[RFC] ACPI: Add GPIO-signaled event simulator.

Message ID	1406217076-17150-1-git-send-email-tomasz.nowicki@linaro.org (mailing list archive)
State	RFC, archived
Headers	show Return-Path: <linux-acpi-owner@kernel.org> From: Tomasz Nowicki <tomasz.nowicki@linaro.org> To: rjw@rjwysocki.net, linus.walleij@linaro.org, gnurou@gmail.com Cc: linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linaro-acpi@lists.linaro.org, Tomasz Nowicki <tomasz.nowicki@linaro.org> Subject: [RFC] ACPI: Add GPIO-signaled event simulator. Date: Thu, 24 Jul 2014 17:51:16 +0200 Message-Id: <1406217076-17150-1-git-send-email-tomasz.nowicki@linaro.org> Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig index fd54a74..59e4c67 100644 --- a/drivers/acpi/Kconfig +++ b/drivers/acpi/Kconfig @@ -122,6 +122,17 @@ config ACPI_BUTTON To compile this driver as a module, choose M here: the module will be called button. +config ACPI_GPIO_EVT_EMULATE + bool "ACPI GPIO-signaled Events Emulation Support" + depends on DEBUG_FS + default n + help + This will enable your system to emulate GPIO-signaled event through + proc file system /sys/kernel/debug/acpi/gpio_event. User needs to print + available GPIO devices and pin map (cat path_to_proc_file) so that he + knows how to trigger given event by echo "XXX YYY" > path_to_proc_file + (where, XXX is a path to GPIO device and YYY is a pin number). + config ACPI_VIDEO tristate "Video" depends on X86 && BACKLIGHT_CLASS_DEVICE diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile index 9fa20ff..fb3c335 100644 --- a/drivers/acpi/Makefile +++ b/drivers/acpi/Makefile @@ -55,6 +55,7 @@ acpi-$(CONFIG_ACPI_PROCFS_POWER) += cm_sbs.o ifdef CONFIG_ACPI_VIDEO acpi-y += video_detect.o endif +acpi-$(CONFIG_ACPI_GPIO_EVT_EMULATE) += gpio_evt_emu.o # These are (potentially) separate modules diff --git a/drivers/acpi/gpio_evt_emu.c b/drivers/acpi/gpio_evt_emu.c new file mode 100644 index 0000000..a2f762c --- /dev/null +++ b/drivers/acpi/gpio_evt_emu.c @@ -0,0 +1,207 @@ +/* + * Code to emulate GPIO-signaled events. + * + * The sole purpose of this module is to help with GPIO event triggering. + * Suggested way of using: + * 1. Perform walk of the namespac device tree looking for GPIO devices + * with associated _AEI resources e.g.: + * $ cat /sys/kernel/debug/acpi/gpio_event + * GPIO device name: /__SB.GPI0 + * Available GPIO pin map: + * /__SB.GPI0 <-> pin 0x100 + * + * 2. Trigger method corresponding to device pin number: + * $ echo "/__SB.GPI0 0x100" > /sys/kernel/debug/acpi/gpio_event + */ + +/* + * Copyright (C) 2014, Linaro Ltd. + * Author: Tomasz Nowicki <tomasz.nowicki@linaro.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/module.h> +#include <linux/uaccess.h> +#include <linux/debugfs.h> +#include <linux/acpi.h> + +#include "acpica/accommon.h" +#include "acpica/acnamesp.h" + +#include "internal.h" + +static struct dentry *gpio_evt_dentry; + +static void gpio_trigger_event(char *gpio_path, u32 pin) +{ + acpi_handle gpio_handle, evt_handle; + char ev_name[5]; + + if (ACPI_FAILURE(acpi_get_handle(NULL, gpio_path, &gpio_handle))) { + pr_err(PREFIX "getting handle to <%s> failed\n", gpio_path); + return; + } + + if (pin <= 255) + sprintf(ev_name, "_L%02X", pin); + else + sprintf(ev_name, "_EVT"); + + + if (ACPI_FAILURE(acpi_get_handle(gpio_handle, ev_name, &evt_handle))) { + pr_err(PREFIX "getting handle to <%s.%s> failed, there is no method related to 0x%02X pin\n", + gpio_path, ev_name, pin); + return; + } + + if (ACPI_FAILURE(acpi_execute_simple_method(evt_handle, NULL, + pin <= 255 ? 0 : pin))) + pr_err(PREFIX "evaluating <%s._EVT for pin %d> failed\n", + gpio_path, pin); + + return; +} + +static ssize_t gpio_evt_write(struct file *file, const char __user *user_buf, + size_t count, loff_t *ppos) +{ + u32 pin_number; + char *gpio_path = NULL; + char *pin_str = NULL; + const char *delim = " "; + char *temp_buf = NULL; + char *temp_buf_addr = NULL; + + temp_buf = kmalloc(count+1, GFP_ATOMIC); + if (!temp_buf) { + pr_warn(PREFIX "%s: Memory allocation failed\n", __func__); + return count; + } + temp_buf[count] = '\0'; + temp_buf_addr = temp_buf; + if (copy_from_user(temp_buf, user_buf, count)) + goto out; + + gpio_path = strsep(&temp_buf, delim); + pin_str = strsep(&temp_buf, delim); + + if (gpio_path && pin_str) { + ssize_t ret; + unsigned long val; + + ret = kstrtoul(pin_str, 10, &val); + if (ret) { + pr_warn(PREFIX "unknown event\n"); + goto out; + } + + pin_number = (u32)val; + } else { + pr_warn(PREFIX "unknown device\n"); + goto out; + } + + pr_info(PREFIX "ACPI device name is <%s>, pin number is <%d>\n", + gpio_path, pin_number); + + gpio_trigger_event(gpio_path, pin_number); + +out: + kfree(temp_buf_addr); + return count; +} + +static acpi_status gpio_list_resource(struct acpi_resource *ares, + void *context) +{ + struct acpi_resource_gpio *agpio; + struct seq_file *m = context; + int pin; + + if (!m) + return AE_OK; + + if (ares->type != ACPI_RESOURCE_TYPE_GPIO) + return AE_OK; + + agpio = &ares->data.gpio; + if (agpio->connection_type != ACPI_RESOURCE_GPIO_TYPE_INT) + return AE_OK; + + pin = agpio->pin_table[0]; + seq_printf(m, "%s <-> pin %d\n", agpio->resource_source.string_ptr, + pin); + + return AE_OK; +} + +static acpi_status gpio_find_resource(acpi_handle handle, u32 lvl, + void *context, void **rv) +{ + struct acpi_namespace_node *node; + struct seq_file *m = context; + + if (ACPI_FAILURE(acpi_walk_resources(handle, METHOD_NAME__AEI, + gpio_list_resource, NULL))) + return AE_OK; + + node = acpi_ns_validate_handle(handle); + if (!node) { + pr_err(PREFIX "Mapping GPIO handle to node failed\n"); + return AE_OK; + } + + seq_printf(m, "GPIO device name: %4.4s\nAvailable GPIO pin map:\n", + ACPI_CAST_PTR(char, &node->name)); + acpi_walk_resources(handle, METHOD_NAME__AEI, gpio_list_resource, + context); + return AE_OK; +} + +static int gpio_evt_show(struct seq_file *m, void *v) +{ + acpi_get_devices(NULL, gpio_find_resource, m, NULL); + return 0; +} + +static int gpio_evt_open(struct inode *inode, struct file *file) +{ + return single_open(file, gpio_evt_show, NULL); +} + +static const struct file_operations gpio_evt_emu_fops = { + .open = gpio_evt_open, + .write = gpio_evt_write, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static int __init gpio_evt_emu_init(void) +{ + if (acpi_debugfs_dir == NULL) + return -ENOENT; + + gpio_evt_dentry = debugfs_create_file("gpio_event", S_IWUSR, + acpi_debugfs_dir, NULL, &gpio_evt_emu_fops); + if (gpio_evt_dentry == NULL) + return -ENODEV; + + return 0; +} + +device_initcall(gpio_evt_emu_init); +ACPI_MODULE_NAME("acpi_evt_emu"); +MODULE_LICENSE("GPL");

[RFC] ACPI: Add GPIO-signaled event simulator.

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