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gpio: 104-dio-48e: Add Counter/Timer support 

The 104-DIO-48E 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 counter/timers use the same addresses as PPI 0 (addresses 0x0
to 0x3), so a raw_spinlock_t is used to synchronize operations between
the two regmap mappings to prevent clobbering.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This commit is contained in:
William Breathitt Gray 2023-07-20 14:49:43 -04:00 committed by Bartosz Golaszewski
parent 27d5a3cc21
commit 92f7a35836
2 changed files with 112 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/gpio/Kconfig
View File

@ -858,6 +858,7 @@ config GPIO_104_DIO_48E
select REGMAP_IRQ
select GPIOLIB_IRQCHIP
select GPIO_I8255
select I8254
help
Enables GPIO support for the ACCES 104-DIO-48E series (104-DIO-48E,
104-DIO-24E). The base port addresses for the devices may be

127
drivers/gpio/gpio-104-dio-48e.c
View File

@ -9,6 +9,7 @@
#include <linux/bits.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/i8254.h>
#include <linux/ioport.h>
#include <linux/irq.h>
#include <linux/isa.h>
@ -16,6 +17,7 @@
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/regmap.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include "gpio-i8255.h"
@ -37,6 +39,8 @@ MODULE_PARM_DESC(irq, "ACCES 104-DIO-48E interrupt line numbers");
#define DIO48E_ENABLE_INTERRUPT 0xB
#define DIO48E_DISABLE_INTERRUPT DIO48E_ENABLE_INTERRUPT
#define DIO48E_ENABLE_COUNTER_TIMER_ADDRESSING 0xD
#define DIO48E_DISABLE_COUNTER_TIMER_ADDRESSING DIO48E_ENABLE_COUNTER_TIMER_ADDRESSING
#define DIO48E_CLEAR_INTERRUPT 0xF
#define DIO48E_NUM_PPI 2
@ -75,18 +79,20 @@ static const struct regmap_access_table dio48e_precious_table = {
.yes_ranges = dio48e_precious_ranges,
.n_yes_ranges = ARRAY_SIZE(dio48e_precious_ranges),
};
static const struct regmap_config dio48e_regmap_config = {
.reg_bits = 8,
.reg_stride = 1,
.val_bits = 8,
.io_port = true,
.max_register = 0xF,
.wr_table = &dio48e_wr_table,
.rd_table = &dio48e_rd_table,
.volatile_table = &dio48e_volatile_table,
.precious_table = &dio48e_precious_table,
.cache_type = REGCACHE_FLAT,
.use_raw_spinlock = 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),
};
/* only bit 3 on each respective Port C supports interrupts */
@ -102,14 +108,56 @@ static const struct regmap_irq dio48e_regmap_irqs[] = {
/**
* struct dio48e_gpio - GPIO device private data structure
* @lock: synchronization lock to prevent I/O race conditions
* @map: Regmap for the device
* @regs: virtual mapping for device registers
* @flags: IRQ flags saved during locking
* @irq_mask: Current IRQ mask state on the device
*/
struct dio48e_gpio {
raw_spinlock_t lock;
struct regmap *map;
void __iomem *regs;
unsigned long flags;
unsigned int irq_mask;
};
static void dio48e_regmap_lock(void *lock_arg) __acquires(&dio48egpio->lock)
{
struct dio48e_gpio *const dio48egpio = lock_arg;
unsigned long flags;
raw_spin_lock_irqsave(&dio48egpio->lock, flags);
dio48egpio->flags = flags;
}
static void dio48e_regmap_unlock(void *lock_arg) __releases(&dio48egpio->lock)
{
struct dio48e_gpio *const dio48egpio = lock_arg;
raw_spin_unlock_irqrestore(&dio48egpio->lock, dio48egpio->flags);
}
static void pit_regmap_lock(void *lock_arg) __acquires(&dio48egpio->lock)
{
struct dio48e_gpio *const dio48egpio = lock_arg;
unsigned long flags;
raw_spin_lock_irqsave(&dio48egpio->lock, flags);
dio48egpio->flags = flags;
iowrite8(0x00, dio48egpio->regs + DIO48E_ENABLE_COUNTER_TIMER_ADDRESSING);
}
static void pit_regmap_unlock(void *lock_arg) __releases(&dio48egpio->lock)
{
struct dio48e_gpio *const dio48egpio = lock_arg;
ioread8(dio48egpio->regs + DIO48E_DISABLE_COUNTER_TIMER_ADDRESSING);
raw_spin_unlock_irqrestore(&dio48egpio->lock, dio48egpio->flags);
}
static int dio48e_handle_mask_sync(const int index,
const unsigned int mask_buf_def,
const unsigned int mask_buf,
@ -176,6 +224,9 @@ static int dio48e_probe(struct device *dev, unsigned int id)
struct i8255_regmap_config config = {};
void __iomem *regs;
struct regmap *map;
struct regmap_config dio48e_regmap_config;
struct regmap_config pit_regmap_config;
struct i8254_regmap_config pit_config;
int err;
struct regmap_irq_chip *chip;
struct dio48e_gpio *dio48egpio;
@ -187,21 +238,58 @@ static int dio48e_probe(struct device *dev, unsigned int id)
return -EBUSY;
}
dio48egpio = devm_kzalloc(dev, sizeof(*dio48egpio), GFP_KERNEL);
if (!dio48egpio)
return -ENOMEM;
regs = devm_ioport_map(dev, base[id], DIO48E_EXTENT);
if (!regs)
return -ENOMEM;
dio48egpio->regs = regs;
raw_spin_lock_init(&dio48egpio->lock);
dio48e_regmap_config = (struct regmap_config) {
.reg_bits = 8,
.reg_stride = 1,
.val_bits = 8,
.lock = dio48e_regmap_lock,
.unlock = dio48e_regmap_unlock,
.lock_arg = dio48egpio,
.io_port = true,
.wr_table = &dio48e_wr_table,
.rd_table = &dio48e_rd_table,
.volatile_table = &dio48e_volatile_table,
.precious_table = &dio48e_precious_table,
.cache_type = REGCACHE_FLAT,
};
map = devm_regmap_init_mmio(dev, regs, &dio48e_regmap_config);
if (IS_ERR(map))
return dev_err_probe(dev, PTR_ERR(map),
"Unable to initialize register map\n");
dio48egpio = devm_kzalloc(dev, sizeof(*dio48egpio), GFP_KERNEL);
if (!dio48egpio)
return -ENOMEM;
dio48egpio->map = map;
pit_regmap_config = (struct regmap_config) {
.name = "i8254",
.reg_bits = 8,
.reg_stride = 1,
.val_bits = 8,
.lock = pit_regmap_lock,
.unlock = pit_regmap_unlock,
.lock_arg = dio48egpio,
.io_port = true,
.wr_table = &pit_wr_table,
.rd_table = &pit_rd_table,
};
pit_config.map = devm_regmap_init_mmio(dev, regs, &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");
chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
if (!chip)
return -ENOMEM;
@ -225,6 +313,12 @@ static int dio48e_probe(struct device *dev, unsigned int id)
if (err)
return dev_err_probe(dev, err, "IRQ registration failed\n");
pit_config.parent = dev;
err = devm_i8254_regmap_register(dev, &pit_config);
if (err)
return err;
config.parent = dev;
config.map = map;
config.num_ppi = DIO48E_NUM_PPI;
@ -245,3 +339,4 @@ module_isa_driver_with_irq(dio48e_driver, num_dio48e, num_irq);
MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("ACCES 104-DIO-48E GPIO driver");
MODULE_LICENSE("GPL v2");
MODULE_IMPORT_NS(I8254);