Hi Krzysztof, On Friday, June 9th, 2023 at 7:29 PM, Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> wrote: > > > Why do you need these checks? This should be called in correct context, > > > so when regulator is valid and enabled. If you have such checks it > > > suggests that code is buggy and this is being called in wrong contexts. > > > > First condition !IS_ERR(pvdd) is to check if pvdd exists. > > Some devices, msm8916-samsung-serranove for example, doesn't need pvdd or > > have it bound in the device tree: > > > If regulator is missing you should get a dummy. > > But anyway the code will not be executed if you don't get proper regulator. > The current patch set is using devm_regulator_get_optional() instead of devm_regulator_get(), which doesn't get a dummy regulator. > > https://github.com/torvalds/linux/commit/ab0f0987e035f908d670fed7d86efa6fac66c0bb > > > > Without !IS_ERR(pvdd), checking it with regulator_is_enabled(pvdd): > > > > [ 50.161882] 8<--- cut here --- > > [ 50.161906] Unable to handle kernel paging request at virtual address fffffff9 when read > > [ 50.161916] [fffffff9] *pgd=affff841, *pte=00000000, *ppte=00000000 > > [ 50.161938] Internal error: Oops: 27 [#1] PREEMPT SMP ARM > > > > Or disabling it directly with regulator_disable(pvdd): > > > > [ 69.439827] 8<--- cut here --- > > [ 69.439841] Unable to handle kernel NULL pointer dereference at virtual address 00000045 when read > > [ 69.439852] [00000045] *pgd=00000000 > > [ 69.439864] Internal error: Oops: 5 [#1] PREEMPT SMP ARM > > > > Second condition regulator_is_enabled(pvdd) is to make sure that pvdd is > > disabled with balance. > > > So you have buggy code and to hide the bug you add checks? No, make the > code correct so the check is not needed. > Do you mean that I should use devm_regulator_get() instead in order to get a dummy regulator, so that it can disable pvdd without unnecessary checks? Actually there is v4 with those buggy codes and checks dropped. Please do let me know if I am understanding and doing it correctly. I would send it after proper period of cooldown. Regards, Raymond
