On Tue, Nov 24, 2020 at 09:59:49AM +0800, Alice Guo wrote: > Directly reading ocotp register depends on that bootloader enables ocotp > clk, which is not always effective, so change to use nvmem API. Using > nvmem API requires to support driver defer probe and thus change > soc-imx8m.c to use platform driver. > > The other reason is that directly reading ocotp register causes kexec > kernel hang because the 1st kernel running will disable unused clks > after kernel boots up, and then ocotp clk will be disabled even if > bootloader enables it. When kexec kernel, ocotp clk needs to be enabled > before reading ocotp registers, and nvmem API with platform driver > supported can accomplish this. > > Signed-off-by: Alice Guo <alice.guo@xxxxxxx> I already reviewed it. You skipped all my review tags from v5. Reviewed-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx> Best regards, Krzysztof > --- > > v2: remove the subject prefix "LF-2571-4" > v3: Keep the original way which uses device_initcall to read soc unique > ID, and add the other way which uses module_platform_driver and > nvmem API, so that it will not break the old version DTBs. > v4: delete "__maybe_unused" > delete MODULE_DEVICE_TABLE(of, imx8m_soc_match); > rename match table, "fsl,imx8mm/n/q/p" is actually a machine > compabile and "fsl,imx8mm/n/q/p-soc" is a compabile of soc@0 > delete "flag" and change to determine whether the pointer is NULL > ues of_find_matching_node_and_match() > delete of_match_ptr() > v5: add cleanup part "of_node_put" > add note to explain that why device_initcall still exists > v6: none
