gpiolib: avr32 at32ap platform support

Teach AVR32 to use the "GPIO Library" when exposing its GPIOs, so that signals
on external chips (like GPIO expanders) can easily be used.

This mostly reorganizes some existing logic, with two minor changes in
behavior:

 - The PSR registers are used instead of the previous "gpio_mask" values,
   matching AT91 behavior and removing some duplication between that role
   and that of "pinmux_mask".

 - NR_IRQs grew to acommodate a bank of external GPIOs.  Eventually this
   number should probably become a board-specific config option.

There's a debugfs dump of status for the built-in GPIOs, showing which pins
have deglitching, pullups, or open drain drive enabled, as well as the ID
string used when requesting each IRQ.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Eric Miao <eric.miao@marvell.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Philipp Zabel <philipp.zabel@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ben Gardner <bgardner@wabtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 92 insertions, 80 deletions

diff --git a/arch/avr32/mach-at32ap/pio.c b/arch/avr32/mach-at32ap/pio.c
index d61a02da898c..38a8fa31c0b5 100644
--- a/arch/avr32/mach-at32ap/pio.c
+++ b/arch/avr32/mach-at32ap/pio.c
@@ -24,11 +24,11 @@
 #define MAX_NR_PIO_DEVICES              8
 
 struct pio_device {
+        struct gpio_chip chip;
         void __iomem *regs;
         const struct platform_device *pdev;
         struct clk *clk;
         u32 pinmux_mask;
-        u32 gpio_mask;
         char name[8];
 };
 
@@ -64,7 +64,8 @@ void __init at32_select_periph(unsigned int pin, unsigned int periph,
                 goto fail;
         }
 
-        if (unlikely(test_and_set_bit(pin_index, &pio->pinmux_mask))) {
+        if (unlikely(test_and_set_bit(pin_index, &pio->pinmux_mask)
+                         || gpiochip_is_requested(&pio->chip, pin_index))) {
                 printk("%s: pin %u is busy\n", pio->name, pin_index);
                 goto fail;
         }
@@ -79,9 +80,6 @@ void __init at32_select_periph(unsigned int pin, unsigned int periph,
         if (!(flags & AT32_GPIOF_PULLUP))
                 pio_writel(pio, PUDR, mask);
 
-        /* gpio_request NOT allowed */
-        set_bit(pin_index, &pio->gpio_mask);
-
         return;
 
 fail:
@@ -130,9 +128,6 @@ void __init at32_select_gpio(unsigned int pin, unsigned long flags)
 
         pio_writel(pio, PER, mask);
 
-        /* gpio_request now allowed */
-        clear_bit(pin_index, &pio->gpio_mask);
-
         return;
 
 fail:
@@ -166,96 +161,50 @@ fail:
 
 /* GPIO API */
 
-int gpio_request(unsigned int gpio, const char *label)
+static int direction_input(struct gpio_chip *chip, unsigned offset)
 {
-        struct pio_device *pio;
-        unsigned int pin;
-
-        pio = gpio_to_pio(gpio);
-        if (!pio)
-                return -ENODEV;
+        struct pio_device *pio = container_of(chip, struct pio_device, chip);
+        u32 mask = 1 << offset;
 
-        pin = gpio & 0x1f;
-        if (test_and_set_bit(pin, &pio->gpio_mask))
-                return -EBUSY;
+        if (!(pio_readl(pio, PSR) & mask))
+                return -EINVAL;
 
+        pio_writel(pio, ODR, mask);
         return 0;
 }
-EXPORT_SYMBOL(gpio_request);
 
-void gpio_free(unsigned int gpio)
+static int gpio_get(struct gpio_chip *chip, unsigned offset)
 {
-        struct pio_device *pio;
-        unsigned int pin;
+        struct pio_device *pio = container_of(chip, struct pio_device, chip);
 
-        pio = gpio_to_pio(gpio);
-        if (!pio) {
-                printk(KERN_ERR
-                       "gpio: attempted to free invalid pin %u\n", gpio);
-                return;
-        }
-
-        pin = gpio & 0x1f;
-        if (!test_and_clear_bit(pin, &pio->gpio_mask))
-                printk(KERN_ERR "gpio: freeing free or non-gpio pin %s-%u\n",
-                       pio->name, pin);
+        return (pio_readl(pio, PDSR) >> offset) & 1;
 }
-EXPORT_SYMBOL(gpio_free);
 
-int gpio_direction_input(unsigned int gpio)
-{
-        struct pio_device *pio;
-        unsigned int pin;
-
-        pio = gpio_to_pio(gpio);
-        if (!pio)
-                return -ENODEV;
-
-        pin = gpio & 0x1f;
-        pio_writel(pio, ODR, 1 << pin);
-
-        return 0;
-}
-EXPORT_SYMBOL(gpio_direction_input);
+static void gpio_set(struct gpio_chip *chip, unsigned offset, int value);
 
-int gpio_direction_output(unsigned int gpio, int value)
+static int direction_output(struct gpio_chip *chip, unsigned offset, int value)
 {
-        struct pio_device *pio;
-        unsigned int pin;
-
-        pio = gpio_to_pio(gpio);
-        if (!pio)
-                return -ENODEV;
+        struct pio_device *pio = container_of(chip, struct pio_device, chip);
+        u32 mask = 1 << offset;
 
-        gpio_set_value(gpio, value);
-
-        pin = gpio & 0x1f;
-        pio_writel(pio, OER, 1 << pin);
+        if (!(pio_readl(pio, PSR) & mask))
+                return -EINVAL;
 
+        gpio_set(chip, offset, value);
+        pio_writel(pio, OER, mask);
         return 0;
 }
-EXPORT_SYMBOL(gpio_direction_output);
 
-int gpio_get_value(unsigned int gpio)
+static void gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 {
-        struct pio_device *pio = &pio_dev[gpio >> 5];
+        struct pio_device *pio = container_of(chip, struct pio_device, chip);
+        u32 mask = 1 << offset;
 
-        return (pio_readl(pio, PDSR) >> (gpio & 0x1f)) & 1;
-}
-EXPORT_SYMBOL(gpio_get_value);
-
-void gpio_set_value(unsigned int gpio, int value)
-{
-        struct pio_device *pio = &pio_dev[gpio >> 5];
-        u32 mask;
-
-        mask = 1 << (gpio & 0x1f);
         if (value)
                 pio_writel(pio, SODR, mask);
         else
                 pio_writel(pio, CODR, mask);
 }
-EXPORT_SYMBOL(gpio_set_value);
 
 /*--------------------------------------------------------------------------*/
 
@@ -339,6 +288,63 @@ gpio_irq_setup(struct pio_device *pio, int irq, int gpio_irq)
 
 /*--------------------------------------------------------------------------*/
 
+#ifdef CONFIG_DEBUG_FS
+
+#include <linux/seq_file.h>
+
+/*
+ * This shows more info than the generic gpio dump code:
+ * pullups, deglitching, open drain drive.
+ */
+static void pio_bank_show(struct seq_file *s, struct gpio_chip *chip)
+{
+        struct pio_device *pio = container_of(chip, struct pio_device, chip);
+        u32                     psr, osr, imr, pdsr, pusr, ifsr, mdsr;
+        unsigned                i;
+        u32                     mask;
+        char                    bank;
+
+        psr = pio_readl(pio, PSR);
+        osr = pio_readl(pio, OSR);
+        imr = pio_readl(pio, IMR);
+        pdsr = pio_readl(pio, PDSR);
+        pusr = pio_readl(pio, PUSR);
+        ifsr = pio_readl(pio, IFSR);
+        mdsr = pio_readl(pio, MDSR);
+
+        bank = 'A' + pio->pdev->id;
+
+        for (i = 0, mask = 1; i < 32; i++, mask <<= 1) {
+                const char *label;
+
+                label = gpiochip_is_requested(chip, i);
+                if (!label)
+                        continue;
+
+                seq_printf(s, " gpio-%-3d P%c%-2d (%-12s) %s %s %s",
+                        chip->base + i, bank, i,
+                        label,
+                        (osr & mask) ? "out" : "in ",
+                        (mask & pdsr) ? "hi" : "lo",
+                        (mask & pusr) ? "  " : "up");
+                if (ifsr & mask)
+                        seq_printf(s, " deglitch");
+                if ((osr & mdsr) & mask)
+                        seq_printf(s, " open-drain");
+                if (imr & mask)
+                        seq_printf(s, " irq-%d edge-both",
+                                gpio_to_irq(chip->base + i));
+                seq_printf(s, "\n");
+        }
+}
+
+#else
+#define pio_bank_show   NULL
+#endif
+
+
+/*--------------------------------------------------------------------------*/
+
 static int __init pio_probe(struct platform_device *pdev)
 {
         struct pio_device *pio = NULL;
@@ -349,6 +355,18 @@ static int __init pio_probe(struct platform_device *pdev)
         pio = &pio_dev[pdev->id];
         BUG_ON(!pio->regs);
 
+        pio->chip.label = pio->name;
+        pio->chip.base = pdev->id * 32;
+        pio->chip.ngpio = 32;
+
+        pio->chip.direction_input = direction_input;
+        pio->chip.get = gpio_get;
+        pio->chip.direction_output = direction_output;
+        pio->chip.set = gpio_set;
+        pio->chip.dbg_show = pio_bank_show;
+
+        gpiochip_add(&pio->chip);
+
         gpio_irq_setup(pio, irq, gpio_irq_base);
 
         platform_set_drvdata(pdev, pio);
@@ -406,12 +424,6 @@ void __init at32_init_pio(struct platform_device *pdev)
         pio->pdev = pdev;
         pio->regs = ioremap(regs->start, regs->end - regs->start + 1);
 
-        /*
-         * request_gpio() is only valid for pins that have been
-         * explicitly configured as GPIO and not previously requested
-         */
-        pio->gpio_mask = ~0UL;
-
         /* start with irqs disabled and acked */
         pio_writel(pio, IDR, ~0UL);
         (void) pio_readl(pio, ISR);