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Message-Id: <dc4d0d5ca6ea28eda18815df114ecb21226cb345.1681665189.git.william.gray@linaro.org>
Date: Sun, 16 Apr 2023 13:36:54 -0400
From: William Breathitt Gray <william.gray@...aro.org>
To: Linus Walleij <linus.walleij@...aro.org>,
Bartosz Golaszewski <brgl@...ev.pl>,
Jonathan Cameron <jic23@...nel.org>
Cc: Lars-Peter Clausen <lars@...afoo.de>, linux-iio@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org,
William Breathitt Gray <william.gray@...aro.org>
Subject: [PATCH 2/3] 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.
Signed-off-by: William Breathitt Gray <william.gray@...aro.org>
---
drivers/gpio/Kconfig | 1 +
drivers/gpio/gpio-104-dio-48e.c | 127 ++++++++++++++++++++++++++++----
2 files changed, 112 insertions(+), 16 deletions(-)
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index badbe0582318..1fcc1245f954 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -840,6 +840,7 @@ 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
diff --git a/drivers/gpio/gpio-104-dio-48e.c b/drivers/gpio/gpio-104-dio-48e.c
index 000a56d5f1d7..2df33650cbf4 100644
--- a/drivers/gpio/gpio-104-dio-48e.c
+++ b/drivers/gpio/gpio-104-dio-48e.c
@@ -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;
@@ -229,6 +317,12 @@ 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;
@@ -249,3 +343,4 @@ module_isa_driver_with_irq(dio48e_driver, num_dio48e, num_irq);
MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@...il.com>");
MODULE_DESCRIPTION("ACCES 104-DIO-48E GPIO driver");
MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(I8254);
--
2.39.2
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