gpio: 104-dio-48e: Migrate to the regmap-irq API
authorWilliam Breathitt Gray <william.gray@linaro.org>
Tue, 27 Dec 2022 14:09:40 +0000 (09:09 -0500)
committerBartosz Golaszewski <bartosz.golaszewski@linaro.org>
Mon, 30 Jan 2023 14:55:27 +0000 (15:55 +0100)
The regmap API supports IO port accessors so we can take advantage of
regmap abstractions rather than handling access to the device registers
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>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
drivers/gpio/Kconfig
drivers/gpio/gpio-104-dio-48e.c

index ec7cfd4..2f8cb03 100644 (file)
@@ -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
index 7b8829c..e053a4e 100644 (file)
@@ -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 = {