apple_gmux: Add support for newer hardware

New gmux devices have a different method for accessing the registers.
Update the driver to cope. Incorporates feedback from Bernhard Froemel.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Bernhard Froemel <froemel@vmars.tuwien.ac.at>
Cc: Seth Forshee <seth.forshee@canonical.com>

diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index c9db507..0d140e1 100644 (file)
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -18,12 +18,15 @@
 #include <linux/pnp.h>
 #include <linux/apple_bl.h>
 #include <linux/slab.h>
+#include <linux/delay.h>
 #include <acpi/video.h>
 #include <asm/io.h>
 
 struct apple_gmux_data {
        unsigned long iostart;
        unsigned long iolen;
+       bool indexed;
+       struct mutex index_lock;
 
        struct backlight_device *bdev;
 };
@@ -45,6 +48,9 @@ struct apple_gmux_data {
 #define GMUX_PORT_DISCRETE_POWER       0x50
 #define GMUX_PORT_MAX_BRIGHTNESS       0x70
 #define GMUX_PORT_BRIGHTNESS           0x74
+#define GMUX_PORT_VALUE                        0xc2
+#define GMUX_PORT_READ                 0xd0
+#define GMUX_PORT_WRITE                        0xd4
 
 #define GMUX_MIN_IO_LEN                        (GMUX_PORT_BRIGHTNESS + 4)
 
@@ -59,24 +65,24 @@ struct apple_gmux_data {
 #define GMUX_BRIGHTNESS_MASK           0x00ffffff
 #define GMUX_MAX_BRIGHTNESS            GMUX_BRIGHTNESS_MASK
 
-static inline u8 gmux_read8(struct apple_gmux_data *gmux_data, int port)
+static u8 gmux_pio_read8(struct apple_gmux_data *gmux_data, int port)
 {
        return inb(gmux_data->iostart + port);
 }
 
-static inline void gmux_write8(struct apple_gmux_data *gmux_data, int port,
+static void gmux_pio_write8(struct apple_gmux_data *gmux_data, int port,
                               u8 val)
 {
        outb(val, gmux_data->iostart + port);
 }
 
-static inline u32 gmux_read32(struct apple_gmux_data *gmux_data, int port)
+static u32 gmux_pio_read32(struct apple_gmux_data *gmux_data, int port)
 {
        return inl(gmux_data->iostart + port);
 }
 
-static inline u32 gmux_write32(struct apple_gmux_data *gmux_data, int port,
-                              u32 val)
+static void gmux_pio_write32(struct apple_gmux_data *gmux_data, int port,
+                            u32 val)
 {
        int i;
        u8 tmpval;
@@ -87,6 +93,144 @@ static inline u32 gmux_write32(struct apple_gmux_data *gmux_data, int port,
        }
 }
 
+static int gmux_index_wait_ready(struct apple_gmux_data *gmux_data)
+{
+       int i = 200;
+       u8 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
+
+       while (i && (gwr & 0x01)) {
+               inb(gmux_data->iostart + GMUX_PORT_READ);
+               gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
+               udelay(100);
+               i--;
+       }
+
+       return !!i;
+}
+
+static int gmux_index_wait_complete(struct apple_gmux_data *gmux_data)
+{
+       int i = 200;
+       u8 gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
+
+       while (i && !(gwr & 0x01)) {
+               gwr = inb(gmux_data->iostart + GMUX_PORT_WRITE);
+               udelay(100);
+               i--;
+       }
+
+       if (gwr & 0x01)
+               inb(gmux_data->iostart + GMUX_PORT_READ);
+
+       return !!i;
+}
+
+static u8 gmux_index_read8(struct apple_gmux_data *gmux_data, int port)
+{
+       u8 val;
+
+       mutex_lock(&gmux_data->index_lock);
+       outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
+       gmux_index_wait_ready(gmux_data);
+       val = inb(gmux_data->iostart + GMUX_PORT_VALUE);
+       mutex_unlock(&gmux_data->index_lock);
+
+       return val;
+}
+
+static void gmux_index_write8(struct apple_gmux_data *gmux_data, int port,
+                             u8 val)
+{
+       mutex_lock(&gmux_data->index_lock);
+       outb(val, gmux_data->iostart + GMUX_PORT_VALUE);
+       gmux_index_wait_ready(gmux_data);
+       outb(port & 0xff, gmux_data->iostart + GMUX_PORT_WRITE);
+       gmux_index_wait_complete(gmux_data);
+       mutex_unlock(&gmux_data->index_lock);
+}
+
+static u32 gmux_index_read32(struct apple_gmux_data *gmux_data, int port)
+{
+       u32 val;
+
+       mutex_lock(&gmux_data->index_lock);
+       outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
+       gmux_index_wait_ready(gmux_data);
+       val = inl(gmux_data->iostart + GMUX_PORT_VALUE);
+       mutex_unlock(&gmux_data->index_lock);
+
+       return val;
+}
+
+static void gmux_index_write32(struct apple_gmux_data *gmux_data, int port,
+                              u32 val)
+{
+       int i;
+       u8 tmpval;
+
+       mutex_lock(&gmux_data->index_lock);
+
+       for (i = 0; i < 4; i++) {
+               tmpval = (val >> (i * 8)) & 0xff;
+               outb(tmpval, gmux_data->iostart + GMUX_PORT_VALUE + i);
+       }
+
+       gmux_index_wait_ready(gmux_data);
+       outb(port & 0xff, gmux_data->iostart + GMUX_PORT_WRITE);
+       gmux_index_wait_complete(gmux_data);
+       mutex_unlock(&gmux_data->index_lock);
+}
+
+static u8 gmux_read8(struct apple_gmux_data *gmux_data, int port)
+{
+       if (gmux_data->indexed)
+               return gmux_index_read8(gmux_data, port);
+       else
+               return gmux_pio_read8(gmux_data, port);
+}
+
+static void gmux_write8(struct apple_gmux_data *gmux_data, int port, u8 val)
+{
+       if (gmux_data->indexed)
+               gmux_index_write8(gmux_data, port, val);
+       else
+               gmux_pio_write8(gmux_data, port, val);
+}
+
+static u32 gmux_read32(struct apple_gmux_data *gmux_data, int port)
+{
+       if (gmux_data->indexed)
+               return gmux_index_read32(gmux_data, port);
+       else
+               return gmux_pio_read32(gmux_data, port);
+}
+
+static void gmux_write32(struct apple_gmux_data *gmux_data, int port,
+                            u32 val)
+{
+       if (gmux_data->indexed)
+               gmux_index_write32(gmux_data, port, val);
+       else
+               gmux_pio_write32(gmux_data, port, val);
+}
+
+static bool gmux_is_indexed(struct apple_gmux_data *gmux_data)
+{
+       u16 val;
+
+       outb(0xaa, gmux_data->iostart + 0xcc);
+       outb(0x55, gmux_data->iostart + 0xcd);
+       outb(0x00, gmux_data->iostart + 0xce);
+
+       val = inb(gmux_data->iostart + 0xcc) |
+               (inb(gmux_data->iostart + 0xcd) << 8);
+
+       if (val == 0x55aa)
+               return true;
+
+       return false;
+}
+
 static int gmux_get_brightness(struct backlight_device *bd)
 {
        struct apple_gmux_data *gmux_data = bl_get_data(bd);
@@ -150,22 +294,29 @@ static int __devinit gmux_probe(struct pnp_dev *pnp,
        }
 
        /*
-        * On some machines the gmux is in ACPI even thought the machine
-        * doesn't really have a gmux. Check for invalid version information
-        * to detect this.
+        * Invalid version information may indicate either that the gmux
+        * device isn't present or that it's a new one that uses indexed
+        * io
         */
+
        ver_major = gmux_read8(gmux_data, GMUX_PORT_VERSION_MAJOR);
        ver_minor = gmux_read8(gmux_data, GMUX_PORT_VERSION_MINOR);
        ver_release = gmux_read8(gmux_data, GMUX_PORT_VERSION_RELEASE);
        if (ver_major == 0xff && ver_minor == 0xff && ver_release == 0xff) {
-               pr_info("gmux device not present\n");
-               ret = -ENODEV;
-               goto err_release;
+               if (gmux_is_indexed(gmux_data)) {
+                       mutex_init(&gmux_data->index_lock);
+                       gmux_data->indexed = true;
+               } else {
+                       pr_info("gmux device not present\n");
+                       ret = -ENODEV;
+                       goto err_release;
+               }
+               pr_info("Found indexed gmux\n");
+       } else {
+               pr_info("Found gmux version %d.%d.%d\n", ver_major, ver_minor,
+                       ver_release);
        }
 
-       pr_info("Found gmux version %d.%d.%d\n", ver_major, ver_minor,
-               ver_release);
-
        memset(&props, 0, sizeof(props));
        props.type = BACKLIGHT_PLATFORM;
        props.max_brightness = gmux_read32(gmux_data, GMUX_PORT_MAX_BRIGHTNESS);