[PATCH] microblaze: Add AXI GPIO driver

[Gedare Bloom]

On Wed, Mar 16, 2022 at 10:25 AM Alex White <alex.white at oarcorp.com> wrote:
>
> On Wed, Mar 16, 2022 at 10:27 AM Gedare Bloom <gedare at rtems.org> wrote:
> >
> > On Tue, Mar 15, 2022 at 2:28 PM Alex White <alex.white at oarcorp.com> wrote:
> > >
> > > ---
> > >  bsps/include/dev/gpio/xilinx-axi-gpio.h       | 311 ++++++++++++++++++
> > >  bsps/shared/dev/gpio/xilinx-axi-gpio.c        | 221 +++++++++++++
> >
> > Is this AXI GPIO interface consistent across Xilinx IP?
>
> Hi Gedare,
>
> Thanks for taking a look at this.
>
> As long as the Xilinx AXI GPIO v2.0 IP is being used, this interface
> should be usable across any platform.
>
> I realize now that there is an older v1.0 AXI GPIO IP so it would be
> wise to specify which version is being supported somewhere.
>
>
> > > +  /*
> > > +   * IP Interrupt Enable Register
> > > +   *
> > > +   * Provides the ability to independtly control whether interrupts for each
> > typo: independently
>
> Will fix.
>
> >
> > > +   * channel are enabled or disabled.
> > > +   *
> > > +   * 0 - No Channel input interrupt
> > > +   * 1 - Channel input interrupt
> > > +   */
> > > +  uint32_t ip_ier;
> > > +} xilinx_axi_gpio;
> >
> > This `xilinx_` is not a proper namespace for RTEMS. it doesn't
> > correspond with any existing components and so it requires some
> > discussion and approval to introduce it.
>
> I used the same struct naming scheme as is used in bsps/include/dev/spi/xilinx-axi-spi-regs.h.
>
> I guess this is different because it is exposed in the user-facing api?
>
> >
> > > +
> > > +typedef struct {
> > > +  volatile xilinx_axi_gpio *regs;
> > > +  bool                      is_dual;
> > > +  uint32_t                  irq;
> > > +  bool                      has_interrupts;
> > > +} xilinx_axi_gpio_context;
> > > +
> > > +/**
> > > + * @brief Set pin configuration for the specified GPIO channel.
> > > + *
> > > + * Changes the pin configuration for a channel. Bits set to 0 are output, and
> > > + * bits set to 1 are input.
> > > + *
> > > + * @param[in] ctx the GPIO context
> > > + * @param[in] channel the GPIO channel
> > > + * @param[in] mask the mask to be applied to @ channel
> > > + *
> > > + * @retval None
> > > + */
> > > +void axi_gpio_set_data_direction(
> >
> > neither is this `axi_`
>
> I realize now that this makes less sense than something like
> `xilinx_axi_gpio_set_data_direction` assuming the context struct name
> above was accepted.
>
> >
> > > +  xilinx_axi_gpio_context *ctx,
> >
> > Mixing the newly proposed namespaces is also confusing.
>
> I agree.
>
> What would make this easiest? Should I start a new thread on Xilinx AXI
> peripheral driver naming in the shared namespace?
>
Yes, that will be best.

> Thanks,
>
> Alex