Re: [PATCH 6/9] clk: davinci: pll: allow dev == NULL

David Lechner
2018-05-30T19:59:08Z

On 05/30/2018 02:46 PM, Michael Turquette wrote:
> Hi David,
>
> Quoting David Lechner (2018-05-25 11:11:47)
>> This modifies the TI Davinci PLL clock driver to allow for the case
>> when dev == NULL. On some (most) SoCs that use this driver, the PLL
>> clock needs to be registered during early boot because it is used
>> for clocksource/clkevent and there will be no platform device available.
>
> A lot of this stuff feels like a step backwards. E.g:
>
>> diff --git a/drivers/clk/davinci/pll.c b/drivers/clk/davinci/pll.c
>> index 23a24c944f1d..2eb981e61185 100644
>> --- a/drivers/clk/davinci/pll.c
>> +++ b/drivers/clk/davinci/pll.c
>> @@ -11,6 +11,7 @@
>>
>> #include <linux/clk-provider.h>
>> #include <linux/clk.h>
>> +#include <linux/clk/davinci.h>
>> #include <linux/delay.h>
>> #include <linux/err.h>
>> #include <linux/io.h>
>> @@ -223,6 +224,7 @@ static const struct clk_ops dm365_pll_ops = {
>>
>> /**
>> * davinci_pll_div_register - common *DIV clock implementation
>> + * @dev: The PLL platform device or NULL
>> * @name: the clock name
>> * @parent_name: the parent clock name
>> * @reg: the *DIV register
>> @@ -240,17 +242,21 @@ static struct clk *davinci_pll_div_register(struct device *dev,
>> const struct clk_ops *divider_ops = &clk_divider_ops;
>> struct clk_gate *gate;
>> struct clk_divider *divider;
>> + struct clk *clk;
>> + int ret;
>>
>> - gate = devm_kzalloc(dev, sizeof(*gate), GFP_KERNEL);
>> + gate = kzalloc(sizeof(*gate), GFP_KERNEL);
>> if (!gate)
>> return ERR_PTR(-ENOMEM);
>>
>> gate->reg = reg;
>> gate->bit_idx = DIV_ENABLE_SHIFT;
>>
>> - divider = devm_kzalloc(dev, sizeof(*divider), GFP_KERNEL);
>> - if (!divider)
>> - return ERR_PTR(-ENOMEM);
>> + divider = kzalloc(sizeof(*divider), GFP_KERNEL);
>> + if (!divider) {
>> + ret = -ENOMEM;
>> + goto err_free_gate;
>> + }
>>
>> divider->reg = reg;
>> divider->shift = DIV_RATIO_SHIFT;
>
> Oh no my poor devm_ helpers!
>
> I understand that we need to support early boot drivers better, so this
> patch can be merged.
>
> However I'm curious if you're tracking Bartosz's early_platform_driver
> efforts? Converting to that if it is ever merged would likely be
> cleaner:
>
> https://lkml.kernel.org/r/20180511162028.20616-1-brgl@bgdev.pl
>
> Best regards,
> Mike
>

Yes. In fact, this is what got Bartosz working on it in the first
place. :-)