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eeprom_93cx6: Add write support

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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>
This commit is contained in:
Ben Dooks 2011-11-21 08:57:57 +00:00 committed by David S. Miller
parent b30f8bdcfa
commit 072bc80156
2 changed files with 91 additions and 0 deletions
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85
drivers/misc/eeprom/eeprom_93cx6.c
View file

@ -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);

6
include/linux/eeprom_93cx6.h
View file

@ -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);