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From: Ben Dooks on 30 Apr 2010 17:50
Add support for writing data to EEPROM.

Signed-off-by: Ben Dooks <ben(a)simtec.co.uk>
Cc: Wolfram Sang <w.sang(a)pengutronix.de>
Cc: Jean Delvare <khali(a)linux-fr.org>
Cc: Linux Kernel <linux-kernel(a)vger.kernel.org>

---
drivers/misc/eeprom/eeprom_93cx6.c | 86 +++++++++++++++++++++++++++++++++++++
include/linux/eeprom_93cx6.h | 7 +++
2 files changed, 93 insertions(+)

Index: b/drivers/misc/eeprom/eeprom_93cx6.c
===================================================================
--- a/drivers/misc/eeprom/eeprom_93cx6.c 2009-10-06 15:51:18.000000000 +0100
+++ b/drivers/misc/eeprom/eeprom_93cx6.c 2009-10-06 15:54:36.000000000 +0100
@@ -241,3 +241,89 @@ void eeprom_93cx6_multiread(struct eepro
}
EXPORT_SYMBOL_GPL(eeprom_93cx6_multiread);

+
+/**
+ * eeprom_93cx6_wren - set the write enable state
+ * @eeprom: Pointer to eeprom structure
+ * @enable: true to enable writes, otherwise disable writes
+ *
+ * Set the EEPROM write enable state to either allow or deny
+ * writes depending on the @enable value.
+ */
+void eeprom_93cx6_wren(struct eeprom_93cx6 *eeprom, bool enable)
+{
+ u16 command;
+
+ /* start the command */
+ eeprom_93cx6_startup(eeprom);
+
+ /* create command to enable/disable */
+
+ command = enable ? PCI_EEPROM_EWEN_OPCODE : PCI_EEPROM_EWDS_OPCODE;
+ command <<= (eeprom->width - 2);
+
+ eeprom_93cx6_write_bits(eeprom, command,
+ PCI_EEPROM_WIDTH_OPCODE + eeprom->width);
+
+ eeprom_93cx6_cleanup(eeprom);
+}
+EXPORT_SYMBOL_GPL(eeprom_93cx6_wren);
+
+/**
+ * eeprom_93cx6_write - write data to the EEPROM
+ * @eeprom: Pointer to eeprom structure
+ * @addr: Address to write data to.
+ * @data: The data to write to address @addr.
+ *
+ * Write the @data to the specified @addr in the EEPROM and
+ * waiting for the device to finish writing.
+ *
+ * Note, since we do not expect large number of write operations
+ * we use msleep() to delay in between parts of the operation to
+ * avoid using excessive amounts of CPU time busy waiting.
+ */
+void eeprom_93cx6_write(struct eeprom_93cx6 *eeprom, u8 addr, u16 data)
+{
+ int timeout = 100;
+ u16 command;
+
+ /* start the command */
+ eeprom_93cx6_startup(eeprom);
+
+ command = PCI_EEPROM_WRITE_OPCODE << eeprom->width;
+ command |= addr;
+
+ /* send write command */
+ eeprom_93cx6_write_bits(eeprom, command,
+ PCI_EEPROM_WIDTH_OPCODE + eeprom->width);
+
+ /* send data */
+ eeprom_93cx6_write_bits(eeprom, data, 16);
+
+ /* get ready to check for busy */
+ eeprom->drive_data = 0;
+ eeprom->reg_chip_select = 1;
+ eeprom->register_write(eeprom);
+
+ /* wait at-least 250ns to get DO to be the busy signal */
+ msleep(1);
+
+ /* wait for DO to go high to signify finish */
+
+ while (true) {
+ eeprom->register_read(eeprom);
+
+ if (eeprom->reg_data_out)
+ break;
+
+ msleep(1);
+
+ if (--timeout <= 0) {
+ printk(KERN_ERR "%s: timeout\n", __func__);
+ break;
+ }
+ }
+
+ eeprom_93cx6_cleanup(eeprom);
+}
+EXPORT_SYMBOL_GPL(eeprom_93cx6_write);
Index: b/include/linux/eeprom_93cx6.h
===================================================================
--- a/include/linux/eeprom_93cx6.h 2009-10-06 15:51:18.000000000 +0100
+++ b/include/linux/eeprom_93cx6.h 2009-10-06 15:53:16.000000000 +0100
@@ -32,6 +32,7 @@
#define PCI_EEPROM_WIDTH_93C66 8
#define PCI_EEPROM_WIDTH_OPCODE 3
#define PCI_EEPROM_WRITE_OPCODE 0x05
+#define PCI_EEPROM_ERASE_OPCODE 0x07
#define PCI_EEPROM_READ_OPCODE 0x06
#define PCI_EEPROM_EWDS_OPCODE 0x10
#define PCI_EEPROM_EWEN_OPCODE 0x13
@@ -73,3 +74,9 @@ extern void eeprom_93cx6_read(struct eep
const u8 word, u16 *data);
extern void eeprom_93cx6_multiread(struct eeprom_93cx6 *eeprom,
const u8 word, __le16 *data, const u16 words);
+
+extern void eeprom_93cx6_wren(struct eeprom_93cx6 *eeprom, bool enable);
+
+extern void eeprom_93cx6_write(struct eeprom_93cx6 *eeprom,
+ u8 addr, u16 data);
+

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Prev: ixgbe: Example usage of the new IRQ affinity_hint callback
Next: [PATCH] ubi: init even if mtd device cannot be attached, if built into kernel