[PATCH v3 3/5] clk: add support for clocks provided by SCP(System Control Processor)
Sudeep Holla
sudeep.holla at arm.com
Fri Jun 5 02:36:36 PDT 2015
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
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