Messages in this thread | | | Date | Wed, 5 Jun 2013 14:28:48 +0300 | From | Grygorii Strashko <> | Subject | Re: [PATCH 1/2] i2c: omap: convert to module_platform_driver() |
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On 06/04/2013 09:29 PM, Kevin Hilman wrote: > Grygorii Strashko <grygorii.strashko@ti.com> writes: > >> Hi Kevin, >> On 06/03/2013 11:59 PM, Kevin Hilman wrote: >>> Grygorii Strashko <grygorii.strashko@ti.com> writes: >>> >>>> The OMAP I2C driver has a relation to pinctrl-single driver. As result, >>>> its probe will be deferred during system boot until late init time, >>>> because the pinctrl-single is initizalized as moudle/device init time. >>>> This, in turn, will delay initialization of all I2C devices (like mfd, >>>> I2C regulators and etc.) and cause boot delay (more over, it can broken >>>> initialization of drivers which are not ready to use deferred probe >>>> mechanism yet, for example DSS). >>>> >>>> There are no sense to keep OMAP I2C initialization on subsys init layer >>>> any more, hence shift it to module/device layer where the i2c <--> >>>> pinctrl-single dependency is resolved in drivers/Makefile now. >>>> >>>> Cc: Wolfram Sang <wsa@the-dreams.de> >>>> Cc: "Ben Dooks (embedded platforms)" <ben-linux@fluff.org> >>>> Cc: Santosh Shilimkar <santosh.shilimkar@ti.com> >>>> Cc: linux-omap@vger.kernel.org >>>> Cc: linux-i2c@vger.kernel.org >>>> Cc: linux-kernel@vger.kernel.org >>>> >>>> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> >>> Testing this patch with PATCH 1/2, the twl_rtc driver fails to correctly >>> initialize on OMAP3: >>> >>> twl_rtc rtc.22: hctosys: invalid date/time >>> >>> instead of the expected result: >>> >>> twl_rtc rtc.22: setting system clock to 2000-01-01 00:00:00 UTC (946684800) >>> >>> so something is still not right for the init sequence. >>> >>> Kevin >> I think, the root cause of the problem isn't this patch - it's just >> yet another side effect >> of using deferred probes :). I've taken a look on twl-rtc code and >> found possible error place >> static int __init twl_rtc_init(void) >> { >> if (twl_class_is_4030()) <------ here, >> rtc_reg_map = (u8 *) twl4030_rtc_reg_map; >> else >> rtc_reg_map = (u8 *) twl6030_rtc_reg_map; >> >> return platform_driver_register(&twl4030rtc_driver); >> } >> In drivers/Makefile: >> obj-$(CONFIG_RTC_LIB) += rtc/ <------ RTC is placed before I2C >> obj-y += i2c/ media/ <----- and only here I2C bus >> instantiates TWL-core device >> and configures twl_priv->twl_id >> >> Thats why it's working on my OMAP4/twl6030 board. Could you check if >> below fix will work on OMAP3: > Yes, your fix works. Thanks for digging into it. > > Care to send a proper patch? Please be sure to send to Andrew Morton > also, since he'll be the one to queue the RTC patch. Hi Kevin,
The similar patch already exists: https://patchwork.kernel.org/patch/2448251/ - [v2,1/2] RTC: rtc-twl: Fix rtc_reg_map initialization from Peter Ujfalusi
-grygorii
> >> diff --git a/drivers/rtc/rtc-twl.c b/drivers/rtc/rtc-twl.c >> index 8751a52..aaa5015 100644 >> --- a/drivers/rtc/rtc-twl.c >> +++ b/drivers/rtc/rtc-twl.c >> @@ -469,6 +469,11 @@ static int twl_rtc_probe(struct platform_device *pdev) >> if (irq <= 0) >> goto out1; >> >> + if (twl_class_is_4030()) >> + rtc_reg_map = (u8 *) twl4030_rtc_reg_map; >> + else >> + rtc_reg_map = (u8 *) twl6030_rtc_reg_map; >> + >> ret = twl_rtc_read_u8(&rd_reg, REG_RTC_STATUS_REG); >> if (ret < 0) >> goto out1; >> @@ -610,11 +615,6 @@ static struct platform_driver twl4030rtc_driver = { >> >> static int __init twl_rtc_init(void) >> { >> - if (twl_class_is_4030()) >> - rtc_reg_map = (u8 *) twl4030_rtc_reg_map; >> - else >> - rtc_reg_map = (u8 *) twl6030_rtc_reg_map; >> - >> return platform_driver_register(&twl4030rtc_driver); >> } >> module_init(twl_rtc_init); >> >> Unfortunately, I have no OMAP3 HW and can't check it. > I suggest you find a Beagle or Gumstix/Overo type board someplace. > There is an abundance of cheap OMAP3 hardware available. > > Kevin >
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