On Tue, Oct 19, 2010 at 05:28:51PM +0800, Yong Shen wrote:
> >
> >
> >
> > > +#include <linux/kernel.h>
> > > +
> > > +static struct cpu_op mx51_cpu_op[] = {
> > > + {
> > > + .cpu_rate = 160000000,},
> > > + {
> > > + .cpu_rate = 800000000,},
> > > +};
> >
> > Why did you remove the values between 800MHz and 160MHz? 400MHz and
> > 200Mhz should work also, no?
> >
> > It proved that those operating points don't work well.
ok
> > > +static struct cpu_op *cpu_op_tbl;
> > > +
> > > +static int set_cpu_freq(int freq)
> > > +{
> > > + int ret = 0;
> > > + int org_cpu_rate;
> > > +
> > > + org_cpu_rate = clk_get_rate(cpu_clk);
> > > + if (org_cpu_rate == freq)
> > > + return ret;
> >
> > You already checked this in mxc_set_target. Once is enough.
> >
>
> Well, this fucntion is not only used in mxc_set_target, so it is safer to
> still keep checking here.
Then you can skip the check in the calling function.
> > > +
> > > +static int __init mxc_cpufreq_init(struct cpufreq_policy *policy)
> > > +{
> > > + int ret;
> > > + int i;
> > > +
> > > + printk(KERN_INFO "i.MXC CPU frequency driver\n");
> > > +
> > > + if (policy->cpu != 0)
> > > + return -EINVAL;
> > > +
> > > + cpu_clk = clk_get(NULL, "cpu_clk");
> > > + if (IS_ERR(cpu_clk)) {
> > > + printk(KERN_ERR "%s: failed to get cpu clock\n", __func__);
> > > + return PTR_ERR(cpu_clk);
> > > + }
> > > +
> > > + cpu_op_tbl = get_cpu_op(&cpu_op_nr);
> >
> > This will crash every board except the babbage board which happens to
> > set this function pointer.
> >
> Add a checking here should avoid that.
indeed
Sascha
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