY_SIZE(aio_data_rd_ranges),
};
static const struct regmap_config aio_data_regmap_config = {
.name = "aio_data",
.reg_bits = 16,
.reg_stride = STX104_AIO_DATA_STRIDE,
.reg_base = STX104_AIO_BASE,
.val_bits = 16,
.io_port = true,
.wr_table = &aio_data_wr_table,
.rd_table = &aio_data_rd_table,
.volatile_table = &aio_data_rd_table,
.cache_type = REGCACHE_FLAT,
};
static const struct regmap_config dio_regmap_config = {
.name = "dio",
.reg_bits = 8,
.reg_stride = 1,
.reg_base = STX104_DIO_REG,
.val_bits = 8,
.io_port = true,
};
static const struct regmap_range pit_wr_ranges[] = {
regmap_reg_range(0x0, 0x3),
};
static const struct regmap_range pit_rd_ranges[] = {
regmap_reg_range(0x0, 0x2),
};
static const struct regmap_access_table pit_wr_table = {
.yes_ranges = pit_wr_ranges,
.n_yes_ranges = ARRAY_SIZE(pit_wr_ranges),
};
static const struct regmap_access_table pit_rd_table = {
.yes_ranges = pit_rd_ranges,
.n_yes_ranges = ARRAY_SIZE(pit_rd_ranges),
};
static const struct regmap_config pit_regmap_config = {
.name = "i8254",
.reg_bits = 8,
.reg_stride = 1,
.reg_base = STX104_I8254_BASE,
.val_bits = 8,
.io_port = true,
.wr_table = &pit_wr_table,
.rd_table = &pit_rd_table,
};
static int stx104_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val, int *val2, long mask)
{
struct stx104_iio *const priv = iio_priv(indio_dev);
int err;
unsigned int adc_config;
unsigned int value;
unsigned int adc_status;
switch (mask) {
case IIO_CHAN_INFO_HARDWAREGAIN:
err = regmap_read(priv->aio_ctl_map, STX104_ADC_CONFIGURATION, &adc_config);
if (err)
return err;
*val = BIT(u8_get_bits(adc_config, STX104_GAIN));
return IIO_VAL_INT;
case IIO_CHAN_INFO_RAW:
if (chan->output) {
err = regmap_read(priv->aio_data_map, STX104_DAC_OFFSET(chan->channel),
&value);
if (err)
return err;
*val = value;
return IIO_VAL_INT;
}
mutex_lock(&priv->lock);
/* select ADC channel */
err = regmap_write(priv->aio_ctl_map, STX104_ADC_CHANNEL,
STX104_SINGLE_CHANNEL(chan->channel));
if (err) {
mutex_unlock(&priv->lock);
return err;
}
/*
* Trigger ADC sample capture by writing to the 8-bit Software Strobe Register and
* wait for completion; the conversion time range is 5 microseconds to 53.68 seconds
* in steps of 25 nanoseconds. The actual Analog Input Frame Timer time interval is
* calculated as:
* ai_time_frame_ns = ( AIFT + 1 ) * ( 25 nanoseconds ).
* Where 0 <= AIFT <= 2147483648.
*/
err = regmap_write(priv->aio_ctl_map, STX104_SOFTWARE_STROBE, 0);
if (err) {
mutex_unlock(&priv->lock);
return err;
}
err = regmap_read_poll_timeout(priv->aio_ctl_map, STX104_ADC_STATUS, adc_status,
!u8_get_bits(adc_status, STX104_CNV), 0, 53687092);
if (err) {
mutex_unlock(&priv->lock);
return err;
}
err = regmap_read(priv->aio_data_map, STX104_ADC_DATA, &value);
if (err) {
mutex_unlock(&priv->lock);
return err;
}
*val = value;
mutex_unlock(&priv->lock);
return IIO_VAL_INT;
case IIO_CHAN_INFO_OFFSET:
/* get ADC bipolar/unipolar configuration */
err = regmap_read(priv->aio_ctl_map, STX104_ADC_CONFIGURATION, &adc_config);
if (err)
return err;
*val = (u8_get_bits(adc_config, STX104_ADBU) == STX104_BIPOLAR) ? -32768 : 0;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
/* get ADC bipolar/unipolar and gain configuration */
err = regmap_read(priv->aio_ctl_map, STX104_ADC_CONFIGURATION, &adc_config);
if (err)
return err;
*val = 5;
*val2 = (u8_get_bits(adc_config, STX104_ADBU) == STX104_BIPOLAR) ? 14 : 15;
*val2 += u8_get_bits(adc_config, STX104_GAIN);
return IIO_VAL_FRACTIONAL_LOG2;
}
return -EINVAL;
}
static int stx104_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int val, int val2, long mask)
{
struct stx104_iio *const priv = iio_priv(indio_dev);
u8 gain;
switch (mask) {
case IIO_CHAN_INFO_HARDWAREGAIN:
/* Only four gain states (x1, x2, x4, x8) */
switch (val) {
case 1:
gain = STX104_GAIN_X1;
break;
case 2:
gain = STX104_GAIN_X2;
break;
case 4:
gain = STX104_GAIN_X4;
break;
case 8:
gain = STX104_GAIN_X8;
break;
default:
return -EINVAL;
}
return regmap_write(priv->aio_ctl_map, STX104_ADC_CONFIGURATION, gain);
case IIO_CHAN_INFO_RAW:
if (!chan->output)
return -EINVAL;
if (val < 0 || val > U16_MAX)
return -EINVAL;
return regmap_write(priv->aio_data_map, STX104_DAC_OFFSET(chan->channel), val);
}
return -EINVAL;
}
static const struct iio_info stx104_info = {
.read_raw = stx104_read_raw,
.write_raw = stx104_write_raw
};
/* single-ended input channels configuration */
static const struct iio_chan_spec stx104_channels_sing[] = {
STX104_OUT_CHAN(0), STX104_OUT_CHAN(1),
STX104_IN_CHAN(0, 0), STX104_IN_CHAN(1, 0), STX104_IN_CHAN(2, 0),
STX104_IN_CHAN(3, 0), STX104_IN_CHAN(4, 0), STX104_IN_CHAN(5, 0),
STX104_IN_CHAN(6, 0), STX104_IN_CHAN(7, 0), STX104_IN_CHAN(8, 0),
STX104_IN_CHAN(9, 0), STX104_IN_CHAN(10, 0), STX104_IN_CHAN(11, 0),
STX104_IN_CHAN(12, 0), STX104_IN_CHAN(13, 0), STX104_IN_CHAN(14, 0),
STX104_IN_CHAN(15, 0)
};
/* differential input channels configuration */
static const struct iio_chan_spec stx104_channels_diff[] = {
STX104_OUT_CHAN(0), STX104_OUT_CHAN(1),
STX104_IN_CHAN(0, 1), STX104_IN_CHAN(1, 1), STX104_IN_CHAN(2, 1),
STX104_IN_CHAN(3, 1), STX104_IN_CHAN(4, 1), STX104_IN_CHAN(5, 1),
STX104_IN_CHAN(6, 1), STX104_IN_CHAN(7, 1)
};
static int stx104_reg_mask_xlate(struct gpio_regmap *const gpio, const unsigned int base,
unsigned int offset, unsigned int *const reg,
unsigned int *const mask)
{
/* Output lines are located at same register bit offsets as input lines */
if (offset >= 4)
offset -= 4;
*reg = base;
*mask = BIT(offset);
return 0;
}
#define STX104_NGPIO 8
static const char *stx104_names[STX104_NGPIO] = {
"DIN0", "DIN1", "DIN2", "DIN3", "DOUT0", "DOUT1", "DOUT2", "DOUT3"
};
static int bank_select_i8254(struct regmap *map)
{
const u8 select_i8254[] = { 0x3, 0xB, 0xA };
size_t i;
int err;
for (i = 0; i < ARRAY_SIZE(select_i8254); i++) {
err = regmap_write_bits(map, STX104_ADC_CONFIGURATION, STX104_RBK, select_i8254[i]);
if (err)
return err;
}
return 0;
}
static int stx104_init_hw(struct stx104_iio *const priv)
{
int err;
/* configure device for software trigger operation */
err = regmap_write(priv->aio_ctl_map, STX104_ADC_CONTROL, STX104_SOFTWARE_TRIGGER);
if (err)
return err;
/* initialize gain setting to x1 */
err = regmap_write(priv->aio_ctl_map, STX104_ADC_CONFIGURATION, STX104_GAIN_X1);
if (err)
return err;
/* initialize DAC outputs to 0V */
err = regmap_write(priv->aio_data_map, STX104_DAC_BASE, 0);
if (err)
return err;
err = regmap_write(priv->aio_data_map, STX104_DAC_BASE + STX104_AIO_DATA_STRIDE, 0);
if (err)
return err;
return bank_select_i8254(priv->aio_ctl_map);
}
static int stx104_probe(struct device *dev, unsigned int id)
{
struct iio_dev *indio_dev;
struct stx104_iio *priv;
struct gpio_regmap_config gpio_config;
struct i8254_regmap_config pit_config;
void __iomem *stx104_base;
struct regmap *aio_ctl_map;
struct regmap *aio_data_map;
struct regmap *dio_map;
int err;
unsigned int adc_status;
indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
if (!indio_dev)
return -ENOMEM;
if (!devm_request_region(dev, base[id], STX104_EXTENT,
dev_name(dev))) {
dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
base[id], base[id] + STX104_EXTENT);
return -EBUSY;
}
stx104_base = devm_ioport_map(dev, base[id], STX104_EXTENT);
if (!stx104_base)
return -ENOMEM;
aio_ctl_map = devm_regmap_init_mmio(dev, stx104_base, &aio_ctl_regmap_config);
if (IS_ERR(aio_ctl_map))
return dev_err_probe(dev, PTR_ERR(aio_ctl_map),
"Unable to initialize aio_ctl register map\n");
aio_data_map = devm_regmap_init_mmio(dev, stx104_base, &aio_data_regmap_config);
if (IS_ERR(aio_data_map))
return dev_err_probe(dev, PTR_ERR(aio_data_map),
"Unable to initialize aio_data register map\n");
dio_map = devm_regmap_init_mmio(dev, stx104_base, &dio_regmap_config);
if (IS_ERR(dio_map))
return dev_err_probe(dev, PTR_ERR(dio_map),
"Unable to initialize dio register map\n");
pit_config.map = devm_regmap_init_mmio(dev, stx104_base, &pit_regmap_config);
if (IS_ERR(pit_config.map))
return dev_err_probe(dev, PTR_ERR(pit_config.map),
"Unable to initialize i8254 register map\n");
priv = iio_priv(indio_dev);
priv->aio_ctl_map = aio_ctl_map;
priv->aio_data_map = aio_data_map;
indio_dev->info = &stx104_info;
indio_dev->modes = INDIO_DIRECT_MODE;
err = regmap_read(aio_ctl_map, STX104_ADC_STATUS, &adc_status);
if (err)
return err;
if (u8_get_bits(adc_status, STX104_SD) == STX104_DIFFERENTIAL) {
indio_dev->num_channels = ARRAY_SIZE(stx104_channels_diff);
indio_dev->channels = stx104_channels_diff;
} else {
indio_dev->num_channels = ARRAY_SIZE(stx104_channels_sing);
indio_dev->channels = stx104_channels_sing;
}
indio_dev->name = dev_name(dev);
mutex_init(&priv->lock);
err = stx104_init_hw(priv);
if (err)
return err;
err = devm_iio_device_register(dev, indio_dev);
if (err)
return err;
gpio_config = (struct gpio_regmap_config) {
.parent = dev,
.regmap = dio_map,
.ngpio = STX104_NGPIO,
.names = stx104_names,
.reg_dat_base = GPIO_REGMAP_ADDR(STX104_DIO_REG),
.reg_set_base = GPIO_REGMAP_ADDR(STX104_DIO_REG),
.ngpio_per_reg = STX104_NGPIO,
.reg_mask_xlate = stx104_reg_mask_xlate,
.drvdata = dio_map,
};
err = PTR_ERR_OR_ZERO(devm_gpio_regmap_register(dev, &gpio_config));
if (err)
return err;
pit_config.parent = dev;
return devm_i8254_regmap_register(dev, &pit_config);
}
static struct isa_driver stx104_driver = {
.probe = stx104_probe,
.driver = {
.name = "stx104"
},
};
module_isa_driver(stx104_driver, num_stx104);
MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("Apex Embedded Systems STX104 IIO driver");
MODULE_LICENSE("GPL v2");
MODULE_IMPORT_NS(I8254);
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