viafb: add interface for output device configuration

This patch extends the proc entry to contain a possibility to view and
change the output devices for each IGA. This is useful for debugging
output problems as it provides a reliable way to query which low level
devices are active after VIAs output device configuration nightmare
happended. It's as well suitable for daily use as one can change the
output configuration on the fly for example to connect a projector.
At the moment it's still unstable. The reason is that we have to handle
a bunch of undocumented output devices (those without a proper name) and
that this patch is the first step to collect and verify the needed
information. Basically the only configuration change that is expected to
work at the moment is switching output devices between IGA1 and IGA2.

Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Cc: Joseph Chan <JosephChan@via.com.tw>
Cc: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 53 insertions, 0 deletions

diff --git a/drivers/video/via/hw.c b/drivers/video/via/hw.c
index 03303232e543..e65edcea46eb 100644
--- a/drivers/video/via/hw.c
+++ b/drivers/video/via/hw.c
@@ -718,6 +718,16 @@ static struct rgbLUT palLUT_table[] = {
                                                                      0x00}
 };
 
+static struct via_device_mapping device_mapping[] = {
+        {VIA_6C, "6C"},
+        {VIA_93, "93"},
+        {VIA_96, "96"},
+        {VIA_CRT, "CRT"},
+        {VIA_DVP1, "DVP1"},
+        {VIA_LVDS1, "LVDS1"},
+        {VIA_LVDS2, "LVDS2"}
+};
+
 static void load_fix_bit_crtc_reg(void);
 static void __devinit init_gfx_chip_info(int chip_type);
 static void __devinit init_tmds_chip_info(void);
@@ -1026,6 +1036,49 @@ void via_set_source(u32 devices, u8 iga)
                 set_lvds2_source(iga);
 }
 
+u32 via_parse_odev(char *input, char **end)
+{
+        char *ptr = input;
+        u32 odev = 0;
+        bool next = true;
+        int i, len;
+
+        while (next) {
+                next = false;
+                for (i = 0; i < ARRAY_SIZE(device_mapping); i++) {
+                        len = strlen(device_mapping[i].name);
+                        if (!strncmp(ptr, device_mapping[i].name, len)) {
+                                odev |= device_mapping[i].device;
+                                ptr += len;
+                                if (*ptr == ',') {
+                                        ptr++;
+                                        next = true;
+                                }
+                        }
+                }
+        }
+
+        *end = ptr;
+        return odev;
+}
+
+void via_odev_to_seq(struct seq_file *m, u32 odev)
+{
+        int i, count = 0;
+
+        for (i = 0; i < ARRAY_SIZE(device_mapping); i++) {
+                if (odev & device_mapping[i].device) {
+                        if (count > 0)
+                                seq_putc(m, ',');
+
+                        seq_puts(m, device_mapping[i].name);
+                        count++;
+                }
+        }
+
+        seq_putc(m, '\n');
+}
+
 static void load_fix_bit_crtc_reg(void)
 {
         /* always set to 1 */