On Wed, 7 Feb 2024 at 14:46, AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx> wrote: > > Il 07/02/24 12:45, Dmitry Baryshkov ha scritto: > > On Wed, 7 Feb 2024 at 11:08, Abel Vesa <abel.vesa@xxxxxxxxxx> wrote: > >> > >> On 24-02-07 09:23:09, Dmitry Baryshkov wrote: > >>> On Wed, 7 Feb 2024 at 09:19, Abel Vesa <abel.vesa@xxxxxxxxxx> wrote: > >>>> > >>>> On 24-02-07 01:55:39, Dmitry Baryshkov wrote: > >>>>> On Wed, 7 Feb 2024 at 01:34, Abel Vesa <abel.vesa@xxxxxxxxxx> wrote: > >>>>>> > >>>>>> Some newer SPMI controllers support multiple bus masters. > >>>>>> Such a master can control multiple slave devices. The generic > >>>>>> framework needs to be able to pass on the master id to the > >>>>>> controller-specific driver. So do that. The framework will > >>>>>> check if the devicetree child nodes are actually bus masters > >>>>>> and will register the devices for each master. The legacy > >>>>>> approach will still be supported for backwards compatibility. > >>>>> > >>>>> Please remind me, are those two actual bus musters driving a single > >>>>> bus in parallel or two SPMI buses being handled by a single device? In > >>>>> the latter case this implementation is incorrect. There should be > >>>>> multiple spmi_controller instances, one for each bus. Allocate them in > >>>>> a loop and set ctrl->dev.of_node after allocating. > >>>> > >>>> It's two SPMI buses (two sets of wires) handled by the same controller, > >>>> HW-wise. > >>>> > >>>> If we register two spmi controllers with the kernel framework, it will > >>>> be HW inaccurate, because there is just one controller which has > >>>> multiple masters. > >>> > >>> struct spmi_controller is a controller for a single bus. Inside your > >>> device you have two SPMI buses, each can be controlled by its own > >>> struct spmi_controller. Just like devices that control multiple I2C, > >>> SPI or USB busses register a separate instance of the bus controller. > >> > >> Well, this is what this patchset is trying to do in the generic part. > >> The SPMI controller supports multiple buses (HW-wise) and therefore SW > >> implementation shouldn't be tied to single bus requirement. > > > > So, after the off-line discussion: > > - add new compatible string for sm8450+ > > - register two spmi controller instances > > Well, I don't know about the actual hardware that you're trying to implement > but, in my opinion, the "idea" of this series does actually make sense. > > The SPMI specification says that SPMI supports up to 4 masters, and up to > 16 slaves. So, that is my main question: whether this supports multiple masters on a same bus or multiple buses. From the SoC pins description I assume the latter is the case. > > Just my two cents. > > Cheers, > Angelo > > > - drop the master-id from the SPMI interface > > - optionally: think about having a new separate driver for v7 SPMI. > > > >> > >>> > >>>> > >>>> I'm not saying it might not work. But, to me, it looks more like a hack. > >>>> > >>>> Basically, we would be mapping HW bus masters to kernel controllers. > >>> > >>> Buses, not just masters. > >>> > >>>> > >>>>> > >>>>>> > >>>>>> Signed-off-by: Abel Vesa <abel.vesa@xxxxxxxxxx> > >>>>>> --- > >>>>>> drivers/spmi/spmi-mtk-pmif.c | 6 ++-- > >>>>>> drivers/spmi/spmi-pmic-arb.c | 10 +++--- > >>>>>> drivers/spmi/spmi.c | 76 ++++++++++++++++++++++++++++++-------------- > >>>>>> include/linux/spmi.h | 10 +++--- > >>>>>> 4 files changed, 67 insertions(+), 35 deletions(-) > >>>>> > >>>>> -- > >>>>> With best wishes > >>>>> Dmitry > >>> > >>> > >>> > >>> -- > >>> With best wishes > >>> Dmitry > > > > > > > > -- With best wishes Dmitry
