[PATCH 1/2] cpufreq: cpufreq-cpu0: support for clock which are not in DT yet.

From: Nishanth Menon
Date: Mon Mar 11 2013 - 19:05:44 EST


On certain SoCs like variants of OMAP, the clock conversion to DT
is not complete. In short, the ability to:
cpus {
cpu@0 {
clocks = <&cpuclk 0>;
};
};
is not possible. However, the clock node is registered.
Allow for clk names to be provided as string so as to be used when needed.
Example (for OMAP3630):
cpus {
cpu@0 {
clock-name = "cpufreq_ck";
};
};

Cc: "Rafael J. Wysocki" <rjw@xxxxxxx>
Cc: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
Cc: Shawn Guo <shawn.guo@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: cpufreq@xxxxxxxxxxxxxxx
Cc: linux-pm@xxxxxxxxxxxxxxx
Cc: linux-omap@xxxxxxxxxxxxxxx

Signed-off-by: Nishanth Menon <nm@xxxxxx>
---
.../devicetree/bindings/cpufreq/cpufreq-cpu0.txt | 3 +++
drivers/cpufreq/cpufreq-cpu0.c | 6 +++++-
2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-cpu0.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-cpu0.txt
index 4416ccc..f180963 100644
--- a/Documentation/devicetree/bindings/cpufreq/cpufreq-cpu0.txt
+++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-cpu0.txt
@@ -12,6 +12,9 @@ Required properties:
for details

Optional properties:
+- clock-name: If the clock is not converted to device tree, then describe
+ the clock name as a string. This may also be replaced with clocks=<&cpuclk>
+ cpu clocks has already been converted to device tree.
- clock-latency: Specify the possible maximum transition latency for clock,
in unit of nanoseconds.
- voltage-tolerance: Specify the CPU voltage tolerance in percentage.
diff --git a/drivers/cpufreq/cpufreq-cpu0.c b/drivers/cpufreq/cpufreq-cpu0.c
index 4e5b7fb..28223c9 100644
--- a/drivers/cpufreq/cpufreq-cpu0.c
+++ b/drivers/cpufreq/cpufreq-cpu0.c
@@ -180,6 +180,7 @@ static int cpu0_cpufreq_probe(struct platform_device *pdev)
{
struct device_node *np;
int ret;
+ const char *clk_name = NULL;

for_each_child_of_node(of_find_node_by_path("/cpus"), np) {
if (of_get_property(np, "operating-points", NULL))
@@ -194,7 +195,10 @@ static int cpu0_cpufreq_probe(struct platform_device *pdev)
cpu_dev = &pdev->dev;
cpu_dev->of_node = np;

- cpu_clk = devm_clk_get(cpu_dev, NULL);
+ /* If clocks are not in DT yet, allow to define it part of CPU node */
+ of_property_read_string(np, "clock-name", &clk_name);
+
+ cpu_clk = devm_clk_get(cpu_dev, clk_name);
if (IS_ERR(cpu_clk)) {
ret = PTR_ERR(cpu_clk);
pr_err("failed to get cpu0 clock: %d\n", ret);
--
1.7.9.5

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