[PATCH 4/4] misc: Add SAR100 angular rate driver.
Stefan Schmidt
stefan at datenfreihafen.org
Mon Apr 26 09:25:06 CEST 2010
Signed-off-by: Stefan Schmidt <stefan at datenfreihafen.org>
---
drivers/misc/Kconfig | 7 +
drivers/misc/Makefile | 1 +
drivers/misc/sar100.c | 296 +++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 304 insertions(+), 0 deletions(-)
create mode 100644 drivers/misc/sar100.c
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index aed9c8c..235ec60 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -505,4 +505,11 @@ config MLX90609
This option enabled the driver for the MLX90609 Angular Rate Sensor
(gyroscope).
+config SAR100
+ tristate "SAR100 Angular Rate Sensor (gyroscope)"
+ depends on SPI
+ help
+ This option enabled the driver for the SAR100 Angular Rate Sensor
+ (gyroscope).
+
endif # MISC_DEVICES
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index d211639..56106af 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -37,4 +37,5 @@ obj-$(CONFIG_MACH_NEO1973) += neo1973_version.o \
neo1973_pm_host.o \
neo1973_pm_resume_reason.o
obj-$(CONFIG_MLX90609) += mlx90609.o
+obj-$(CONFIG_SAR100) += sar100.o
diff --git a/drivers/misc/sar100.c b/drivers/misc/sar100.c
new file mode 100644
index 0000000..ba5a531
--- /dev/null
+++ b/drivers/misc/sar100.c
@@ -0,0 +1,296 @@
+/* Linux kernel driver for the Sensonor SAR100 Angular Rate Sensor
+ *
+ * Copyright (C) 2010 DLR
+ * Author: Stefan Schmidt <stefan at datenfreihafen.org>
+ *
+ * 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/types.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/sysfs.h>
+#include <linux/spi/spi.h>
+
+/* Read commands */
+#define RARH 0x80 /* Read angular rate, high byte */
+#define RARLX 0x8E /* Read angular rate, low byte extended */
+#define RTMP 0xB0 /* Read internal temperature */
+#define RSR 0xB4 /* Read status register */
+
+/* SafeGuard commands, address goes before command */
+#define SGDIS1 0xD74E /* SafeGuard disable command 1 */
+#define SGDIS2 0x5063 /* SafeGuard disable command 2 */
+#define SGDIS3 0xA812 /* SafeGuard disable command 3 */
+#define SGEN 0x55 /* SafeGuard enable command */
+
+/* Replies */
+#define SGR1 0x80
+#define SGR2 0x00
+#define ERR_MASK 0xF0
+#define RARLX_MASK 0x0F
+#define ERROR 0x80
+
+/* Error handling commands */
+#define PRCEN 0xAA /* Re-enable signal processing after error condition */
+
+struct sar100_info {
+ struct spi_device *spi_dev;
+ struct device *dev;
+ u8 tx_buf[2];
+ u8 rx_buf[1];
+ struct mutex lock;
+};
+
+static int sar100_spi(struct sar100_info *sar, u8 cmd, u8 *data)
+{
+ struct spi_message message;
+ struct spi_transfer xfer;
+ int status;
+
+ /* Build our spi message */
+ spi_message_init(&message);
+ memset(&xfer, 0, sizeof(xfer));
+ xfer.len = 1;
+ xfer.tx_buf = sar->tx_buf;
+ xfer.rx_buf = sar->rx_buf;
+
+ /* Put our command in the output buffer */
+ sar->tx_buf[0] = cmd;
+
+ spi_message_add_tail(&xfer, &message);
+
+ mutex_lock(&sar->lock);
+ status = spi_sync(sar->spi_dev, &message);
+ mutex_unlock(&sar->lock);
+
+ if (status == 0)
+ *data = sar->rx_buf[0];
+ return status;
+}
+
+static int sar100_spi16(struct sar100_info *sar, u16 cmd)
+{
+ struct spi_message message;
+ struct spi_transfer xfer;
+ int status;
+
+ /* Build our spi message */
+ spi_message_init(&message);
+ memset(&xfer, 0, sizeof(xfer));
+ xfer.len = 2;
+ xfer.tx_buf = sar->tx_buf;
+ xfer.rx_buf = sar->rx_buf;
+
+ /* Put our command in the output buffer */
+ sar->tx_buf[0] = cmd >> 8;
+ sar->tx_buf[1] = cmd;
+
+ spi_message_add_tail(&xfer, &message);
+
+ mutex_lock(&sar->lock);
+ status = spi_sync(sar->spi_dev, &message);
+ mutex_unlock(&sar->lock);
+
+ return status;
+}
+
+static int read_status(struct sar100_info *sar)
+{
+ u8 rsr;
+
+ sar100_spi(sar, RSR, &rsr);
+ sar100_spi(sar, 0x0F, &rsr); /* Dummy command */
+
+ return rsr;
+}
+
+static int handle_safeguard(struct sar100_info *sar)
+{
+ u8 status, ret;
+
+ /* Test for ADC_OK or EXC_OK problems */
+ status = read_status(sar);
+ if (!(status >> 7)) {
+ dev_info(&sar->spi_dev->dev, "ADC overflow, recovering\n");
+ goto recover;
+ }
+ status &= 0x03;
+ status >>= 1;
+ if (!status) {
+ dev_info(&sar->spi_dev->dev, "Control loop failed, recovering\n");
+ goto recover;
+ }
+ else {
+ /* Not recoverable error found: power ccle needed */
+ dev_info(&sar->spi_dev->dev, "Unrecoverable error condition. Power clycle needed.\n");
+ return -EIO;
+ }
+
+recover:
+ /* Execute safegurad sequence */
+ msleep(100);
+ sar100_spi16(sar, SGDIS1);
+ sar100_spi16(sar, SGDIS2);
+ sar100_spi16(sar, SGDIS3);
+ sar100_spi(sar, PRCEN, &ret);
+ sar100_spi(sar, SGEN, &ret);
+ return 0;
+}
+
+static int read_rate(struct sar100_info *sar)
+{
+ int ret;
+ u8 rarh, rarlx;
+
+ sar100_spi(sar, RARH, &rarh);
+ sar100_spi(sar, 0x0F, &rarh); /* Dummy command */
+ sar100_spi(sar, RARLX, &rarlx);
+ sar100_spi(sar, 0x0F, &rarlx); /* Dummy command */
+
+ /* If any monitored error is found the answer will be 0x80 */
+ if (rarh == ERROR && rarlx == ERROR) {
+ handle_safeguard(sar);
+ dev_info(&sar->spi_dev->dev, "Error detected\n");
+ return -EIO;
+ }
+
+ rarlx &= RARLX_MASK;
+ ret = ((s8)rarh) << 8 | ((s8)rarlx) << 4;
+
+ return ret >> 4;
+}
+
+static int read_temp(struct sar100_info *sar)
+{
+ u8 rtmp;
+
+ sar100_spi(sar, RTMP, &rtmp);
+ sar100_spi(sar, 0x0F, &rtmp); /* Dummy command */
+
+ return rtmp;
+}
+
+/* Sysfs interface for temperature and angular rate */
+static ssize_t show_temperature(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct sar100_info *sar = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%i\n", read_temp(sar));
+}
+
+static DEVICE_ATTR(temperature, S_IRUGO, show_temperature, NULL);
+
+static ssize_t show_angular_rate(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct sar100_info *sar = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%i\n", read_rate(sar));
+}
+
+static DEVICE_ATTR(angular_rate, S_IRUGO, show_angular_rate, NULL);
+
+static struct attribute *sar100_sysfs_entries[] = {
+ &dev_attr_angular_rate.attr,
+ &dev_attr_temperature.attr,
+ NULL
+};
+
+static struct attribute_group sar100_attr_group = {
+ .name = NULL,
+ .attrs = sar100_sysfs_entries,
+};
+
+/* Device driver infrastructure */
+static int __devinit sar100_probe(struct spi_device *spi)
+{
+ int rc, status;
+ struct sar100_info *sar;
+
+ sar = kzalloc(sizeof(*sar), GFP_KERNEL);
+ if (!sar)
+ return -ENOMEM;
+
+ sar->spi_dev = spi;
+ dev_set_drvdata(&spi->dev, sar);
+ mutex_init(&sar->lock);
+
+ rc = sysfs_create_group(&spi->dev.kobj, &sar100_attr_group);
+ if (rc) {
+ dev_err(&spi->dev, "Error creating sysfs group\n");
+ goto err_out;
+ }
+
+ msleep(200); /* Start Up time ?? */
+
+ dev_info(&spi->dev, "SAR100 driver loaded\n");
+ status = read_status(sar);
+ if (status == 0xFF)
+ dev_info(&spi->dev, "Power and status is ok\n");
+ else {
+ dev_info(&spi->dev, "Power or another problem\n");
+ goto err_out;
+ }
+
+ return 0;
+
+err_out:
+ dev_set_drvdata(&spi->dev, NULL);
+ kfree(sar);
+ return rc;
+}
+
+static int __devexit sar100_remove(struct spi_device *spi)
+{
+ struct sar100_info *sar = dev_get_drvdata(&spi->dev);
+
+ sysfs_remove_group(&spi->dev.kobj, &sar100_attr_group);
+ dev_set_drvdata(&spi->dev, NULL);
+ kfree(sar);
+
+ return 0;
+}
+
+static struct spi_driver sar100_driver = {
+ .driver = {
+ .name = "sar100",
+ .owner = THIS_MODULE,
+ },
+ .probe = sar100_probe,
+ .remove = __devexit_p(sar100_remove),
+};
+
+static int __init sar100_init(void)
+{
+ return spi_register_driver(&sar100_driver);
+}
+
+static void __exit sar100_exit(void)
+{
+ spi_unregister_driver(&sar100_driver);
+}
+
+MODULE_DESCRIPTION("SPI driver for the SAR100 angular rate sensor");
+MODULE_AUTHOR("Stefan Schmidt <stefan at datenfreihafen.org>");
+MODULE_LICENSE("GPL");
+
+module_init(sar100_init);
+module_exit(sar100_exit);
--
1.7.0.5
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