pinctrl: allow exlusive GPIO/mux pin allocation
Disallow simultaneous use of the the GPIO and peripheral mux functions by setting a flag "strict" in struct pinctrl_desc. The blackfin pinmux and gpio controller doesn't allow user to set up a pin for both GPIO and peripheral function. So, add flag strict in struct pinctrl_desc to check both gpio_owner and mux_owner before approving the pin request. v2-changes: - if strict flag is set, check gpio_owner and mux_onwer in if and else clause v3-changes: - add kerneldoc for this struct - augment Documentation/pinctrl.txt Signed-off-by: Sonic Zhang <sonic.zhang@analog.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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@ -73,6 +73,7 @@ static struct pinctrl_desc foo_desc = {
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.pins = foo_pins,
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.npins = ARRAY_SIZE(foo_pins),
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.owner = THIS_MODULE,
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.strict = true,
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};
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int __init foo_probe(void)
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@ -830,6 +831,11 @@ separate memory range only intended for GPIO driving, and the register
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range dealing with pin config and pin multiplexing get placed into a
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different memory range and a separate section of the data sheet.
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A flag "strict" in struct pinctrl_desc is available to check and deny
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simultaneous access to the same pin from GPIO and pin multiplexing
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consumers on hardware of this type. The pinctrl driver should set this flag
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accordingly.
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(B)
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pin config
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@ -850,6 +856,11 @@ possible that the GPIO, pin config and pin multiplex registers are placed into
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the same memory range and the same section of the data sheet, although that
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need not be the case.
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In some pin controllers, although the physical pins are designed in the same
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way as (B), the GPIO function still can't be enabled at the same time as the
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peripheral functions. So again the "strict" flag should be set, denying
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simultaneous activation by GPIO and other muxed in devices.
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From a kernel point of view, however, these are different aspects of the
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hardware and shall be put into different subsystems:
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@ -710,6 +710,7 @@ static struct pinctrl_desc adi_pinmux_desc = {
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.name = DRIVER_NAME,
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.pctlops = &adi_pctrl_ops,
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.pmxops = &adi_pinmux_ops,
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.strict = true,
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.owner = THIS_MODULE,
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};
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@ -107,6 +107,13 @@ static int pin_request(struct pinctrl_dev *pctldev,
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desc->name, desc->gpio_owner, owner);
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goto out;
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}
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if (pctldev->desc->strict && desc->mux_usecount &&
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strcmp(desc->mux_owner, owner)) {
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dev_err(pctldev->dev,
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"pin %s already requested by %s; cannot claim for %s\n",
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desc->name, desc->mux_owner, owner);
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goto out;
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}
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desc->gpio_owner = owner;
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} else {
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@ -116,6 +123,12 @@ static int pin_request(struct pinctrl_dev *pctldev,
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desc->name, desc->mux_owner, owner);
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goto out;
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}
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if (pctldev->desc->strict && desc->gpio_owner) {
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dev_err(pctldev->dev,
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"pin %s already requested by %s; cannot claim for %s\n",
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desc->name, desc->gpio_owner, owner);
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goto out;
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}
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desc->mux_usecount++;
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if (desc->mux_usecount > 1)
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@ -114,6 +114,8 @@ struct pinctrl_ops {
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* of the pins field above
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* @pctlops: pin control operation vtable, to support global concepts like
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* grouping of pins, this is optional.
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* @strict: check both gpio_owner and mux_owner strictly before approving
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the pin request
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* @pmxops: pinmux operations vtable, if you support pinmuxing in your driver
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* @confops: pin config operations vtable, if you support pin configuration in
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* your driver
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@ -132,6 +134,7 @@ struct pinctrl_desc {
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const struct pinctrl_ops *pctlops;
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const struct pinmux_ops *pmxops;
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const struct pinconf_ops *confops;
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bool strict;
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struct module *owner;
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#ifdef CONFIG_GENERIC_PINCONF
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unsigned int num_custom_params;
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