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

Michael Turquette
2018-05-30T19:46:11Z

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