Hi Sean, On Thu, 27 Jan 2022 at 08:43, Sean Anderson <sean...@gmail.com> wrote: > > On 1/27/22 10:05 AM, Simon Glass wrote: > > Hi Sean, > > > > On Sat, 15 Jan 2022 at 15:25, Sean Anderson <sean...@gmail.com> wrote: > >> > >> When freeing a clock there is not much we can do if there is an error, and > >> most callers do not actually check the return value. Even e.g. checking to > >> make sure that clk->id is valid should have been done in request() in the > >> first place (unless someone is messing with the driver behind our back). > >> Just return void and don't bother returning an error. > >> > >> Signed-off-by: Sean Anderson <sean...@gmail.com> > >> --- > >> > >> drivers/clk/clk-uclass.c | 7 +++---- > >> drivers/clk/clk_sandbox.c | 6 +++--- > >> include/clk-uclass.h | 8 +++----- > >> 3 files changed, 9 insertions(+), 12 deletions(-) > >> > > > > We have the same thing in other places too, but I am a little worried > > about removing error checking. We try to avoid checking arguments too > > much in U-Boot, due to code-size concerns, so I suppose I agree that > > an invalid clk should be caught by a debug assertion rather than a > > full check. But with driver model we have generally added an error > > return to every uclass method, for consistency and to permit returning > > error information if needed. > > > > Regards, > > Simon > > > > So there are a few reasons why I don't think a return value is useful > here. To illustrate this, consider a typical user of the clock API: > > struct clk a, b; > > ret = clk_get_by_name(dev, "a", &a); > if (ret) > return ret; > > ret = clk_get_by_name(dev, "b", &b); > if (ret) > goto free_a; > > ret = clk_set_rate(&a, 5000000); > if (ret) > goto free_b; > > ret = clk_enable(&b); > > free_b: > clk_free(&b); > free_a: > clk_free(&a); > return ret; > > - Because a and b are "thick pointers" they do not need any cleanup to > free their own resources. The only cleanup might be if the clock > driver has allocated something in clk_request (more on this below) > - By the time we call clk_free, the mutable portions of the function > have already completed. In effect, the function has succeeded, > regardless of whether clk_free fails. Additionally, we cannot take any > action if it fails, since we still have to free both clocks. > - clk_free occurs during the error path of the function. Even if it > errored, we do not want to override the existing error from one of the > functions doing "real" work. > > The last thing is that no clock driver actually does anything in rfree. > The only driver with this function is the sandbox driver. I would like > to remove the function altogether. As I understand it, the existing API > is inspired by the reset drivers, so I would like to review its usage in > the reset subsystem before removing it for the clock subsystem. I also > want to make some changes to how rates and enables/disables are > calculated which might provide a case for rfree. But once that is > complete I think there will be no users still.
What does this all look like in Linux? Regards, Simon