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authorBen Dooks <ben@simtec.co.uk>2011-11-21 08:57:57 +0000
committerDavid S. Miller <davem@davemloft.net>2011-11-26 14:59:39 -0500
commit072bc80156729f853e8bcafe1b17c48c74462887 (patch)
treefd48bf8aa8e730a75ea40375275e75afa0d2994e /drivers/misc/eeprom
parentb30f8bdcfa7dd05f4268348f3388ff903132f28e (diff)
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>
Diffstat (limited to 'drivers/misc/eeprom')
-rw-r--r--drivers/misc/eeprom/eeprom_93cx6.c85
1 files changed, 85 insertions, 0 deletions
diff --git a/drivers/misc/eeprom/eeprom_93cx6.c b/drivers/misc/eeprom/eeprom_93cx6.c
index a6037af6f076..0ff4b02177be 100644
--- 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);