[PATCH] lm70: New hardware monitoring driver

This driver implements support for the National Semiconductor LM70 temperature sensor. The LM70 temperature sensor chip supports a single temperature sensor. It communicates with a host processor (or microcontroller) via an SPI/Microwire Bus interface. Communication with the LM70 is simple: when the temperature is to be sensed, the driver accesses the LM70 using SPI communication: 16 SCLK cycles comprise the MOSI/MISO loop. At the end of the transfer, the 11-bit 2's complement digital temperature (sent via the SIO line), is available in the driver for interpretation. This driver makes use of the kernel's in-core SPI support. Signed-off-by: Kaiwan N Billimoria <kaiwan@designergraphix.com> Signed-off-by: Jean Delvare <khali@linux-fr.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] lm70: New hardware monitoring driver
This driver implements support for the National Semiconductor LM70 temperature sensor. The LM70 temperature sensor chip supports a single temperature sensor. It communicates with a host processor (or microcontroller) via an SPI/Microwire Bus interface. Communication with the LM70 is simple: when the temperature is to be sensed, the driver accesses the LM70 using SPI communication: 16 SCLK cycles comprise the MOSI/MISO loop. At the end of the transfer, the 11-bit 2's complement digital temperature (sent via the SIO line), is available in the driver for interpretation. This driver makes use of the kernel's in-core SPI support. Signed-off-by: Kaiwan N Billimoria <kaiwan@designergraphix.com> Signed-off-by: Jean Delvare <khali@linux-fr.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Kaiwan N Billimoria · Greg Kroah-Hartman
1 parent 060b2f5584
Showing 4 changed files with 207 additions and 0 deletions Side-by-side Diff
Documentation/hwmon/lm70
drivers/hwmon/Kconfig
drivers/hwmon/Makefile
drivers/hwmon/lm70.c
+Kernel driver lm70
+==================
+
+Supported chip:
+  * National Semiconductor LM70
+    Datasheet: http://www.national.com/pf/LM/LM70.html
+
+Author:
+        Kaiwan N Billimoria <kaiwan@designergraphix.com>
+
+Description
+-----------
+
+This driver implements support for the National Semiconductor LM70
+temperature sensor.
+
+The LM70 temperature sensor chip supports a single temperature sensor.
+It communicates with a host processor (or microcontroller) via an
+SPI/Microwire Bus interface.
+
+Communication with the LM70 is simple: when the temperature is to be sensed,
+the driver accesses the LM70 using SPI communication: 16 SCLK cycles
+comprise the MOSI/MISO loop. At the end of the transfer, the 11-bit 2's
+complement digital temperature (sent via the SIO line), is available in the
+driver for interpretation. This driver makes use of the kernel's in-core
+SPI support.
+
+Thanks to
+---------
+Jean Delvare <khali@linux-fr.org> for mentoring the hwmon-side driver
+development.
@@ -204,6 +204,16 @@
 	  This driver can also be built as a module.  If so, the module
 	  will be called lm63.
  
+config SENSORS_LM70
+	tristate "National Semiconductor LM70"
+	depends on HWMON && SPI_MASTER && EXPERIMENTAL
+	help
+	  If you say yes here you get support for the National Semiconductor
+	  LM70 digital temperature sensor chip.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called lm70.
+
 config SENSORS_LM75
 	tristate "National Semiconductor LM75 and compatibles"
 	depends on HWMON && I2C
@@ -28,6 +28,7 @@
 obj-$(CONFIG_SENSORS_HDAPS)	+= hdaps.o
 obj-$(CONFIG_SENSORS_IT87)	+= it87.o
 obj-$(CONFIG_SENSORS_LM63)	+= lm63.o
+obj-$(CONFIG_SENSORS_LM70)	+= lm70.o
 obj-$(CONFIG_SENSORS_LM75)	+= lm75.o
 obj-$(CONFIG_SENSORS_LM77)	+= lm77.o
 obj-$(CONFIG_SENSORS_LM78)	+= lm78.o
+/*
+ * lm70.c
+ *
+ * The LM70 is a temperature sensor chip from National Semiconductor (NS).
+ * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com>
+ *
+ * The LM70 communicates with a host processor via an SPI/Microwire Bus
+ * interface. The complete datasheet is available at National's website
+ * here:
+ * http://www.national.com/pf/LM/LM70.html
+ *
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/sysfs.h>
+#include <linux/hwmon.h>
+#include <linux/spi/spi.h>
+#include <asm/semaphore.h>
+
+#define DRVNAME		"lm70"
+
+struct lm70 {
+	struct class_device *cdev;
+	struct semaphore sem;
+};
+
+/* sysfs hook function */
+static ssize_t lm70_sense_temp(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	int status, val;
+	u8 rxbuf[2];
+	s16 raw=0;
+	struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
+
+	if (down_interruptible(&p_lm70->sem))
+		return -ERESTARTSYS;
+
+	/*
+	 * spi_read() requires a DMA-safe buffer; so we use
+	 * spi_write_then_read(), transmitting 0 bytes.
+	 */
+	status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2);
+	if (status < 0) {
+		printk(KERN_WARNING
+		"spi_write_then_read failed with status %d\n", status);
+		goto out;
+	}
+	dev_dbg(dev, "rxbuf[1] : 0x%x rxbuf[0] : 0x%x\n", rxbuf[1], rxbuf[0]);
+
+	raw = (rxbuf[1] << 8) + rxbuf[0];
+	dev_dbg(dev, "raw=0x%x\n", raw);
+
+	/*
+	 * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's
+	 * complement value. Only the MSB 11 bits (1 sign + 10 temperature
+	 * bits) are meaningful; the LSB 5 bits are to be discarded.
+	 * See the datasheet.
+	 *
+	 * Further, each bit represents 0.25 degrees Celsius; so, multiply
+	 * by 0.25. Also multiply by 1000 to represent in millidegrees
+	 * Celsius.
+	 * So it's equivalent to multiplying by 0.25 * 1000 = 250.
+	 */
+	val = ((int)raw/32) * 250;
+	status = sprintf(buf, "%+d\n", val); /* millidegrees Celsius */
+out:
+	up(&p_lm70->sem);
+	return status;
+}
+
+static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL);
+
+/*----------------------------------------------------------------------*/
+
+static int __devinit lm70_probe(struct spi_device *spi)
+{
+	struct lm70 *p_lm70;
+	int status;
+
+	p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL);
+	if (!p_lm70)
+		return -ENOMEM;
+
+	init_MUTEX(&p_lm70->sem);
+
+	/* sysfs hook */
+	p_lm70->cdev = hwmon_device_register(&spi->dev);
+	if (IS_ERR(p_lm70->cdev)) {
+		dev_dbg(&spi->dev, "hwmon_device_register failed.\n");
+		status = PTR_ERR(p_lm70->cdev);
+		goto out_dev_reg_failed;
+	}
+	dev_set_drvdata(&spi->dev, p_lm70);
+
+	if ((status = device_create_file(&spi->dev, &dev_attr_temp1_input))) {
+		dev_dbg(&spi->dev, "device_create_file failure.\n");
+		goto out_dev_create_file_failed;
+	}
+
+	return 0;
+
+out_dev_create_file_failed:
+	hwmon_device_unregister(p_lm70->cdev);
+out_dev_reg_failed:
+	dev_set_drvdata(&spi->dev, NULL);
+	kfree(p_lm70);
+	return status;
+}
+
+static int __exit lm70_remove(struct spi_device *spi)
+{
+	struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
+
+	device_remove_file(&spi->dev, &dev_attr_temp1_input);
+	hwmon_device_unregister(p_lm70->cdev);
+	dev_set_drvdata(&spi->dev, NULL);
+	kfree(p_lm70);
+
+	return 0;
+}
+
+static struct spi_driver lm70_driver = {
+	.driver = {
+		.name	= "lm70",
+		.owner	= THIS_MODULE,
+	},
+	.probe	= lm70_probe,
+	.remove	= __devexit_p(lm70_remove),
+};
+
+static int __init init_lm70(void)
+{
+	return spi_register_driver(&lm70_driver);
+}
+
+static void __exit cleanup_lm70(void)
+{
+	spi_unregister_driver(&lm70_driver);
+}
+
+module_init(init_lm70);
+module_exit(cleanup_lm70);
+
+MODULE_AUTHOR("Kaiwan N Billimoria");
+MODULE_DESCRIPTION("National Semiconductor LM70 Linux driver");
+MODULE_LICENSE("GPL");
	1	+Kernel driver lm70
	2	+==================
	3	+
	4	+Supported chip:
	5	+ * National Semiconductor LM70
	6	+ Datasheet: http://www.national.com/pf/LM/LM70.html
	7	+
	8	+Author:
	9	+ Kaiwan N Billimoria <kaiwan@designergraphix.com>
	10	+
	11	+Description
	12	+-----------
	13	+
	14	+This driver implements support for the National Semiconductor LM70
	15	+temperature sensor.
	16	+
	17	+The LM70 temperature sensor chip supports a single temperature sensor.
	18	+It communicates with a host processor (or microcontroller) via an
	19	+SPI/Microwire Bus interface.
	20	+
	21	+Communication with the LM70 is simple: when the temperature is to be sensed,
	22	+the driver accesses the LM70 using SPI communication: 16 SCLK cycles
	23	+comprise the MOSI/MISO loop. At the end of the transfer, the 11-bit 2's
	24	+complement digital temperature (sent via the SIO line), is available in the
	25	+driver for interpretation. This driver makes use of the kernel's in-core
	26	+SPI support.
	27	+
	28	+Thanks to
	29	+---------
	30	+Jean Delvare <khali@linux-fr.org> for mentoring the hwmon-side driver
	31	+development.
...	...	@@ -204,6 +204,16 @@
204	204	This driver can also be built as a module. If so, the module
205	205	will be called lm63.
206	206
	207	+config SENSORS_LM70
	208	+ tristate "National Semiconductor LM70"
	209	+ depends on HWMON && SPI_MASTER && EXPERIMENTAL
	210	+ help
	211	+ If you say yes here you get support for the National Semiconductor
	212	+ LM70 digital temperature sensor chip.
	213	+
	214	+ This driver can also be built as a module. If so, the module
	215	+ will be called lm70.
	216	+
207	217	config SENSORS_LM75
208	218	tristate "National Semiconductor LM75 and compatibles"
209	219	depends on HWMON && I2C
...	...	@@ -28,6 +28,7 @@
28	28	obj-$(CONFIG_SENSORS_HDAPS) += hdaps.o
29	29	obj-$(CONFIG_SENSORS_IT87) += it87.o
30	30	obj-$(CONFIG_SENSORS_LM63) += lm63.o
	31	+obj-$(CONFIG_SENSORS_LM70) += lm70.o
31	32	obj-$(CONFIG_SENSORS_LM75) += lm75.o
32	33	obj-$(CONFIG_SENSORS_LM77) += lm77.o
33	34	obj-$(CONFIG_SENSORS_LM78) += lm78.o
	1	+/*
	2	+ * lm70.c
	3	+ *
	4	+ * The LM70 is a temperature sensor chip from National Semiconductor (NS).
	5	+ * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com>
	6	+ *
	7	+ * The LM70 communicates with a host processor via an SPI/Microwire Bus
	8	+ * interface. The complete datasheet is available at National's website
	9	+ * here:
	10	+ * http://www.national.com/pf/LM/LM70.html
	11	+ *
	12	+ * This program is free software; you can redistribute it and/or modify
	13	+ * it under the terms of the GNU General Public License as published by
	14	+ * the Free Software Foundation; either version 2 of the License, or
	15	+ * (at your option) any later version.
	16	+ *
	17	+ * This program is distributed in the hope that it will be useful,
	18	+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
	19	+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	20	+ * GNU General Public License for more details.
	21	+ *
	22	+ * You should have received a copy of the GNU General Public License
	23	+ * along with this program; if not, write to the Free Software
	24	+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	25	+ */
	26	+
	27	+#include <linux/init.h>
	28	+#include <linux/module.h>
	29	+#include <linux/kernel.h>
	30	+#include <linux/device.h>
	31	+#include <linux/err.h>
	32	+#include <linux/sysfs.h>
	33	+#include <linux/hwmon.h>
	34	+#include <linux/spi/spi.h>
	35	+#include <asm/semaphore.h>
	36	+
	37	+#define DRVNAME "lm70"
	38	+
	39	+struct lm70 {
	40	+ struct class_device *cdev;
	41	+ struct semaphore sem;
	42	+};
	43	+
	44	+/* sysfs hook function */
	45	+static ssize_t lm70_sense_temp(struct device *dev,
	46	+ struct device_attribute attr, char buf)
	47	+{
	48	+ struct spi_device *spi = to_spi_device(dev);
	49	+ int status, val;
	50	+ u8 rxbuf[2];
	51	+ s16 raw=0;
	52	+ struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
	53	+
	54	+ if (down_interruptible(&p_lm70->sem))
	55	+ return -ERESTARTSYS;
	56	+
	57	+ /*
	58	+ * spi_read() requires a DMA-safe buffer; so we use
	59	+ * spi_write_then_read(), transmitting 0 bytes.
	60	+ */
	61	+ status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2);
	62	+ if (status < 0) {
	63	+ printk(KERN_WARNING
	64	+ "spi_write_then_read failed with status %d\n", status);
	65	+ goto out;
	66	+ }
	67	+ dev_dbg(dev, "rxbuf[1] : 0x%x rxbuf[0] : 0x%x\n", rxbuf[1], rxbuf[0]);
	68	+
	69	+ raw = (rxbuf[1] << 8) + rxbuf[0];
	70	+ dev_dbg(dev, "raw=0x%x\n", raw);
	71	+
	72	+ /*
	73	+ * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's
	74	+ * complement value. Only the MSB 11 bits (1 sign + 10 temperature
	75	+ * bits) are meaningful; the LSB 5 bits are to be discarded.
	76	+ * See the datasheet.
	77	+ *
	78	+ * Further, each bit represents 0.25 degrees Celsius; so, multiply
	79	+ * by 0.25. Also multiply by 1000 to represent in millidegrees
	80	+ * Celsius.
	81	+ * So it's equivalent to multiplying by 0.25 * 1000 = 250.
	82	+ */
	83	+ val = ((int)raw/32) * 250;
	84	+ status = sprintf(buf, "%+d\n", val); /* millidegrees Celsius */
	85	+out:
	86	+ up(&p_lm70->sem);
	87	+ return status;
	88	+}
	89	+
	90	+static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL);
	91	+
	92	+/----------------------------------------------------------------------/
	93	+
	94	+static int __devinit lm70_probe(struct spi_device *spi)
	95	+{
	96	+ struct lm70 *p_lm70;
	97	+ int status;
	98	+
	99	+ p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL);
	100	+ if (!p_lm70)
	101	+ return -ENOMEM;
	102	+
	103	+ init_MUTEX(&p_lm70->sem);
	104	+
	105	+ /* sysfs hook */
	106	+ p_lm70->cdev = hwmon_device_register(&spi->dev);
	107	+ if (IS_ERR(p_lm70->cdev)) {
	108	+ dev_dbg(&spi->dev, "hwmon_device_register failed.\n");
	109	+ status = PTR_ERR(p_lm70->cdev);
	110	+ goto out_dev_reg_failed;
	111	+ }
	112	+ dev_set_drvdata(&spi->dev, p_lm70);
	113	+
	114	+ if ((status = device_create_file(&spi->dev, &dev_attr_temp1_input))) {
	115	+ dev_dbg(&spi->dev, "device_create_file failure.\n");
	116	+ goto out_dev_create_file_failed;
	117	+ }
	118	+
	119	+ return 0;
	120	+
	121	+out_dev_create_file_failed:
	122	+ hwmon_device_unregister(p_lm70->cdev);
	123	+out_dev_reg_failed:
	124	+ dev_set_drvdata(&spi->dev, NULL);
	125	+ kfree(p_lm70);
	126	+ return status;
	127	+}
	128	+
	129	+static int __exit lm70_remove(struct spi_device *spi)
	130	+{
	131	+ struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
	132	+
	133	+ device_remove_file(&spi->dev, &dev_attr_temp1_input);
	134	+ hwmon_device_unregister(p_lm70->cdev);
	135	+ dev_set_drvdata(&spi->dev, NULL);
	136	+ kfree(p_lm70);
	137	+
	138	+ return 0;
	139	+}
	140	+
	141	+static struct spi_driver lm70_driver = {
	142	+ .driver = {
	143	+ .name = "lm70",
	144	+ .owner = THIS_MODULE,
	145	+ },
	146	+ .probe = lm70_probe,
	147	+ .remove = __devexit_p(lm70_remove),
	148	+};
	149	+
	150	+static int __init init_lm70(void)
	151	+{
	152	+ return spi_register_driver(&lm70_driver);
	153	+}
	154	+
	155	+static void __exit cleanup_lm70(void)
	156	+{
	157	+ spi_unregister_driver(&lm70_driver);
	158	+}
	159	+
	160	+module_init(init_lm70);
	161	+module_exit(cleanup_lm70);
	162	+
	163	+MODULE_AUTHOR("Kaiwan N Billimoria");
	164	+MODULE_DESCRIPTION("National Semiconductor LM70 Linux driver");
	165	+MODULE_LICENSE("GPL");