Re: [PATCH v3 3/5] clk: add support for clocks provided by SCP(System Control Processor)

[Sudeep Holla]

On 04/06/15 21:20, Stephen Boyd wrote:
> On 05/27, Sudeep Holla wrote:
> > +
> > +#include <linux/clk-provider.h>
> > +#include <linux/device.h>
> > +#include <linux/err.h>
> > +#include <linux/of.h>
> > +#include <linux/module.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/scpi_protocol.h>
> > +
> > +struct scpi_clk {
> > +	u32 id;
> > +	const char *name;
> > +	struct clk_hw hw;
> > +	struct scpi_dvfs_info *info;
> > +	unsigned long rate_min;
> > +	unsigned long rate_max;
> > +};
> > +
> > +#define to_scpi_clk(clk) container_of(clk, struct scpi_clk, hw)
> > +
> > +static struct scpi_ops *scpi_ops;
>
> Why do we need this singleton? Can we put this pointer into scpi_clk?

Yes I will move it.

> > +
> > +static unsigned long scpi_clk_recalc_rate(struct clk_hw *hw,
> > +					  unsigned long parent_rate)
> > +{
> > +	struct scpi_clk *clk = to_scpi_clk(hw);
> > +
> > +	return scpi_ops->clk_get_val(clk->id);
> > +}
> > +
> > +static long scpi_clk_round_rate(struct clk_hw *hw, unsigned long rate,
> > +				unsigned long *parent_rate)
> > +{
> > +	struct scpi_clk *clk = to_scpi_clk(hw);
> > +
> > +	if (WARN_ON(clk->rate_min && rate < clk->rate_min))
> > +		rate = clk->rate_min;
> > +	if (WARN_ON(clk->rate_max && rate > clk->rate_max))
> > +		rate = clk->rate_max;
> > +
> > +	return rate;
> > +}
>
> Hm.. this seems really generic. It might be better to support a
> way to tell the framework to limit the min/max rate that's
> accepted for a clk. That could be done later though.

True, framework have some boundary checks in place. I will check if
I can use it with minimum changes to the core. If not, we can take this
up later as you suggested.

> > +
> > +static int scpi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> > +			     unsigned long parent_rate)
> > +{
> > +	struct scpi_clk *clk = to_scpi_clk(hw);
> > +
> > +	return scpi_ops->clk_set_val(clk->id, rate);
> > +}
> > +
> [..]
> > +
> > +static int scpi_clk_add(struct device *dev, struct device_node *np)
> > +{
> > +	struct clk **clks;
> > +	int idx, count;
> > +	struct clk_onecell_data *clk_data;
> > +
> > +	count = of_property_count_strings(np, "clock-output-names");
> > +	if (count < 0) {
> > +		dev_err(dev, "%s: invalid clock output count\n", np->name);
> > +		return -EINVAL;
> > +	}
> > +
> > +	clk_data = devm_kmalloc(dev, sizeof(*clk_data), GFP_KERNEL);
> > +	if (!clk_data)
> > +		return -ENOMEM;
> > +
> > +	clks = devm_kcalloc(dev, count, sizeof(*clks), GFP_KERNEL);
> > +	if (!clks)
> > +		return -ENOMEM;
> > +
> > +	for (idx = 0; idx < count; idx++) {
> > +		struct scpi_clk *sclk;
> > +		u32 val;
> > +
> > +		sclk = devm_kzalloc(dev, sizeof(*sclk), GFP_KERNEL);
> > +		if (!sclk)
> > +			return -ENOMEM;
> > +
> > +		if (of_property_read_string_index(np, "clock-output-names",
> > +						  idx, &sclk->name)) {
> > +			dev_err(dev, "invalid clock name @ %s\n", np->name);
> > +			return -EINVAL;
> > +		}
> > +
> > +		if (of_property_read_u32_index(np, "clock-indices",
> > +					       idx, &val)) {
> > +			dev_err(dev, "invalid clock index @ %s\n", np->name);
> > +			return -EINVAL;
> > +		}
> > +
> > +		sclk->id = val;
> > +
> > +		clks[idx] = scpi_clk_ops_init(dev, np, sclk);
> > +		if (IS_ERR_OR_NULL(clks[idx]))
> > +			dev_err(dev, "failed to register clock '%s'\n",
> > +				sclk->name);
> > +		else
> > +			dev_dbg(dev, "Registered clock '%s'\n", sclk->name);
> > +	}
> > +
> > +	clk_data->clks = clks;
> > +	clk_data->clk_num = idx;
> > +	of_clk_add_provider(np, of_clk_src_onecell_get, clk_data);
>
> And if of_clk_add_provider() fails?

Ah, my bad, will fix it.

Regards,
Sudeep
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/