gpio updates for v6.10-rc3

- set of interrupt handling and Kconfig fixes for gpio-tqmx86
 - add a buffer for storing output values in gpio-tqmx86 as reading back the
   registers always returns the input values
 - add missing MODULE_DESCRIPTION()s to several GPIO drivers
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Merge tag 'gpio-fixes-for-v6.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux

Pull gpio fixes from Bartosz Golaszewski:

 - interrupt handling and Kconfig fixes for gpio-tqmx86

 - add a buffer for storing output values in gpio-tqmx86 as reading back
   the registers always returns the input values

 - add missing MODULE_DESCRIPTION()s to several GPIO drivers

* tag 'gpio-fixes-for-v6.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux:
  gpio: add missing MODULE_DESCRIPTION() macros
  gpio: tqmx86: fix broken IRQ_TYPE_EDGE_BOTH interrupt type
  gpio: tqmx86: store IRQ trigger type and unmask status separately
  gpio: tqmx86: introduce shadow register for GPIO output value
  gpio: tqmx86: fix typo in Kconfig label

drivers/gpio/Kconfig

@@ -1576,7 +1576,7 @@ config GPIO_TPS68470
 	  are "output only" GPIOs.
 
 config GPIO_TQMX86
-	tristate "TQ-Systems QTMX86 GPIO"
+	tristate "TQ-Systems TQMx86 GPIO"
 	depends on MFD_TQMX86 || COMPILE_TEST
 	depends on HAS_IOPORT_MAP
 	select GPIOLIB_IRQCHIP

drivers/gpio/gpio-gw-pld.c

@@ -130,5 +130,6 @@ static struct i2c_driver gw_pld_driver = {
 };
 module_i2c_driver(gw_pld_driver);
 
+MODULE_DESCRIPTION("Gateworks I2C PLD GPIO expander");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");

drivers/gpio/gpio-mc33880.c

@@ -168,5 +168,6 @@ static void __exit mc33880_exit(void)
 module_exit(mc33880_exit);
 
 MODULE_AUTHOR("Mocean Laboratories <info@mocean-labs.com>");
+MODULE_DESCRIPTION("MC33880 high-side/low-side switch GPIO driver");
 MODULE_LICENSE("GPL v2");
 

drivers/gpio/gpio-pcf857x.c

@@ -438,5 +438,6 @@ static void __exit pcf857x_exit(void)
 }
 module_exit(pcf857x_exit);
 
+MODULE_DESCRIPTION("Driver for pcf857x, pca857x, and pca967x I2C GPIO expanders");
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("David Brownell");

drivers/gpio/gpio-pl061.c

@@ -438,4 +438,5 @@ static struct amba_driver pl061_gpio_driver = {
 };
 module_amba_driver(pl061_gpio_driver);
 
+MODULE_DESCRIPTION("Driver for the ARM PrimeCell(tm) General Purpose Input/Output (PL061)");
 MODULE_LICENSE("GPL v2");

drivers/gpio/gpio-tqmx86.c

@@ -6,6 +6,7 @@
  *   Vadim V.Vlasov <vvlasov@dev.rtsoft.ru>
  */
 
+#include <linux/bitmap.h>
 #include <linux/bitops.h>
 #include <linux/errno.h>
 #include <linux/gpio/driver.h>
@@ -28,16 +29,25 @@
 #define TQMX86_GPIIC	3	/* GPI Interrupt Configuration Register */
 #define TQMX86_GPIIS	4	/* GPI Interrupt Status Register */
 
+#define TQMX86_GPII_NONE	0
 #define TQMX86_GPII_FALLING	BIT(0)
 #define TQMX86_GPII_RISING	BIT(1)
+/* Stored in irq_type as a trigger type, but not actually valid as a register
+ * value, so the name doesn't use "GPII"
+ */
+#define TQMX86_INT_BOTH		(BIT(0) | BIT(1))
 #define TQMX86_GPII_MASK	(BIT(0) | BIT(1))
 #define TQMX86_GPII_BITS	2
+/* Stored in irq_type with GPII bits */
+#define TQMX86_INT_UNMASKED	BIT(2)
 
 struct tqmx86_gpio_data {
 	struct gpio_chip	chip;
 	void __iomem		*io_base;
 	int			irq;
+	/* Lock must be held for accessing output and irq_type fields */
 	raw_spinlock_t		spinlock;
+	DECLARE_BITMAP(output, TQMX86_NGPIO);
 	u8			irq_type[TQMX86_NGPI];
 };
 
@@ -64,15 +74,10 @@ static void tqmx86_gpio_set(struct gpio_chip *chip, unsigned int offset,
 {
 	struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
 	unsigned long flags;
-	u8 val;
 
 	raw_spin_lock_irqsave(&gpio->spinlock, flags);
-	val = tqmx86_gpio_read(gpio, TQMX86_GPIOD);
-	if (value)
-		val |= BIT(offset);
-	else
-		val &= ~BIT(offset);
-	tqmx86_gpio_write(gpio, val, TQMX86_GPIOD);
+	__assign_bit(offset, gpio->output, value);
+	tqmx86_gpio_write(gpio, bitmap_get_value8(gpio->output, 0), TQMX86_GPIOD);
 	raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
 }
 
@@ -107,21 +112,38 @@ static int tqmx86_gpio_get_direction(struct gpio_chip *chip,
 	return GPIO_LINE_DIRECTION_OUT;
 }
 
+static void tqmx86_gpio_irq_config(struct tqmx86_gpio_data *gpio, int offset)
+	__must_hold(&gpio->spinlock)
+{
+	u8 type = TQMX86_GPII_NONE, gpiic;
+
+	if (gpio->irq_type[offset] & TQMX86_INT_UNMASKED) {
+		type = gpio->irq_type[offset] & TQMX86_GPII_MASK;
+
+		if (type == TQMX86_INT_BOTH)
+			type = tqmx86_gpio_get(&gpio->chip, offset + TQMX86_NGPO)
+				? TQMX86_GPII_FALLING
+				: TQMX86_GPII_RISING;
+	}
+
+	gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
+	gpiic &= ~(TQMX86_GPII_MASK << (offset * TQMX86_GPII_BITS));
+	gpiic |= type << (offset * TQMX86_GPII_BITS);
+	tqmx86_gpio_write(gpio, gpiic, TQMX86_GPIIC);
+}
+
 static void tqmx86_gpio_irq_mask(struct irq_data *data)
 {
 	unsigned int offset = (data->hwirq - TQMX86_NGPO);
 	struct tqmx86_gpio_data *gpio = gpiochip_get_data(
 		irq_data_get_irq_chip_data(data));
 	unsigned long flags;
-	u8 gpiic, mask;
-
-	mask = TQMX86_GPII_MASK << (offset * TQMX86_GPII_BITS);
 
 	raw_spin_lock_irqsave(&gpio->spinlock, flags);
-	gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
-	gpiic &= ~mask;
-	tqmx86_gpio_write(gpio, gpiic, TQMX86_GPIIC);
+	gpio->irq_type[offset] &= ~TQMX86_INT_UNMASKED;
+	tqmx86_gpio_irq_config(gpio, offset);
 	raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
+
 	gpiochip_disable_irq(&gpio->chip, irqd_to_hwirq(data));
 }
 
@@ -131,16 +153,12 @@ static void tqmx86_gpio_irq_unmask(struct irq_data *data)
 	struct tqmx86_gpio_data *gpio = gpiochip_get_data(
 		irq_data_get_irq_chip_data(data));
 	unsigned long flags;
-	u8 gpiic, mask;
-
-	mask = TQMX86_GPII_MASK << (offset * TQMX86_GPII_BITS);
 
 	gpiochip_enable_irq(&gpio->chip, irqd_to_hwirq(data));
+
 	raw_spin_lock_irqsave(&gpio->spinlock, flags);
-	gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
-	gpiic &= ~mask;
-	gpiic |= gpio->irq_type[offset] << (offset * TQMX86_GPII_BITS);
-	tqmx86_gpio_write(gpio, gpiic, TQMX86_GPIIC);
+	gpio->irq_type[offset] |= TQMX86_INT_UNMASKED;
+	tqmx86_gpio_irq_config(gpio, offset);
 	raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
 }
 
@@ -151,7 +169,7 @@ static int tqmx86_gpio_irq_set_type(struct irq_data *data, unsigned int type)
 	unsigned int offset = (data->hwirq - TQMX86_NGPO);
 	unsigned int edge_type = type & IRQF_TRIGGER_MASK;
 	unsigned long flags;
-	u8 new_type, gpiic;
+	u8 new_type;
 
 	switch (edge_type) {
 	case IRQ_TYPE_EDGE_RISING:
@@ -161,19 +179,16 @@ static int tqmx86_gpio_irq_set_type(struct irq_data *data, unsigned int type)
 		new_type = TQMX86_GPII_FALLING;
 		break;
 	case IRQ_TYPE_EDGE_BOTH:
-		new_type = TQMX86_GPII_FALLING | TQMX86_GPII_RISING;
+		new_type = TQMX86_INT_BOTH;
 		break;
 	default:
 		return -EINVAL; /* not supported */
 	}
 
-	gpio->irq_type[offset] = new_type;
-
 	raw_spin_lock_irqsave(&gpio->spinlock, flags);
-	gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
-	gpiic &= ~((TQMX86_GPII_MASK) << (offset * TQMX86_GPII_BITS));
-	gpiic |= new_type << (offset * TQMX86_GPII_BITS);
-	tqmx86_gpio_write(gpio, gpiic, TQMX86_GPIIC);
+	gpio->irq_type[offset] &= ~TQMX86_GPII_MASK;
+	gpio->irq_type[offset] |= new_type;
+	tqmx86_gpio_irq_config(gpio, offset);
 	raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
 
 	return 0;
@@ -184,8 +199,8 @@ static void tqmx86_gpio_irq_handler(struct irq_desc *desc)
 	struct gpio_chip *chip = irq_desc_get_handler_data(desc);
 	struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
 	struct irq_chip *irq_chip = irq_desc_get_chip(desc);
-	unsigned long irq_bits;
-	int i = 0;
+	unsigned long irq_bits, flags;
+	int i;
 	u8 irq_status;
 
 	chained_irq_enter(irq_chip, desc);
@@ -194,6 +209,34 @@ static void tqmx86_gpio_irq_handler(struct irq_desc *desc)
 	tqmx86_gpio_write(gpio, irq_status, TQMX86_GPIIS);
 
 	irq_bits = irq_status;
+
+	raw_spin_lock_irqsave(&gpio->spinlock, flags);
+	for_each_set_bit(i, &irq_bits, TQMX86_NGPI) {
+		/*
+		 * Edge-both triggers are implemented by flipping the edge
+		 * trigger after each interrupt, as the controller only supports
+		 * either rising or falling edge triggers, but not both.
+		 *
+		 * Internally, the TQMx86 GPIO controller has separate status
+		 * registers for rising and falling edge interrupts. GPIIC
+		 * configures which bits from which register are visible in the
+		 * interrupt status register GPIIS and defines what triggers the
+		 * parent IRQ line. Writing to GPIIS always clears both rising
+		 * and falling interrupt flags internally, regardless of the
+		 * currently configured trigger.
+		 *
+		 * In consequence, we can cleanly implement the edge-both
+		 * trigger in software by first clearing the interrupt and then
+		 * setting the new trigger based on the current GPIO input in
+		 * tqmx86_gpio_irq_config() - even if an edge arrives between
+		 * reading the input and setting the trigger, we will have a new
+		 * interrupt pending.
+		 */
+		if ((gpio->irq_type[i] & TQMX86_GPII_MASK) == TQMX86_INT_BOTH)
+			tqmx86_gpio_irq_config(gpio, i);
+	}
+	raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
+
 	for_each_set_bit(i, &irq_bits, TQMX86_NGPI)
 		generic_handle_domain_irq(gpio->chip.irq.domain,
 					  i + TQMX86_NGPO);
@@ -277,6 +320,13 @@ static int tqmx86_gpio_probe(struct platform_device *pdev)
 
 	tqmx86_gpio_write(gpio, (u8)~TQMX86_DIR_INPUT_MASK, TQMX86_GPIODD);
 
+	/*
+	 * Reading the previous output state is not possible with TQMx86 hardware.
+	 * Initialize all outputs to 0 to have a defined state that matches the
+	 * shadow register.
+	 */
+	tqmx86_gpio_write(gpio, 0, TQMX86_GPIOD);
+
 	chip = &gpio->chip;
 	chip->label = "gpio-tqmx86";
 	chip->owner = THIS_MODULE;