Hi Alexey, On Fri, Mar 6, 2009 at 7:05 AM, Alexey Klimov <klimov.linux@xxxxxxxxx> wrote: > Hello, all > > On Thu, Mar 5, 2009 at 7:42 PM, Curran, Dominic <dcurran@xxxxxx> wrote: >> >> Hi Kim >> >>> -----Original Message----- >>> From: linux-omap-owner@xxxxxxxxxxxxxxx [mailto:linux-omap- >>> owner@xxxxxxxxxxxxxxx] On Behalf Of DongSoo(Nathaniel) Kim >>> Sent: Wednesday, March 04, 2009 8:58 PM >>> To: Aguirre Rodriguez, Sergio Alberto >>> Cc: linux-media@xxxxxxxxxxxxxxx; linux-omap@xxxxxxxxxxxxxxx; Sakari Ailus; >>> Tuukka.O Toivonen; Hiroshi DOYU; MiaoStanley; Nagalla, Hari; Hiremath, >>> Vaibhav; Lakhani, Amish; Menon, Nishanth >>> Subject: Re: [PATCH 4/5] OMAP3430SDP: Add support for Camera Kit v3 >>> >>> Hi Sergio, >>> >>> >>> >>> On Wed, Mar 4, 2009 at 5:44 AM, Aguirre Rodriguez, Sergio Alberto >>> <saaguirre@xxxxxx> wrote: >>> > + /* turn on analog power */ >>> > + twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, >>> > + VAUX_2_8_V, TWL4030_VAUX2_DEDICATED); >>> > + twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, >>> > + VAUX_DEV_GRP_P1, TWL4030_VAUX2_DEV_GRP); >>> > + >>> > + /* out of standby */ >>> > + gpio_set_value(MT9P012_STANDBY_GPIO, 0); >>> > + udelay(1000); >>> >>> It seems better using msleep rather than udelay for 1000us much. Just >>> to be safe :) >>> How about you? >>> >> >> Why is msleep safer than udelay ? > > I have small guess that he is wondering why you are using big delays > with help of udelay(). (It's may be obvious but as we know udelay uses > cpu loops to make delay and msleep calls to scheduler) So, msleep is > more flexible and "softer" but if you need precise time or you can't > sleep in code you need udelay. Sometimes using udelay is reasonably > required. I totally agree with you. But besides the "udelay and mdelay accuracy" issue, Sergio's power up timing for MT9P012 seems to delay too much. (not for lens controller.) I also have experience using MT9P012 sensor with other ISP, but in case of mine it took 600 to 800 ms for whole power up sequence. But if that delay depends on SDP board and Sergio had no options without making delay for that much, then it explains everything. So I'm saying if there was no other option than making long delay to bring up MT9P012 sensor properly, if I were Sergio I should rather use mdelay than udelay. But if that delay is necessary to bring up MT9P012 with SDP board, I have no idea what to say. In that case, Sergio should be right. Cheers, Nate > > -- > Best regards, Klimov Alexey > -- ======================================================== DongSoo(Nathaniel), Kim Engineer Mobile S/W Platform Lab. S/W Team. DMC Samsung Electronics CO., LTD. e-mail : dongsoo.kim@xxxxxxxxx dongsoo45.kim@xxxxxxxxxxx ======================================================== -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
