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>

1 files changed, 165 insertions, 14 deletions

diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index c9db50729f6f..0d140e1879e7 100644
--- 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);