[PATCH v5 2/8] gpio: 104-dio-48e: Migrate to the regmap-irq API

William Breathitt Gray
2022-12-27T14:33:18Z

directly in the driver.

For the 104-dio-48e we have the following IRQ registers (0xB and 0xF):

Base Address +B (Write): Enable Interrupt
Base Address +B (Read): Disable Interrupt
Base Address +F (Read/Write): Clear Interrupt

Any write to 0xB will enable interrupts, while any read will disable
interrupts. Interrupts are cleared by a write to 0xF. There's no IRQ
status register, so software has to assume that if an interrupt is
raised then it was for the 104-DIO-48E device.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
---
drivers/gpio/Kconfig | 2 +
drivers/gpio/gpio-104-dio-48e.c | 275 +++++++++++++++-----------------
2 files changed, 135 insertions(+), 142 deletions(-)

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index ec7cfd4f52b1..2f8cb03bd975 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -845,6 +845,8 @@ config GPIO_104_DIO_48E
tristate "ACCES 104-DIO-48E GPIO support"
depends on PC104
select ISA_BUS_API
+ select REGMAP_MMIO
+ select REGMAP_IRQ
select GPIOLIB_IRQCHIP
select GPIO_I8255
help
diff --git a/drivers/gpio/gpio-104-dio-48e.c b/drivers/gpio/gpio-104-dio-48e.c
index 7b8829c8e423..e053a4e46b27 100644
--- a/drivers/gpio/gpio-104-dio-48e.c
+++ b/drivers/gpio/gpio-104-dio-48e.c
@@ -8,17 +8,15 @@
*/
#include <linux/bits.h>
#include <linux/device.h>
-#include <linux/errno.h>
+#include <linux/err.h>
#include <linux/gpio/driver.h>
-#include <linux/io.h>
#include <linux/ioport.h>
-#include <linux/interrupt.h>
-#include <linux/irqdesc.h>
+#include <linux/irq.h>
#include <linux/isa.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
-#include <linux/spinlock.h>
+#include <linux/regmap.h>
#include <linux/types.h>

#include "gpio-i8255.h"
@@ -38,46 +36,30 @@ static unsigned int num_irq;
module_param_hw_array(irq, uint, irq, &num_irq, 0);
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_CLEAR_INTERRUPT 0xF
+
#define DIO48E_NUM_PPI 2

/**
* struct dio48e_reg - device register structure
* @ppi: Programmable Peripheral Interface groups
- * @enable_buffer: Enable/Disable Buffer groups
- * @unused1: Unused
- * @enable_interrupt: Write: Enable Interrupt
- * Read: Disable Interrupt
- * @unused2: Unused
- * @enable_counter: Write: Enable Counter/Timer Addressing
- * Read: Disable Counter/Timer Addressing
- * @unused3: Unused
- * @clear_interrupt: Clear Interrupt
*/
struct dio48e_reg {
struct i8255 ppi[DIO48E_NUM_PPI];
- u8 enable_buffer[DIO48E_NUM_PPI];
- u8 unused1;
- u8 enable_interrupt;
- u8 unused2;
- u8 enable_counter;
- u8 unused3;
- u8 clear_interrupt;
};

/**
* struct dio48e_gpio - GPIO device private data structure
* @chip: instance of the gpio_chip
* @ppi_state: PPI device states
- * @lock: synchronization lock to prevent I/O race conditions
* @reg: I/O address offset for the device registers
- * @irq_mask: I/O bits affected by interrupts
*/
struct dio48e_gpio {
struct gpio_chip chip;
struct i8255_state ppi_state[DIO48E_NUM_PPI];
- raw_spinlock_t lock;
struct dio48e_reg __iomem *reg;
- unsigned char irq_mask;
};

static int dio48e_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
@@ -144,106 +126,95 @@ static void dio48e_gpio_set_multiple(struct gpio_chip *chip,
bits, chip->ngpio);
}

-static void dio48e_irq_ack(struct irq_data *data)
-{
-}
-
-static void dio48e_irq_mask(struct irq_data *data)
-{
- struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
- struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
- const unsigned long offset = irqd_to_hwirq(data);
- unsigned long flags;
-
- /* only bit 3 on each respective Port C supports interrupts */
- if (offset != 19 && offset != 43)
- return;
-
- raw_spin_lock_irqsave(&dio48egpio->lock, flags);
-
- if (offset == 19)
- dio48egpio->irq_mask &= ~BIT(0);
- else
- dio48egpio->irq_mask &= ~BIT(1);
- gpiochip_disable_irq(chip, offset);
-
- if (!dio48egpio->irq_mask)
- /* disable interrupts */
- ioread8(&dio48egpio->reg->enable_interrupt);
-
- raw_spin_unlock_irqrestore(&dio48egpio->lock, flags);
-}
-
-static void dio48e_irq_unmask(struct irq_data *data)
-{
- struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
- struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
- const unsigned long offset = irqd_to_hwirq(data);
- unsigned long flags;
-
- /* only bit 3 on each respective Port C supports interrupts */
- if (offset != 19 && offset != 43)
- return;
-
- raw_spin_lock_irqsave(&dio48egpio->lock, flags);
+static const struct regmap_range dio48e_wr_ranges[] = {
+ regmap_reg_range(0x0, 0x9), regmap_reg_range(0xB, 0xB),
+ regmap_reg_range(0xD, 0xD), regmap_reg_range(0xF, 0xF),
+};
+static const struct regmap_range dio48e_rd_ranges[] = {
+ regmap_reg_range(0x0, 0x2), regmap_reg_range(0x4, 0x6),
+ regmap_reg_range(0xB, 0xB), regmap_reg_range(0xD, 0xD),
+ regmap_reg_range(0xF, 0xF),
+};
+static const struct regmap_range dio48e_volatile_ranges[] = {
+ i8255_volatile_regmap_range(0x0), i8255_volatile_regmap_range(0x4),
+ regmap_reg_range(0xB, 0xB), regmap_reg_range(0xD, 0xD),
+ regmap_reg_range(0xF, 0xF),
+};
+static const struct regmap_range dio48e_precious_ranges[] = {
+ regmap_reg_range(0xB, 0xB), regmap_reg_range(0xD, 0xD),
+ regmap_reg_range(0xF, 0xF),
+};
+static const struct regmap_access_table dio48e_wr_table = {
+ .yes_ranges = dio48e_wr_ranges,
+ .n_yes_ranges = ARRAY_SIZE(dio48e_wr_ranges),
+};
+static const struct regmap_access_table dio48e_rd_table = {
+ .yes_ranges = dio48e_rd_ranges,
+ .n_yes_ranges = ARRAY_SIZE(dio48e_rd_ranges),
+};
+static const struct regmap_access_table dio48e_volatile_table = {
+ .yes_ranges = dio48e_volatile_ranges,
+ .n_yes_ranges = ARRAY_SIZE(dio48e_volatile_ranges),
+};
+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,
+};

- if (!dio48egpio->irq_mask) {
- /* enable interrupts */
- iowrite8(0x00, &dio48egpio->reg->clear_interrupt);
- iowrite8(0x00, &dio48egpio->reg->enable_interrupt);
+/* only bit 3 on each respective Port C supports interrupts */
+#define DIO48E_REGMAP_IRQ(_ppi) \
+ [19 + (_ppi) * 24] = { \
+ .mask = BIT(_ppi), \
+ .type = { .types_supported = IRQ_TYPE_EDGE_RISING }, \
}

- gpiochip_enable_irq(chip, offset);
- if (offset == 19)
- dio48egpio->irq_mask |= BIT(0);
- else
- dio48egpio->irq_mask |= BIT(1);
-
- raw_spin_unlock_irqrestore(&dio48egpio->lock, flags);
-}
-
-static int dio48e_irq_set_type(struct irq_data *data, unsigned int flow_type)
-{
- const unsigned long offset = irqd_to_hwirq(data);
-
- /* only bit 3 on each respective Port C supports interrupts */
- if (offset != 19 && offset != 43)
- return -EINVAL;
-
- if (flow_type != IRQ_TYPE_NONE && flow_type != IRQ_TYPE_EDGE_RISING)
- return -EINVAL;
-
- return 0;
-}
-
-static const struct irq_chip dio48e_irqchip = {
- .name = "104-dio-48e",
- .irq_ack = dio48e_irq_ack,
- .irq_mask = dio48e_irq_mask,
- .irq_unmask = dio48e_irq_unmask,
- .irq_set_type = dio48e_irq_set_type,
- .flags = IRQCHIP_IMMUTABLE,
- GPIOCHIP_IRQ_RESOURCE_HELPERS,
+static const struct regmap_irq dio48e_regmap_irqs[] = {
+ DIO48E_REGMAP_IRQ(0), DIO48E_REGMAP_IRQ(1),
};

-static irqreturn_t dio48e_irq_handler(int irq, void *dev_id)
+static int dio48e_handle_mask_sync(struct regmap *const map, const int index,
+ const unsigned int mask_buf_def,
+ const unsigned int mask_buf,
+ void *const irq_drv_data)
{
- struct dio48e_gpio *const dio48egpio = dev_id;
- struct gpio_chip *const chip = &dio48egpio->chip;
- const unsigned long irq_mask = dio48egpio->irq_mask;
- unsigned long gpio;
+ unsigned int *const irq_mask = irq_drv_data;
+ const unsigned int prev_mask = *irq_mask;
+ const unsigned int all_masked = GENMASK(1, 0);
+ int err;
+ unsigned int val;

- for_each_set_bit(gpio, &irq_mask, 2)
- generic_handle_domain_irq(chip->irq.domain,
- 19 + gpio*24);
+ /* exit early if no change since the previous mask */
+ if (mask_buf == prev_mask)
+ return 0;

- raw_spin_lock(&dio48egpio->lock);
+ /* remember the current mask for the next mask sync */
+ *irq_mask = mask_buf;

- iowrite8(0x00, &dio48egpio->reg->clear_interrupt);
+ /* if all previously masked, enable interrupts when unmasking */
+ if (prev_mask == all_masked) {
+ err = regmap_write(map, DIO48E_CLEAR_INTERRUPT, 0x00);
+ if (err)
+ return err;
+ return regmap_write(map, DIO48E_ENABLE_INTERRUPT, 0x00);
+ }

- raw_spin_unlock(&dio48egpio->lock);
+ /* if all are currently masked, disable interrupts */
+ if (mask_buf == all_masked)
+ return regmap_read(map, DIO48E_DISABLE_INTERRUPT, &val);

- return IRQ_HANDLED;
+ return 0;
}

#define DIO48E_NGPIO 48
@@ -266,14 +237,12 @@ static const char *dio48e_names[DIO48E_NGPIO] = {
"PPI Group 1 Port C 5", "PPI Group 1 Port C 6", "PPI Group 1 Port C 7"
};

-static int dio48e_irq_init_hw(struct gpio_chip *gc)
+static int dio48e_irq_init_hw(struct regmap *const map)
{
- struct dio48e_gpio *const dio48egpio = gpiochip_get_data(gc);
+ unsigned int val;

/* Disable IRQ by default */
- ioread8(&dio48egpio->reg->enable_interrupt);
-
- return 0;
+ return regmap_read(map, DIO48E_DISABLE_INTERRUPT, &val);
}

static void dio48e_init_ppi(struct i8255 __iomem *const ppi,
@@ -295,8 +264,12 @@ static int dio48e_probe(struct device *dev, unsigned int id)
{
struct dio48e_gpio *dio48egpio;
const char *const name = dev_name(dev);
- struct gpio_irq_chip *girq;
+ void __iomem *regs;
+ struct regmap *map;
int err;
+ struct regmap_irq_chip *chip;
+ unsigned int irq_mask;
+ struct regmap_irq_chip_data *chip_data;

dio48egpio = devm_kzalloc(dev, sizeof(*dio48egpio), GFP_KERNEL);
if (!dio48egpio)
@@ -308,10 +281,46 @@ static int dio48e_probe(struct device *dev, unsigned int id)
return -EBUSY;
}

- dio48egpio->reg = devm_ioport_map(dev, base[id], DIO48E_EXTENT);
- if (!dio48egpio->reg)
+ regs = devm_ioport_map(dev, base[id], DIO48E_EXTENT);
+ if (!regs)
+ return -ENOMEM;
+ dio48egpio->reg = regs;
+
+ 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");
+
+ chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ chip->irq_drv_data = devm_kzalloc(dev, sizeof(irq_mask), GFP_KERNEL);
+ if (!chip->irq_drv_data)
return -ENOMEM;

+ chip->name = name;
+ /* No IRQ status register so use CLEAR_INTERRUPT register instead */
+ chip->status_base = DIO48E_CLEAR_INTERRUPT;
+ chip->mask_base = DIO48E_ENABLE_INTERRUPT;
+ chip->ack_base = DIO48E_CLEAR_INTERRUPT;
+ /* CLEAR_INTERRUPT doubles as status register so we need it cleared */
+ chip->clear_ack = true;
+ chip->status_invert = true;
+ chip->num_regs = 1;
+ chip->irqs = dio48e_regmap_irqs;
+ chip->num_irqs = ARRAY_SIZE(dio48e_regmap_irqs);
+ chip->handle_mask_sync = dio48e_handle_mask_sync;
+
+ /* Initialize to prevent spurious interrupts before we're ready */
+ err = dio48e_irq_init_hw(map);
+ if (err)
+ return err;
+
+ err = devm_regmap_add_irq_chip(dev, map, irq[id], 0, 0, chip, &chip_data);
+ if (err)
+ return dev_err_probe(dev, err, "IRQ registration failed\n");
+
dio48egpio->chip.label = name;
dio48egpio->chip.parent = dev;
dio48egpio->chip.owner = THIS_MODULE;
@@ -326,18 +335,6 @@ static int dio48e_probe(struct device *dev, unsigned int id)
dio48egpio->chip.set = dio48e_gpio_set;
dio48egpio->chip.set_multiple = dio48e_gpio_set_multiple;

- girq = &dio48egpio->chip.irq;
- gpio_irq_chip_set_chip(girq, &dio48e_irqchip);
- /* This will let us handle the parent IRQ in the driver */
- girq->parent_handler = NULL;
- girq->num_parents = 0;
- girq->parents = NULL;
- girq->default_type = IRQ_TYPE_NONE;
- girq->handler = handle_edge_irq;
- girq->init_hw = dio48e_irq_init_hw;
-
- raw_spin_lock_init(&dio48egpio->lock);
-
i8255_state_init(dio48egpio->ppi_state, DIO48E_NUM_PPI);
dio48e_init_ppi(dio48egpio->reg->ppi, dio48egpio->ppi_state);

@@ -347,14 +344,8 @@ static int dio48e_probe(struct device *dev, unsigned int id)
return err;
}

- err = devm_request_irq(dev, irq[id], dio48e_irq_handler, 0, name,
- dio48egpio);
- if (err) {
- dev_err(dev, "IRQ handler registering failed (%d)\n", err);
- return err;
- }
-
- return 0;
+ return gpiochip_irqchip_add_domain(&dio48egpio->chip,
+ regmap_irq_get_domain(chip_data));
}

static struct isa_driver dio48e_driver = {
--
2.38.1