Re: [PATCH] Remove voodoo code from i2c
From: Kronos <hidden>
Date: 2004-03-06 01:02:30
Il Sat, Mar 06, 2004 at 10:55:14AM +1100, Benjamin Herrenschmidt ha scritto:
On Sat, 2004-03-06 at 08:52, Kronos wrote:quoted
Hi, radeon_probe_i2c_connector contains very strange code that just send empty start-stop sequencies on the I2C bus. I copied the code from XFree86, but speaking with I2C gurus the general feeling is that this code can go away without any harm. I tested it on 3 different setup (all x86...) and it works well. I don't have any "old" monitor around to fiddle with though. Oh, if you think that this code should stay I'll send you another patch to make it more readable.I'd rather keep the code as close to XFree as possible at this point..
Ok, what about this (cosmetic) patch:
--- linux-2.6/drivers/video/aty/radeon_i2c.c.orig Sat Feb 28 18:11:42 2004
+++ linux-2.6/drivers/video/aty/radeon_i2c.c Sat Feb 28 18:49:31 2004@@ -174,65 +174,59 @@ int radeon_probe_i2c_connector(struct radeonfb_info *rinfo, int conn, u8 **out_edid) { u32 reg = rinfo->i2c[conn-1].ddc_reg; + struct radeon_i2c_chan *chan = &rinfo->i2c[conn-1]; u8 *edid = NULL; int i, j; OUTREG(reg, INREG(reg) & ~(VGA_DDC_DATA_OUTPUT | VGA_DDC_CLK_OUTPUT)); - OUTREG(reg, INREG(reg) & ~(VGA_DDC_CLK_OUT_EN)); - (void)INREG(reg); + radeon_gpio_setscl(chan, 1); for (i = 0; i < 3; i++) { /* For some old monitors we need the * following process to initialize/stop DDC */ - OUTREG(reg, INREG(reg) & ~(VGA_DDC_DATA_OUT_EN)); - (void)INREG(reg); + radeon_gpio_setsda(chan, 1); wait_ms(13); - OUTREG(reg, INREG(reg) & ~(VGA_DDC_CLK_OUT_EN)); - (void)INREG(reg); + radeon_gpio_setscl(chan, 1); for (j = 0; j < 5; j++) { + /* Wait for ack */ wait_ms(10); - if (INREG(reg) & VGA_DDC_CLK_INPUT) + if (radeon_gpio_getscl(chan)) break; } if (j == 5) continue; - OUTREG(reg, INREG(reg) | VGA_DDC_DATA_OUT_EN); - (void)INREG(reg); + radeon_gpio_setsda(chan, 0); wait_ms(15); - OUTREG(reg, INREG(reg) | VGA_DDC_CLK_OUT_EN); - (void)INREG(reg); + radeon_gpio_setscl(chan, 0); wait_ms(15); - OUTREG(reg, INREG(reg) & ~(VGA_DDC_DATA_OUT_EN)); - (void)INREG(reg); + radeon_gpio_setsda(chan, 1); wait_ms(15); /* Do the real work */ - edid = radeon_do_probe_i2c_edid(&rinfo->i2c[conn-1]); + edid = radeon_do_probe_i2c_edid(chan); - OUTREG(reg, INREG(reg) | - (VGA_DDC_DATA_OUT_EN | VGA_DDC_CLK_OUT_EN)); - (void)INREG(reg); + radeon_gpio_setsda(chan, 0); + radeon_gpio_setscl(chan, 0); wait_ms(15); - - OUTREG(reg, INREG(reg) & ~(VGA_DDC_CLK_OUT_EN)); - (void)INREG(reg); + + radeon_gpio_setscl(chan, 1); for (j = 0; j < 10; j++) { + /* Wait for ack */ wait_ms(10); - if (INREG(reg) & VGA_DDC_CLK_INPUT) + if (radeon_gpio_getscl(chan)) break; } - OUTREG(reg, INREG(reg) & ~(VGA_DDC_DATA_OUT_EN)); - (void)INREG(reg); + radeon_gpio_setsda(chan, 1); wait_ms(15); - OUTREG(reg, INREG(reg) | - (VGA_DDC_DATA_OUT_EN | VGA_DDC_CLK_OUT_EN)); - (void)INREG(reg); + + radeon_gpio_setsda(chan, 0); + radeon_gpio_setscl(chan, 0); if (edid) break; }
In this way it clearer what's going on. Luca -- Home: http://kronoz.cjb.net "Sei l'unica donna della mia vita". (Adamo) ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click