On 08/11/2017 at 14:02:31 +0530, Keerthy wrote: > > > On Wednesday 08 November 2017 02:01 PM, Keerthy wrote: > > > > > > On Wednesday 08 November 2017 01:51 PM, Alexandre Belloni wrote: > >> On 08/11/2017 at 13:36:15 +0530, Keerthy wrote: > >>> > >>> > >>> On Wednesday 08 November 2017 12:46 PM, Alexandre Belloni wrote: > >>>> On 08/11/2017 at 12:38:05 +0530, Keerthy wrote: > >>>>> > >>>>> > >>>>> On Wednesday 08 November 2017 11:57 AM, Alexandre Belloni wrote: > >>>>>> Hi, > >>>>>> > >>>>>> On 08/11/2017 at 11:30:45 +0530, Keerthy wrote: > >>>>>>>>>> +static int omap_rtc_scratch_read(void *priv, unsigned int offset, void *_val, > >>>>>>>>>> + size_t bytes) > >>>>>>>>>> +{ > >>>>>>>>>> + struct omap_rtc *rtc = priv; > >>>>>>>>>> + u32 *val = _val; > >>>>>>>>>> + int i; > >>>>>>>>>> + > >>>>>>>>>> + for (i = 0; i < bytes / 4; i++) > >>>>>>>>>> + val[i] = rtc_readl(rtc, > >>>>>>>>>> + OMAP_RTC_SCRATCH0_REG + offset + (i * 4)); > >>>>>>> > >>>>>>> Can the offset be the Scratch register number instead of bytes offset? > >>>>>>> More intuitive to me. > >>>>>>> > >>>>>>> So that one can request using offset as 0, 1, 2 instead of 0, 4, 8? > >>>>>>> > >>>>>> > >>>>>> Well, the offset is coming from the nvmem core, itself getting it from > >>>>>> the Linux file API (and it is in bytes). However, you have the guarantee > >>>>>> that it will be aligned on a word, see: > >>>>>> http://elixir.free-electrons.com/linux/latest/source/drivers/nvmem/core.c#L88 > >>>>> > >>>>> Okay Alexandre. Thanks for clarifying. Looks good to me. > >>>>> I have tested on AM437X-GP-EVM. > >>>>> > >>>> > >>>> If needed, you can define nvmem cells (and I guess that is what you > >>>> want): > >>>> http://elixir.free-electrons.com/linux/latest/source/Documentation/devicetree/bindings/nvmem/nvmem.txt > >>> > >>> With this patch we cannot still use nvmem_device_write and > >>> nvmem_device_read as the nvmem_device is still not registered. > >>> > >>> How can a driver write to scratch pad registers? Should we be calling > >>> nvmem_register in the probe? > >> > >> It is not needed, it is registered by rtc_nvmem_register(). > > > > Let me go through the chain: > > > > rtc_register_device -> __rtc_register_device --> rtc_nvmem_register -> > > rtc_nvram_register > > > > I am seeing that for rtc-omap driver there is rtc_register_device call > > I mean there NO rtc_register_device call. > > > and i see that rtc_nvmem_register is not getting called. > > > > Should we add rtc_register_device in probe of rtc-omap? > > Do you also have that patch: https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux.git/commit/?h=rtc-next&id=57072758623fa4f3019bce65e2b00f24af8dfdd7 ? > >> > >> nvmem_device_read/write are working because that is what I'm using to > >> implement the old sysfs ABI with rtc_nvram_read/write. > >> -- Alexandre Belloni, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- 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