Em Mon, 01 Apr 2013 19:14:03 +0200 Frank Schäfer <fschaefer.oss@xxxxxxxxxxxxxx> escreveu: > Am 18.03.2013 22:22, schrieb Mauro Carvalho Chehab: > > Em Wed, 06 Mar 2013 18:44:07 +0100 > > Frank Schäfer <fschaefer.oss@xxxxxxxxxxxxxx> escreveu: > > > >> Am 05.03.2013 16:43, schrieb Devin Heitmueller: > >>> 2013/3/5 Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>: > >>>> The em2874 chips and upper have 2 buses. On all known devices, bus 0 is > >>>> currently used only by eeprom, and bus 1 for the rest. Add support to > >>>> register both buses. > >>> Did you add a mutex to ensure that both buses cannot be used at the > >>> same time? Because using the bus requires you to toggle a register > >>> (thus you cannot be using both busses at the same time), you cannot > >>> rely on the existing i2c adapter lock anymore. > >>> > >>> You don't want a situation where something is actively talking on bus > >>> 0, and then something else tries to talk on bus 1, flips the register > >>> bit and then the thread talking on bus 0 starts failing. > >>> > >>> Devin > >> Hmm... there are several writes to EM28XX_R06_I2C_CLK in em28xx-dvb... > >> See hauppauge_hvr930c_init(), terratec_h5_init() and > >> terratec_htc_stick_init(). > >> These functions are called from em28xx_dvb_init() at module init. > >> Module init is async, so yes, this is (or could at least become) a > >> problem... > >> > >> I wonder if we can't simply remove all those writes to > >> EM28XX_R06_I2C_CLK from em28xx-dvb. > >> This is what the functions are doing: > >> > >> hauppauge_hvr930c_init() > >> ... > >> em28xx_write_reg(dev, EM28XX_R06_I2C_CLK, 0x40); > >> msleep(10); > >> em28xx_write_reg(dev, EM28XX_R06_I2C_CLK, 0x44); > >> msleep(10); > >> ... [init sequence for slave at address 0x82] > >> em28xx_write_reg(dev, EM28XX_R06_I2C_CLK, 0x44); > >> msleep(30); > >> em28xx_write_reg(dev, EM28XX_R06_I2C_CLK, 0x45); > >> msleep(10); > >> > >> terratec_h5_init(): > >> ... > >> em28xx_write_reg(dev, EM28XX_R06_I2C_CLK, 0x40); > >> msleep(10); > >> em28xx_write_reg(dev, EM28XX_R06_I2C_CLK, 0x45); > >> msleep(10); > >> ... > >> > >> terratec_htc_stick_init() > >> ... > >> em28xx_write_reg(dev, EM28XX_R06_I2C_CLK, 0x40); > >> msleep(10); > >> em28xx_write_reg(dev, EM28XX_R06_I2C_CLK, 0x44); > >> msleep(10); > >> ... > >> > >> All three boards are using the following settings: > >> .i2c_speed = EM2874_I2C_SECONDARY_BUS_SELECT | > >> EM28XX_I2C_CLK_WAIT_ENABLE | EM28XX_I2C_FREQ_400_KHZ = 0x45 > >> > >> So what these functions are doing is > >> - switch to bus A and do nothing fo 10ms > >> - overwrite board settings for reg 0x06 with a local value (clears > >> EM28XX_I2C_FREQ_400_KHZ permanently for the HTC-Stick !). > >> > >> I can test the HVR-930C next week. > > Ok, I finally had the chance to test with a HVR-930C, but it seems my > device () is different. > It has no slave device at i2c address 0x82, so I can't test this part. > Btw, which slave device is this ? > > Removing the temporary switches to bus A makes no difference (as expected). > > > There are some things there on the init sequence that can be > > cleaned/removed. Those sequences generally comes from observing > > what the original driver does. While it produces a working driver, > > in general, it is not optimized and part of the init sequence can > > be removed. > > Do you want me to send patches to remove these writes ? > Which i2c speed settings do you suggest for the HVR-930C and the > HTC-Stick (board settings: > EM28XX_I2C_FREQ_400_KHZ, code overwrites it with EM28XX_I2C_FREQ_100_KHZ) ? Sure. The better would be to even remove the hauppauge_hvr930c_init() function, as this is just a hack, and use the setup via the em28xx-cards commented entries: .tuner_type = TUNER_XC5000, .tuner_addr = 0x41, .dvb_gpio = hauppauge_930c_digital, .tuner_gpio = hauppauge_930c_gpio, Regards, Mauro -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
