[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>

4 files changed, 307 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);
+
diff --git a/include/linux/eeprom_93cx6.h b/include/linux/eeprom_93cx6.h
new file mode 100644
index 000000000000..d774b7778c91
--- /dev/null
+++ b/include/linux/eeprom_93cx6.h
@@ -0,0 +1,72 @@
+/*
+        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 datastructures for 93cx6 chipsets.
+        Supported chipsets: 93c46 & 93c66.
+ */
+
+/*
+ * EEPROM operation defines.
+ */
+#define PCI_EEPROM_WIDTH_93C46  6
+#define PCI_EEPROM_WIDTH_93C66  8
+#define PCI_EEPROM_WIDTH_OPCODE 3
+#define PCI_EEPROM_WRITE_OPCODE 0x05
+#define PCI_EEPROM_READ_OPCODE  0x06
+#define PCI_EEPROM_EWDS_OPCODE  0x10
+#define PCI_EEPROM_EWEN_OPCODE  0x13
+
+/**
+ * struct eeprom_93cx6 - control structure for setting the commands
+ * for reading the eeprom data.
+ * @data: private pointer for the driver.
+ * @register_read(struct eeprom_93cx6 *eeprom): handler to
+ * read the eeprom register, this function should set all reg_* fields.
+ * @register_write(struct eeprom_93cx6 *eeprom): handler to
+ * write to the eeprom register by using all reg_* fields.
+ * @width: eeprom width, should be one of the PCI_EEPROM_WIDTH_* defines
+ * @reg_data_in: register field to indicate data input
+ * @reg_data_out: register field to indicate data output
+ * @reg_data_clock: register field to set the data clock
+ * @reg_chip_select: register field to set the chip select
+ *
+ * This structure is used for the communication between the driver
+ * and the eeprom_93cx6 handlers for reading the eeprom.
+ */
+struct eeprom_93cx6 {
+        void *data;
+
+        void (*register_read)(struct eeprom_93cx6 *eeprom);
+        void (*register_write)(struct eeprom_93cx6 *eeprom);
+
+        int width;
+
+        char reg_data_in;
+        char reg_data_out;
+        char reg_data_clock;
+        char reg_chip_select;
+};
+
+extern void eeprom_93cx6_read(struct eeprom_93cx6 *eeprom,
+        const u8 word, u16 *data);
+extern void eeprom_93cx6_multiread(struct eeprom_93cx6 *eeprom,
+        const u8 word, __le16 *data, const u16 words);