[PATCH][input] add Honeywell hmc5843 3-Axis Magnetometer (digital compass) driver.
From: Steven King
Date: Fri Dec 11 2009 - 01:50:28 EST
Signed-off-by: Steven King <sfking@xxxxxxxxx>
---
drivers/input/misc/Kconfig | 10 +
drivers/input/misc/Makefile | 1 +
drivers/input/misc/hmc5843.c | 515 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 526 insertions(+), 0 deletions(-)
create mode 100644 drivers/input/misc/hmc5843.c
diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index a9bb254..7564b96 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -317,4 +317,14 @@ config INPUT_PCAP
To compile this driver as a module, choose M here: the
module will be called pcap_keys.
+config INPUT_HMC5843
+ tristate "Honeywell HMC5843 3-Axis Magnetometer"
+ depends on I2C && SYSFS
+ select INPUT_POLLDEV
+ help
+ Say Y here to add support for the Honeywell HMC 5843 3-Axis
+ Magnetometer (digital compass).
+
+ To compile this driver as a module, choose M here: the module
+ will be called hmc5843.
endif
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index a8b8485..825b70c 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -30,4 +30,5 @@ obj-$(CONFIG_INPUT_WINBOND_CIR) += winbond-cir.o
obj-$(CONFIG_INPUT_WISTRON_BTNS) += wistron_btns.o
obj-$(CONFIG_INPUT_WM831X_ON) += wm831x-on.o
obj-$(CONFIG_INPUT_YEALINK) += yealink.o
+obj-$(CONFIG_INPUT_HMC5843) += hmc5843.o
diff --git a/drivers/input/misc/hmc5843.c b/drivers/input/misc/hmc5843.c
new file mode 100644
index 0000000..51bb86c
--- /dev/null
+++ b/drivers/input/misc/hmc5843.c
@@ -0,0 +1,515 @@
+/*
+ * Driver for the Honeywell HMC5843 3-Axis Magnetometer.
+ *
+ * Author: Steven King <sfking@xxxxxxxxx>
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/jiffies.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/input-polldev.h>
+
+#define HMC5843_CFG_A_REG 0
+#define HMC5843_CFG_A_BIAS_MASK 0x03
+#define HMC5843_CFG_A_RATE_MASK 0x1c
+#define HMC5843_CFG_A_RATE_SHIFT 2
+#define HMC5843_CFG_B_REG 1
+#define MMC5843_CFG_B_GAIN_MASK 0xe0
+#define MMC5843_CFG_B_GAIN_SHIFT 5
+#define HMC5843_MODE_REG 2
+#define HMC5843_MODE_REPEAT 0
+#define HMC5843_MODE_ONCE 1
+#define HMC5843_MODE_IDLE 2
+#define HMC5843_MODE_SLEEP 3
+#define HMC5843_X_DATA_REG 3
+#define HMC5843_Y_DATA_REG 5
+#define HMC5843_Z_DATA_REG 7
+#define HMC5843_STATUS_REG 9
+#define HMC5843_STATUS_REN 0x04
+#define HMC5843_STATUS_LOCK 0x02
+#define HMC5843_STATUS_RDY 0x01
+#define HMC5843_ID_REG_A 10
+#define HMC5843_ID_REG_B 11
+#define HMC5843_ID_REG_C 12
+#define HMC5843_LAST_REG 12
+#define HMC5843_NUM_REG 13
+
+struct hmc5843 {
+ struct i2c_client *client;
+ struct mutex lock;
+ struct input_polled_dev *ipdev;
+ int bias;
+ int gain;
+ int rate;
+ int mode;
+ int index;
+};
+
+/* interval between samples for the different rates, in msecs */
+static const unsigned int hmc5843_sample_interval[] = {
+ 1000 * 2, 1000, 1000 / 2, 1000 / 5,
+ 1000 / 10, 1000 / 20, 1000 / 50,
+};
+
+/*
+ * From the datasheet:
+ *
+ * The devices uses an address pointer to indicate which register location is
+ * to be read from or written to. These pointer locations are sent from the
+ * master to this slave device and succeed the 7-bit address plus 1 bit
+ * read/write identifier.
+ *
+ * To minimize the communication between the master and this device, the
+ * address pointer updated automatically without master intervention. This
+ * automatic address pointer update has two additional features. First when
+ * address 12 or higher is accessed the pointer updates to address 00 and
+ * secondly when address 09 is reached, the pointer rolls back to address 03.
+ * Logically, the address pointer operation functions as shown below.
+ *
+ * If (address pointer = 09) then address pointer = 03
+ * Else if (address pointer >= 12) then address pointer = 0
+ * Else (address pointer) = (address pointer) + 1
+ *
+ * Since the set of operations performed by this driver is pretty simple,
+ * we keep track of the register being written to when updating the
+ * configuration and when reading data only update the address ptr when its not
+ * pointing to the first data register.
+*/
+
+static int hmc5843_write_register(struct hmc5843 *hmc5843, int index)
+{
+ u8 buf[2];
+ int result;
+
+ buf[0] = index;
+ if (index == HMC5843_CFG_A_REG)
+ buf[1] = hmc5843->bias |
+ (hmc5843->rate << HMC5843_CFG_A_RATE_SHIFT);
+ else if (index == HMC5843_CFG_B_REG)
+ buf[1] = hmc5843->gain << MMC5843_CFG_B_GAIN_SHIFT;
+ else if (index == HMC5843_MODE_REG)
+ buf[1] = hmc5843->mode;
+ else
+ return -EINVAL;
+ result = i2c_master_send(hmc5843->client, buf, sizeof(buf));
+
+ if (result != 2) {
+ hmc5843->index = -1;
+ return result;
+ }
+ hmc5843->index = index + 1;
+ return 0;
+}
+
+static int hmc5843_read_xyz(struct hmc5843 *hmc5843, int *x, int *y, int *z)
+{
+ struct i2c_msg msgs[2];
+ u8 buf[6];
+ int n = 0;
+ int result;
+
+ if (hmc5843->index != HMC5843_X_DATA_REG) {
+ buf[0] = HMC5843_X_DATA_REG;
+
+ msgs[0].addr = hmc5843->client->addr;
+ msgs[0].flags = 0;
+ msgs[0].buf = buf;
+ msgs[0].len = 1;
+
+ hmc5843->index = HMC5843_X_DATA_REG;
+ n = 1;
+ }
+ msgs[n].addr = hmc5843->client->addr;
+ msgs[n].flags = I2C_M_RD;
+ msgs[n].buf = buf;
+ msgs[n].len = 6;
+ ++n;
+
+ result = i2c_transfer(hmc5843->client->adapter, msgs, n);
+ if (result != n) {
+ hmc5843->index = -1;
+ return result;
+ }
+
+ *x = (((int)((s8)buf[0])) << 8) | buf[1];
+ *y = (((int)((s8)buf[2])) << 8) | buf[3];
+ *z = (((int)((s8)buf[4])) << 8) | buf[5];
+ return 0;
+}
+
+/* sysfs stuff */
+
+/* bias */
+static ssize_t hmc5843_show_bias(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct hmc5843 *hmc5843 = i2c_get_clientdata(client);
+
+ return sprintf(buf, "%d\n", hmc5843->bias);
+}
+
+static ssize_t hmc5843_store_bias(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct hmc5843 *hmc5843 = i2c_get_clientdata(client);
+ unsigned long val;
+ int status = count;
+
+ if ((strict_strtol(buf, 10, &val) < 0) || (val > 2))
+ return -EINVAL;
+ mutex_lock(&hmc5843->lock);
+ if (hmc5843->bias != val) {
+ hmc5843->bias = val;
+ status = hmc5843_write_register(hmc5843, HMC5843_CFG_A_REG);
+ }
+ mutex_unlock(&hmc5843->lock);
+ return status;
+}
+
+static DEVICE_ATTR(bias, S_IWUSR | S_IRUGO, hmc5843_show_bias,
+ hmc5843_store_bias);
+
+/* rate */
+static ssize_t hmc5843_show_rate(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct hmc5843 *hmc5843 = i2c_get_clientdata(client);
+
+ return sprintf(buf, "%d\n", hmc5843->rate);
+}
+
+static ssize_t hmc5843_store_rate(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct hmc5843 *hmc5843 = i2c_get_clientdata(client);
+ unsigned long val;
+ int status = count;
+
+ if ((strict_strtol(buf, 10, &val) < 0) || (val > 6))
+ return -EINVAL;
+ mutex_lock(&hmc5843->lock);
+ if (hmc5843->rate != val) {
+ hmc5843->rate = val;
+ hmc5843->ipdev->poll_interval = hmc5843_sample_interval[val];
+ status = hmc5843_write_register(hmc5843, HMC5843_CFG_A_REG);
+ }
+ mutex_unlock(&hmc5843->lock);
+ return status;
+}
+
+static DEVICE_ATTR(rate, S_IWUSR | S_IRUGO, hmc5843_show_rate,
+ hmc5843_store_rate);
+
+/* gain */
+static ssize_t hmc5843_show_gain(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct hmc5843 *hmc5843 = i2c_get_clientdata(client);
+
+ return sprintf(buf, "%d\n", hmc5843->gain);
+}
+
+static ssize_t hmc5843_store_gain(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct hmc5843 *hmc5843 = i2c_get_clientdata(client);
+ unsigned long val;
+ int status = count;
+
+ if ((strict_strtol(buf, 10, &val) < 0) || (val > 6))
+ return -EINVAL;
+ mutex_lock(&hmc5843->lock);
+ if (hmc5843->gain != val) {
+ hmc5843->gain = val;
+ status = hmc5843_write_register(hmc5843, HMC5843_CFG_B_REG);
+ }
+ mutex_unlock(&hmc5843->lock);
+ return status;
+}
+
+static DEVICE_ATTR(gain, S_IWUSR | S_IRUGO, hmc5843_show_gain,
+ hmc5843_store_gain);
+
+/* mode */
+static ssize_t hmc5843_show_mode(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct hmc5843 *hmc5843 = i2c_get_clientdata(client);
+
+ return sprintf(buf, "%d\n", hmc5843->mode);
+}
+
+static ssize_t hmc5843_store_mode(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct hmc5843 *hmc5843 = i2c_get_clientdata(client);
+ unsigned long val;
+ int status = count;
+
+ if ((strict_strtol(buf, 10, &val) < 0) || (val > 3))
+ return -EINVAL;
+ mutex_lock(&hmc5843->lock);
+ if (hmc5843->mode != val) {
+ hmc5843->mode = val;
+ status = hmc5843_write_register(hmc5843, HMC5843_MODE_REG);
+ }
+ mutex_unlock(&hmc5843->lock);
+ return status;
+}
+
+static DEVICE_ATTR(mode, S_IWUSR | S_IRUGO, hmc5843_show_mode,
+ hmc5843_store_mode);
+
+static struct attribute *hmc5843_attributes[] = {
+ &dev_attr_bias.attr,
+ &dev_attr_rate.attr,
+ &dev_attr_gain.attr,
+ &dev_attr_mode.attr,
+ NULL,
+};
+
+static const struct attribute_group hmc5843_attr_group = {
+ .attrs = hmc5843_attributes,
+};
+
+/* use polled input device */
+
+static void hmc5843_poll(struct input_polled_dev *ipdev)
+{
+ struct hmc5843 *hmc5843 = ipdev->private;
+ int x, y, z;
+
+ mutex_lock(&hmc5843->lock);
+ if (!hmc5843_read_xyz(hmc5843, &x, &y, &z)) {
+ input_report_abs(ipdev->input, ABS_X, x);
+ input_report_abs(ipdev->input, ABS_Y, y);
+ input_report_abs(ipdev->input, ABS_Z, z);
+ input_sync(ipdev->input);
+ }
+ mutex_unlock(&hmc5843->lock);
+}
+
+static int __devinit hmc5843_input_init(struct hmc5843 *hmc5843)
+{
+ int status;
+ struct input_polled_dev *ipdev;
+
+ ipdev = input_allocate_polled_device();
+ if (!ipdev) {
+ dev_dbg(&hmc5843->client->dev, "error creating input device\n");
+ return -ENOMEM;
+ }
+ ipdev->poll = hmc5843_poll;
+ ipdev->poll_interval = hmc5843_sample_interval[hmc5843->rate];
+ ipdev->private = hmc5843;
+
+ ipdev->input->name = "Honeywell HMC5843 3-Axis Magnetometer";
+ ipdev->input->phys = "hmc5843/input0";
+ ipdev->input->id.bustype = BUS_HOST;
+
+ set_bit(EV_ABS, ipdev->input->evbit);
+
+ input_set_abs_params(ipdev->input, ABS_X, -2047, 2047, 0, 0);
+ input_set_abs_params(ipdev->input, ABS_Y, -2047, 2047, 0, 0);
+ input_set_abs_params(ipdev->input, ABS_Z, -2047, 2047, 0, 0);
+
+ status = input_register_polled_device(ipdev);
+ if (status) {
+ dev_dbg(&hmc5843->client->dev,
+ "error registering input device\n");
+ input_free_polled_device(ipdev);
+ goto exit;
+ }
+ hmc5843->ipdev = ipdev;
+exit:
+ return status;
+}
+
+static int __devinit hmc5843_device_init(struct hmc5843 *hmc5843)
+{
+ struct i2c_client *client = hmc5843->client;
+ int status;
+
+ struct i2c_msg msgs[2];
+ u8 buf[6] = { HMC5843_ID_REG_A }; /* start reading at 1st id reg */
+
+ msgs[0].addr = client->addr;
+ msgs[0].flags = 0;
+ msgs[0].buf = buf;
+ msgs[0].len = 1;
+ msgs[1].addr = client->addr;
+ msgs[1].flags = I2C_M_RD;
+ msgs[1].buf = buf; /* overwrite sent address on read */
+ msgs[1].len = 6; /* 3 id regs + cfg_a, cfg_b & mode reg */
+
+ status = i2c_transfer(client->adapter, msgs, 2);
+ if (status != 2) {
+ dev_dbg(&client->dev, "unable to contact device\n");
+ return status;
+ }
+ if (strncmp(buf, "H43", 3)) {
+ dev_dbg(&client->dev, "incorrect device id %-3.3s", buf);
+ return -EINVAL;
+ }
+ /* the read will have wrapped to 0, bytes 3-6 are cfg_a, cfg_b, mode */
+ hmc5843->bias = buf[3] & HMC5843_CFG_A_BIAS_MASK;
+ hmc5843->rate = buf[3] >> HMC5843_CFG_A_RATE_SHIFT;
+ hmc5843->gain = buf[4] >> MMC5843_CFG_B_GAIN_SHIFT;
+ hmc5843->mode = buf[5];
+
+ hmc5843->index = 3;
+ mutex_init(&hmc5843->lock);
+ return 0;
+}
+
+static int __devinit hmc5843_i2c_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int status;
+ struct hmc5843 *hmc5843;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+ dev_dbg(&client->dev, "adapter doesn't support I2C\n");
+ return -ENODEV;
+ }
+
+ hmc5843 = kzalloc(sizeof(*hmc5843), GFP_KERNEL);
+ if (!hmc5843) {
+ dev_dbg(&client->dev, "unable to allocate memory\n");
+ return -ENOMEM;
+ }
+
+ hmc5843->client = client;
+ i2c_set_clientdata(client, hmc5843);
+
+ status = hmc5843_device_init(hmc5843);
+ if (status)
+ goto fail0;
+
+ status = hmc5843_input_init(hmc5843);
+ if (status)
+ goto fail0;
+
+ status = sysfs_create_group(&client->dev.kobj, &hmc5843_attr_group);
+ if (status) {
+ dev_dbg(&client->dev, "could not create sysfs files\n");
+ goto fail1;
+ }
+ return 0;
+fail1:
+ input_unregister_polled_device(hmc5843->ipdev);
+fail0:
+ kfree(hmc5843);
+ return status;
+}
+
+static int __devexit hmc5843_i2c_remove(struct i2c_client *client)
+{
+ struct hmc5843 *hmc5843 = i2c_get_clientdata(client);
+
+ sysfs_remove_group(&client->dev.kobj, &hmc5843_attr_group);
+ input_unregister_polled_device(hmc5843->ipdev);
+ i2c_set_clientdata(client, NULL);
+ kfree(hmc5843);
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int hmc5843_suspend(struct device *dev)
+{
+ struct i2c_client *client = dev_get_drvdata(dev);
+ struct hmc5843 *hmc5843 = i2c_get_clientdata(client);
+
+ /* save our current mode for resume and put device to sleep */
+ int m = hmc5843->mode;
+ hmc5843->mode = HMC5843_MODE_SLEEP;
+ hmc5843_write_register(hmc5843, HMC5843_MODE_REG);
+ hmc5843->mode = m;
+ return 0;
+}
+
+static int hmc5843_resume(struct device *dev)
+{
+ struct i2c_client *client = dev_get_drvdata(dev);
+ struct hmc5843 *hmc5843 = i2c_get_clientdata(client);
+
+ /* restore whatever mode we were in before suspending */
+ hmc5843_write_register(hmc5843, HMC5843_MODE_REG);
+ return 0;
+}
+
+static struct dev_pm_ops hmc5843_dev_pm_ops = {
+ .suspend = hmc5843_suspend,
+ .resume = hmc5843_resume,
+};
+
+#define HMC5843_DEV_PM_OPS (&hmc5843_dev_pm_ops)
+#else
+#define HMC5843_DEV_PM_OPS NULL
+#endif
+
+static const struct i2c_device_id hmc5843_id[] = {
+ { "hmc5843", 0 },
+ { },
+};
+
+MODULE_DEVICE_TABLE(i2c, hmc5843_id);
+
+static struct i2c_driver hmc5843_i2c_driver = {
+ .driver = {
+ .name = "hmc5843",
+ .owner = THIS_MODULE,
+ .pm = HMC5843_DEV_PM_OPS,
+ },
+ .probe = hmc5843_i2c_probe,
+ .remove = __devexit_p(hmc5843_i2c_remove),
+ .id_table = hmc5843_id,
+};
+
+static int __init hmc5843_init(void)
+{
+ return i2c_add_driver(&hmc5843_i2c_driver);
+}
+module_init(hmc5843_init);
+
+static void __exit hmc5843_exit(void)
+{
+ i2c_del_driver(&hmc5843_i2c_driver);
+}
+module_exit(hmc5843_exit);
+
+MODULE_AUTHOR("Steven King <sfking@xxxxxxxxx>");
+MODULE_DESCRIPTION("Honeywell HMC5843 3-Axis Magnetometer driver");
+MODULE_LICENSE("GPL");
--
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