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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: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
Link: https://lore.kernel.org/r/20210511210727.24895-2-linkmauve@linkmauve.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Emmanuel Gil Peyrot 2021-05-11 23:07:24 +02:00 committed by Greg Kroah-Hartman
parent 9ac78c8a0c
commit 4a5ff99bbb
1 changed files with 32 additions and 25 deletions
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57
drivers/misc/eeprom/eeprom_93xx46.c
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@ -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;