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Commit 072bc801 authored by Ben Dooks's avatar Ben Dooks Committed by David S. Miller
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eeprom_93cx6: Add write support 



Add support for writing data to EEPROM.

Signed-off-by: default avatarBen 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: default avatarStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b30f8bdc

drivers/misc/eeprom/eeprom_93cx6.c

+85 −0
Original line number Diff line number Diff line
@@ -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);

include/linux/eeprom_93cx6.h

+6 −0
Original line number Diff line number Diff line
@@ -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);