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iio: addac: stx104: Add 8254 Counter/Timer support

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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>
This commit is contained in:
William Breathitt Gray 2023-09-16 07:20:31 -04:00 committed by Jonathan Cameron
parent 9dc03309fe
commit 66fe531268
2 changed files with 60 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/iio/addac/Kconfig
View File

@ -38,6 +38,7 @@ config STX104
select REGMAP_MMIO
select GPIOLIB
select GPIO_REGMAP
select I8254
help
Say yes here to build support for the Apex Embedded Systems STX104
integrated analog PC/104 card.

61
drivers/iio/addac/stx104.c
View File

@ -8,6 +8,7 @@
#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>
@ -55,6 +56,7 @@ MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
#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))
@ -77,6 +79,7 @@ MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
/* 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
@ -168,6 +171,32 @@ static const struct regmap_config dio_regmap_config = {
.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)
{
@ -339,6 +368,21 @@ 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;
@ -361,7 +405,7 @@ static int stx104_init_hw(struct stx104_iio *const priv)
if (err)
return err;
return 0;
return bank_select_i8254(priv->aio_ctl_map);
}
static int stx104_probe(struct device *dev, unsigned int id)
@ -369,6 +413,7 @@ 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;
@ -406,6 +451,11 @@ static int stx104_probe(struct device *dev, unsigned int id)
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;
@ -449,7 +499,13 @@ static int stx104_probe(struct device *dev, unsigned int id)
.drvdata = dio_map,
};
return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(dev, &gpio_config));
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 = {
@ -464,3 +520,4 @@ 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);