[PATCH] Add 93cx6 eeprom library

This patch adds a library for reading from 93cx6 eeproms.

Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 235 insertions, 1 deletions

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 616eee9c04f1..bd601efa7bd1 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -34,6 +34,11 @@ config PHANTOM
 	  If you choose to build module, its name will be phantom. If unsure,
 	  say N here.
 
+config EEPROM_93CX6
+	tristate "EEPROM 93CX6 support"
+	---help---
+	  This is a driver for the EEPROM chipsets 93c46 and 93c66.
+	  The driver supports both read as well as write commands.
 
 	  If unsure, say N.
 
@@ -187,5 +192,4 @@ config THINKPAD_ACPI_BAY
 
 	  If you are not sure, say Y here.
 
-
 endmenu
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 8abbf2f07a65..b5ce0e3dba86 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -14,3 +14,4 @@ obj-$(CONFIG_PHANTOM)		+= phantom.o
 obj-$(CONFIG_SGI_IOC4)		+= ioc4.o
 obj-$(CONFIG_SONY_LAPTOP)	+= sony-laptop.o
 obj-$(CONFIG_THINKPAD_ACPI)	+= thinkpad_acpi.o
+obj-$(CONFIG_EEPROM_93CX6)	+= eeprom_93cx6.o
diff --git a/drivers/misc/eeprom_93cx6.c b/drivers/misc/eeprom_93cx6.c
new file mode 100644
index 000000000000..bfcb43424dcd
--- /dev/null
+++ b/drivers/misc/eeprom_93cx6.c
@@ -0,0 +1,229 @@
+/*
+	Copyright (C) 2004 - 2006 rt2x00 SourceForge Project
+	<http://rt2x00.serialmonkey.com>
+
+	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.
+ */
+
+/*
+	Module: eeprom_93cx6
+	Abstract: EEPROM reader routines for 93cx6 chipsets.
+	Supported chipsets: 93c46 & 93c66.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/version.h>
+#include <linux/delay.h>
+#include <linux/eeprom_93cx6.h>
+
+MODULE_AUTHOR("http://rt2x00.serialmonkey.com");
+MODULE_VERSION("1.0");
+MODULE_DESCRIPTION("EEPROM 93cx6 chip driver");
+MODULE_LICENSE("GPL");
+
+static inline void eeprom_93cx6_pulse_high(struct eeprom_93cx6 *eeprom)
+{
+	eeprom->reg_data_clock = 1;
+	eeprom->register_write(eeprom);
+	udelay(1);
+}
+
+static inline void eeprom_93cx6_pulse_low(struct eeprom_93cx6 *eeprom)
+{
+	eeprom->reg_data_clock = 0;
+	eeprom->register_write(eeprom);
+	udelay(1);
+}
+
+static void eeprom_93cx6_startup(struct eeprom_93cx6 *eeprom)
+{
+	/*
+	 * Clear all flags, and enable chip select.
+	 */
+	eeprom->register_read(eeprom);
+	eeprom->reg_data_in = 0;
+	eeprom->reg_data_out = 0;
+	eeprom->reg_data_clock = 0;
+	eeprom->reg_chip_select = 1;
+	eeprom->register_write(eeprom);
+
+	/*
+	 * kick a pulse.
+	 */
+	eeprom_93cx6_pulse_high(eeprom);
+	eeprom_93cx6_pulse_low(eeprom);
+}
+
+static void eeprom_93cx6_cleanup(struct eeprom_93cx6 *eeprom)
+{
+	/*
+	 * Clear chip_select and data_in flags.
+	 */
+	eeprom->register_read(eeprom);
+	eeprom->reg_data_in = 0;
+	eeprom->reg_chip_select = 0;
+	eeprom->register_write(eeprom);
+
+	/*
+	 * kick a pulse.
+	 */
+	eeprom_93cx6_pulse_high(eeprom);
+	eeprom_93cx6_pulse_low(eeprom);
+}
+
+static void eeprom_93cx6_write_bits(struct eeprom_93cx6 *eeprom,
+	const u16 data, const u16 count)
+{
+	unsigned int i;
+
+	eeprom->register_read(eeprom);
+
+	/*
+	 * Clear data flags.
+	 */
+	eeprom->reg_data_in = 0;
+	eeprom->reg_data_out = 0;
+
+	/*
+	 * Start writing all bits.
+	 */
+	for (i = count; i > 0; i--) {
+		/*
+		 * Check if this bit needs to be set.
+		 */
+		eeprom->reg_data_in = !!(data & (1 << (i - 1)));
+
+		/*
+		 * Write the bit to the eeprom register.
+		 */
+		eeprom->register_write(eeprom);
+
+		/*
+		 * Kick a pulse.
+		 */
+		eeprom_93cx6_pulse_high(eeprom);
+		eeprom_93cx6_pulse_low(eeprom);
+	}
+
+	eeprom->reg_data_in = 0;
+	eeprom->register_write(eeprom);
+}
+
+static void eeprom_93cx6_read_bits(struct eeprom_93cx6 *eeprom,
+	u16 *data, const u16 count)
+{
+	unsigned int i;
+	u16 buf = 0;
+
+	eeprom->register_read(eeprom);
+
+	/*
+	 * Clear data flags.
+	 */
+	eeprom->reg_data_in = 0;
+	eeprom->reg_data_out = 0;
+
+	/*
+	 * Start reading all bits.
+	 */
+	for (i = count; i > 0; i--) {
+		eeprom_93cx6_pulse_high(eeprom);
+
+		eeprom->register_read(eeprom);
+
+		/*
+		 * Clear data_in flag.
+		 */
+		eeprom->reg_data_in = 0;
+
+		/*
+		 * Read if the bit has been set.
+		 */
+		if (eeprom->reg_data_out)
+			buf |= (1 << (i - 1));
+
+		eeprom_93cx6_pulse_low(eeprom);
+	}
+
+	*data = buf;
+}
+
+/**
+ * eeprom_93cx6_read - Read multiple words from eeprom
+ * @eeprom: Pointer to eeprom structure
+ * @word: Word index from where we should start reading
+ * @data: target pointer where the information will have to be stored
+ *
+ * This function will read the eeprom data as host-endian word
+ * into the given data pointer.
+ */
+void eeprom_93cx6_read(struct eeprom_93cx6 *eeprom, const u8 word,
+	u16 *data)
+{
+	u16 command;
+
+	/*
+	 * Initialize the eeprom register
+	 */
+	eeprom_93cx6_startup(eeprom);
+
+	/*
+	 * Select the read opcode and the word to be read.
+	 */
+	command = (PCI_EEPROM_READ_OPCODE << eeprom->width) | word;
+	eeprom_93cx6_write_bits(eeprom, command,
+		PCI_EEPROM_WIDTH_OPCODE + eeprom->width);
+
+	/*
+	 * Read the requested 16 bits.
+	 */
+	eeprom_93cx6_read_bits(eeprom, data, 16);
+
+	/*
+	 * Cleanup eeprom register.
+	 */
+	eeprom_93cx6_cleanup(eeprom);
+}
+EXPORT_SYMBOL_GPL(eeprom_93cx6_read);
+
+/**
+ * eeprom_93cx6_multiread - Read multiple words from eeprom
+ * @eeprom: Pointer to eeprom structure
+ * @word: Word index from where we should start reading
+ * @data: target pointer where the information will have to be stored
+ * @words: Number of words that should be read.
+ *
+ * This function will read all requested words from the eeprom,
+ * this is done by calling eeprom_93cx6_read() multiple times.
+ * But with the additional change that while the eeprom_93cx6_read
+ * will return host ordered bytes, this method will return little
+ * endian words.
+ */
+void eeprom_93cx6_multiread(struct eeprom_93cx6 *eeprom, const u8 word,
+	__le16 *data, const u16 words)
+{
+	unsigned int i;
+	u16 tmp;
+
+	for (i = 0; i < words; i++) {
+		tmp = 0;
+		eeprom_93cx6_read(eeprom, word + i, &tmp);
+		data[i] = cpu_to_le16(tmp);
+	}
+}
+EXPORT_SYMBOL_GPL(eeprom_93cx6_multiread);
+