cregit-Linux how code gets into the kernel

Release 4.7 drivers/input/misc/ideapad_slidebar.c

/*
 * Input driver for slidebars on some Lenovo IdeaPad laptops
 *
 * Copyright (C) 2013 Andrey Moiseev <o2g.org.ru@gmail.com>
 *
 * Reverse-engineered from Lenovo SlideNav software (SBarHook.dll).
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * Trademarks are the property of their respective owners.
 */

/*
 * Currently tested and works on:
 *      Lenovo IdeaPad Y550
 *      Lenovo IdeaPad Y550P
 *
 * Other models can be added easily. To test,
 * load with 'force' parameter set 'true'.
 *
 * LEDs blinking and input mode are managed via sysfs,
 * (hex, unsigned byte value):
 * /sys/devices/platform/ideapad_slidebar/slidebar_mode
 *
 * The value is in byte range, however, I only figured out
 * how bits 0b10011001 work. Some other bits, probably,
 * are meaningfull too.
 *
 * Possible states:
 *
 * STD_INT, ONMOV_INT, OFF_INT, LAST_POLL, OFF_POLL
 *
 * Meaning:
 *           released      touched
 * STD       'heartbeat'   lights follow the finger
 * ONMOV     no lights     lights follow the finger
 * LAST      at last pos   lights follow the finger
 * OFF       no lights     no lights
 *
 * INT       all input events are generated, interrupts are used
 * POLL      no input events by default, to get them,
 *           send 0b10000000 (read below)
 *
 * Commands: write
 *
 * All      |  0b01001 -> STD_INT
 * possible |  0b10001 -> ONMOV_INT
 * states   |  0b01000 -> OFF_INT
 *
 *                      |  0b0 -> LAST_POLL
 * STD_INT or ONMOV_INT |
 *                      |  0b1 -> STD_INT
 *
 *                      |  0b0 -> OFF_POLL
 * OFF_INT or OFF_POLL  |
 *                      |  0b1 -> OFF_INT
 *
 * Any state |   0b10000000 ->  if the slidebar has updated data,
 *                              produce one input event (last position),
 *                              switch to respective POLL mode
 *                              (like 0x0), if not in POLL mode yet.
 *
 * Get current state: read
 *
 * masked by 0x11 read value means:
 *
 * 0x00   LAST
 * 0x01   STD
 * 0x10   OFF
 * 0x11   ONMOV
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/dmi.h>
#include <linux/spinlock.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/i8042.h>
#include <linux/serio.h>


#define IDEAPAD_BASE	0xff29


static bool force;
module_param(force, bool, 0);
MODULE_PARM_DESC(force, "Force driver load, ignore DMI data");

static DEFINE_SPINLOCK(io_lock);


static struct input_dev *slidebar_input_dev;

static struct platform_device *slidebar_platform_dev;


static u8 slidebar_pos_get(void) { u8 res; unsigned long flags; spin_lock_irqsave(&io_lock, flags); outb(0xf4, 0xff29); outb(0xbf, 0xff2a); res = inb(0xff2b); spin_unlock_irqrestore(&io_lock, flags); return res; }

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static u8 slidebar_mode_get(void) { u8 res; unsigned long flags; spin_lock_irqsave(&io_lock, flags); outb(0xf7, 0xff29); outb(0x8b, 0xff2a); res = inb(0xff2b); spin_unlock_irqrestore(&io_lock, flags); return res; }

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static void slidebar_mode_set(u8 mode) { unsigned long flags; spin_lock_irqsave(&io_lock, flags); outb(0xf7, 0xff29); outb(0x8b, 0xff2a); outb(mode, 0xff2b); spin_unlock_irqrestore(&io_lock, flags); }

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static bool slidebar_i8042_filter(unsigned char data, unsigned char str, struct serio *port) { static bool extended = false; /* We are only interested in data coming form KBC port */ if (str & I8042_STR_AUXDATA) return false; /* Scancodes: e03b on move, e0bb on release. */ if (data == 0xe0) { extended = true; return true; } if (!extended) return false; extended = false; if (likely((data & 0x7f) != 0x3b)) { serio_interrupt(port, 0xe0, 0); return false; } if (data & 0x80) { input_report_key(slidebar_input_dev, BTN_TOUCH, 0); } else { input_report_key(slidebar_input_dev, BTN_TOUCH, 1); input_report_abs(slidebar_input_dev, ABS_X, slidebar_pos_get()); } input_sync(slidebar_input_dev); return true; }

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static ssize_t show_slidebar_mode(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%x\n", slidebar_mode_get()); }

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static ssize_t store_slidebar_mode(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { u8 mode; int error; error = kstrtou8(buf, 0, &mode); if (error) return error; slidebar_mode_set(mode); return count; }

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static DEVICE_ATTR(slidebar_mode, S_IWUSR | S_IRUGO, show_slidebar_mode, store_slidebar_mode); static struct attribute *ideapad_attrs[] = { &dev_attr_slidebar_mode.attr, NULL }; static struct attribute_group ideapad_attr_group = { .attrs = ideapad_attrs }; static const struct attribute_group *ideapad_attr_groups[] = { &ideapad_attr_group, NULL };
static int __init ideapad_probe(struct platform_device* pdev) { int err; if (!request_region(IDEAPAD_BASE, 3, "ideapad_slidebar")) { dev_err(&pdev->dev, "IO ports are busy\n"); return -EBUSY; } slidebar_input_dev = input_allocate_device(); if (!slidebar_input_dev) { dev_err(&pdev->dev, "Failed to allocate input device\n"); err = -ENOMEM; goto err_release_ports; } slidebar_input_dev->name = "IdeaPad Slidebar"; slidebar_input_dev->id.bustype = BUS_HOST; slidebar_input_dev->dev.parent = &pdev->dev; input_set_capability(slidebar_input_dev, EV_KEY, BTN_TOUCH); input_set_capability(slidebar_input_dev, EV_ABS, ABS_X); input_set_abs_params(slidebar_input_dev, ABS_X, 0, 0xff, 0, 0); err = i8042_install_filter(slidebar_i8042_filter); if (err) { dev_err(&pdev->dev, "Failed to install i8042 filter: %d\n", err); goto err_free_dev; } err = input_register_device(slidebar_input_dev); if (err) { dev_err(&pdev->dev, "Failed to register input device: %d\n", err); goto err_remove_filter; } return 0; err_remove_filter: i8042_remove_filter(slidebar_i8042_filter); err_free_dev: input_free_device(slidebar_input_dev); err_release_ports: release_region(IDEAPAD_BASE, 3); return err; }

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static int ideapad_remove(struct platform_device *pdev) { i8042_remove_filter(slidebar_i8042_filter); input_unregister_device(slidebar_input_dev); release_region(IDEAPAD_BASE, 3); return 0; }

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static struct platform_driver slidebar_drv = { .driver = { .name = "ideapad_slidebar", }, .remove = ideapad_remove, };
static int __init ideapad_dmi_check(const struct dmi_system_id *id) { pr_info("Laptop model '%s'\n", id->ident); return 1; }

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static const struct dmi_system_id ideapad_dmi[] __initconst = { { .ident = "Lenovo IdeaPad Y550", .matches = { DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"), DMI_MATCH(DMI_PRODUCT_NAME, "20017"), DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo IdeaPad Y550") }, .callback = ideapad_dmi_check }, { .ident = "Lenovo IdeaPad Y550P", .matches = { DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"), DMI_MATCH(DMI_PRODUCT_NAME, "20035"), DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo IdeaPad Y550P") }, .callback = ideapad_dmi_check }, { NULL, } }; MODULE_DEVICE_TABLE(dmi, ideapad_dmi);
static int __init slidebar_init(void) { int err; if (!force && !dmi_check_system(ideapad_dmi)) { pr_err("DMI does not match\n"); return -ENODEV; } slidebar_platform_dev = platform_device_alloc("ideapad_slidebar", -1); if (!slidebar_platform_dev) { pr_err("Not enough memory\n"); return -ENOMEM; } slidebar_platform_dev->dev.groups = ideapad_attr_groups; err = platform_device_add(slidebar_platform_dev); if (err) { pr_err("Failed to register platform device\n"); goto err_free_dev; } err = platform_driver_probe(&slidebar_drv, ideapad_probe); if (err) { pr_err("Failed to register platform driver\n"); goto err_delete_dev; } return 0; err_delete_dev: platform_device_del(slidebar_platform_dev); err_free_dev: platform_device_put(slidebar_platform_dev); return err; }

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static void __exit slidebar_exit(void) { platform_device_unregister(slidebar_platform_dev); platform_driver_unregister(&slidebar_drv); }

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module_init(slidebar_init); module_exit(slidebar_exit); MODULE_AUTHOR("Andrey Moiseev <o2g.org.ru@gmail.com>"); MODULE_DESCRIPTION("Slidebar input support for some Lenovo IdeaPad laptops"); MODULE_LICENSE("GPL");

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