@@ -7,12 +7,9 @@ This subsystem deals with:
- Multiplexing of pins, pads, fingers (etc) see below for details
-The intention is to also deal with:
-
-- Software-controlled biasing and driving mode specific pins, such as
- pull-up/down, open drain etc, load capacitance configuration when controlled
- by software, etc.
-
+- Configuration of pins, pads, fingers (etc), such as software-controlled
+ biasing and driving mode specific pins, such as pull-up/down, open drain,
+ load capacitance etc.
Top-level interface
===================
@@ -88,6 +85,11 @@ int __init foo_probe(void)
pr_err("could not register foo pin driver\n");
}
+To enable the pinctrl subsystem and the subgroups for PINMUX and PINCONF and
+selected drivers, you need to select them from your machine's Kconfig entry,
+since these are so tightly integrated with the machines they are used on.
+See for example arch/arm/mach-u300/Kconfig for an example.
+
Pins usually have fancier names than this. You can find these in the dataheet
for your chip. Notice that the core pinctrl.h file provides a fancy macro
called PINCTRL_PIN() to create the struct entries. As you can see I enumerated
@@ -193,6 +195,97 @@ structure, for example specific register ranges associated with each group
and so on.
+Pin configuration
+=================
+
+Pins can sometimes be software-configured in an various ways, mostly related
+to their electronic properties when used as inputs or outputs. For example you
+may be able to make an output pin high impedance, or "tristate" meaning it is
+effectively disconnected. You may be able to connect an input pin to VDD or GND
+using a certain resistor value - pull up and pull down - so that the pin has a
+stable value when nothing is driving the rail it is connected to, or when it's
+unconnected.
+
+The pin control system supports an interface partly abstracting these
+properties while leaving the details to the pin control driver. We assume that
+the things a controller may want configure are enumerable, and thus the
+parameters such as PIN_CONFIG_BIAS_PULL_UP are defined by the core, whereas
+the arguments to the parameter may need to be on a custom format only
+understandable by the driver. However we strive to use SI-derived entities for
+these where applicable, which means the core may step in and do sematic
+analysis of the passed values in select cases.
+
+For example, a platform may do this:
+
+struct pin_config_tuple myconfig {
+ .param = PIN_CONFIG_BIAS_PULL_UP,
+ .data = 100000,
+};
+
+ret = pin_config(dev, 128, &myconfig, 1);
+
+To pull up a pin to VDD with a 100KOhm resistor. The pin configuration driver
+implements callbacks for changing pin configuration in the pin controller ops
+like this:
+
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinconf.h>
+
+int foo_pin_config (struct pinctrl_dev *pctldev,
+ const struct pin_config *conf,
+ unsigned pin,
+ const struct pin_config_tuple *configs,
+ unsigned num_configs)
+{
+ int i;
+
+ for (i = 0; i < num_configs; i++) {
+ const struct pin_config_tuple *config = &configs[i];
+ switch (config->param) {
+ case PIN_CONFIG_BIAS_PULL_UP:
+ ...
+ }
+ }
+}
+
+int foo_pin_config_group (struct pinctrl_dev *pctldev,
+ unsigned selector,
+ const struct pin_config_tuple *configs,
+ unsigned num_configs)
+{
+ ...
+}
+
+static struct pinconf_ops foo_pconf_ops = {
+ .pin_config = foo_pin_config,
+ .pin_config_group = foo_pin_config_group,
+};
+
+/* Pin config operations are handled by some pin controller */
+static struct pinctrl_desc foo_desc = {
+ ...
+ .confops = &foo_pconf_ops,
+};
+
+The pin config core keeps track of the pin state, since not all hardware
+support reading this out in a sane way. The current state is the logical sum
+of all applied configurations and can be inspected in debugfs. There is
+an optional hook in the pinconf_ops, .pin_get_initial_config() which can
+read out the initial state of each pin as it is registered, if there is need
+for this on your system. This way the pin config core can keep track of the
+state of each pin at any time. Notice that the .pin_config() callback pass
+the current state of the pin as an argument to the driver so that it can
+exploit the current state of each pin if need be.
+
+Since some controllers have special logic for handling entire groups of pins
+they can exploit the special whole-group pin control function. The
+pin_config_group() callback is allowed to return the error code -EAGAIN,
+for groups it does not want to handle, or if it just wants to do some
+group-level handling and then fall through to iterate over all pins, in which
+case each individual pin will be treated by separate pin_config() calls as
+well.
+
+
Interaction with the GPIO subsystem
===================================
@@ -12,7 +12,10 @@ menu "Pin controllers"
depends on PINCTRL
config PINMUX
- bool "Support pinmux controllers"
+ bool "Support pin multiplexing controllers"
+
+config PINCONF
+ bool "Support pin configuration controllers"
config DEBUG_PINCTRL
bool "Debug PINCTRL calls"
@@ -4,5 +4,6 @@ ccflags-$(CONFIG_DEBUG_PINMUX) += -DDEBUG
obj-$(CONFIG_PINCTRL) += core.o
obj-$(CONFIG_PINMUX) += pinmux.o
+obj-$(CONFIG_PINCONF) += pinconf.o
obj-$(CONFIG_PINMUX_SIRF) += pinmux-sirf.o
obj-$(CONFIG_PINMUX_U300) += pinmux-u300.o
@@ -28,6 +28,7 @@
#include <linux/pinctrl/machine.h>
#include "core.h"
#include "pinmux.h"
+#include "pinconf.h"
/* Global list of pin control devices */
static DEFINE_MUTEX(pinctrldev_list_mutex);
@@ -149,6 +150,7 @@ static int pinctrl_register_one_pin(struct pinctrl_dev *pctldev,
unsigned number, const char *name)
{
struct pin_desc *pindesc;
+ int ret;
pindesc = pin_desc_get(pctldev, number);
if (pindesc != NULL) {
@@ -160,6 +162,7 @@ static int pinctrl_register_one_pin(struct pinctrl_dev *pctldev,
pindesc = kzalloc(sizeof(*pindesc), GFP_KERNEL);
if (pindesc == NULL)
return -ENOMEM;
+
spin_lock_init(&pindesc->lock);
/* Set owner */
@@ -168,6 +171,10 @@ static int pinctrl_register_one_pin(struct pinctrl_dev *pctldev,
/* Copy basic pin info */
pindesc->name = name;
+ ret = pinconf_init_config(pctldev, pindesc, number);
+ if (ret)
+ return ret;
+
spin_lock(&pctldev->pin_desc_tree_lock);
radix_tree_insert(&pctldev->pin_desc_tree, number, pindesc);
spin_unlock(&pctldev->pin_desc_tree_lock);
@@ -315,6 +322,7 @@ int pinctrl_get_group_selector(struct pinctrl_dev *pctldev,
return -EINVAL;
}
+
#ifdef CONFIG_DEBUG_FS
static int pinctrl_pins_show(struct seq_file *s, void *what)
@@ -492,6 +500,7 @@ static void pinctrl_init_device_debugfs(struct pinctrl_dev *pctldev)
debugfs_create_file("gpio-ranges", S_IFREG | S_IRUGO,
device_root, pctldev, &pinctrl_gpioranges_ops);
pinmux_init_device_debugfs(device_root, pctldev);
+ pinconf_init_device_debugfs(device_root, pctldev);
}
static void pinctrl_init_debugfs(void)
@@ -548,6 +557,16 @@ struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,
}
}
+ /* If we're implementing pinconfig, check the ops for sanity */
+ if (pctldesc->confops) {
+ ret = pinconf_check_ops(pctldesc->confops);
+ if (ret) {
+ pr_err("%s pin config ops lacks necessary functions\n",
+ pctldesc->name);
+ return NULL;
+ }
+ }
+
pctldev = kzalloc(sizeof(struct pinctrl_dev), GFP_KERNEL);
if (pctldev == NULL)
return NULL;
@@ -9,6 +9,10 @@
* License terms: GNU General Public License (GPL) version 2
*/
+#include <linux/pinctrl/pinconf.h>
+
+struct pinctrl_gpio_range;
+
/**
* struct pinctrl_dev - pin control class device
* @node: node to include this pin controller in the global pin controller list
@@ -52,6 +56,8 @@ struct pinctrl_dev {
* @mux_requested: whether the pin is already requested by pinmux or not
* @mux_function: a named muxing function for the pin that will be passed to
* subdrivers and shown in debugfs etc
+ * @config_lock: a lock to protect the pin configuration portions
+ * @pin_configs: a list of configuration settings for this pin
*/
struct pin_desc {
struct pinctrl_dev *pctldev;
@@ -61,6 +67,10 @@ struct pin_desc {
#ifdef CONFIG_PINMUX
const char *mux_function;
#endif
+#ifdef CONFIG_PINCONF
+ struct mutex config_lock;
+ struct pin_config config;
+#endif
};
struct pinctrl_dev *get_pinctrl_dev_from_dev(struct device *dev,
new file mode 100644
@@ -0,0 +1,366 @@
+/*
+ * Core driver for the pin config portions of the pin control subsystem
+ *
+ * Copyright (C) 2011 ST-Ericsson SA
+ * Written on behalf of Linaro for ST-Ericsson
+ * Based on bits of regulator core, gpio core and clk core
+ *
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ */
+#define pr_fmt(fmt) "pinconfig core: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/pinctrl/machine.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinconf.h>
+#include "core.h"
+
+static void pinconf_update_state(struct pin_config *conf,
+ const struct pin_config_tuple *new)
+{
+ switch (new->param) {
+ case PIN_CONFIG_BIAS_DISABLE:
+ case PIN_CONFIG_BIAS_HIGH_IMPEDANCE:
+ case PIN_CONFIG_BIAS_PULL_UP:
+ case PIN_CONFIG_BIAS_PULL_DOWN:
+ case PIN_CONFIG_BIAS_HIGH:
+ case PIN_CONFIG_BIAS_GROUND:
+ /* These are mutually exclusive */
+ conf->bias.param = new->param;
+ conf->bias.data = new->data;
+ break;
+ case PIN_CONFIG_DRIVE_PUSH_PULL:
+ case PIN_CONFIG_DRIVE_OPEN_DRAIN:
+ case PIN_CONFIG_DRIVE_OPEN_SOURCE:
+ case PIN_CONFIG_DRIVE_OFF:
+ conf->drive.param = new->param;
+ conf->drive.data = new->data;
+ break;
+ case PIN_CONFIG_INPUT_SCHMITT:
+ conf->schmitt.param = new->param;
+ conf->schmitt.data = new->data;
+ break;
+ case PIN_CONFIG_INPUT_DEBOUNCE:
+ conf->debounce.param = new->param;
+ conf->debounce.data = new->data;
+ break;
+ case PIN_CONFIG_SLEW_RATE_RISING:
+ conf->slewrate_rising.param = new->param;
+ conf->slewrate_rising.data = new->data;
+ break;
+ case PIN_CONFIG_SLEW_RATE_FALLING:
+ conf->slewrate_falling.param = new->param;
+ conf->slewrate_falling.data = new->data;
+ break;
+ case PIN_CONFIG_POWER_SOURCE:
+ conf->power_source.param = new->param;
+ conf->power_source.data = new->data;
+ break;
+ case PIN_CONFIG_LOW_POWER_MODE:
+ conf->low_power.param = new->param;
+ conf->low_power.data = new->data;
+ break;
+ case PIN_CONFIG_WAKEUP:
+ conf->wakeup.param = new->param;
+ conf->wakeup.data = new->data;
+ break;
+ default:
+ /* TODO: Error? Custom? */
+ break;
+ }
+}
+
+static void pinconf_update_states(struct pin_config *conf,
+ const struct pin_config_tuple *configs,
+ unsigned num_configs)
+{
+ int i;
+
+ for (i = 0; i < num_configs; i++)
+ pinconf_update_state(conf, &configs[i]);
+}
+
+int pin_config(struct pinctrl_dev *pctldev, int pin,
+ const struct pin_config_tuple *configs,
+ unsigned num_configs)
+{
+ const struct pinconf_ops *ops = pctldev->desc->confops;
+ struct pin_desc *desc;
+ struct pin_config *conf;
+ int ret;
+
+ desc = pin_desc_get(pctldev, pin);
+ if (desc == NULL) {
+ dev_err(&pctldev->dev, "tried to configure unregistered pin\n");
+ return -EINVAL;
+ }
+
+ conf = &desc->config;
+
+ if (!ops || !ops->pin_config) {
+ dev_err(&pctldev->dev, "cannot configure pin, missing "
+ "config function in driver\n");
+ return -EINVAL;
+ }
+
+ mutex_lock(&desc->config_lock);
+ ret = ops->pin_config(pctldev, conf, pin, configs, num_configs);
+ if (ret) {
+ dev_err(&pctldev->dev,
+ "unable to set pin configuration on pin %d\n", pin);
+ return ret;
+ }
+ pinconf_update_states(conf, configs, num_configs);
+ mutex_unlock(&desc->config_lock);
+
+ return 0;
+}
+
+int pin_config_group(struct pinctrl_dev *pctldev, const char *pin_group,
+ const struct pin_config_tuple *configs,
+ unsigned num_configs)
+{
+ const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
+ const struct pinconf_ops *ops = pctldev->desc->confops;
+ int selector;
+ const unsigned *pins;
+ unsigned num_pins;
+ int ret;
+ int i;
+
+ if (!ops || (!ops->pin_config_group && !ops->pin_config)) {
+ dev_err(&pctldev->dev, "cannot configure pin group, missing "
+ "config function in driver\n");
+ return -EINVAL;
+ }
+
+ selector = pinctrl_get_group_selector(pctldev, pin_group);
+ if (selector < 0)
+ return selector;
+
+ ret = pctlops->get_group_pins(pctldev, selector, &pins, &num_pins);
+ if (ret) {
+ dev_err(&pctldev->dev, "cannot configure pin group, error "
+ "getting pins\n");
+ return ret;
+ }
+
+ /*
+ * If the pin controller supports handling entire groups we use that
+ * capability.
+ */
+ if (ops->pin_config_group) {
+ ret = ops->pin_config_group(pctldev, selector,
+ configs, num_configs);
+
+ /* Success, update per-pin state */
+ if (ret == 0) {
+ for (i = 0; i < num_pins; i++) {
+ struct pin_desc *desc;
+
+ desc = pin_desc_get(pctldev, pins[i]);
+ if (desc == NULL) {
+ dev_err(&pctldev->dev, "error updating state\n");
+ return -EINVAL;
+ }
+ mutex_lock(&desc->config_lock);
+ pinconf_update_states(&desc->config,
+ configs, num_configs);
+ mutex_unlock(&desc->config_lock);
+ }
+ }
+ /*
+ * If the pin controller prefer that a certain group be handled
+ * pin-by-pin as well, it returns -EAGAIN.
+ */
+ if (ret != -EAGAIN)
+ return ret;
+ }
+
+ /*
+ * If the controller cannot handle entire groups, we configure each pin
+ * individually.
+ */
+ for (i = 0; i < num_pins; i++) {
+ ret = pin_config(pctldev, pins[i], configs, num_configs);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+int pinconf_check_ops(const struct pinconf_ops *ops)
+{
+ /* We have to be able to config the pins in SOME way */
+ if (!ops->pin_config_group && !ops->pin_config)
+ return -EINVAL;
+ return 0;
+}
+
+int pinconf_init_config(struct pinctrl_dev *pctldev, struct pin_desc *desc,
+ unsigned number)
+{
+ const struct pinconf_ops *ops = pctldev->desc->confops;
+ struct pin_config *conf = &desc->config;
+ int ret;
+
+ mutex_init(&desc->config_lock);
+
+ /* This controller does not support pin config */
+ if (!ops)
+ return 0;
+
+ /* Retrieve initial pin config if the driver supports it */
+ if (ops->pin_get_initial_config) {
+ ret = ops->pin_get_initial_config(pctldev, conf, number);
+ if (ret)
+ dev_err(&pctldev->dev, "unable to get initial config "
+ "for pin %d (%s)\n", number, desc->name);
+ return ret;
+ } else {
+ /* Put them all in assumed states then */
+ conf->bias.param = PIN_CONFIG_BIAS_DISABLE;
+ conf->drive.param = PIN_CONFIG_DRIVE_OFF;
+ }
+
+ return 0;
+}
+
+#ifdef CONFIG_DEBUG_FS
+
+static void pinconf_dump_pin(struct seq_file *s, struct pin_config *conf)
+{
+ switch (conf->bias.param) {
+ case PIN_CONFIG_BIAS_DISABLE:
+ seq_puts(s, "bias disabled ");
+ break;
+ case PIN_CONFIG_BIAS_HIGH_IMPEDANCE:
+ seq_puts(s, "bias high impedance ");
+ break;
+ case PIN_CONFIG_BIAS_PULL_UP:
+ seq_puts(s, "bias pull up ");
+ if (conf->bias.data > 0)
+ seq_printf(s, "(%lu Ohm) ", conf->bias.data);
+ break;
+ case PIN_CONFIG_BIAS_PULL_DOWN:
+ seq_puts(s, "bias pull down ");
+ if (conf->bias.data > 0)
+ seq_printf(s, "(%lu Ohm) ", conf->bias.data);
+ break;
+ case PIN_CONFIG_BIAS_HIGH:
+ seq_puts(s, "bias high ");
+ break;
+ case PIN_CONFIG_BIAS_GROUND:
+ seq_puts(s, "bias ground ");
+ break;
+ default:
+ break;
+ }
+
+ switch (conf->drive.param) {
+ case PIN_CONFIG_DRIVE_PUSH_PULL:
+ seq_puts(s, "drive push/pull ");
+ break;
+ case PIN_CONFIG_DRIVE_OPEN_DRAIN:
+ seq_puts(s, "drive open drain ");
+ break;
+ case PIN_CONFIG_DRIVE_OPEN_SOURCE:
+ seq_puts(s, "drive open source ");
+ break;
+ case PIN_CONFIG_DRIVE_OFF:
+ seq_puts(s, "drive off ");
+ break;
+ default:
+ break;
+ }
+ /* Print drive strength */
+ if (conf->drive.data != 0 ||
+ conf->drive.param == PIN_CONFIG_DRIVE_PUSH_PULL ||
+ conf->drive.param == PIN_CONFIG_DRIVE_OPEN_DRAIN ||
+ conf->drive.param == PIN_CONFIG_DRIVE_OPEN_SOURCE)
+ seq_printf(s, "(%luX) ", conf->drive.data);
+
+ if (conf->schmitt.data > 0)
+ seq_printf(s, "schmitt trigger (%lu)", conf->schmitt.data);
+ if (conf->debounce.data > 0)
+ seq_printf(s, "debounce (%lu)", conf->debounce.data);
+ if (conf->slewrate_rising.data > 0)
+ seq_printf(s, "slewrate rising (%lu) ",
+ conf->slewrate_rising.data);
+ if (conf->slewrate_falling.data > 0)
+ seq_printf(s, "slewrate falling (%lu) ",
+ conf->slewrate_falling.data);
+ if (conf->power_source.data > 0)
+ seq_printf(s, "power source %lu ",
+ conf->power_source.data);
+ if (conf->low_power.data > 0)
+ seq_printf(s, "low power mode (%lu) ",
+ conf->low_power.data);
+ if (conf->wakeup.data > 0)
+ seq_puts(s, "wakeup enabled ");
+}
+
+static int pinconf_pins_show(struct seq_file *s, void *what)
+{
+ struct pinctrl_dev *pctldev = s->private;
+ unsigned pin;
+
+ seq_puts(s, "Pin config settings per pin\n");
+ seq_puts(s, "Format: pin (name): pinmux setting array\n");
+
+ /* The highest pin number need to be included in the loop, thus <= */
+ for (pin = 0; pin <= pctldev->desc->maxpin; pin++) {
+ struct pin_desc *desc;
+
+ desc = pin_desc_get(pctldev, pin);
+ /* Pin space may be sparse */
+ if (desc == NULL)
+ continue;
+
+ seq_printf(s, "pin %d (%s): ", pin,
+ desc->name ? desc->name : "unnamed");
+
+ mutex_lock(&desc->config_lock);
+ pinconf_dump_pin(s, &desc->config);
+ mutex_unlock(&desc->config_lock);
+
+ seq_printf(s, "\n");
+ }
+
+ return 0;
+}
+
+static int pinconf_pins_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, pinconf_pins_show, inode->i_private);
+}
+
+static const struct file_operations pinconf_pins_ops = {
+ .open = pinconf_pins_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+void pinconf_init_device_debugfs(struct dentry *devroot,
+ struct pinctrl_dev *pctldev)
+{
+ debugfs_create_file("pinconf-pins", S_IFREG | S_IRUGO,
+ devroot, pctldev, &pinconf_pins_ops);
+}
+
+#else
+
+#endif
new file mode 100644
@@ -0,0 +1,41 @@
+/*
+ * Internal interface between the core pin control system and the
+ * pin config portions
+ *
+ * Copyright (C) 2011 ST-Ericsson SA
+ * Written on behalf of Linaro for ST-Ericsson
+ * Based on bits of regulator core, gpio core and clk core
+ *
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ */
+
+#ifdef CONFIG_PINCONF
+
+int pinconf_check_ops(const struct pinconf_ops *ops);
+int pinconf_init_config(struct pinctrl_dev *pctldev, struct pin_desc *desc,
+ unsigned number);
+void pinconf_init_device_debugfs(struct dentry *devroot,
+ struct pinctrl_dev *pctldev);
+
+#else
+
+static inline int pinconf_check_ops(const struct pinconf_ops *ops)
+{
+ return 0;
+}
+
+static inline int pinconf_init_config(struct pinctrl_dev *pctldev,
+ struct pin_desc *desc,
+ unsigned number)
+{
+ return 0;
+}
+
+static inline void pinconf_init_device_debugfs(struct dentry *devroot,
+ struct pinctrl_dev *pctldev)
+{
+}
+
+#endif
new file mode 100644
@@ -0,0 +1,209 @@
+/*
+ * Interface the pinconfig portions of the pinctrl subsystem
+ *
+ * Copyright (C) 2011 ST-Ericsson SA
+ * Written on behalf of Linaro for ST-Ericsson
+ * This interface is used in the core to keep track of pins.
+ *
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ */
+#ifndef __LINUX_PINCTRL_PINCONF_H
+#define __LINUX_PINCTRL_PINCONF_H
+
+/**
+ * enum pin_config_param - possible pin configuration parameters
+ * @PIN_CONFIG_BIAS_DISABLE: disable any pin bias on the pin, a
+ * transition from say pull-up to pull-down implies that you disable
+ * pull-up in the process, this setting disables all biasing.
+ * @PIN_CONFIG_BIAS_HIGH_IMPEDANCE: the pin will be set to a high impedance
+ * mode, also know as "third-state" (tristate) or "high-Z" or "floating".
+ * On output pins this effectively disconnects the pin, which is useful
+ * if for example some other pin is going to drive the signal connected
+ * to it for a while. Pins used for input are usually always high
+ * impedance.
+ * @PIN_CONFIG_BIAS_PULL_UP: the pin will be pulled up (usually with high
+ * impedance to VDD), if the controller supports specifying a certain
+ * pull-up resistance, this is given as an argument (in Ohms) when
+ * setting this parameter.
+ * @PIN_CONFIG_BIAS_PULL_DOWN: the pin will be pulled down (usually with high
+ * impedance to GROUND), if the controller supports specifying a certain
+ * pull-down resistance, this is given as an argument (in Ohms) when
+ * setting this parameter.
+ * @PIN_CONFIG_BIAS_HIGH: the pin will be wired high, connected to VDD
+ * @PIN_CONFIG_BIAS_GROUND: the pin will be grounded, connected to GROUND
+ * @PIN_CONFIG_DRIVE_PUSH_PULL: the pin will be driven actively high and
+ * low, this is the most typical case and is typically achieved with two
+ * active transistors on the output. If the pin can support different
+ * drive strengths for push/pull, the strength is given in the argument
+ * as the number of driving stages vs nominal load impedance, so say
+ * quadruple driving stages (usually 8 transistors rather than two) will
+ * be configured with the 8 passed as argument.
+ * @PIN_CONFIG_DRIVE_OPEN_DRAIN: the pin will be driven with open drain (open
+ * collector) which means it is usually wired with other output ports
+ * which are then pulled up with an external resistor. If the pin can
+ * support different drive strengths for the open drain pin, the format
+ * is the same as for PIN_CONFIG_DRIVE_PUSH_PULL.
+ * @PIN_CONFIG_DRIVE_OPEN_SOURCE: the pin will be driven with open drain
+ * (open emitter) which is the same as open drain but pulled to ground.
+ * If the pin can support different drive strengths for the open drain
+ * pin, the format is the same as for PIN_CONFIG_DRIVE_PUSH_PULL.
+ * @PIN_CONFIG_DRIVE_OFF: the pin is set to inactive drive mode, off.
+ * @PIN_CONFIG_INPUT_SCHMITT: this will configure an input pin to run in
+ * schmitt-trigger mode. If the schmitt-trigger has adjustable hysteresis,
+ * the threshold value is given on a custom format as argument when
+ * setting pins to this mode. The argument zero turns the schmitt trigger
+ * off.
+ * @PIN_CONFIG_INPUT_DEBOUNCE: this will configure the pin to debounce mode,
+ * which means it will wait for signals to settle when reading inputs. The
+ * argument gives the debounce time on a custom format. Setting the
+ * argument to zero turns debouncing off.
+ * @PIN_CONFIG_SLEW_RATE_RISING: this will configure the slew rate for rising
+ * signals on the pin. The argument gives the rise time in fractions
+ * compared to maximum rise time, 0 means nominal rise time. If you can
+ * control slew rate in 4 steps these will likely be equidistant like
+ * 1/4, 1/2, 3/4 or full nominal slew rate, which means argument 4 gives
+ * you 1/4 of nominal slew rate and the argument 4 has the same meaning
+ * as 0 - nominal slew rate (fastest possible, steep edges). You may want
+ * to adjust slew rates so that signal edges don't get too steep, causing
+ * disturbances in surrounding electronics known as electromagnetic
+ * interference (EMI) for example.
+ * @PIN_CONFIG_SLEW_RATE_FALLING: this will configure the slew rate for falling
+ * signals on the pin. The argument gives the fall time in fractions
+ * compared to nominal fall time.
+ * @PIN_CONFIG_POWER_SOURCE: if the pin can select between different power
+ * supplies, the argument to this parameter (on a custom format) tells
+ * the driver which alternative power source to use.
+ * @PIN_CONFIG_LOW_POWER_MODE: this will configure the pin for low power
+ * operation, if several modes of operation are supported these can be
+ * passed in the argument on a custom form, else just use argument 1
+ * to indicate low power mode, argument 0 turns low power mode off.
+ * @PIN_CONFIG_WAKEUP: this will configure an input pin such that if a
+ * signal transition arrives at the pin when the pin controller/system
+ * is sleeping, it will wake up the system if argument 1 is passed along.
+ * Pass argument 0 to turn wakeup enablement off.
+ * @PIN_CONFIG_END: this is the last enumerator for pin configurations, if
+ * you need to pass in custom configurations to the pin controller, use
+ * PIN_CONFIG_END+1 as the base offset.
+ */
+enum pin_config_param {
+ PIN_CONFIG_BIAS_DISABLE,
+ PIN_CONFIG_BIAS_HIGH_IMPEDANCE,
+ PIN_CONFIG_BIAS_PULL_UP,
+ PIN_CONFIG_BIAS_PULL_DOWN,
+ PIN_CONFIG_BIAS_HIGH,
+ PIN_CONFIG_BIAS_GROUND,
+ PIN_CONFIG_DRIVE_PUSH_PULL,
+ PIN_CONFIG_DRIVE_OPEN_DRAIN,
+ PIN_CONFIG_DRIVE_OPEN_SOURCE,
+ PIN_CONFIG_DRIVE_OFF,
+ PIN_CONFIG_INPUT_SCHMITT,
+ PIN_CONFIG_INPUT_DEBOUNCE,
+ PIN_CONFIG_SLEW_RATE_RISING,
+ PIN_CONFIG_SLEW_RATE_FALLING,
+ PIN_CONFIG_POWER_SOURCE,
+ PIN_CONFIG_LOW_POWER_MODE,
+ PIN_CONFIG_WAKEUP,
+ PIN_CONFIG_END,
+};
+
+/**
+ * struct pin_config_tuple - a composite parameter and argument config item
+ * @param: the parameter to configure
+ * @data: argument to the parameter, meaning depend on parameter
+ */
+struct pin_config_tuple {
+ enum pin_config_param param;
+ unsigned long data;
+};
+
+/**
+ * struct pin_config - configuration state holder for a single config of a pin
+ * @bias: bias configuration tuple
+ * @drive: drive configuration tuple
+ * @schmitt: schmitt-trigger configuration tuple
+ * @debounce: debounce configuration tuple
+ * @slewrate_rising: rising edge slew rate configuration tuple
+ * @slewrate_falling: falling edge slew rate configuration tuple
+ * @power_source: selected power source tuple for the pin
+ * @low_power: low power mode tuple
+ * @wakeup: wakeup config tuple
+ *
+ * This holds one configuration item for one pin, a pin may have several such
+ * configurations since it may be configured for several non-conflicting modes
+ * simultaneously.
+ */
+struct pin_config {
+ struct pin_config_tuple bias;
+ struct pin_config_tuple drive;
+ struct pin_config_tuple schmitt;
+ struct pin_config_tuple debounce;
+ struct pin_config_tuple slewrate_rising;
+ struct pin_config_tuple slewrate_falling;
+ struct pin_config_tuple power_source;
+ struct pin_config_tuple low_power;
+ struct pin_config_tuple wakeup;
+};
+
+#ifdef CONFIG_PINCONF
+
+struct pinctrl_dev;
+
+/**
+ * struct pinconf_ops - pin config operations, to be implemented by
+ * pin configuration capable drivers.
+ * @pin_get_initial_config: called to get the initial config of each pin
+ * if you cannot read out the configuration of your pins at startup, just
+ * leave this as NULL
+ * @pin_config: configure an individual pin
+ * @pin_config_group: configure all pins in a group
+ * @pin_config_dbg_show: optional debugfs display hook that will provide
+ * per-device info for a certain pin in debugfs
+ */
+struct pinconf_ops {
+ int (*pin_get_initial_config) (struct pinctrl_dev *pctldev,
+ struct pin_config *conf,
+ unsigned pin);
+ int (*pin_config) (struct pinctrl_dev *pctldev,
+ const struct pin_config *conf,
+ unsigned pin,
+ const struct pin_config_tuple *configs,
+ unsigned num_configs);
+ int (*pin_config_group) (struct pinctrl_dev *pctldev,
+ unsigned selector,
+ const struct pin_config_tuple *configs,
+ unsigned num_configs);
+ void (*pin_config_dbg_show) (struct pinctrl_dev *pctldev,
+ struct seq_file *s,
+ unsigned offset);
+};
+
+
+extern int pin_config(struct pinctrl_dev *pctldev, int pin,
+ const struct pin_config_tuple *configs,
+ unsigned num_configs);
+extern int pin_config_group(struct pinctrl_dev *pctldev, const char *pin_group,
+ const struct pin_config_tuple *configs,
+ unsigned num_configs);
+
+#else
+
+static inline int pin_config(struct pinctrl_dev *pctldev, int pin,
+ const struct pin_config_tuple *configs,
+ unsigned num_configs)
+{
+ return 0;
+}
+
+static inline int pin_config_group(struct pinctrl_dev *pctldev,
+ const char *pin_group,
+ const struct pin_config_tuple *configs,
+ unsigned num_configs)
+{
+ return 0;
+}
+
+#endif
+
+#endif /* __LINUX_PINCTRL_PINCONF_H */
@@ -21,6 +21,7 @@
struct pinctrl_dev;
struct pinmux_ops;
+struct pinconf_ops;
struct gpio_chip;
/**
@@ -97,7 +98,9 @@ struct pinctrl_ops {
* but may be equal to npins if you have no holes in the pin range.
* @pctlops: pin control operation vtable, to support global concepts like
* grouping of pins, this is optional.
- * @pmxops: pinmux operation vtable, if you support pinmuxing in your driver
+ * @pmxops: pinmux operations vtable, if you support pinmuxing in your driver
+ * @confops: pin config operations vtable, if you support pin configuration in
+ * your driver
* @owner: module providing the pin controller, used for refcounting
*/
struct pinctrl_desc {
@@ -107,6 +110,7 @@ struct pinctrl_desc {
unsigned int maxpin;
struct pinctrl_ops *pctlops;
struct pinmux_ops *pmxops;
+ struct pinconf_ops *confops;
struct module *owner;
};
@@ -123,9 +127,7 @@ extern const char *pinctrl_dev_get_name(struct pinctrl_dev *pctldev);
extern void *pinctrl_dev_get_drvdata(struct pinctrl_dev *pctldev);
#else
-struct pinctrl_dev;
-
-/* Sufficiently stupid default function when pinctrl is not in use */
+/* Sufficiently stupid default functions when pinctrl is not in use */
static inline bool pin_is_valid(struct pinctrl_dev *pctldev, int pin)
{
return pin >= 0;