On Tue, Jan 4, 2011 at 3:16 PM, Yong Shen yong.shen@linaro.org wrote:
In the last several weeks, Jeremy and I reviewed the clock debug code based on common clock struct. In this code, I used below code to expose clock information:
+static int clk_debug_rate_get(void *data, u64 *val) +{
- struct clk *clk = data;
- *val = (u64)clk_get_rate(clk);
- return 0;
+} +DEFINE_SIMPLE_ATTRIBUTE(clk_debug_rate_fops, clk_debug_rate_get, NULL,
- "%llu\n");
.....
- d = debugfs_create_file("rate", S_IRUGO, clk->dentry, (void *)clk,
- &clk_debug_rate_fops);
Therefore, whenever the clock information is accessed, it can reflect the truth, since it calls clk interface like clk_get_rate() to get the right value.
Why is it called clk_debug_rate_get()? Is there not a standard clk_rate_get() that we can use?
There is. clk_get_rate() is called inside this function. By using these lines of code, the purpose is to advocate using functions provided by clock system like clk_rate_get() directly, instead of using variable to store clock information.
I guess I am confused why we don't directly use clk_get_rate() instead of clk_debug_get_rate() in the 'show' call for the sysfs entry.
/Amit