[PATCH v2] s3fb: add DDC support

From: Ondrej Zary
Date: Fri Aug 13 2010 - 12:36:44 EST


Add I2C support for the DDC bus to s3fb driver. This is only bus support,
driver does not use EDID.

Tested on Trio64V+, Trio64V2/DX, Virge (2 cards), Virge/DX (4 cards) and
Trio3D/2X (3 cards) with i2cdetect and decode-edid.

Will probably not work on Trio32 - my 2 cards have DDC support in BIOS that
looks different from the other cards but the DDC pins on the VGA connector
are not connected.

Virge/GX, Virge/GX2 and Virge/VX are untested.


Signed-off-by: Ondrej Zary <linux@xxxxxxxxxxxxxxxxxxxx>
---
This time with Kconfig part present.

--- linux-2.6.35-rc2/drivers/video/s3fb.c 2010-06-06 05:43:24.000000000 +0200
+++ linux-2.6.35-rc3/drivers/video/s3fb.c 2010-08-10 19:42:38.000000000 +0200
@@ -25,6 +25,10 @@
#include <linux/console.h> /* Why should fb driver call console functions? because acquire_console_sem() */
#include <video/vga.h>

+#include <linux/i2c.h>
+#include <linux/i2c-id.h>
+#include <linux/i2c-algo-bit.h>
+
#ifdef CONFIG_MTRR
#include <asm/mtrr.h>
#endif
@@ -36,6 +40,12 @@
struct mutex open_lock;
unsigned int ref_count;
u32 pseudo_palette[16];
+#ifdef CONFIG_FB_S3_DDC
+ u8 __iomem *mmio;
+ bool ddc_registered;
+ struct i2c_adapter ddc_adapter;
+ struct i2c_algo_bit_data ddc_algo;
+#endif
};


@@ -102,6 +112,9 @@
#define CHIP_UNDECIDED_FLAG 0x80
#define CHIP_MASK 0xFF

+#define MMIO_OFFSET 0x1000000
+#define MMIO_SIZE 0x10000
+
/* CRT timing register sets */

static const struct vga_regset s3_h_total_regs[] = {{0x00, 0, 7}, {0x5D, 0, 0}, VGA_REGSET_END};
@@ -164,6 +177,118 @@

/* ------------------------------------------------------------------------- */

+#ifdef CONFIG_FB_S3_DDC
+
+#define DDC_REG 0xaa /* Trio 3D and probably Virge/GX2 */
+#define DDC_MMIO_REG 0xff20 /* Trio, Virge, Virge/DX, not sure about Virge/GX and VX */
+#define DDC_SCL_OUT (1 << 0)
+#define DDC_SDA_OUT (1 << 1)
+#define DDC_SCL_IN (1 << 2)
+#define DDC_SDA_IN (1 << 3)
+#define DDC_DRIVE_EN (1 << 4)
+
+static bool s3fb_ddc_needs_mmio(int chip)
+{
+ return !(chip == CHIP_356_VIRGE_GX2 ||
+ chip == CHIP_357_VIRGE_GX2P ||
+ chip == CHIP_359_VIRGE_GX2P ||
+ chip == CHIP_360_TRIO3D_1X ||
+ chip == CHIP_362_TRIO3D_2X ||
+ chip == CHIP_368_TRIO3D_2X);
+}
+
+static u8 s3fb_ddc_read(struct s3fb_info *par)
+{
+ if (s3fb_ddc_needs_mmio(par->chip))
+ return readb(par->mmio + DDC_MMIO_REG);
+ else
+ return vga_rcrt(NULL, DDC_REG);
+}
+
+static void s3fb_ddc_write(struct s3fb_info *par, u8 val)
+{
+ if (s3fb_ddc_needs_mmio(par->chip))
+ writeb(val, par->mmio + DDC_MMIO_REG);
+ else
+ vga_wcrt(NULL, DDC_REG, val);
+}
+
+static void s3fb_ddc_setscl(void *data, int val)
+{
+ struct s3fb_info *par = data;
+ unsigned char reg;
+
+ reg = s3fb_ddc_read(par) | DDC_DRIVE_EN;
+ if (val)
+ reg |= DDC_SCL_OUT;
+ else
+ reg &= ~DDC_SCL_OUT;
+ s3fb_ddc_write(par, reg);
+}
+
+static void s3fb_ddc_setsda(void *data, int val)
+{
+ struct s3fb_info *par = data;
+ unsigned char reg;
+
+ reg = s3fb_ddc_read(par) | DDC_DRIVE_EN;
+ if (val)
+ reg |= DDC_SDA_OUT;
+ else
+ reg &= ~DDC_SDA_OUT;
+ s3fb_ddc_write(par, reg);
+}
+
+static int s3fb_ddc_getscl(void *data)
+{
+ struct s3fb_info *par = data;
+
+ return !!(s3fb_ddc_read(par) & DDC_SCL_IN);
+}
+
+static int s3fb_ddc_getsda(void *data)
+{
+ struct s3fb_info *par = data;
+
+ return !!(s3fb_ddc_read(par) & DDC_SDA_IN);
+}
+
+static int __devinit s3fb_setup_ddc_bus(struct fb_info *info)
+{
+ struct s3fb_info *par = info->par;
+
+ strlcpy(par->ddc_adapter.name, info->fix.id,
+ sizeof(par->ddc_adapter.name));
+ par->ddc_adapter.owner = THIS_MODULE;
+ par->ddc_adapter.class = I2C_CLASS_DDC;
+ par->ddc_adapter.algo_data = &par->ddc_algo;
+ par->ddc_adapter.dev.parent = info->device;
+ par->ddc_algo.setsda = s3fb_ddc_setsda;
+ par->ddc_algo.setscl = s3fb_ddc_setscl;
+ par->ddc_algo.getsda = s3fb_ddc_getsda;
+ par->ddc_algo.getscl = s3fb_ddc_getscl;
+ par->ddc_algo.udelay = 10;
+ par->ddc_algo.timeout = 20;
+ par->ddc_algo.data = par;
+
+ i2c_set_adapdata(&par->ddc_adapter, par);
+
+ /*
+ * some Virge cards have external MUX to switch chip I2C bus between
+ * DDC and extension pins - switch it do DDC
+ */
+/* vga_wseq(NULL, 0x08, 0x06); - not needed, already unlocked */
+ svga_wseq_mask(0x0d, 0x00, 0x03);
+ /* some Virge need this or the DDC is ignored */
+ svga_wcrt_mask(0x5c, 0x03, 0x03);
+
+ return i2c_bit_add_bus(&par->ddc_adapter);
+}
+#endif /* CONFIG_FB_S3_DDC */
+
+
+/* ------------------------------------------------------------------------- */
+
/* Set font in S3 fast text mode */

static void s3fb_settile_fast(struct fb_info *info, struct fb_tilemap *map)
@@ -1019,6 +1144,21 @@
info->fix.accel = FB_ACCEL_NONE;
info->pseudo_palette = (void*) (par->pseudo_palette);

+#ifdef CONFIG_FB_S3_DDC
+ /* Enable MMIO if needed */
+ if (s3fb_ddc_needs_mmio(par->chip)) {
+ par->mmio = ioremap(info->fix.smem_start + MMIO_OFFSET, MMIO_SIZE);
+ if (par->mmio)
+ svga_wcrt_mask(0x53, 0x08, 0x08); /* enable MMIO */
+ else
+ dev_err(info->device, "unable to map MMIO at 0x%lx, disabling DDC",
+ info->fix.smem_start + MMIO_OFFSET);
+ }
+ if (!s3fb_ddc_needs_mmio(par->chip) || par->mmio)
+ if (s3fb_setup_ddc_bus(info) == 0)
+ par->ddc_registered = true;
+#endif
+
/* Prepare startup mode */
rc = fb_find_mode(&(info->var), info, mode_option, NULL, 0, NULL, 8);
if (! ((rc == 1) || (rc == 2))) {
@@ -1064,6 +1204,12 @@
fb_dealloc_cmap(&info->cmap);
err_alloc_cmap:
err_find_mode:
+#ifdef CONFIG_FB_S3_DDC
+ if (par->ddc_registered)
+ i2c_del_adapter(&par->ddc_adapter);
+ if (par->mmio)
+ iounmap(par->mmio);
+#endif
pci_iounmap(dev, info->screen_base);
err_iomap:
pci_release_regions(dev);
@@ -1095,6 +1241,13 @@
unregister_framebuffer(info);
fb_dealloc_cmap(&info->cmap);

+#ifdef CONFIG_FB_S3_DDC
+ if (par->ddc_registered)
+ i2c_del_adapter(&par->ddc_adapter);
+ if (par->mmio)
+ iounmap(par->mmio);
+#endif
+
pci_iounmap(dev, info->screen_base);
pci_release_regions(dev);
/* pci_disable_device(dev); */
--- linux-2.6.35-rc2/drivers/video/Kconfig 2010-06-06 05:43:24.000000000 +0200
+++ linux-2.6.35-rc3/drivers/video/Kconfig 2010-08-08 18:48:31.000000000 +0200
@@ -1435,6 +1444,15 @@ config FB_S3
---help---
Driver for graphics boards with S3 Trio / S3 Virge chip.

+config FB_S3_DDC
+ bool "DDC for S3 support"
+ depends on FB_S3
+ select FB_DDC
+ default y
+ help
+ Say Y here if you want DDC support for your S3 graphics card
+ This is only I2C bus support, driver does not use EDID.
+
config FB_SAVAGE
tristate "S3 Savage support"
depends on FB && PCI && EXPERIMENTAL



--
Ondrej Zary
--
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