From 1a78958dc212f3698fdc543857af80155cb30f7f Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Wed, 17 Oct 2012 20:51:54 +0200 Subject: [PATCH] pinctrl: reserve pins when states are activated This switches the way that pins are reserved for multiplexing: We used to do this when the map was parsed, at the creation of the settings inside the pinctrl handle, in pinmux_map_to_setting(). However this does not work for us, because we want to use the same set of pins with different devices at different times: the current code assumes that the pin groups in a pinmux state will only be used with one single device, albeit different groups can be active at different times. For example if a single I2C driver block is used to drive two different busses located on two pin groups A and B, then the pins for all possible states of a function are reserved when fetching the pinctrl handle: the I2C bus can choose either set A or set B by a mux state at runtime, but all pins in both group A and B (the superset) are effectively reserved for that I2C function and mapped to the device. Another device can never get in and use the pins in group A, even if the device/function is using group B at the moment. Instead: let use reserve the pins when the state is activated and drop them when the state is disabled, i.e. when we move to another state. This way different devices/functions can use the same pins at different times. We know that this is an odd way of doing things, but we really need to switch e.g. an SD-card slot to become a tracing output sink at runtime: we plug in a special "tracing card" then mux the pins that used to be an SD slot around to the tracing unit and push out tracing data there instead of SD-card traffic. As a side effect pinmux_free_setting() is unused but the stubs are kept for future additions of code. Cc: Patrice Chotard Cc: Loic Pallardy Acked-by: Stephen Warren Tested-by: Jean Nicolas Graux Signed-off-by: Linus Walleij --- Documentation/pinctrl.txt | 4 ++- drivers/pinctrl/core.c | 2 ++ drivers/pinctrl/core.h | 2 ++ drivers/pinctrl/pinmux.c | 67 +++++++++++++-------------------------- 4 files changed, 29 insertions(+), 46 deletions(-) diff --git a/Documentation/pinctrl.txt b/Documentation/pinctrl.txt index 3b4ee5328868..a1cd2f9428d7 100644 --- a/Documentation/pinctrl.txt +++ b/Documentation/pinctrl.txt @@ -1193,4 +1193,6 @@ foo_switch() ... } -The above has to be done from process context. +The above has to be done from process context. The reservation of the pins +will be done when the state is activated, so in effect one specific pin +can be used by different functions at different times on a running system. diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c index 2e39c04fc16b..cec6072cd7c1 100644 --- a/drivers/pinctrl/core.c +++ b/drivers/pinctrl/core.c @@ -563,6 +563,8 @@ static int add_setting(struct pinctrl *p, struct pinctrl_map const *map) return -EPROBE_DEFER; } + setting->dev_name = map->dev_name; + switch (map->type) { case PIN_MAP_TYPE_MUX_GROUP: ret = pinmux_map_to_setting(map, setting); diff --git a/drivers/pinctrl/core.h b/drivers/pinctrl/core.h index 1f40ff68a8c4..12f5694f3d5d 100644 --- a/drivers/pinctrl/core.h +++ b/drivers/pinctrl/core.h @@ -105,12 +105,14 @@ struct pinctrl_setting_configs { * @type: the type of setting * @pctldev: pin control device handling to be programmed. Not used for * PIN_MAP_TYPE_DUMMY_STATE. + * @dev_name: the name of the device using this state * @data: Data specific to the setting type */ struct pinctrl_setting { struct list_head node; enum pinctrl_map_type type; struct pinctrl_dev *pctldev; + const char *dev_name; union { struct pinctrl_setting_mux mux; struct pinctrl_setting_configs configs; diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c index 9301a7a95eff..0ef01ee2835f 100644 --- a/drivers/pinctrl/pinmux.c +++ b/drivers/pinctrl/pinmux.c @@ -314,14 +314,11 @@ int pinmux_map_to_setting(struct pinctrl_map const *map, { struct pinctrl_dev *pctldev = setting->pctldev; const struct pinmux_ops *pmxops = pctldev->desc->pmxops; - const struct pinctrl_ops *pctlops = pctldev->desc->pctlops; char const * const *groups; unsigned num_groups; int ret; const char *group; int i; - const unsigned *pins; - unsigned num_pins; if (!pmxops) { dev_err(pctldev->dev, "does not support mux function\n"); @@ -376,53 +373,12 @@ int pinmux_map_to_setting(struct pinctrl_map const *map, } setting->data.mux.group = ret; - ret = pctlops->get_group_pins(pctldev, setting->data.mux.group, &pins, - &num_pins); - if (ret) { - dev_err(pctldev->dev, - "could not get pins for device %s group selector %d\n", - pinctrl_dev_get_name(pctldev), setting->data.mux.group); - return -ENODEV; - } - - /* Try to allocate all pins in this group, one by one */ - for (i = 0; i < num_pins; i++) { - ret = pin_request(pctldev, pins[i], map->dev_name, NULL); - if (ret) { - dev_err(pctldev->dev, - "could not request pin %d on device %s\n", - pins[i], pinctrl_dev_get_name(pctldev)); - /* On error release all taken pins */ - i--; /* this pin just failed */ - for (; i >= 0; i--) - pin_free(pctldev, pins[i], NULL); - return -ENODEV; - } - } - return 0; } void pinmux_free_setting(struct pinctrl_setting const *setting) { - struct pinctrl_dev *pctldev = setting->pctldev; - const struct pinctrl_ops *pctlops = pctldev->desc->pctlops; - const unsigned *pins; - unsigned num_pins; - int ret; - int i; - - ret = pctlops->get_group_pins(pctldev, setting->data.mux.group, - &pins, &num_pins); - if (ret) { - dev_err(pctldev->dev, - "could not get pins for device %s group selector %d\n", - pinctrl_dev_get_name(pctldev), setting->data.mux.group); - return; - } - - for (i = 0; i < num_pins; i++) - pin_free(pctldev, pins[i], NULL); + /* This function is currently unused */ } int pinmux_enable_setting(struct pinctrl_setting const *setting) @@ -446,6 +402,22 @@ int pinmux_enable_setting(struct pinctrl_setting const *setting) num_pins = 0; } + /* Try to allocate all pins in this group, one by one */ + for (i = 0; i < num_pins; i++) { + ret = pin_request(pctldev, pins[i], setting->dev_name, NULL); + if (ret) { + dev_err(pctldev->dev, + "could not request pin %d on device %s\n", + pins[i], pinctrl_dev_get_name(pctldev)); + /* On error release all taken pins */ + i--; /* this pin just failed */ + for (; i >= 0; i--) + pin_free(pctldev, pins[i], NULL); + return -ENODEV; + } + } + + /* Now that we have acquired the pins, encode the mux setting */ for (i = 0; i < num_pins; i++) { desc = pin_desc_get(pctldev, pins[i]); if (desc == NULL) { @@ -482,6 +454,7 @@ void pinmux_disable_setting(struct pinctrl_setting const *setting) num_pins = 0; } + /* Flag the descs that no setting is active */ for (i = 0; i < num_pins; i++) { desc = pin_desc_get(pctldev, pins[i]); if (desc == NULL) { @@ -493,6 +466,10 @@ void pinmux_disable_setting(struct pinctrl_setting const *setting) desc->mux_setting = NULL; } + /* And release the pins */ + for (i = 0; i < num_pins; i++) + pin_free(pctldev, pins[i], NULL); + if (ops->disable) ops->disable(pctldev, setting->data.mux.func, setting->data.mux.group); } -- 2.20.1