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

From: David Lechner
Date: Wed May 30 2018 - 15:59:09 EST


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@xxxxxxxx

Best regards,
Mike


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