gpio: gpio-ich: Share ownership of GPIO groups

The ICH chips have their GPIO pins organized in 2 or 3 independent
groups of 32 GPIO pins. It can happen that the ACPI BIOS wants to make
use of pins in one group, preventing the OS to access these. This does
not prevent the OS from accessing the other group(s).

This is the case for example on my Asus Z8NA-D6 board. The ACPI BIOS
wants to control GPIO 18 (group 1), while I (the OS) need to control
GPIO 52 and 53 (group 2) for SMBus multiplexing.

So instead of checking for ACPI resource conflict on the whole I/O
range, check on a per-group basis, and consider it a success if at
least one of the groups is available for the OS to use.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Peter Tyser <ptyser@xes-inc.com>
Cc: Aaron Sierra <asierra@xes-inc.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 69 insertions, 10 deletions

diff --git a/drivers/gpio/gpio-ich.c b/drivers/gpio/gpio-ich.c
index b7c06517403d..d4d617966696 100644
--- a/drivers/gpio/gpio-ich.c
+++ b/drivers/gpio/gpio-ich.c
@@ -49,6 +49,10 @@ static const u8 ichx_regs[3][3] = {
         {0x0c, 0x38, 0x48},     /* LVL[1-3] offsets */
 };
 
+static const u8 ichx_reglen[3] = {
+        0x30, 0x10, 0x10,
+};
+
 #define ICHX_WRITE(val, reg, base_res)  outl(val, (reg) + (base_res)->start)
 #define ICHX_READ(reg, base_res)        inl((reg) + (base_res)->start)
 
@@ -75,6 +79,7 @@ static struct {
         struct resource *pm_base;       /* Power Mangagment IO base */
         struct ichx_desc *desc; /* Pointer to chipset-specific description */
         u32 orig_gpio_ctrl;     /* Orig CTRL value, used to restore on exit */
+        u8 use_gpio;            /* Which GPIO groups are usable */
 } ichx_priv;
 
 static int modparam_gpiobase = -1;      /* dynamic */
@@ -123,8 +128,16 @@ static int ichx_read_bit(int reg, unsigned nr)
         return data & (1 << bit) ? 1 : 0;
 }
 
+static int ichx_gpio_check_available(struct gpio_chip *gpio, unsigned nr)
+{
+        return (ichx_priv.use_gpio & (1 << (nr / 32))) ? 0 : -ENXIO;
+}
+
 static int ichx_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
 {
+        if (!ichx_gpio_check_available(gpio, nr))
+                return -ENXIO;
+
         /*
          * Try setting pin as an input and verify it worked since many pins
          * are output-only.
@@ -138,6 +151,9 @@ static int ichx_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
 static int ichx_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
                                         int val)
 {
+        if (!ichx_gpio_check_available(gpio, nr))
+                return -ENXIO;
+
         /* Set GPIO output value. */
         ichx_write_bit(GPIO_LVL, nr, val, 0);
 
@@ -153,6 +169,9 @@ static int ichx_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
 
 static int ichx_gpio_get(struct gpio_chip *chip, unsigned nr)
 {
+        if (!ichx_gpio_check_available(chip, nr))
+                return -ENXIO;
+
         return ichx_read_bit(GPIO_LVL, nr);
 }
 
@@ -161,6 +180,9 @@ static int ich6_gpio_get(struct gpio_chip *chip, unsigned nr)
         unsigned long flags;
         u32 data;
 
+        if (!ichx_gpio_check_available(chip, nr))
+                return -ENXIO;
+
         /*
          * GPI 0 - 15 need to be read from the power management registers on
          * a ICH6/3100 bridge.
@@ -291,6 +313,46 @@ static struct ichx_desc intel5_desc = {
         .ngpio = 76,
 };
 
+static int __devinit ichx_gpio_request_regions(struct resource *res_base,
+                                                const char *name, u8 use_gpio)
+{
+        int i;
+
+        if (!res_base || !res_base->start || !res_base->end)
+                return -ENODEV;
+
+        for (i = 0; i < ARRAY_SIZE(ichx_regs[0]); i++) {
+                if (!(use_gpio & (1 << i)))
+                        continue;
+                if (!request_region(res_base->start + ichx_regs[0][i],
+                                    ichx_reglen[i], name))
+                        goto request_err;
+        }
+        return 0;
+
+request_err:
+        /* Clean up: release already requested regions, if any */
+        for (i--; i >= 0; i--) {
+                if (!(use_gpio & (1 << i)))
+                        continue;
+                release_region(res_base->start + ichx_regs[0][i],
+                               ichx_reglen[i]);
+        }
+        return -EBUSY;
+}
+
+static void ichx_gpio_release_regions(struct resource *res_base, u8 use_gpio)
+{
+        int i;
+
+        for (i = 0; i < ARRAY_SIZE(ichx_regs[0]); i++) {
+                if (!(use_gpio & (1 << i)))
+                        continue;
+                release_region(res_base->start + ichx_regs[0][i],
+                               ichx_reglen[i]);
+        }
+}
+
 static int __devinit ichx_gpio_probe(struct platform_device *pdev)
 {
         struct resource *res_base, *res_pm;
@@ -329,12 +391,11 @@ static int __devinit ichx_gpio_probe(struct platform_device *pdev)
         }
 
         res_base = platform_get_resource(pdev, IORESOURCE_IO, ICH_RES_GPIO);
-        if (!res_base || !res_base->start || !res_base->end)
-                return -ENODEV;
-
-        if (!request_region(res_base->start, resource_size(res_base),
-                                pdev->name))
-                return -EBUSY;
+        ichx_priv.use_gpio = ich_info->use_gpio;
+        err = ichx_gpio_request_regions(res_base, pdev->name,
+                                        ichx_priv.use_gpio);
+        if (err)
+                return err;
 
         ichx_priv.gpio_base = res_base;
 
@@ -374,8 +435,7 @@ init:
         return 0;
 
 add_err:
-        release_region(ichx_priv.gpio_base->start,
-                        resource_size(ichx_priv.gpio_base));
+        ichx_gpio_release_regions(ichx_priv.gpio_base, ichx_priv.use_gpio);
         if (ichx_priv.pm_base)
                 release_region(ichx_priv.pm_base->start,
                                 resource_size(ichx_priv.pm_base));
@@ -393,8 +453,7 @@ static int __devexit ichx_gpio_remove(struct platform_device *pdev)
                 return err;
         }
 
-        release_region(ichx_priv.gpio_base->start,
-                                resource_size(ichx_priv.gpio_base));
+        ichx_gpio_release_regions(ichx_priv.gpio_base, ichx_priv.use_gpio);
         if (ichx_priv.pm_base)
                 release_region(ichx_priv.pm_base->start,
                                 resource_size(ichx_priv.pm_base));