On Fri, Feb 28, 2025 at 12:13:00AM +0900, William Breathitt Gray wrote: > On Thu, Feb 27, 2025 at 03:37:28PM +0100, Alexandre Belloni wrote: > > On 27/02/2025 23:22:36+0900, William Breathitt Gray wrote: > > > Skimming through the driver, it looks like what we'll need is for > > > mchp_tc_counts[] to have all three TCCs defined, then have > > > mchp_tc_probe() match on a TCB node and configure each TCC. Once that's > > > setup, then whenever we need to identify which TCC a callback is > > > exposing, we can get it from count->id. > > > > > > So for example, the TC_CV register offset is calculated as 0x00 + > > > channel * 0x40 + 0x10. In the count_read() callback we can leverage > > > count->id to identify the TCC and thus get the respective TC_CV register > > > at offset + count->id * 0x40 + 0x10. > > > > > > > We can't do that because the TCC of a single TCB can have a mix of > > different features. I struggled with the breakage to move away from the > > one TCB, one feature state we had. > > Be fore this, it was not possible to mix features on a single TCB, now, > > we can have e.g. the clocksource on TCC 0 and 1 of TCB0 and a PWM on > > TCC 2. mchp_tc_probe must not match on a TCB node... > > Okay I see what you mean, if we match on a TCB mode then we wouldn't be > able to define the cases where one TCC is different from the next in the > same TCB. > > The goal however isn't to support all functionality (i.e. PWM-related > settings, etc.) in the counter driver, but just expose the TCB > configuration options that affect the TCCs when configured for counter > mode. For example, the sysfs attributes can be created, but they don't > have to be available until the TCC is in the appropriate mode (e.g. > return -EBUSY until they are in a counter mode). > > Is there a way to achieve that? Maybe there's a way we can populate the > sysfs tree on the first encountered TCC, and then somehow indicate when > additional TCCs match. Attributes can become available then dynamically > based on the TCCs that match. > > William Breathitt Gray Sorry, let me step back for a moment because maybe I'm trying to solve a problem that might not actually be a problem. I see functionality settings available in the TC Block Mode Register (BMR) that can affect multiple TCCs at a time. Are these BMR settings exposed already to users in someway? If not, do we have a way to introduce these settings if someone wants them; e.g. would the AutoCorrection function enable bit be exposed as a sysfs attribute, or configured in the devicetree? Finally, if there's not much interest in general for exposing these BMR settings, then I suppose there is no need to change how things are right now with the microchip-tcb-capture module and we can just keep it the way it is. That's my only concern, whether there are users that want to control these settings but don't have a way right now. William Breathitt Gray
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