davinci: gpio bugfixes

Update the DaVinci GPIO code to work better on non-dm6446 parts,
notably the dm355:

 - Only handle the number of GPIOs the chip actually has.  So
   for example on dm6467, GPIO-42 is the last GPIO, and trying
   to use GPIO-43 now fails cleanly; or GPIO-72 on dm6446.

 - Enable GPIO interrupts on each 16-bit GPIO-irq bank ...
   previously, only the first five were enabled, so GPIO-80
   and above (on dm355) wouldn't trigger IRQs.

 - Use the right IRQ for each GPIO bank.  The wrong values were
   used for dm355 chips, so GPIO IRQs got routed incorrectly.

 - Handle up to four pairs of 16-bit GPIO banks ... previously
   only three were handled, so accessing GPIO-96 and up (e.g. on
   dm355) would oops.

 - Update several comments that were dm6446-specific.

Verified by receiving GPIO-1 (dm9000) and GPIO-5 (msp430) IRQs
on the DM355 EVM.

One thing this doesn't do is handle the way some of the GPIO
numbers on dm6467 are reserved but aren't valid as GPIOs.  Some
bitmap logic could fix that if needed.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

1 files changed, 59 insertions, 23 deletions

diff --git a/arch/arm/mach-davinci/gpio.c b/arch/arm/mach-davinci/gpio.c
index b49e9d092aab..1aba41c6351e 100644
--- a/arch/arm/mach-davinci/gpio.c
+++ b/arch/arm/mach-davinci/gpio.c
@@ -20,6 +20,7 @@
 #include <linux/irq.h>
 #include <linux/bitops.h>
 
+#include <mach/cputype.h>
 #include <mach/irqs.h>
 #include <mach/hardware.h>
 #include <mach/gpio.h>
@@ -36,9 +37,10 @@ struct davinci_gpio {
 
 static struct davinci_gpio chips[DIV_ROUND_UP(DAVINCI_N_GPIO, 32)];
 
+static unsigned __initdata ngpio;
 
 /* create a non-inlined version */
-static struct gpio_controller *__iomem __init gpio2controller(unsigned gpio)
+static struct gpio_controller __iomem * __init gpio2controller(unsigned gpio)
 {
         return __gpio_to_controller(gpio);
 }
@@ -114,9 +116,30 @@ static int __init davinci_gpio_setup(void)
 {
         int i, base;
 
-        for (i = 0, base = 0;
-                        i < ARRAY_SIZE(chips);
-                        i++, base += 32) {
+        /* The gpio banks conceptually expose a segmented bitmap,
+         * and "ngpio" is one more than the largest zero-based
+         * bit index that's valid.
+         */
+        if (cpu_is_davinci_dm355()) {           /* or dm335() */
+                ngpio = 104;
+        } else if (cpu_is_davinci_dm644x()) {   /* or dm337() */
+                ngpio = 71;
+        } else if (cpu_is_davinci_dm646x()) {
+                /* NOTE:  each bank has several "reserved" bits,
+                 * unusable as GPIOs.  Only 33 of the GPIO numbers
+                 * are usable, and we're not rejecting the others.
+                 */
+                ngpio = 43;
+        } else {
+                /* if cpu_is_davinci_dm643x() ngpio = 111 */
+                pr_err("GPIO setup:  how many GPIOs?\n");
+                return -EINVAL;
+        }
+
+        if (WARN_ON(DAVINCI_N_GPIO < ngpio))
+                ngpio = DAVINCI_N_GPIO;
+
+        for (i = 0, base = 0; base < ngpio; i++, base += 32) {
                 chips[i].chip.label = "DaVinci";
 
                 chips[i].chip.direction_input = davinci_direction_in;
@@ -125,7 +148,7 @@ static int __init davinci_gpio_setup(void)
                 chips[i].chip.set = davinci_gpio_set;
 
                 chips[i].chip.base = base;
-                chips[i].chip.ngpio = DAVINCI_N_GPIO - base;
+                chips[i].chip.ngpio = ngpio - base;
                 if (chips[i].chip.ngpio > 32)
                         chips[i].chip.ngpio = 32;
 
@@ -143,11 +166,11 @@ pure_initcall(davinci_gpio_setup);
  * We expect irqs will normally be set up as input pins, but they can also be
  * used as output pins ... which is convenient for testing.
  *
- * NOTE:  GPIO0..GPIO7 also have direct INTC hookups, which work in addition
- * to their GPIOBNK0 irq (but with a bit less overhead).  But we don't have
- * a good way to hook those up ...
+ * NOTE:  The first few GPIOs also have direct INTC hookups in addition
+ * to their GPIOBNK0 irq, with a bit less overhead but less flexibility
+ * on triggering (e.g. no edge options).  We don't try to use those.
  *
- * All those INTC hookups (GPIO0..GPIO7 plus five IRQ banks) can also
+ * All those INTC hookups (direct, plus several IRQ banks) can also
  * serve as EDMA event triggers.
  */
 
@@ -235,29 +258,42 @@ gpio_irq_handler(unsigned irq, struct irq_desc *desc)
 }
 
 /*
- * NOTE:  for suspend/resume, probably best to make a sysdev (and class)
- * with its suspend/resume calls hooking into the results of the set_wake()
+ * NOTE:  for suspend/resume, probably best to make a platform_device with
+ * suspend_late/resume_resume calls hooking into results of the set_wake()
  * calls ... so if no gpios are wakeup events the clock can be disabled,
  * with outputs left at previously set levels, and so that VDD3P3V.IOPWDN0
- * can be set appropriately for GPIOV33 pins.
+ * (dm6446) can be set appropriately for GPIOV33 pins.
  */
 
 static int __init davinci_gpio_irq_setup(void)
 {
         unsigned        gpio, irq, bank;
+        unsigned        bank_irq;
         struct clk      *clk;
+        u32             binten = 0;
+
+        if (cpu_is_davinci_dm355()) {           /* or dm335() */
+                bank_irq = IRQ_DM355_GPIOBNK0;
+        } else if (cpu_is_davinci_dm644x()) {
+                bank_irq = IRQ_GPIOBNK0;
+        } else if (cpu_is_davinci_dm646x()) {
+                bank_irq = IRQ_DM646X_GPIOBNK0;
+        } else {
+                printk(KERN_ERR "Don't know first GPIO bank IRQ.\n");
+                return -EINVAL;
+        }
 
         clk = clk_get(NULL, "gpio");
         if (IS_ERR(clk)) {
                 printk(KERN_ERR "Error %ld getting gpio clock?\n",
                        PTR_ERR(clk));
-                return 0;
+                return PTR_ERR(clk);
         }
-
         clk_enable(clk);
 
-        for (gpio = 0, irq = gpio_to_irq(0), bank = IRQ_GPIOBNK0;
-             gpio < DAVINCI_N_GPIO; bank++) {
+        for (gpio = 0, irq = gpio_to_irq(0), bank = 0;
+                        gpio < ngpio;
+                        bank++, bank_irq++) {
                 struct gpio_controller  *__iomem g = gpio2controller(gpio);
                 unsigned                i;
 
@@ -265,28 +301,28 @@ static int __init davinci_gpio_irq_setup(void)
                 __raw_writel(~0, &g->clr_rising);
 
                 /* set up all irqs in this bank */
-                set_irq_chained_handler(bank, gpio_irq_handler);
-                set_irq_chip_data(bank, g);
-                set_irq_data(bank, (void *)irq);
+                set_irq_chained_handler(bank_irq, gpio_irq_handler);
+                set_irq_chip_data(bank_irq, g);
+                set_irq_data(bank_irq, (void *)irq);
 
-                for (i = 0; i < 16 && gpio < DAVINCI_N_GPIO;
-                     i++, irq++, gpio++) {
+                for (i = 0; i < 16 && gpio < ngpio; i++, irq++, gpio++) {
                         set_irq_chip(irq, &gpio_irqchip);
                         set_irq_chip_data(irq, g);
                         set_irq_handler(irq, handle_simple_irq);
                         set_irq_flags(irq, IRQF_VALID);
                 }
+
+                binten |= BIT(bank);
         }
 
         /* BINTEN -- per-bank interrupt enable. genirq would also let these
          * bits be set/cleared dynamically.
          */
-        __raw_writel(0x1f, (void *__iomem)
+        __raw_writel(binten, (void *__iomem)
                      IO_ADDRESS(DAVINCI_GPIO_BASE + 0x08));
 
         printk(KERN_INFO "DaVinci: %d gpio irqs\n", irq - gpio_to_irq(0));
 
         return 0;
 }
-
 arch_initcall(davinci_gpio_irq_setup);