Commit 4a5ff99b authored by Emmanuel Gil Peyrot's avatar Emmanuel Gil Peyrot Committed by Greg Kroah-Hartman
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misc: eeprom_93xx46: Remove hardcoded bit lengths 



This avoids using magic numbers based on the length of an address or a
command, while we only want to differentiate between 8-bit and 16-bit.

The driver was previously wrapping around the offset in the write
operation, this now returns -EINVAL instead (but should never happen in
the first place).

If two pointer indirections are too many, we could move the flags to the
main struct instead, but I doubt it’s going to make any sensible
difference on any hardware.

Reviewed-by: default avatarJonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: default avatarEmmanuel Gil Peyrot <linkmauve@linkmauve.fr>
Link: https://lore.kernel.org/r/20210511210727.24895-2-linkmauve@linkmauve.fr


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9ac78c8a

drivers/misc/eeprom/eeprom_93xx46.c

+32 −25
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include <linux/device.h>

#include <linux/gpio/consumer.h>

#include <linux/kernel.h>

#include <linux/log2.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/of.h>
@@ -70,6 +71,7 @@ static int eeprom_93xx46_read(void *priv, unsigned int off, 
	struct eeprom_93xx46_dev *edev = priv;

	char *buf = val;

	int err = 0;

	int bits;



	if (unlikely(off >= edev->size))

		return 0;
@@ -83,21 +85,21 @@ static int eeprom_93xx46_read(void *priv, unsigned int off, 
	if (edev->pdata->prepare)

		edev->pdata->prepare(edev);



	/* The opcode in front of the address is three bits. */

	bits = edev->addrlen + 3;



	while (count) {

		struct spi_message m;

		struct spi_transfer t[2] = { { 0 } };

		u16 cmd_addr = OP_READ << edev->addrlen;

		size_t nbytes = count;

		int bits;



		if (edev->addrlen == 7) {

			cmd_addr |= off & 0x7f;

			bits = 10;

		if (edev->pdata->flags & EE_ADDR8) {

			cmd_addr |= off;

			if (has_quirk_single_word_read(edev))

				nbytes = 1;

		} else {

			cmd_addr |= (off >> 1) & 0x3f;

			bits = 9;

			cmd_addr |= (off >> 1);

			if (has_quirk_single_word_read(edev))

				nbytes = 2;

		}
@@ -152,14 +154,14 @@ static int eeprom_93xx46_ew(struct eeprom_93xx46_dev *edev, int is_on) 
	int bits, ret;

	u16 cmd_addr;



	/* The opcode in front of the address is three bits. */

	bits = edev->addrlen + 3;



	cmd_addr = OP_START << edev->addrlen;

	if (edev->addrlen == 7) {

	if (edev->pdata->flags & EE_ADDR8)

		cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS) << 1;

		bits = 10;

	} else {

	else

		cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS);

		bits = 9;

	}



	if (has_quirk_instruction_length(edev)) {

		cmd_addr <<= 2;
@@ -205,15 +207,19 @@ eeprom_93xx46_write_word(struct eeprom_93xx46_dev *edev, 
	int bits, data_len, ret;

	u16 cmd_addr;



	if (unlikely(off >= edev->size))

		return -EINVAL;



	/* The opcode in front of the address is three bits. */

	bits = edev->addrlen + 3;



	cmd_addr = OP_WRITE << edev->addrlen;



	if (edev->addrlen == 7) {

		cmd_addr |= off & 0x7f;

		bits = 10;

	if (edev->pdata->flags & EE_ADDR8) {

		cmd_addr |= off;

		data_len = 1;

	} else {

		cmd_addr |= (off >> 1) & 0x3f;

		bits = 9;

		cmd_addr |= (off >> 1);

		data_len = 2;

	}
@@ -253,7 +259,7 @@ static int eeprom_93xx46_write(void *priv, unsigned int off, 
		return count;



	/* only write even number of bytes on 16-bit devices */

	if (edev->addrlen == 6) {

	if (edev->pdata->flags & EE_ADDR16) {

		step = 2;

		count &= ~1;

	}
@@ -295,14 +301,14 @@ static int eeprom_93xx46_eral(struct eeprom_93xx46_dev *edev) 
	int bits, ret;

	u16 cmd_addr;



	/* The opcode in front of the address is three bits. */

	bits = edev->addrlen + 3;



	cmd_addr = OP_START << edev->addrlen;

	if (edev->addrlen == 7) {

	if (edev->pdata->flags & EE_ADDR8)

		cmd_addr |= ADDR_ERAL << 1;

		bits = 10;

	} else {

	else

		cmd_addr |= ADDR_ERAL;

		bits = 9;

	}



	if (has_quirk_instruction_length(edev)) {

		cmd_addr <<= 2;
@@ -455,10 +461,12 @@ static int eeprom_93xx46_probe(struct spi_device *spi) 
	if (!edev)

		return -ENOMEM;



	edev->size = 128;



	if (pd->flags & EE_ADDR8)

		edev->addrlen = 7;

		edev->addrlen = ilog2(edev->size);

	else if (pd->flags & EE_ADDR16)

		edev->addrlen = 6;

		edev->addrlen = ilog2(edev->size) - 1;

	else {

		dev_err(&spi->dev, "unspecified address type\n");

		return -EINVAL;
@@ -469,7 +477,6 @@ static int eeprom_93xx46_probe(struct spi_device *spi) 
	edev->spi = spi;

	edev->pdata = pd;



	edev->size = 128;

	edev->nvmem_config.type = NVMEM_TYPE_EEPROM;

	edev->nvmem_config.name = dev_name(&spi->dev);

	edev->nvmem_config.dev = &spi->dev;