Re: [PATCH 06/17] gpio: mvebu: add suspend/resume support

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Fri, Oct 24, 2014 at 1:59 PM, Thomas Petazzoni
<thomas.petazzoni@xxxxxxxxxxxxxxxxxx> wrote:

> This commit adds the implementation of ->suspend() and ->resume()
> platform_driver hooks in order to save and restore the state of the
> GPIO configuration. In order to achieve that, additional fields are
> added to the mvebu_gpio_chip structure.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
> Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
> Cc: Alexandre Courbot <gnurou@xxxxxxxxx>
> Cc: linux-gpio@xxxxxxxxxxxxxxx

(...)
> +       mvchip->out_reg = readl(mvebu_gpioreg_out(mvchip));
> +       mvchip->io_conf_reg = readl(mvebu_gpioreg_io_conf(mvchip));
> +       mvchip->blink_en_reg = readl(mvebu_gpioreg_blink(mvchip));
> +       mvchip->in_pol_reg = readl(mvebu_gpioreg_in_pol(mvchip));

OK...

> +       switch (mvchip->soc_variant) {
> +       case MVEBU_GPIO_SOC_VARIANT_ORION:
> +               mvchip->edge_mask_regs[0] =
> +                       readl(mvchip->membase + GPIO_EDGE_MASK_OFF);
> +               mvchip->level_mask_regs[0] =
> +                       readl(mvchip->membase + GPIO_LEVEL_MASK_OFF);
> +               break;

You are assigning index [0] twice, why? There must be some
reason, and it should be stated in a comment. If the first read
is necessary for hardware reasons, don't assign it but
discard the result.

(void) readl(...);

(This pattern repeats for each save call below.)

> +       switch (mvchip->soc_variant) {
> +       case MVEBU_GPIO_SOC_VARIANT_ORION:
> +               writel(mvchip->edge_mask_regs[0],
> +                      mvchip->membase + GPIO_EDGE_MASK_OFF);
> +               writel(mvchip->level_mask_regs[0],
> +                      mvchip->membase + GPIO_LEVEL_MASK_OFF);

And on the way up same thing. Now you write
each register twice. Why?

Yours,
Linus Walleij
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