Re: [RFC 2/3] pinctrl: e3xx: Adding support for NI Ettus Research USRP E3xx pinconf

From: Linus Walleij
Date: Mon Nov 09 2015 - 05:21:29 EST


On Fri, Nov 6, 2015 at 12:41 AM, Moritz Fischer
<moritz.fischer@xxxxxxxxx> wrote:

> The USRP E3XX series requires pinctrl to configure the idle state
> FPGA image for minimizing power consumption.
> This is required since different daughtercards have different uses
> for pins on a common connector.
>
> Signed-off-by: Moritz Fischer <moritz.fischer@xxxxxxxxx>
(...)

> +static const struct pinctrl_pin_desc e3xx_pins[] = {
> + /* pin0 doesn't exist */
> + PINCTRL_PIN(1, "DB_1"),
> + PINCTRL_PIN(2, "DB_2"),
(...)
> + PINCTRL_PIN(119, "DB_119"),
> + PINCTRL_PIN(120, "DB_120"),
> +};

These should be the names on the data sheet for the balls/pins on the ASIC.
Is this the case? I saw some discussion with Arnd that indicated it was
rather rail names for a certain board and that is not OK.

> +static int e3xx_pinctrl_get_groups_count(struct pinctrl_dev *pctldev)
> +{
> + return 0;
> +}
> +
> +static const char *e3xx_pinctrl_get_group_name(struct pinctrl_dev *pctldev,
> + unsigned selector)
> +{
> + return NULL;
> +}
> +
> +static int e3xx_pinctrl_get_group_pins(struct pinctrl_dev *pctldev,
> + unsigned selector,
> + const unsigned **pins,
> + unsigned *num_pins)
> +{
> + return -ENOTSUPP;
> +}

Hm maybe we should make these group callbacks optional
in the pinctrl core?

> +static int e3xx_pinconf_cfg_set(struct pinctrl_dev *pctldev,
> + unsigned pin,
> + unsigned long *configs,
> + unsigned num_configs)
> +{
> + u32 reg, mask;
> + int i;
> + struct e3xx_pinctrl *pctrl;
> + unsigned int param, arg;
> +
> + if (pin >= E3XX_NUM_DB_PINS)
> + return -ENOTSUPP;
> + mask = BIT(pin % E3XX_PINS_PER_REG);
> +
> + pctrl = pinctrl_dev_get_drvdata(pctldev);
> +
> + clk_enable(pctrl->clk);

Have you considered using pm_runtime_get_sync() etc with
callbacks instead of hammering clk_enable/disable all the
time? See
drivers/hwtracing/coresight/coresight-replicator.c
for an example of how to do it in the runtime PM ops
callbacks. It requires some tweaks (look closely at all setup
there) but it pays off.

> +static int e3xx_pinconf_group_set(struct pinctrl_dev *pctldev,
> + unsigned selector,
> + unsigned long *configs,
> + unsigned num_configs)
> +{
> + return -EAGAIN;
> +}

Maybe you should group this with the other group callbacks.

Apart from these remarks it looks pretty nice.

Yours,
Linus Walleij
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