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Message-ID: <20100617141440.030f1de9@lxorguk.ukuu.org.uk>
Date: Thu, 17 Jun 2010 14:14:40 +0100
From: Alan Cox <alan@...rguk.ukuu.org.uk>
To: Jonathan Cameron <jic23@....ac.uk>
Cc: Jean Delvare <khali@...ux-fr.org>, linux-i2c@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] hmc6352: Add driver for the HMC6352 compass
Ok - cleaning up the sysfs API to match the docs also cleans up the code
a tiny bit more so do it that way
--
hmc6352: Add driver for the HMC6352 compass
From: Kalhan Trisal <kalhan.trisal@...el.com>
This driver will report the heading values in degrees to the sysfs interface.
The values returned are headings . e.g. 245.6
Alan: Cleanups requested now all folded in and a sysfs description to keep
Andrew happy. The sysfs description now resembles hwmon.
Signed-off-by: Kalhan Trisal <kalhan.trisal@...el.com>
Signed-off-by: Alan Cox <alan@...ux.intel.com>
---
.../ABI/testing/sysfs-bus-i2c-devices-hm6352 | 21 +++
drivers/misc/Kconfig | 7 +
drivers/misc/Makefile | 1
drivers/misc/hmc6352.c | 165 ++++++++++++++++++++
4 files changed, 194 insertions(+), 0 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-bus-i2c-devices-hm6352
create mode 100644 drivers/misc/hmc6352.c
diff --git a/Documentation/ABI/testing/sysfs-bus-i2c-devices-hm6352 b/Documentation/ABI/testing/sysfs-bus-i2c-devices-hm6352
new file mode 100644
index 0000000..feb2e4a
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-i2c-devices-hm6352
@@ -0,0 +1,21 @@
+Where: /sys/bus/i2c/devices/.../heading0_input
+Date: April 2010
+Kernel Version: 2.6.36?
+Contact: alan.cox@...el.com
+Description: Reports the current heading from the compass as a floating
+ point value in degrees.
+
+Where: /sys/bus/i2c/devices/.../power_state
+Date: April 2010
+Kernel Version: 2.6.36?
+Contact: alan.cox@...el.com
+Description: Sets the power state of the device. 0 sets the device into
+ sleep mode, 1 wakes it up.
+
+Where: /sys/bus/i2c/devices/.../calibration
+Date: April 2010
+Kernel Version: 2.6.36?
+Contact: alan.cox@...el.com
+Description: Sets the calibration on or off (1 = on, 0 = off). See the
+ chip data sheet.
+
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 26386a9..9e825cb 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -304,6 +304,13 @@ 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 6ed06a1..48597df 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -28,6 +28,7 @@ obj-$(CONFIG_DS1682) += ds1682.o
obj-$(CONFIG_TI_DAC7512) += ti_dac7512.o
obj-$(CONFIG_C2PORT) += c2port/
obj-$(CONFIG_IWMC3200TOP) += iwmc3200top/
+obj-$(CONFIG_HMC6352) += hmc6352.o
obj-y += eeprom/
obj-y += cb710/
obj-$(CONFIG_VMWARE_BALLOON) += vmware_balloon.o
diff --git a/drivers/misc/hmc6352.c b/drivers/misc/hmc6352.c
new file mode 100644
index 0000000..63d9519
--- /dev/null
+++ b/drivers/misc/hmc6352.c
@@ -0,0 +1,165 @@
+/*
+ * 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 DEFINE_MUTEX(compass_mutex);
+
+static int compass_command(struct i2c_client *c, u8 cmd)
+{
+ int ret = i2c_master_send(c, &cmd, 1);
+ if (ret < 0)
+ dev_warn(&c->dev, "command '%c' failed.\n", cmd);
+ return ret;
+}
+
+static int compass_store(struct device *dev, const char *buf, size_t count,
+ const char *map)
+{
+ struct i2c_client *c = to_i2c_client(dev);
+ int ret;
+ unsigned long val;
+
+ if (strict_strtoul(buf, 10, &val))
+ return -EINVAL;
+ if (val >= strlen(map))
+ return -EINVAL;
+ mutex_lock(&compass_mutex);
+ ret = compass_command(c, map[val]);
+ mutex_unlock(&compass_mutex);
+ return ret;
+}
+
+static ssize_t compass_calibration_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ return compass_store(dev, buf, count, "EC");
+}
+
+static ssize_t compass_power_mode_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ return compass_store(dev, buf, count, "SW");
+}
+
+static ssize_t compass_heading_data_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+
+ struct i2c_client *client = to_i2c_client(dev);
+ unsigned char i2c_data[2];
+ unsigned int ret;
+
+ mutex_lock(&compass_mutex);
+ ret = compass_command(client, 'A');
+ if (ret != 1) {
+ mutex_unlock(&compass_mutex);
+ return ret;
+ }
+ msleep(10); /* sending 'A' cmd we need to wait for 7-10 millisecs */
+ ret = i2c_master_recv(client, i2c_data, 2);
+ mutex_unlock(&compass_mutex);
+ if (ret != 1) {
+ dev_warn(dev, "i2c read data cmd failed\n");
+ return ret;
+ }
+ ret = (i2c_data[0] << 8) | i2c_data[1];
+ return sprintf(buf, "%d.%d\n", ret/10, ret%10);
+}
+
+
+static DEVICE_ATTR(heading0_input, 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_heading0_input.attr,
+ &dev_attr_calibration.attr,
+ &dev_attr_power_state.attr,
+ NULL
+};
+
+static const 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, "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@...el.com");
+MODULE_DESCRIPTION("hmc6352 Compass Driver");
+MODULE_LICENSE("GPL v2");
--
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