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From:   William Breathitt Gray <william.gray@linaro.org>
To:     Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <brgl@bgdev.pl>
Cc:     linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        William Breathitt Gray <william.gray@linaro.org>
Subject: [PATCH v5 3/4] gpio: pci-idio-16: Migrate to the regmap API
Date:   Tue,  4 Apr 2023 10:32:47 -0400
Message-Id: <5ba5405c64aca984d5cf3bdbdffa04c325e5a147.1680618405.git.william.gray@linaro.org>
In-Reply-To: <cover.1680618405.git.william.gray@linaro.org>
References: <cover.1680618405.git.william.gray@linaro.org>
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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. Migrate the pci-idio-16 module to the new
idio-16 library interface leveraging the gpio-regmap API.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
---
Changes in v5:
 - Remove regmap_config max_register line as superfluous
 - Enable use_raw_spinlock to prevent deadlocks when running -rt kernels

 drivers/gpio/Kconfig            |   2 +-
 drivers/gpio/gpio-pci-idio-16.c | 294 +++++++-------------------------
 2 files changed, 62 insertions(+), 234 deletions(-)

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 9f7ec4f3fdbf..e19b2612e67c 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1580,7 +1580,7 @@ config GPIO_PCH
 
 config GPIO_PCI_IDIO_16
 	tristate "ACCES PCI-IDIO-16 GPIO support"
-	select GPIOLIB_IRQCHIP
+	select REGMAP_MMIO
 	select GPIO_IDIO_16
 	help
 	  Enables GPIO support for the ACCES PCI-IDIO-16. An interrupt is
diff --git a/drivers/gpio/gpio-pci-idio-16.c b/drivers/gpio/gpio-pci-idio-16.c
index 6726c32e31e6..44c0a21b1d1d 100644
--- a/drivers/gpio/gpio-pci-idio-16.c
+++ b/drivers/gpio/gpio-pci-idio-16.c
@@ -5,214 +5,75 @@
  */
 #include <linux/bits.h>
 #include <linux/device.h>
-#include <linux/errno.h>
-#include <linux/gpio/driver.h>
-#include <linux/interrupt.h>
-#include <linux/irqdesc.h>
+#include <linux/err.h>
+#include <linux/irq.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/pci.h>
-#include <linux/spinlock.h>
+#include <linux/regmap.h>
 #include <linux/types.h>
 
 #include "gpio-idio-16.h"
 
-/**
- * struct idio_16_gpio - GPIO device private data structure
- * @chip:	instance of the gpio_chip
- * @lock:	synchronization lock to prevent I/O race conditions
- * @reg:	I/O address offset for the GPIO device registers
- * @state:	ACCES IDIO-16 device state
- * @irq_mask:	I/O bits affected by interrupts
- */
-struct idio_16_gpio {
-	struct gpio_chip chip;
-	raw_spinlock_t lock;
-	struct idio_16 __iomem *reg;
-	struct idio_16_state state;
-	unsigned long irq_mask;
+static const struct regmap_range idio_16_wr_ranges[] = {
+	regmap_reg_range(0x0, 0x2), regmap_reg_range(0x3, 0x4),
 };
-
-static int idio_16_gpio_get_direction(struct gpio_chip *chip,
-	unsigned int offset)
-{
-	if (idio_16_get_direction(offset))
-		return GPIO_LINE_DIRECTION_IN;
-
-	return GPIO_LINE_DIRECTION_OUT;
-}
-
-static int idio_16_gpio_direction_input(struct gpio_chip *chip,
-	unsigned int offset)
-{
-	return 0;
-}
-
-static int idio_16_gpio_direction_output(struct gpio_chip *chip,
-	unsigned int offset, int value)
-{
-	chip->set(chip, offset, value);
-	return 0;
-}
-
-static int idio_16_gpio_get(struct gpio_chip *chip, unsigned int offset)
-{
-	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
-
-	return idio_16_get(idio16gpio->reg, &idio16gpio->state, offset);
-}
-
-static int idio_16_gpio_get_multiple(struct gpio_chip *chip,
-	unsigned long *mask, unsigned long *bits)
-{
-	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
-
-	idio_16_get_multiple(idio16gpio->reg, &idio16gpio->state, mask, bits);
-	return 0;
-}
-
-static void idio_16_gpio_set(struct gpio_chip *chip, unsigned int offset,
-	int value)
-{
-	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
-
-	idio_16_set(idio16gpio->reg, &idio16gpio->state, offset, value);
-}
-
-static void idio_16_gpio_set_multiple(struct gpio_chip *chip,
-	unsigned long *mask, unsigned long *bits)
-{
-	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
-
-	idio_16_set_multiple(idio16gpio->reg, &idio16gpio->state, mask, bits);
-}
-
-static void idio_16_irq_ack(struct irq_data *data)
-{
-}
-
-static void idio_16_irq_mask(struct irq_data *data)
-{
-	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
-	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
-	const unsigned long mask = BIT(irqd_to_hwirq(data));
-	unsigned long flags;
-
-	idio16gpio->irq_mask &= ~mask;
-
-	if (!idio16gpio->irq_mask) {
-		raw_spin_lock_irqsave(&idio16gpio->lock, flags);
-
-		iowrite8(0, &idio16gpio->reg->irq_ctl);
-
-		raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
-	}
-
-	gpiochip_disable_irq(chip, irqd_to_hwirq(data));
-}
-
-static void idio_16_irq_unmask(struct irq_data *data)
-{
-	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
-	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
-	const unsigned long mask = BIT(irqd_to_hwirq(data));
-	const unsigned long prev_irq_mask = idio16gpio->irq_mask;
-	unsigned long flags;
-
-	gpiochip_enable_irq(chip, irqd_to_hwirq(data));
-
-	idio16gpio->irq_mask |= mask;
-
-	if (!prev_irq_mask) {
-		raw_spin_lock_irqsave(&idio16gpio->lock, flags);
-
-		ioread8(&idio16gpio->reg->irq_ctl);
-
-		raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
-	}
-}
-
-static int idio_16_irq_set_type(struct irq_data *data, unsigned int flow_type)
-{
-	/* The only valid irq types are none and both-edges */
-	if (flow_type != IRQ_TYPE_NONE &&
-		(flow_type & IRQ_TYPE_EDGE_BOTH) != IRQ_TYPE_EDGE_BOTH)
-		return -EINVAL;
-
-	return 0;
-}
-
-static const struct irq_chip idio_16_irqchip = {
-	.name = "pci-idio-16",
-	.irq_ack = idio_16_irq_ack,
-	.irq_mask = idio_16_irq_mask,
-	.irq_unmask = idio_16_irq_unmask,
-	.irq_set_type = idio_16_irq_set_type,
-	.flags = IRQCHIP_IMMUTABLE,
-	GPIOCHIP_IRQ_RESOURCE_HELPERS,
+static const struct regmap_range idio_16_rd_ranges[] = {
+	regmap_reg_range(0x1, 0x2), regmap_reg_range(0x5, 0x6),
 };
-
-static irqreturn_t idio_16_irq_handler(int irq, void *dev_id)
-{
-	struct idio_16_gpio *const idio16gpio = dev_id;
-	unsigned int irq_status;
-	struct gpio_chip *const chip = &idio16gpio->chip;
-	int gpio;
-
-	raw_spin_lock(&idio16gpio->lock);
-
-	irq_status = ioread8(&idio16gpio->reg->irq_status);
-
-	raw_spin_unlock(&idio16gpio->lock);
-
-	/* Make sure our device generated IRQ */
-	if (!(irq_status & 0x3) || !(irq_status & 0x4))
-		return IRQ_NONE;
-
-	for_each_set_bit(gpio, &idio16gpio->irq_mask, chip->ngpio)
-		generic_handle_domain_irq(chip->irq.domain, gpio);
-
-	raw_spin_lock(&idio16gpio->lock);
-
-	/* Clear interrupt */
-	iowrite8(0, &idio16gpio->reg->in0_7);
-
-	raw_spin_unlock(&idio16gpio->lock);
-
-	return IRQ_HANDLED;
-}
-
-#define IDIO_16_NGPIO 32
-static const char *idio_16_names[IDIO_16_NGPIO] = {
-	"OUT0", "OUT1", "OUT2", "OUT3", "OUT4", "OUT5", "OUT6", "OUT7",
-	"OUT8", "OUT9", "OUT10", "OUT11", "OUT12", "OUT13", "OUT14", "OUT15",
-	"IIN0", "IIN1", "IIN2", "IIN3", "IIN4", "IIN5", "IIN6", "IIN7",
-	"IIN8", "IIN9", "IIN10", "IIN11", "IIN12", "IIN13", "IIN14", "IIN15"
+static const struct regmap_range idio_16_precious_ranges[] = {
+	regmap_reg_range(0x2, 0x2),
+};
+static const struct regmap_access_table idio_16_wr_table = {
+	.yes_ranges = idio_16_wr_ranges,
+	.n_yes_ranges = ARRAY_SIZE(idio_16_wr_ranges),
+};
+static const struct regmap_access_table idio_16_rd_table = {
+	.yes_ranges = idio_16_rd_ranges,
+	.n_yes_ranges = ARRAY_SIZE(idio_16_rd_ranges),
+};
+static const struct regmap_access_table idio_16_precious_table = {
+	.yes_ranges = idio_16_precious_ranges,
+	.n_yes_ranges = ARRAY_SIZE(idio_16_precious_ranges),
+};
+static const struct regmap_config idio_16_regmap_config = {
+	.reg_bits = 8,
+	.reg_stride = 1,
+	.val_bits = 8,
+	.io_port = true,
+	.wr_table = &idio_16_wr_table,
+	.rd_table = &idio_16_rd_table,
+	.volatile_table = &idio_16_rd_table,
+	.precious_table = &idio_16_precious_table,
+	.cache_type = REGCACHE_FLAT,
+	.use_raw_spinlock = true,
 };
 
-static int idio_16_irq_init_hw(struct gpio_chip *gc)
-{
-	struct idio_16_gpio *const idio16gpio = gpiochip_get_data(gc);
-
-	/* Disable IRQ by default and clear any pending interrupt */
-	iowrite8(0, &idio16gpio->reg->irq_ctl);
-	iowrite8(0, &idio16gpio->reg->in0_7);
+/* Only input lines (GPIO 16-31) support interrupts */
+#define IDIO_16_REGMAP_IRQ(_id)						\
+	[16 + _id] = {							\
+		.mask = BIT(2),						\
+		.type = { .types_supported = IRQ_TYPE_EDGE_BOTH },	\
+	}
 
-	return 0;
-}
+static const struct regmap_irq idio_16_regmap_irqs[] = {
+	IDIO_16_REGMAP_IRQ(0), IDIO_16_REGMAP_IRQ(1), IDIO_16_REGMAP_IRQ(2), /* 0-2 */
+	IDIO_16_REGMAP_IRQ(3), IDIO_16_REGMAP_IRQ(4), IDIO_16_REGMAP_IRQ(5), /* 3-5 */
+	IDIO_16_REGMAP_IRQ(6), IDIO_16_REGMAP_IRQ(7), IDIO_16_REGMAP_IRQ(8), /* 6-8 */
+	IDIO_16_REGMAP_IRQ(9), IDIO_16_REGMAP_IRQ(10), IDIO_16_REGMAP_IRQ(11), /* 9-11 */
+	IDIO_16_REGMAP_IRQ(12), IDIO_16_REGMAP_IRQ(13), IDIO_16_REGMAP_IRQ(14), /* 12-14 */
+	IDIO_16_REGMAP_IRQ(15), /* 15 */
+};
 
 static int idio_16_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	struct device *const dev = &pdev->dev;
-	struct idio_16_gpio *idio16gpio;
 	int err;
 	const size_t pci_bar_index = 2;
 	const char *const name = pci_name(pdev);
-	struct gpio_irq_chip *girq;
-
-	idio16gpio = devm_kzalloc(dev, sizeof(*idio16gpio), GFP_KERNEL);
-	if (!idio16gpio)
-		return -ENOMEM;
+	struct idio_16_regmap_config config = {};
+	void __iomem *regs;
+	struct regmap *map;
 
 	err = pcim_enable_device(pdev);
 	if (err) {
@@ -226,53 +87,20 @@ static int idio_16_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		return err;
 	}
 
-	idio16gpio->reg = pcim_iomap_table(pdev)[pci_bar_index];
+	regs = pcim_iomap_table(pdev)[pci_bar_index];
 
-	/* Deactivate input filters */
-	iowrite8(0, &idio16gpio->reg->filter_ctl);
+	map = devm_regmap_init_mmio(dev, regs, &idio_16_regmap_config);
+	if (IS_ERR(map))
+		return dev_err_probe(dev, PTR_ERR(map), "Unable to initialize register map\n");
 
-	idio16gpio->chip.label = name;
-	idio16gpio->chip.parent = dev;
-	idio16gpio->chip.owner = THIS_MODULE;
-	idio16gpio->chip.base = -1;
-	idio16gpio->chip.ngpio = IDIO_16_NGPIO;
-	idio16gpio->chip.names = idio_16_names;
-	idio16gpio->chip.get_direction = idio_16_gpio_get_direction;
-	idio16gpio->chip.direction_input = idio_16_gpio_direction_input;
-	idio16gpio->chip.direction_output = idio_16_gpio_direction_output;
-	idio16gpio->chip.get = idio_16_gpio_get;
-	idio16gpio->chip.get_multiple = idio_16_gpio_get_multiple;
-	idio16gpio->chip.set = idio_16_gpio_set;
-	idio16gpio->chip.set_multiple = idio_16_gpio_set_multiple;
-
-	idio_16_state_init(&idio16gpio->state);
-
-	girq = &idio16gpio->chip.irq;
-	gpio_irq_chip_set_chip(girq, &idio_16_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 = idio_16_irq_init_hw;
-
-	raw_spin_lock_init(&idio16gpio->lock);
-
-	err = devm_gpiochip_add_data(dev, &idio16gpio->chip, idio16gpio);
-	if (err) {
-		dev_err(dev, "GPIO registering failed (%d)\n", err);
-		return err;
-	}
-
-	err = devm_request_irq(dev, pdev->irq, idio_16_irq_handler, IRQF_SHARED,
-		name, idio16gpio);
-	if (err) {
-		dev_err(dev, "IRQ handler registering failed (%d)\n", err);
-		return err;
-	}
+	config.parent = dev;
+	config.map = map;
+	config.regmap_irqs = idio_16_regmap_irqs;
+	config.num_regmap_irqs = ARRAY_SIZE(idio_16_regmap_irqs);
+	config.irq = pdev->irq;
+	config.filters = true;
 
-	return 0;
+	return devm_idio_16_regmap_register(dev, &config);
 }
 
 static const struct pci_device_id idio_16_pci_dev_id[] = {
-- 
2.39.2