Hi Sascha,
On 4 March 2015 at 19:21, Sascha Hauer s.hauer@pengutronix.de wrote:
On Wed, Mar 04, 2015 at 06:49:11PM +0800, pi-cheng.chen wrote:
This patch adds CPU mux clocks which are used by Mediatek cpufreq driver for intermediate clock source switching. This patch is based on Mediatek clock driver patches[1].
[1] http://thread.gmane.org/gmane.linux.kernel/1892436
Signed-off-by: pi-cheng.chen pi-cheng.chen@linaro.org
+static long clk_cpumux_determine_rate(struct clk_hw *hw, unsigned long rate,
unsigned long min_rate,
unsigned long max_rate,
unsigned long *best_parent_rate,
struct clk_hw **best_parent_p)
+{
struct clk *clk = hw->clk, *parent;
unsigned long parent_rate;
int i;
for (i = MAINPLL_INDEX; i >= ARMPLL_INDEX; i--) {
parent = clk_get_parent_by_index(clk, i);
if (!parent)
return 0;
if (i == MAINPLL_INDEX) {
parent_rate = __clk_get_rate(parent);
if (parent_rate == rate)
break;
}
parent_rate = __clk_round_rate(parent, rate);
}
*best_parent_rate = parent_rate;
*best_parent_p = __clk_get_hw(parent);
return parent_rate;
+}
Why this determine_rate hook? If you want to switch the clock to some intermediate parent I would assume you do this explicitly by setting the parent and not implicitly by setting a rate.
I use determine_rate hook here because I am using generic cpufreq-dt driver and I want to make clock switching transparent to cpufreq-dt. I.e. when I am trying to switch the clock from ARMPLL to MAINPLL, I call clk_set_rate() with the rate of MAINPLL, and determine_rate will select MAINPLL as the new parent.
+int mtk_clk_register_cpumuxes(struct device_node *node,
struct mtk_composite *clks, int num,
struct clk_onecell_data *clk_data)
+{
int i;
struct clk *clk;
struct regmap *regmap;
if (!clk_data)
return -ENOMEM;
regmap = syscon_node_to_regmap(node);
if (IS_ERR(regmap)) {
pr_err("Cannot find regmap for %s: %ld\n", node->full_name,
PTR_ERR(regmap));
return PTR_ERR(regmap);
}
for (i = 0; i < num; i++) {
struct mtk_composite *mux = &clks[i];
clk = mtk_clk_register_cpumux(mux->name, mux->parent_names,
mux->num_parents, regmap,
mux->mux_reg, mux->mux_shift,
mux->mux_width);
Pass 'mux' directly instead of dispatching this struct into the individual fields. Also, probably better to move this function to drivers/clk/mediatek/clk-cpumux.c
Will do it. Thanks for reviewing.
Best Regards, Pi-Cheng
Sascha
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