Re: [PATCH 2/3] pinctrl: Add pincontrol driver for ARTPEC-6 SoC

[Jesper Nilsson <jesper.nilsson@axis.com>]

On Thu, Mar 30, 2017 at 02:07:33PM +0200, Linus Walleij wrote:
> On Thu, Mar 30, 2017 at 1:33 PM, Jesper Nilsson <jesper.nilsson@axis.com> wrote:
> 
> > Add pinctrl driver support for the Axis ARTPEC-6 SoC.
> > There are only some pins that actually have different
> > functions available, but all can control bias (pull-up/-down)
> > and drive strength.
> > Code originally written by Chris Paterson.
> >
> > Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
> 
> Very good start, but look at this:
> 
> > +#define ARTPEC6_PINMUX_P0_0_CTRL       0x000
> > +#define ARTPEC6_PINMUX_P0_1_CTRL       0x004
> > +#define ARTPEC6_PINMUX_P0_2_CTRL       0x008
> > +#define ARTPEC6_PINMUX_P0_3_CTRL       0x00C
> > +#define ARTPEC6_PINMUX_P0_4_CTRL       0x010
> > +#define ARTPEC6_PINMUX_P0_5_CTRL       0x014
> > +#define ARTPEC6_PINMUX_P0_6_CTRL       0x018
> > +#define ARTPEC6_PINMUX_P0_7_CTRL       0x01C
> > +#define ARTPEC6_PINMUX_P0_8_CTRL       0x020
> > +#define ARTPEC6_PINMUX_P0_9_CTRL       0x024
> > +#define ARTPEC6_PINMUX_P0_10_CTRL      0x028
> > +#define ARTPEC6_PINMUX_P0_11_CTRL      0x02C
> > +#define ARTPEC6_PINMUX_P0_12_CTRL      0x030
> > +#define ARTPEC6_PINMUX_P0_13_CTRL      0x034
> > +#define ARTPEC6_PINMUX_P0_14_CTRL      0x038
> > +#define ARTPEC6_PINMUX_P0_15_CTRL      0x03C
> 
> It's pretty clear that the stride is always 4 bytes is it not.

Agreed.

> > +static const unsigned int pin_regs[] = {
> > +       ARTPEC6_PINMUX_P0_0_CTRL,       /* Pin 0 */
> > +       ARTPEC6_PINMUX_P0_1_CTRL,
> > +       ARTPEC6_PINMUX_P0_2_CTRL,
> > +       ARTPEC6_PINMUX_P0_3_CTRL,
> > +       ARTPEC6_PINMUX_P0_4_CTRL,
> > +       ARTPEC6_PINMUX_P0_5_CTRL,
> > +       ARTPEC6_PINMUX_P0_6_CTRL,
> > +       ARTPEC6_PINMUX_P0_7_CTRL,
> > +       ARTPEC6_PINMUX_P0_8_CTRL,
> > +       ARTPEC6_PINMUX_P0_9_CTRL,
> > +       ARTPEC6_PINMUX_P0_10_CTRL,
> > +       ARTPEC6_PINMUX_P0_11_CTRL,
> > +       ARTPEC6_PINMUX_P0_12_CTRL,
> > +       ARTPEC6_PINMUX_P0_13_CTRL,
> > +       ARTPEC6_PINMUX_P0_14_CTRL,
> > +       ARTPEC6_PINMUX_P0_15_CTRL,
> 
> The oceans of redundant information are rising ;)
> 
> > +static const unsigned int uart0_regs0[] = {
> > +       ARTPEC6_PINMUX_P1_0_CTRL,
> > +       ARTPEC6_PINMUX_P1_1_CTRL,
> > +       ARTPEC6_PINMUX_P1_2_CTRL,
> > +       ARTPEC6_PINMUX_P1_3_CTRL,
> > +       ARTPEC6_PINMUX_P1_4_CTRL,
> > +       ARTPEC6_PINMUX_P1_5_CTRL,
> > +       ARTPEC6_PINMUX_P1_6_CTRL,
> > +       ARTPEC6_PINMUX_P1_7_CTRL,
> > +       ARTPEC6_PINMUX_P1_8_CTRL,
> > +       ARTPEC6_PINMUX_P1_9_CTRL,
> > +};
> 
> And rising.

:-)

> > +       {
> > +               .name = "uart0grp0",
> > +               .pins = uart0_pins0,
> > +               .num_pins = ARRAY_SIZE(uart0_pins0),
> > +               .reg_offsets = uart0_regs0,
> > +               .num_regs = ARRAY_SIZE(uart0_regs0),
> > +               .config = ARTPEC6_CONFIG_1,
> > +       },
> 
> So what if the struct artpec6_pin_group...
> 
> > +struct artpec6_pin_group {
> > +       const char         *name;
> > +       const unsigned int *pins;
> > +       const unsigned int num_pins;
> > +       const unsigned int *reg_offsets;
> > +       const unsigned int num_regs;
> > +       unsigned char      config;
> > +};
> 
> Instead of reg_offsets had reg_offset_base, and you just
> calculate it with base + pin * 4 when you need it?

Yes, that would be much clearer.

> I also highly suspect that num_pins and num_regs above
> are exactly the same number in all cases, correct? You
> probably only need num_pins.

Agreed.

> > +static struct artpec6_pmx_func artpec6_pmx_functions[] = {
> 
> Needs const
> 
> > +static void artpec6_pmx_select_func(struct pinctrl_dev *pctldev,
> > +                                   unsigned int function, unsigned int group,
> > +                                   bool enable)
> > +{
> > +       unsigned int regval, val;
> > +       int i;
> > +       const unsigned int *pmx_regs;
> > +       struct artpec6_pmx *pmx = pinctrl_dev_get_drvdata(pctldev);
> > +
> > +       pmx_regs = artpec6_pin_groups[group].reg_offsets;
> > +
> > +       for (i = 0; i < artpec6_pin_groups[group].num_regs; i++) {
> > +               /* Ports 4-8 do not have a SEL field and are always selected */
> > +               if (pmx_regs[i] >= ARTPEC6_PINMUX_P4_0_CTRL)
> > +                       continue;
> > +
> > +               if (!strcmp(artpec6_pmx_get_fname(pctldev, function), "gpio")) {
> > +                       /* GPIO is always config 0 */
> > +                       val = ARTPEC6_CONFIG_0 << ARTPEC6_PINMUX_SEL_SHIFT;
> > +               } else {
> > +                       if (enable)
> > +                               val = artpec6_pin_groups[group].config
> > +                                       << ARTPEC6_PINMUX_SEL_SHIFT;
> > +                       else
> > +                               val = ARTPEC6_CONFIG_0
> > +                                       << ARTPEC6_PINMUX_SEL_SHIFT;
> > +               }
> > +
> > +               regval = readl(pmx->base + pmx_regs[i]);
> > +               regval &= ~ARTPEC6_PINMUX_SEL_MASK;
> > +               regval |= val;
> > +               writel(regval, pmx->base + pmx_regs[i]);
> > +       }
> 
> So thus look can be different and include something like +=4 for the registers
> for each iteration.
> 
> > --- /dev/null
> > +++ b/drivers/pinctrl/pinctrl-artpec6.h
> 
> You don't need to have these defines in their own file, just copy it into
> the top of the driver file.

Ok.

> > +/* Pinmux control register offset definitions */
> > +
> > +#define ARTPEC6_PINMUX_P1_0_CTRL       0x040
> > +#define ARTPEC6_PINMUX_P1_1_CTRL       0x044
> (...)
> 
> So for these defines you only need the first one.
> 
> With these things fixes I'm pretty sure it is close to finished.

Thanks for the feedback, will rework and resend. :-)

> Yours,
> Linus Walleij

/^JN - Jesper Nilsson
-- 
               Jesper Nilsson -- jesper.nilsson@axis.com