On 21-01-20 16:50:01, Sascha Hauer wrote: > On Wed, Jan 20, 2021 at 05:28:13PM +0200, Abel Vesa wrote: > > On 21-01-20 16:13:05, Sascha Hauer wrote: > > > Hi Abel, > > > > > > On Wed, Jan 20, 2021 at 04:44:54PM +0200, Abel Vesa wrote: > > > > On 21-01-18 08:00:43, Adam Ford wrote: > > > > > On Mon, Jan 18, 2021 at 6:52 AM Abel Vesa <abel.v...@nxp.com> wrote: > > > > ... > > > > > > > > > > > > > > > > > > > TBH, I'm against the idea of having to call consumer API from a > > > > > > clock provider driver. > > > > > > I'm still investigating a way of moving the uart clock control > > > > > > calls in drivers/serial/imx, > > > > > > where they belong. > > > > > > > > > > That makes sense. > > > > > > > > > > > > > Just a thought. The uart clock used for console remains on from u-boot, > > > > so maybe it's enough to just add the CLK_IGNORE_UNUSED flag to all the > > > > uart root clocks and remove the prepare/enable calls for uart clocks > > > > for good. I don't really have a way to test it right now, but maybe > > > > you could give it a try. > > > > > > That would mean that UART clocks will never be disabled, regardless of > > > whether they are used for console or not. That doesn't sound very > > > appealing. > > > > AFAIK, the only uart clock that is enabled by u-boot is the one used for > > the console. Later on, when the serial driver probes, it will enable it > > itself. > > > > Unless I'm missing something, this is exactly what we need. > > It might enable it, but with CLK_IGNORE_UNUSED the clock won't be > disabled again when a port is closed after usage
OK, tell me what I'm getting wrong in the following scenario: U-boot leaves the console uart clock enabled. All the other ones are disabled. Kernel i.MX clk driver registers the uart clocks with flag CLK_IGNORE_UNUSED. Serial driver probes, then enables/disables the clocks when the port opens/closes. The clk_disable_unused will ignore the uart clocks entirely due to the flag.
