diff options
author | Stephen Warren <swarren@nvidia.com> | 2012-03-05 17:22:15 -0700 |
---|---|---|
committer | Linus Walleij <linus.walleij@linaro.org> | 2012-03-12 22:43:09 +0100 |
commit | 652162d469a73450a66b6c8049b16c2b7828fa24 (patch) | |
tree | 4df09c6e5e370a4bd73569503d1a124599871db5 /drivers/pinctrl | |
parent | a6c3b33f02c799db69a3cd82545e45e9df3d69ca (diff) | |
download | linux-652162d469a73450a66b6c8049b16c2b7828fa24.tar.bz2 |
pinctrl: allow concurrent gpio and mux function ownership of pins
Per recent updates to Documentation/gpio.txt, gpiolib drivers should
inform pinctrl when a GPIO is requested. pinctrl then marks that pin as
in-use for that GPIO function.
When an SoC muxes pins in a group, it's quite possible for the group to
contain e.g. 6 pins, but only 4 of them actually be needed by the HW
module that's mux'd to them. In this case, the other 2 pins could be
used as GPIOs. However, pinctrl marks all the pins within the group as
in-use by the selected mux function. To allow the expected gpiolib
interaction, separate the concepts of pin ownership into two parts: One
for the mux function and one for GPIO usage. Finally, allow those two
ownerships to exist in parallel.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/pinctrl')
-rw-r--r-- | drivers/pinctrl/core.h | 13 | ||||
-rw-r--r-- | drivers/pinctrl/pinmux.c | 72 |
2 files changed, 56 insertions, 29 deletions
diff --git a/drivers/pinctrl/core.h b/drivers/pinctrl/core.h index efbfb62ab147..17ecf651b123 100644 --- a/drivers/pinctrl/core.h +++ b/drivers/pinctrl/core.h @@ -119,15 +119,15 @@ struct pinctrl_setting { * @name: a name for the pin, e.g. the name of the pin/pad/finger on a * datasheet or such * @dynamic_name: if the name of this pin was dynamically allocated - * @usecount: If zero, the pin is not claimed, and @owner should be NULL. + * @mux_usecount: If zero, the pin is not claimed, and @owner should be NULL. * If non-zero, this pin is claimed by @owner. This field is an integer * rather than a boolean, since pinctrl_get() might process multiple * mapping table entries that refer to, and hence claim, the same group * or pin, and each of these will increment the @usecount. - * @owner: The name of the entity owning the pin. Typically, this is the name - * of the device that called pinctrl_get(). Alternatively, it may be the - * name of the GPIO passed to pinctrl_request_gpio(). + * @mux_owner: The name of device that called pinctrl_get(). * @mux_setting: The most recent selected mux setting for this pin, if any. + * @gpio_owner: If pinctrl_request_gpio() was called for this pin, this is + * the name of the GPIO that "owns" this pin. */ struct pin_desc { struct pinctrl_dev *pctldev; @@ -135,9 +135,10 @@ struct pin_desc { bool dynamic_name; /* These fields only added when supporting pinmux drivers */ #ifdef CONFIG_PINMUX - unsigned usecount; - const char *owner; + unsigned mux_usecount; + const char *mux_owner; const struct pinctrl_setting_mux *mux_setting; + const char *gpio_owner; #endif }; diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c index 86e401754116..4e62783a573a 100644 --- a/drivers/pinctrl/pinmux.c +++ b/drivers/pinctrl/pinmux.c @@ -94,17 +94,28 @@ static int pin_request(struct pinctrl_dev *pctldev, goto out; } - if (desc->usecount && strcmp(desc->owner, owner)) { - dev_err(pctldev->dev, - "pin already requested\n"); - goto out; - } + if (gpio_range) { + /* There's no need to support multiple GPIO requests */ + if (desc->gpio_owner) { + dev_err(pctldev->dev, + "pin already requested\n"); + goto out; + } - desc->usecount++; - if (desc->usecount > 1) - return 0; + desc->gpio_owner = owner; + } else { + if (desc->mux_usecount && strcmp(desc->mux_owner, owner)) { + dev_err(pctldev->dev, + "pin already requested\n"); + goto out; + } - desc->owner = owner; + desc->mux_usecount++; + if (desc->mux_usecount > 1) + return 0; + + desc->mux_owner = owner; + } /* Let each pin increase references to this module */ if (!try_module_get(pctldev->owner)) { @@ -135,9 +146,13 @@ static int pin_request(struct pinctrl_dev *pctldev, out_free_pin: if (status) { - desc->usecount--; - if (!desc->usecount) - desc->owner = NULL; + if (gpio_range) { + desc->gpio_owner = NULL; + } else { + desc->mux_usecount--; + if (!desc->mux_usecount) + desc->mux_owner = NULL; + } } out: if (status) @@ -172,9 +187,11 @@ static const char *pin_free(struct pinctrl_dev *pctldev, int pin, return NULL; } - desc->usecount--; - if (desc->usecount) - return NULL; + if (!gpio_range) { + desc->mux_usecount--; + if (desc->mux_usecount) + return NULL; + } /* * If there is no kind of request function for the pin we just assume @@ -185,9 +202,15 @@ static const char *pin_free(struct pinctrl_dev *pctldev, int pin, else if (ops->free) ops->free(pctldev, pin); - owner = desc->owner; - desc->owner = NULL; - desc->mux_setting = NULL; + if (gpio_range) { + owner = desc->gpio_owner; + desc->gpio_owner = NULL; + } else { + owner = desc->mux_owner; + desc->mux_owner = NULL; + desc->mux_setting = NULL; + } + module_put(pctldev->owner); return owner; @@ -493,7 +516,7 @@ static int pinmux_pins_show(struct seq_file *s, void *what) unsigned i, pin; seq_puts(s, "Pinmux settings per pin\n"); - seq_puts(s, "Format: pin (name): owner\n"); + seq_puts(s, "Format: pin (name): mux_owner gpio_owner hog?\n"); mutex_lock(&pinctrl_mutex); @@ -508,13 +531,16 @@ static int pinmux_pins_show(struct seq_file *s, void *what) if (desc == NULL) continue; - if (desc->owner && - !strcmp(desc->owner, pinctrl_dev_get_name(pctldev))) + if (desc->mux_owner && + !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev))) is_hog = true; - seq_printf(s, "pin %d (%s): %s%s", pin, + seq_printf(s, "pin %d (%s): %s %s%s", pin, desc->name ? desc->name : "unnamed", - desc->owner ? desc->owner : "UNCLAIMED", + desc->mux_owner ? desc->mux_owner + : "(MUX UNCLAIMED)", + desc->gpio_owner ? desc->gpio_owner + : "(GPIO UNCLAIMED)", is_hog ? " (HOG)" : ""); if (desc->mux_setting) |