Hi Sakari, On 22-09-19, Sakari Ailus wrote: ... > > > > + ret = clk_prepare_enable(mt9m111->clk); > > > > + if (ret < 0) > > > > + return ret; > > > > + > > > > + extclk_rate = clk_get_rate(mt9m111->clk); > > > > + clk_disable_unprepare(mt9m111->clk); > > > > > > I don't think you'll need to enable a clock to just get its frequency. > > > > The official API states that you need to turn on the clk before > > requesting it and it makes sense. Also there is a new helper > > devm_clk_get_enabled() which addresses simple clk usage since most of > > drivers don't enable it before requesting the rate. > > I guess the rate could change in the meantime, unless exclusive access is > requested. Not only that, there are a bunch of clk provider hw around which may need to turned on first. Anyway, I really don't care on this topic. As I said I wanted to fullfil the API and if drop clk_prepare_enable() I don't. So if this okay for you I will go that way. > The clock framework currently doesn't offer a way to set the assigned > rate and prevent changing it. But above, couldn't the clock frequency > be changed again once the clock has been disabled? Yes it could. Regards, Marco
