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Date: Thu, 23 Feb 2012 07:08:35 +0100
From: Linus Walleij <linus.walleij@...aro.org>
To: Stephen Warren <swarren@...dia.com>
Cc: Linus Walleij <linus.walleij@...ricsson.com>, B29396@...escale.com,
s.hauer@...gutronix.de, dongas86@...il.com, shawn.guo@...aro.org,
thomas.abraham@...aro.org, tony@...mide.com,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 20/20] pinctrl: Enhance mapping table to support pin
config operations
On Mon, Feb 20, 2012 at 7:46 AM, Stephen Warren <swarren@...dia.com> wrote:
> The pinctrl mapping table can now contain entries to:
> * Set the mux function of a pin group
> * Apply a set of pin config options to a pin or a group
>
> This allows pinctrl_select_state() to apply pin configs settings as well
> as mux settings.
>
> Signed-off-by: Stephen Warren <swarren@...dia.com>
Overall excellent, just smaller things below:
> @@ -817,7 +827,40 @@ it even more compact which assumes you want to use pinctrl-foo and position
> 0 for mapping, for example:
>
> static struct pinctrl_map __initdata mapping[] = {
> - PIN_MAP("default", "pinctrl-foo", "i2c0", "foo-i2c.0"),
> + PIN_MAP_MUX_GROUP("foo-i2c.o", "default", "pinctrl-foo", NULL, "i2c0"),
> +};
OK looks good!
> +The mapping table may also contain pin configuration entries. It's common for
> +each pin/group to have a number of configuration entries that affect it, so
> +the table entries for configuration reference an array of config parameters
> +and values. An example using the convenience macros is shown below:
> +
> +static unsigned long i2c_grp_configs[] = {
> + FOO_PIN_DRIVEN,
> + FOO_PIN_PULLUP,
> +};
> +
> +static unsigned long i2c_pin_configs[] = {
> + FOO_OPEN_COLLECTOR,
> + FOO_SLEW_RATE_SLOW,
> +};
> +
> +static struct pinctrl_map __initdata mapping[] = {
> + PIN_MAP_MUX_GROUP("foo-i2c.0", "default", "pinctrl-foo", "i2c0", "i2c0"),
> + PIN_MAP_MUX_CONFIGS_GROUP("foo-i2c.0", "default", "pinctrl-foo", "i2c0", i2c_grp_configs),
> + PIN_MAP_MUX_CONFIGS_PIN("foo-i2c.0", "default", "pinctrl-foo", "i2c0scl", i2c_pin_configs),
> + PIN_MAP_MUX_CONFIGS_PIN("foo-i2c.0", "default", "pinctrl-foo", "i2c0sda", i2c_pin_configs),
> +};
I buy this too...
> +Finally, some devices expect the mapping table to contain certain specific
> +named states. When running on hardware that doesn't need any pin controller
> +configuration, the mapping table must still contain those named states, in
> +order to explicitly indicate that the states were provided and intended to
> +be empty. Table entry macro PIN_MAP_DUMMY_STATE serves the purpose of defining
> +a named state without causing any pin controller to be programmed:
> +
> +static struct pinctrl_map __initdata mapping[] = {
> + PIN_MAP_DUMMY_STATE("foo-i2c.0", "default"),
> };
Looks useful so why not.
> @@ -1022,7 +1074,7 @@ Since it may be common to request the core to hog a few always-applicable
> mux settings on the primary pin controller, there is a convenience macro for
> this:
>
> -PIN_MAP_SYS_HOG("active", "pinctrl-foo", "power_func")
> +PIN_MAP_MUX_GROUP("pinctrl-foo", "active", "pinctrl-foo", NULL, "power_func")
Please keep the explicit _HOG macros for readability. Relying on
the implicit relation between dev and pctldev being the same and to be
parsed by humans is vulnerable.
PIN_MAP_MUX_GROUP_HOG()
in this case, with the same arguments (though with PINCTRL_STATE_DEFAULT
in place for "active") is better IMO.
> /* Pinmux settings */
> static struct pinctrl_map __initdata u300_pinmux_map[] = {
> /* anonymous maps for chip power and EMIFs */
> - PIN_MAP_SYS_HOG("default", "pinmux-u300", "power"),
> - PIN_MAP_SYS_HOG("default", "pinmux-u300", "emif0"),
> - PIN_MAP_SYS_HOG("default", "pinmux-u300", "emif1"),
> + PIN_MAP_MUX_GROUP("pinmux-u300", "default", "pinmux-u300", NULL, "power"),
> + PIN_MAP_MUX_GROUP("pinmux-u300", "default", "pinmux-u300", NULL, "emif0"),
> + PIN_MAP_MUX_GROUP("pinmux-u300", "default", "pinmux-u300", NULL, "emif1"),
> /* per-device maps for MMC/SD, SPI and UART */
> - PIN_MAP("default", "pinmux-u300", "mmc0", "mmci"),
> - PIN_MAP("default", "pinmux-u300", "spi0", "pl022"),
> - PIN_MAP("default", "pinmux-u300", "uart0", "uart0"),
> + PIN_MAP_MUX_GROUP("mmci", "default", "pinmux-u300", NULL, "mmc0"),
> + PIN_MAP_MUX_GROUP("pl022", "default", "pinmux-u300", NULL, "spi0"),
> + PIN_MAP_MUX_GROUP("uart0", "default", "pinmux-u300", NULL, "uart0"),
> };
PIN_MAP_MUX_GROUP_HOG() please. PINCTRL_STATE_DEFAULT instead
of "default".
Or maybe we should imply that PIN_MAP_MUX_GROUP_HOG() hogs the
default state, or have PIN_MAP_MUX_GROUP_HOG_DEFAULT() even?
> --- a/drivers/pinctrl/core.c
> +++ b/drivers/pinctrl/core.c
> @@ -341,6 +341,31 @@ int pinctrl_get_group_selector(struct pinctrl_dev *pctldev,
> }
>
> /**
> + * pinctrl_get_pin_id() - returns the group selector for a group
> + * @pctldev: the pin controller handling the group
> + * @pin_group: the pin group to look up
This kerneldoc is wrong... pin, not group.
> + */
> +int pinctrl_get_pin_id(struct pinctrl_dev *pctldev,
> + const char *pin)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < pctldev->desc->npins; i++) {
> + if (pctldev->desc->pins[i].name == NULL)
> + continue;
> + if (!strcmp(pin, pctldev->desc->pins[i].name)) {
> + dev_dbg(pctldev->dev, "found pin id %u for %s\n",
> + i, pin);
> + return i;
> + }
> + }
(...)
> /* First sanity check the new mapping */
> for (i = 0; i < num_maps; i++) {
> + if (!maps[i].dev_name) {
> + pr_err("failed to register map %s (%d): no device given\n",
> + maps[i].name, i);
> + return -EINVAL;
> + }
> +
Hm should this not be done earlier in the patch series?
> + /*
> + * FIXME: We should really get the pin controler to dump the config
> + * values, so they can be decoded to something meaningful.
> + */
> + for (i = 0; i < setting->data.configs.num_configs; i++)
> + seq_printf(s, " %08lx", setting->data.configs.configs[i]);
> +
> + seq_printf(s, "\n");
> +}
Per-device config print function? But no need to rush that.
Apart from this I mostly just trust this patch, like the previous one.
Yours,
Linus Walleij
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