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SubjectRe: [PATCH 1/4] hmc6352: Add driver for the HMC6352 compass
Ripping it out of hwmon and applying the hedge trimmers to everything not
needed and we get this for drivers/misc. I've also swapped the command
codes to characters as the datasheet specifies them in ascii.

--------------------------------8<------------------------------
hmc6352: Add driver for the HMC6352 compass

From: Kalhan Trisal <kalhan.trisal@intel.com>

This driver will report the heading values in degrees to the sysfs interface.
The values returned are headings . e.g. 245.6

(Some cleanups from Alan Cox)

Signed-off-by: Kalhan Trisal <kalhan.trisal@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
---
drivers/misc/Kconfig | 7 ++
drivers/misc/Makefile | 1
drivers/misc/hmc6352.c | 199 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 207 insertions(+), 0 deletions(-)
create mode 100644 drivers/misc/hmc6352.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 2191c8d..e626bac 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -278,6 +278,13 @@ config SENSORS_TSL2550
This driver can also be built as a module. If so, the module
will be called tsl2550.

+config HMC6352
+ tristate "Honeywell HMC6352 compass"
+ depends on I2C
+ help
+ This driver provides support for the Honeywell HMC6352 compass,
+ providing configuration and heading data via sysfs.
+
config EP93XX_PWM
tristate "EP93xx PWM support"
depends on ARCH_EP93XX
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 208ae30..620cf0b 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -26,5 +26,6 @@ obj-$(CONFIG_DS1682) += ds1682.o
obj-$(CONFIG_TI_DAC7512) += ti_dac7512.o
obj-$(CONFIG_C2PORT) += c2port/
obj-$(CONFIG_IWMC3200TOP) += iwmc3200top/
+obj-$(CONFIG_HMC6352) += hmc6352.o
obj-y += eeprom/
obj-y += cb710/
diff --git a/drivers/misc/hmc6352.c b/drivers/misc/hmc6352.c
new file mode 100644
index 0000000..f4162ea
--- /dev/null
+++ b/drivers/misc/hmc6352.c
@@ -0,0 +1,199 @@
+/*
+ * hmc6352.c - Honeywell Compass Driver
+ *
+ * Copyright (C) 2009 Intel Corp
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * 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; version 2 of the License.
+ *
+ * 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/init.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/sysfs.h>
+
+static ssize_t compass_calibration_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ int ret;
+ unsigned long val;
+ char cmd = 'C'; /* Calibrate */
+ char cmd1 = 'E'; /* Exit calibration mode */
+ struct i2c_msg msg[] = {
+ { client->addr, 0, 1, &cmd },
+ };
+ struct i2c_msg msg1[] = {
+ { client->addr, 0, 1, &cmd1 },
+ };
+
+ if (strict_strtoul(buf, 10, &val))
+ return -EINVAL;
+ if (val == 1) {
+ ret = i2c_transfer(client->adapter, msg, 1);
+ if (ret != 1) {
+ dev_warn(dev, "hmc6352_comp: i2c calib start cmd failed\n");
+ return ret;
+ }
+ } else if (val == 2) {
+ ret = i2c_transfer(client->adapter, msg1, 1);
+ if (ret != 1) {
+ dev_warn(dev, "hmc6352_comp: i2c calib stop cmd failed\n");
+ return ret;
+ }
+ } else
+ return -EINVAL;
+
+ return count;
+}
+
+static ssize_t compass_heading_data_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+
+ struct i2c_client *client = to_i2c_client(dev);
+ static char cmd = 'A'; /* Get Data */
+ unsigned char i2c_data[2];
+ unsigned int ret, ret_val;
+ struct i2c_msg msg[] = {
+ { client->addr, 0, 1, &cmd },
+ };
+ struct i2c_msg msg1[] = {
+ { client->addr, I2C_M_RD, 2, i2c_data },
+ };
+
+ ret = i2c_transfer(client->adapter, msg, 1);
+ if (ret != 1) {
+ dev_warn(dev, "hmc6352: i2c cmd 0x41 failed\n");
+ return ret;
+ }
+ msleep(10); /* sending 0x41 cmd we need to wait for 7-10 milli second*/
+ ret = i2c_transfer(client->adapter, msg1, 1);
+ if (ret != 1) {
+ dev_warn(dev, "hmc6352: i2c read data cmd failed\n");
+ return ret;
+ }
+ ret_val = i2c_data[0];
+ ret_val = ((ret_val << 8) | i2c_data[1]);
+ return sprintf(buf, "%d.%d\n", ret_val/10, ret_val%10);
+}
+
+static ssize_t compass_power_mode_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+
+ struct i2c_client *client = to_i2c_client(dev);
+ unsigned long val;
+ unsigned int ret;
+ static char cmd = 'S'; /* Sleep mode */
+ static char cmd1 = 'W'; /* Wake up */
+ struct i2c_msg msg[] = {
+ { client->addr, 0, 1, &cmd },
+ };
+ struct i2c_msg msg1[] = {
+ { client->addr, 0, 1, &cmd1 },
+ };
+
+ if (strict_strtoul(buf, 10, &val))
+ return -EINVAL;
+
+ if (val == 0) {
+ ret = i2c_transfer(client->adapter, msg, 1);
+ if (ret != 1)
+ dev_warn(dev, "hmc6352: i2c cmd sleep mode failed\n");
+ } else if (val == 1) {
+ ret = i2c_transfer(client->adapter, msg1, 1);
+ if (ret != 1)
+ dev_warn(dev, "hmc6352: i2c cmd active mode failed\n");
+ } else
+ return -EINVAL;
+
+ return count;
+}
+
+static DEVICE_ATTR(heading, S_IRUGO, compass_heading_data_show, NULL);
+static DEVICE_ATTR(calibration, S_IWUSR, NULL, compass_calibration_store);
+static DEVICE_ATTR(power_state, S_IWUSR, NULL, compass_power_mode_store);
+
+static struct attribute *mid_att_compass[] = {
+ &dev_attr_heading.attr,
+ &dev_attr_calibration.attr,
+ &dev_attr_power_state.attr,
+ NULL
+};
+
+static struct attribute_group m_compass_gr = {
+ .name = "hmc6352",
+ .attrs = mid_att_compass
+};
+
+static int hmc6352_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int res;
+
+ res = sysfs_create_group(&client->dev.kobj, &m_compass_gr);
+ if (res) {
+ dev_err(&client->dev, "hmc6352: device_create_file failed\n");
+ return res;
+ }
+ dev_info(&client->dev, "%s HMC6352 compass chip found\n",
+ client->name);
+ return 0;
+}
+
+static int hmc6352_remove(struct i2c_client *client)
+{
+ sysfs_remove_group(&client->dev.kobj, &m_compass_gr);
+ return 0;
+}
+
+static struct i2c_device_id hmc6352_id[] = {
+ { "hmc6352", 0 },
+ { }
+};
+
+MODULE_DEVICE_TABLE(i2c, hmc6352_id);
+
+static struct i2c_driver hmc6352_driver = {
+ .driver = {
+ .name = "hmc6352",
+ },
+ .probe = hmc6352_probe,
+ .remove = hmc6352_remove,
+ .id_table = hmc6352_id,
+};
+
+static int __init sensor_hmc6352_init(void)
+{
+ return i2c_add_driver(&hmc6352_driver);
+}
+
+static void __exit sensor_hmc6352_exit(void)
+{
+ i2c_del_driver(&hmc6352_driver);
+}
+
+module_init(sensor_hmc6352_init);
+module_exit(sensor_hmc6352_exit);
+
+MODULE_AUTHOR("Kalhan Trisal <kalhan.trisal@intel.com");
+MODULE_DESCRIPTION("hmc6352 Compass Driver");
+MODULE_LICENSE("GPL v2");

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