eeprom_93cx6: Add write support

Add support for writing data to EEPROM.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Cc: Wolfram Sang <w.sang@pengutronix.de>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/misc/eeprom/eeprom_93cx6.c b/drivers/misc/eeprom/eeprom_93cx6.c
index a6037af..0ff4b02 100644 (file)
--- a/drivers/misc/eeprom/eeprom_93cx6.c
+++ b/drivers/misc/eeprom/eeprom_93cx6.c
@@ -234,3 +234,88 @@ void eeprom_93cx6_multiread(struct eeprom_93cx6 *eeprom, const u8 word,
 }
 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 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 */
+       usleep_range(1000, 2000);
+
+       /* wait for DO to go high to signify finish */
+
+       while (true) {
+               eeprom->register_read(eeprom);
+
+               if (eeprom->reg_data_out)
+                       break;
+
+               usleep_range(1000, 2000);
+
+               if (--timeout <= 0) {
+                       printk(KERN_ERR "%s: timeout\n", __func__);
+                       break;
+               }
+       }
+
+       eeprom_93cx6_cleanup(eeprom);
+}
+EXPORT_SYMBOL_GPL(eeprom_93cx6_write);

diff --git a/include/linux/eeprom_93cx6.h b/include/linux/eeprom_93cx6.h
index e04546e..e50f98b 100644 (file)
--- a/include/linux/eeprom_93cx6.h
+++ b/include/linux/eeprom_93cx6.h
@@ -33,6 +33,7 @@
 #define PCI_EEPROM_WIDTH_93C86 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
@@ -74,3 +75,8 @@ 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);
+
+extern void eeprom_93cx6_wren(struct eeprom_93cx6 *eeprom, bool enable);
+
+extern void eeprom_93cx6_write(struct eeprom_93cx6 *eeprom,
+                              u8 addr, u16 data);