[patch] IBM HDAPS accelerometer driver.

Robert Love
2005-08-26T15:18:17Z

Andrew,

Of late I have been working on a driver for the IBM Hard Drive Active
Protection System (HDAPS), which provides a two-axis accelerometer and
some other misc. data. The hardware is found on recent IBM ThinkPad
laptops.

The following patch adds the driver to 2.6.13-rc6-mm2. It is
self-contained and fairly simple.

Please, apply.

Robert Love

Driver for the IBM HDAPS, an accelerometer

Signed-off-by: Robert Love <rml@novell.com>

MAINTAINERS | 7
drivers/hwmon/Kconfig | 17 +
drivers/hwmon/Makefile | 1
drivers/hwmon/hdaps.c | 594 +++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 619 insertions(+)

diff -urN linux-2.6.13-rc6-mm2/drivers/hwmon/hdaps.c linux/drivers/hwmon/hdaps.c
--- linux-2.6.13-rc6-mm2/drivers/hwmon/hdaps.c 1969-12-31 19:00:00.000000000 -0500
+++ linux/drivers/hwmon/hdaps.c 2005-08-26 11:07:53.000000000 -0400
@@ -0,0 +1,594 @@
+/*
+ * drivers/hwmon/hdaps.c - driver for IBM's Hard Drive Active Protection System
+ *
+ * Copyright (C) 2005 Robert Love <rml@novell.com>
+ * Copyright (C) 2005 Jesper Juhl <jesper.juhl@gmail.com>
+ *
+ * The HardDisk Active Protection System (hdaps) is present in the IBM ThinkPad
+ * T41, T42, T43, and R51, at least. It provides a basic two-axis
+ * accelerometer and other misc. data.
+ *
+ * Based on the document by Mark A. Smith available at
+ * http://www.almaden.ibm.com/cs/people/marksmith/tpaps.html and a lot of trial
+ * and error.
+ *
+ * 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.
+ *
+ * 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/delay.h>
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/timer.h>
+#include <linux/spinlock.h>
+#include <asm/io.h>
+
+#define HDAPS_LOW_PORT 0x1600 /* first port used by accelerometer */
+#define HDAPS_NR_PORTS 0x30 /* number of ports (0x1600 - 0x162f) */
+
+#define STATE_FRESH 0x50 /* accelerometer data is fresh */
+
+#define REFRESH_ASYNC 0x00 /* do asynchronous refresh */
+#define REFRESH_SYNC 0x01 /* do synchronous refresh */
+
+#define HDAPS_PORT_STATE 0x1611 /* device state */
+#define HDAPS_PORT_XPOS 0x1612 /* x-axis position */
+#define HDAPS_PORT_YPOS 0x1614 /* y-axis position */
+#define HDAPS_PORT_TEMP 0x1616 /* device temperature, in celcius */
+#define HDAPS_PORT_XVAR 0x1617 /* x-axis variance (what is this?) */
+#define HDAPS_PORT_YVAR 0x1619 /* y-axis variance (what is this?) */
+#define HDAPS_PORT_TEMP2 0x161b /* device temperature (again?) */
+#define HDAPS_PORT_UNKNOWN 0x161c /* what is this? */
+#define HDAPS_PORT_KMACT 0x161d /* keyboard or mouse activity */
+
+#define HDAPS_READ_MASK 0xff /* some reads have the low 8 bits set */
+
+#define KEYBD_MASK 0x20 /* set if keyboard activity */
+#define MOUSE_MASK 0x40 /* set if mouse activity */
+
+#define KEYBD_ISSET(n) (!! (n & KEYBD_MASK))
+#define MOUSE_ISSET(n) (!! (n & MOUSE_MASK))
+
+static spinlock_t hdaps_lock = SPIN_LOCK_UNLOCKED;
+
+
+/*
+ * __get_latch - Get the value from a given port latch. Callers must hold
+ * hdaps_lock.
+ */
+static inline unsigned short __get_latch(unsigned short port)
+{
+ return inb(port) & HDAPS_READ_MASK;
+}
+
+/*
+ * __check_latch - Check a port latch for a given value. Callers must hold
+ * hdaps_lock.
+ */
+static inline unsigned int __check_latch(unsigned short port, unsigned char val)
+{
+ if (__get_latch(port) == val)
+ return 1;
+ return 0;
+}
+
+/*
+ * __wait_latch - Wait up to 100us for a port latch to get a certain value,
+ * returning nonzero if the value is obtained and zero otherwise. Callers
+ * must hold hdaps_lock.
+ */
+static unsigned int __wait_latch(unsigned short port, unsigned char val)
+{
+ unsigned int i;
+
+ for (i = 0; i < 20; i++) {
+ if (__check_latch(port, val))
+ return 1;
+ udelay(5);
+ }
+
+#if 0
+ printk(KERN_WARNING "hdaps: wait on %04x returned %02x, not %02x!\n",
+ port, __check_latch(port, val), val);
+#endif
+
+ return 0;
+}
+
+/*
+ * __request_refresh - Request a refresh from the accelerometer.
+ *
+ * If sync is REFRESH_SYNC, we perform a synchronous refresh and will wait for
+ * the refresh. Returns nonzero if successful or zero on error.
+ *
+ * If sync is REFRESH_ASYNC, we merely kick off a new refresh if the device is
+ * not up-to-date. Always returns true. On the next read from the device, the
+ * data should be up-to-date but a synchronous wait should be performed to be
+ * sure.
+ *
+ * Callers must hold hdaps_lock.
+ */
+static int __request_refresh(int sync)
+{
+ unsigned char state;
+
+ state = inb(0x1604);
+ if (state == STATE_FRESH)
+ return 1;
+ else {
+ outb(0x11, 0x1610);
+ outb(0x01, 0x161f);
+ if (sync == REFRESH_ASYNC)
+ return 1;
+ }
+
+ return __wait_latch(0x1604, STATE_FRESH);
+}
+
+/*
+ * __tell_accelerometer_done - Indicate to the accelerometer that we are done
+ * reading data. Callers must hold hdaps_lock.
+ */
+static inline void __tell_accelerometer_done(void)
+{
+ inb(0x161f);
+ inb(0x1604);
+}
+
+/* internal lockless helper for accelerometer_readb_one */
+static int __accelerometer_readb_one(unsigned int port, u8 *val)
+{
+ int ret = 0;
+
+ /* do a sync refresh - we need to be sure we read fresh data */
+ if (unlikely(!__request_refresh(REFRESH_SYNC))) {
+ ret = -EIO;
+ goto out;
+ }
+
+ *val = inb(port);
+
+ __tell_accelerometer_done();
+
+ if (unlikely(!__request_refresh(REFRESH_ASYNC)))
+ ret = -EIO;
+
+out:
+ return ret;
+}
+
+/*
+ * accelerometer_readb_one - reads a byte from a single given I/O port,
+ * placing the value in the given pointer. Returns zero on success or a
+ * negative error on failure.
+ */
+static int accelerometer_readb_one(unsigned int port, u8 *val)
+{
+ int ret = 0;
+
+ spin_lock(&hdaps_lock);
+ ret = __accelerometer_readb_one(port, val);
+ spin_unlock(&hdaps_lock);
+ return ret;
+}
+
+/*
+ * accelerometer_read_pair - reads the values from a given pair of I/O ports,
+ * placing the values in the given pointers. Returns zero on success or a
+ * negative error on failure.
+ */
+static int accelerometer_read_pair(unsigned int port1, unsigned int port2,
+ int *val1, int *val2)
+{
+ int ret = 0;
+
+ spin_lock(&hdaps_lock);
+
+ /* do a sync refresh - we need to be sure we read fresh data */
+ if (unlikely(!__request_refresh(REFRESH_SYNC))) {
+ ret = -EIO;
+ goto out;
+ }
+
+ *val1 = inw(port1);
+ *val2 = inw(port2);
+
+ __tell_accelerometer_done();
+
+ if (unlikely(!__request_refresh(REFRESH_ASYNC)))
+ ret = -EIO;
+
+out:
+ spin_unlock(&hdaps_lock);
+ return ret;
+}
+
+#define INIT_TIMEOUT_MSECS 4000 /* wait up to 4s for device init ... */
+#define INIT_WAIT_MSECS 200 /* ... in 200ms increments */
+
+/* initialize the accelerometer */
+static int accelerometer_init(void)
+{
+ unsigned int total_msecs = INIT_TIMEOUT_MSECS;
+ unsigned int msecs_per_wait = INIT_WAIT_MSECS;
+ int ret = -EIO;
+
+ spin_lock(&hdaps_lock);
+
+ outb(0x13, 0x1610);
+ outb(0x01, 0x161f);
+ if (unlikely(!__wait_latch(0x161f, 0x00)))
+ goto out;
+
+ /*
+ * The 0x3 value appears to only work on some thinkpads, such as the
+ * T42p. Others return 0x1.
+ *
+ * The 0x2 value occurs when the chip has been previously initialized.
+ */
+ if (unlikely(!__check_latch(0x1611, 0x03) &&
+ !__check_latch(0x1611, 0x02) &&
+ !__check_latch(0x1611, 0x01)))
+ goto out;
+
+ printk(KERN_DEBUG "hdaps: initial latch check good (0x%02x)\n",
+ __get_latch(0x1611));
+
+ outb(0x17, 0x1610);
+ outb(0x81, 0x1611);
+ outb(0x01, 0x161f);
+ if (unlikely(!__wait_latch(0x161f, 0x00)))
+ goto out;
+ if (unlikely(!__wait_latch(0x1611, 0x00)))
+ goto out;
+ if (unlikely(!__wait_latch(0x1612, 0x60)))
+ goto out;
+ if (unlikely(!__wait_latch(0x1613, 0x00)))
+ goto out;
+ outb(0x14, 0x1610);
+ outb(0x01, 0x1611);
+ outb(0x01, 0x161f);
+ if (unlikely(!__wait_latch(0x161f, 0x00)))
+ goto out;
+ outb(0x10, 0x1610);
+ outb(0xc8, 0x1611);
+ outb(0x00, 0x1612);
+ outb(0x02, 0x1613);
+ outb(0x01, 0x161f);
+ if (unlikely(!__wait_latch(0x161f, 0x00)))
+ goto out;
+ if (unlikely(!__request_refresh(REFRESH_SYNC)))
+ goto out;
+ if (unlikely(!__wait_latch(0x1611, 0x00)))
+ goto out;
+
+ /* we have done our dance, now let's wait for the applause */
+ ret = -ENXIO;
+ while (total_msecs > 0) {
+ u8 ignored;
+
+ /* a read of the device helps push it into action */
+ __accelerometer_readb_one(HDAPS_PORT_TEMP2, &ignored);
+ if (__wait_latch(0x1611, 0x02)) {
+ ret = 0;
+ break;
+ }
+ spin_unlock(&hdaps_lock);
+
+ msleep(msecs_per_wait);
+ total_msecs -= msecs_per_wait;
+
+ spin_lock(&hdaps_lock);
+ }
+
+out:
+ spin_unlock(&hdaps_lock);
+ return ret;
+}
+
+
+/* device class stuff */
+
+static DECLARE_COMPLETION(hdaps_obj_is_free);
+static void hdaps_release_dev(struct device *dev)
+{
+ complete(&hdaps_obj_is_free);
+}
+
+static int hdaps_resume(struct device* dev, u32 level)
+{
+ return accelerometer_init();
+}
+
+static struct device_driver hdaps_driver = {
+ .owner = THIS_MODULE,
+ .name = "hdaps",
+ .bus = &platform_bus_type,
+ .resume = hdaps_resume,
+};
+
+struct platform_device hdaps_plat_dev = {
+ .name = "hdaps",
+ .id = -1,
+ .dev = {
+ .release = hdaps_release_dev,
+ .driver = &hdaps_driver,
+ }
+};
+
+
+/* Input device stuff */
+
+static struct input_dev hdaps_idev;
+static struct timer_list hdaps_poll_timer;
+static unsigned int hdaps_mousedev_threshold = 4;
+static unsigned long hdaps_poll_ms = 25;
+static int hdaps_mousedev_registered;
+static u16 rest_x;
+static u16 rest_y;
+
+static void hdaps_calibrate(void)
+{
+ int x, y, ret;
+
+ ret = accelerometer_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y);
+ if (unlikely(ret))
+ return;
+
+ rest_x = x;
+ rest_y = y;
+}
+
+static void hdaps_mousedev_poll(unsigned long unused)
+{
+ int movex, movey, x, y, ret;
+
+ ret = accelerometer_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y);
+ if (unlikely(ret))
+ return;
+
+ movex = rest_x - x;
+ movey = rest_y - y;
+ if (abs(movex) > hdaps_mousedev_threshold)
+ input_report_rel(&hdaps_idev, REL_Y, movex);
+ if (abs(movey) > hdaps_mousedev_threshold)
+ input_report_rel(&hdaps_idev, REL_X, movey);
+ input_sync(&hdaps_idev);
+
+ mod_timer(&hdaps_poll_timer, jiffies + msecs_to_jiffies(hdaps_poll_ms));
+}
+
+static void hdaps_mousedev_enable(void)
+{
+ /* calibrate the device before enabling */
+ hdaps_calibrate();
+
+ init_input_dev(&hdaps_idev);
+ hdaps_idev.dev = &hdaps_plat_dev.dev;
+ hdaps_idev.evbit[0] = BIT(EV_KEY) | BIT(EV_REL);
+ hdaps_idev.relbit[0] = BIT(REL_X) | BIT(REL_Y);
+ hdaps_idev.keybit[LONG(BTN_LEFT)] = BIT(BTN_LEFT);
+ input_register_device(&hdaps_idev);
+
+ hdaps_mousedev_registered = 1;
+
+ init_timer(&hdaps_poll_timer);
+ hdaps_poll_timer.function = hdaps_mousedev_poll;
+ hdaps_poll_timer.expires = jiffies + msecs_to_jiffies(hdaps_poll_ms);
+ add_timer(&hdaps_poll_timer);
+
+ printk(KERN_INFO "hdaps: input device enabled\n");
+}
+
+static void hdaps_mousedev_disable(void)
+{
+ if (!hdaps_mousedev_registered)
+ return;
+
+ del_timer_sync(&hdaps_poll_timer);
+ input_unregister_device(&hdaps_idev);
+}
+
+
+/* Sysfs Files */
+
+static ssize_t hdaps_position_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int ret, x, y;
+
+ ret = accelerometer_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y);
+ if (unlikely(ret))
+ return ret;
+
+ return sprintf(buf, "(%d,%d)\n", x, y);
+}
+static DEVICE_ATTR(position, 0444, hdaps_position_show, NULL);
+
+static ssize_t hdaps_variance_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int ret, x, y;
+
+ ret = accelerometer_read_pair(HDAPS_PORT_XVAR, HDAPS_PORT_YVAR, &x, &y);
+ if (unlikely(ret))
+ return ret;
+
+ return sprintf(buf, "(%d,%d)\n", x, y);
+}
+static DEVICE_ATTR(variance, 0444, hdaps_variance_show, NULL);
+
+static ssize_t hdaps_temp_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ u8 temp;
+ int ret;
+
+ ret = accelerometer_readb_one(HDAPS_PORT_TEMP, &temp);
+ if (unlikely(ret < 0))
+ return ret;
+
+ return sprintf(buf, "%u\n", temp);
+}
+static DEVICE_ATTR(temp, 0444, hdaps_temp_show, NULL);
+
+static ssize_t hdaps_mousedev_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", hdaps_mousedev_registered);
+}
+
+static ssize_t hdaps_mousedev_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ int enable;
+
+ if (sscanf(buf, "%d\n", &enable) != 1)
+ return -EINVAL;
+
+ if (enable == 1)
+ hdaps_mousedev_enable();
+ else if (enable == 0)
+ hdaps_mousedev_disable();
+
+ return count;
+}
+
+static DEVICE_ATTR(mousedev, 0644, hdaps_mousedev_show, hdaps_mousedev_store);
+
+static ssize_t hdaps_calibrate_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ hdaps_calibrate();
+ return count;
+}
+static DEVICE_ATTR(calibrate, 0200, NULL, hdaps_calibrate_store);
+
+static ssize_t hdaps_threshold_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%u\n", hdaps_mousedev_threshold);
+}
+
+static ssize_t hdaps_threshold_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ unsigned int threshold;
+
+ if (sscanf(buf, "%u\n", &threshold) != 1 || threshold == 0)
+ return -EINVAL;
+ hdaps_mousedev_threshold = threshold;
+
+ return count;
+}
+
+static DEVICE_ATTR(mousedev_threshold, 0644, hdaps_threshold_show,
+ hdaps_threshold_store);
+
+static ssize_t hdaps_poll_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%lu\n", hdaps_poll_ms);
+}
+
+static ssize_t hdaps_poll_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ unsigned int poll;
+
+ if (sscanf(buf, "%u\n", &poll) != 1 || poll == 0)
+ return -EINVAL;
+ hdaps_poll_ms = poll;
+
+ return count;
+}
+
+static DEVICE_ATTR(mousedev_poll_ms, 0644, hdaps_poll_show, hdaps_poll_store);
+
+
+/* Module stuff */
+
+static unsigned int mousedev;
+module_param(mousedev, bool, 0);
+MODULE_PARM_DESC(mousedev, "enable the input class device on module load");
+
+static int __init hdaps_init(void)
+{
+ int ret;
+
+ if (unlikely(!request_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS, "hdaps")))
+ return -ENXIO;
+
+ ret = accelerometer_init();
+ if (unlikely(ret))
+ goto out_release;
+
+ ret = driver_register(&hdaps_driver);
+ if (unlikely(ret))
+ goto out_release;
+
+ ret = platform_device_register(&hdaps_plat_dev);
+ if (unlikely(ret))
+ goto out_driver;
+
+ device_create_file(&hdaps_plat_dev.dev, &dev_attr_position);
+ device_create_file(&hdaps_plat_dev.dev, &dev_attr_variance);
+ device_create_file(&hdaps_plat_dev.dev, &dev_attr_temp);
+ device_create_file(&hdaps_plat_dev.dev, &dev_attr_calibrate);
+ device_create_file(&hdaps_plat_dev.dev, &dev_attr_mousedev);
+ device_create_file(&hdaps_plat_dev.dev, &dev_attr_mousedev_threshold);
+ device_create_file(&hdaps_plat_dev.dev, &dev_attr_mousedev_poll_ms);
+
+ if (mousedev)
+ hdaps_mousedev_enable();
+
+ printk(KERN_INFO "hdaps: initialized.\n");
+
+ return 0;
+
+out_driver:
+ driver_unregister(&hdaps_driver);
+out_release:
+ release_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS);
+ printk(KERN_WARNING "hdaps: initilization failed! ret=%d\n", ret);
+ return ret;
+}
+
+static void __exit hdaps_exit(void)
+{
+ hdaps_mousedev_disable();
+
+ device_remove_file(&hdaps_plat_dev.dev, &dev_attr_mousedev_poll_ms);
+ device_remove_file(&hdaps_plat_dev.dev, &dev_attr_mousedev_threshold);
+ device_remove_file(&hdaps_plat_dev.dev, &dev_attr_mousedev);
+ device_remove_file(&hdaps_plat_dev.dev, &dev_attr_temp);
+ device_remove_file(&hdaps_plat_dev.dev, &dev_attr_calibrate);
+ device_remove_file(&hdaps_plat_dev.dev, &dev_attr_variance);
+ device_remove_file(&hdaps_plat_dev.dev, &dev_attr_position);
+ platform_device_unregister(&hdaps_plat_dev);
+ driver_unregister(&hdaps_driver);
+
+ release_region(HDAPS_LOW_PORT, HDAPS_NR_PORTS);
+}
+
+module_init(hdaps_init);
+module_exit(hdaps_exit);
+
+MODULE_LICENSE("GPL");
diff -urN linux-2.6.13-rc6-mm2/drivers/hwmon/Kconfig linux/drivers/hwmon/Kconfig
--- linux-2.6.13-rc6-mm2/drivers/hwmon/Kconfig 2005-08-26 11:06:49.000000000 -0400
+++ linux/drivers/hwmon/Kconfig 2005-08-26 11:07:53.000000000 -0400
@@ -411,6 +411,23 @@
This driver can also be built as a module. If so, the module
will be called w83627ehf.

+config SENSORS_HDAPS
+ tristate "IBM Hard Drive Active Protection System (hdaps)"
+ depends on HWMON
+ default n
+ help
+ This driver provides support for the IBM Hard Drive Active Protection
+ System (hdaps), which provides an accelerometer and other misc. data.
+ Supported laptops include the IBM ThinkPad T41, T42, T43, and R51.
+ The accelerometer data is readable via sysfs.
+
+ This driver also provides an input class device, allowing the
+ laptop to act as a pinball machine-esque mouse. This is off by
+ default but enabled via sysfs or the module parameter "mousedev".
+
+ Say Y here if you have an applicable laptop and want to experience
+ the awesome power of hdaps.
+
config HWMON_DEBUG_CHIP
bool "Hardware Monitoring Chip debugging messages"
depends on HWMON
diff -urN linux-2.6.13-rc6-mm2/drivers/hwmon/Makefile linux/drivers/hwmon/Makefile
--- linux-2.6.13-rc6-mm2/drivers/hwmon/Makefile 2005-08-26 11:06:50.000000000 -0400
+++ linux/drivers/hwmon/Makefile 2005-08-26 11:07:53.000000000 -0400
@@ -22,6 +22,7 @@
obj-$(CONFIG_SENSORS_FSCPOS) += fscpos.o
obj-$(CONFIG_SENSORS_GL518SM) += gl518sm.o
obj-$(CONFIG_SENSORS_GL520SM) += gl520sm.o
+obj-$(CONFIG_SENSORS_HDAPS) += hdaps.o
obj-$(CONFIG_SENSORS_IT87) += it87.o
obj-$(CONFIG_SENSORS_LM63) += lm63.o
obj-$(CONFIG_SENSORS_LM75) += lm75.o
diff -urN linux-2.6.13-rc6-mm2/MAINTAINERS linux/MAINTAINERS
--- linux-2.6.13-rc6-mm2/MAINTAINERS 2005-08-26 11:06:58.000000000 -0400
+++ linux/MAINTAINERS 2005-08-26 11:07:53.000000000 -0400
@@ -984,6 +984,13 @@
W: http://www.nyx.net/~arobinso
S: Maintained

+HDAPS
+P: Robert Love
+M: rlove@rlove.org
+M: linux-kernel@vger.kernel.org
+W: http://www.kernel.org/pub/linux/kernel/people/rml/hdaps/
+S: Maintained
+
HFS FILESYSTEM
P: Roman Zippel
M: zippel@linux-m68k.org