Re: [PATCH v5 4/4] clk: bd71837: Add driver for BD71837 PMIC clock

From: Matti Vaittinen
Date: Fri Aug 03 2018 - 04:09:27 EST


On Tue, Jul 31, 2018 at 11:28:58AM +0300, Matti Vaittinen wrote:
> On Tue, Jun 26, 2018 at 11:13:19AM +0300, Matti Vaittinen wrote:
> > On Mon, Jun 25, 2018 at 04:44:57PM -0700, Stephen Boyd wrote:
> > > Quoting Matti Vaittinen (2018-06-12 01:23:54)
> > > > On Tue, Jun 12, 2018 at 12:44:11AM -0700, Stephen Boyd wrote:
> > > > > Quoting Matti Vaittinen (2018-06-04 06:19:13)

[snip]

>
> > 3. Create devm_of_clk_add_hw_provider_w_node() which does something
>

After giving this second thought - I think there is limited amount of
use cases where other than own or parent nodes should be used. Actually,
the MFD node being parent is pretty much only use case I can think of
where something else but own node should be used. Hence function like
suggested devm_of_clk_add_hw_provider_w_node might invite thinking of
clever hacks... So, perhaps introducing
devm_of_clk_add_hw_provider_parent() (see idea below) would be option to
consider? I feel the bd71837 driver is not only case where MFD is being
parent which has the clock stuff in DT.

static int __devm_of_clk_add_hw_provider(struct device *dev,
struct clk_hw *(*get)(struct of_phandle_args *clkspec, void *data),
struct device_node *of_node, void *data)
{
struct device_node **ptr;
int ret;
ptr = devres_alloc(devm_of_clk_release_provider, sizeof(*ptr),
GFP_KERNEL);
if (!ptr)
return -ENOMEM;

*ptr = of_node;
ret = of_clk_add_hw_provider(of_node, get, data);
if (!ret)
devres_add(dev, ptr);
else
devres_free(ptr);
return ret;
}

int devm_of_clk_add_hw_provider(struct device *dev,
struct clk_hw *(*get)(struct of_phandle_args *clkspec, void *data),
void *data)
{
return __devm_of_clk_add_hw_provider(dev, get, dev->of_node, data);
}
EXPORT_SYMBOL_GPL(devm_of_clk_add_hw_provider);

int devm_of_clk_add_hw_provider_parent(struct device *dev,
struct clk_hw *(*get)(struct of_phandle_args *clkspec, void *data),
void *data)
{
return __devm_of_clk_add_hw_provider(*dev, get, dev->parent->of_node,
data);
}
EXPORT_SYMBOL_GPL(devm_of_clk_add_hw_provider_parent);

> just a friendly reminder, what's your opinion on adding this kind of
> function (devm_of_clk_add_hw_provider_w_node)? or solutions 1/2? And are
> these options safe what comes to reference counting of of_nodes?

I thik the reference counting should not be a problem when use is
limited to (MFD) parent device nodes, right?

Best regards
Matti Vaittinen