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apple_gmux: Add support for newer hardware
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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>
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Matthew Garrett committed Aug 17, 2012
1 parent 7e30ed6 commit 96ff705
Showing 1 changed file with 165 additions and 14 deletions.
179 changes: 165 additions & 14 deletions drivers/platform/x86/apple-gmux.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
};
Expand All @@ -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)

Expand All @@ -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;
Expand All @@ -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);
Expand Down Expand Up @@ -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);
Expand Down

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