[PATCH] hwmon/lm70: adding support for NS LM74 chip

[Christophe Leroy <christophe.leroy@c-s.fr>]

Hello,

This Patch adds support for the LM74 chip from National Semiconductor (NS) 
in the lm70 driver

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>

diff -u linux-3.5-vanilla/drivers/hwmon/Kconfig linux-3.5/drivers/hwmon/Kconfig
--- linux-3.5-vanilla/drivers/hwmon/Kconfig	2012-07-21 22:58:29.000000000 +0200
+++ linux-3.5/drivers/hwmon/Kconfig	2012-08-21 13:46:47.000000000 +0200
@@ -530,11 +530,11 @@
 	  will be called lm63.
 
 config SENSORS_LM70
-	tristate "National Semiconductor LM70 / Texas Instruments TMP121"
+	tristate "National Semiconductor LM70&LM74 / Texas Instruments TMP121"
 	depends on SPI_MASTER
 	help
 	  If you say yes here you get support for the National Semiconductor
-	  LM70 and Texas Instruments TMP121/TMP123 digital temperature
+	  LM70 and LM74 and Texas Instruments TMP121/TMP123 digital temperature
 	  sensor chips.
 
 	  This driver can also be built as a module.  If so, the module
diff -u linux-3.5-vanilla/drivers/hwmon/lm70.c linux-3.5/drivers/hwmon/lm70.c
--- linux-3.5-vanilla/drivers/hwmon/lm70.c	2012-07-21 22:58:29.000000000 +0200
+++ linux-3.5/drivers/hwmon/lm70.c	2012-08-21 13:46:31.000000000 +0200
@@ -3,11 +3,12 @@
  *
  * The LM70 is a temperature sensor chip from National Semiconductor (NS).
  * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com>
+ * Copyright (C) 2012 Christophe Leroy <christophe.leroy@c-s.fr>
  *
  * 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
+ * http://www.ti.com/product/LM70
  *
  * 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
@@ -43,6 +44,7 @@
 
 #define LM70_CHIP_LM70		0	/* original NS LM70 */
 #define LM70_CHIP_TMP121	1	/* TI TMP121/TMP123 */
+#define LM70_CHIP_LM74		2	/* original NS LM74 */
 
 struct lm70 {
 	struct device *hwmon_dev;
@@ -98,6 +100,7 @@
 		break;
 
 	case LM70_CHIP_TMP121:
+	case LM70_CHIP_LM74:
 		val = ((int)raw / 8) * 625 / 10;
 		break;
 	}
@@ -123,6 +126,9 @@
 	case LM70_CHIP_TMP121:
 		ret = sprintf(buf, "tmp121\n");
 		break;
+	case LM70_CHIP_LM74:
+		ret = sprintf(buf, "lm74\n");
+		break;
 	default:
 		ret = -EINVAL;
 	}
@@ -139,12 +145,13 @@
 	struct lm70 *p_lm70;
 	int status;
 
-	/* signaling is SPI_MODE_0 for both LM70 and TMP121 */
+	/* signaling is SPI_MODE_0 for LM70, LM74 and TMP121 */
 	if (spi->mode & (SPI_CPOL | SPI_CPHA))
 		return -EINVAL;
 
-	/* 3-wire link (shared SI/SO) for LM70 */
-	if (chip == LM70_CHIP_LM70 && !(spi->mode & SPI_3WIRE))
+	/* 3-wire link (shared SI/SO) for LM70 and LM74 */
+	if ((chip == LM70_CHIP_LM70 || chip == LM70_CHIP_LM74)
+			&& !(spi->mode & SPI_3WIRE))
 		return -EINVAL;
 
 	/* NOTE:  we assume 8-bit words, and convert to 16 bits manually */
@@ -202,6 +209,7 @@
 static const struct spi_device_id lm70_ids[] = {
 	{ "lm70",   LM70_CHIP_LM70 },
 	{ "tmp121", LM70_CHIP_TMP121 },
+	{ "lm74",   LM70_CHIP_LM74 },
 	{ },
 };
 MODULE_DEVICE_TABLE(spi, lm70_ids);
@@ -219,5 +227,5 @@
 module_spi_driver(lm70_driver);
 
 MODULE_AUTHOR("Kaiwan N Billimoria");
-MODULE_DESCRIPTION("NS LM70 / TI TMP121/TMP123 Linux driver");
+MODULE_DESCRIPTION("NS LM70 & LM74 / TI TMP121/TMP123 Linux driver");
 MODULE_LICENSE("GPL");
diff -u linux-3.5-vanilla/Documentation/hwmon/lm70 linux-3.5/Documentation/hwmon/lm70
--- linux-3.5-vanilla/Documentation/hwmon/lm70	2012-07-21 22:58:29.000000000 +0200
+++ linux-3.5/Documentation/hwmon/lm70	2012-08-21 13:38:24.000000000 +0200
@@ -3,7 +3,9 @@
 
 Supported chips:
   * National Semiconductor LM70
-    Datasheet: http://www.national.com/pf/LM/LM70.html
+    Datasheet: http://www.ti.com/product/LM70
+  * National Semiconductor LM74
+    Datasheet: http://www.ti.com/product/LM74
   * Texas Instruments TMP121/TMP123
     Information: http://focus.ti.com/docs/prod/folders/print/tmp121.html
 
@@ -31,9 +33,11 @@
 with a "SPI master controller driver", see drivers/spi/spi_lm70llp.c
 and its associated documentation.
 
-The TMP121/TMP123 are very similar; main differences are 4 wire SPI inter-
-face (read only) and 13-bit temperature data (0.0625 degrees celsius reso-
-lution).
+The LM74 is very similar; main differences is 13-bit temperature data 
+(0.0625 degrees celsius resolution).
+
+The TMP121/TMP123 are very similar to the LM74; main difference is 4 wire
+SPI interface (read only).
 
 Thanks to
 ---------