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eeprom: at24: convert magic numbers to structs
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Fundamental properties such as capacity and page size differ among
at24-type chips. But these chips do not have an id register, so this
can't be discovered at runtime.

Traditionally, at24-type eeprom properties were determined in two ways:
- by passing a 'struct at24_platform_data' via platform_data, or
- by naming the chip type in the devicetree, which passes a 'magic
  number' to probe(), which is then converted to a 'struct
  at24_platform_data'.

Recently a bug was discovered because the magic number rounds down all
chip sizes to the lowest power of two. This was addressed by
a work-around commit 5478e47 ("eeprom: at24: correctly set the
size for at24mac402"), with the wish that magic numbers should over
time be converted to structs.

This patch replaces the magic numbers with 'struct at24_chip_data'.

Signed-off-by: Sven Van Asbroeck <svendev@arcx.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
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Sven Van Asbroeck authored and Bartosz Golaszewski committed Jan 1, 2018
1 parent eef6939 commit b680f4f
Showing 1 changed file with 100 additions and 121 deletions.
221 changes: 100 additions & 121 deletions drivers/misc/eeprom/at24.c
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Original file line number Diff line number Diff line change
Expand Up @@ -105,16 +105,6 @@ static unsigned int at24_write_timeout = 25;
module_param_named(write_timeout, at24_write_timeout, uint, 0);
MODULE_PARM_DESC(at24_write_timeout, "Time (in ms) to try writes (default 25)");

#define AT24_SIZE_BYTELEN 5
#define AT24_SIZE_FLAGS 8

#define AT24_BITMASK(x) (BIT(x) - 1)

/* create non-zero magic value for given eeprom parameters */
#define AT24_DEVICE_MAGIC(_len, _flags) \
((1 << AT24_SIZE_FLAGS | (_flags)) \
<< AT24_SIZE_BYTELEN | ilog2(_len))

/*
* Both reads and writes fail if the previous write didn't complete yet. This
* macro loops a few times waiting at least long enough for one entire page
Expand All @@ -132,113 +122,108 @@ MODULE_PARM_DESC(at24_write_timeout, "Time (in ms) to try writes (default 25)");
op_time ? time_before(op_time, tout) : true; \
usleep_range(1000, 1500), op_time = jiffies)

struct at24_chip_data {
/*
* these fields mirror their equivalents in
* struct at24_platform_data
*/
u32 byte_len;
u8 flags;
};

#define AT24_CHIP_DATA(_name, _len, _flags) \
static const struct at24_chip_data _name = { \
.byte_len = _len, .flags = _flags, \
}

/* needs 8 addresses as A0-A2 are ignored */
AT24_CHIP_DATA(at24_data_24c00, 128 / 8, AT24_FLAG_TAKE8ADDR);
/* old variants can't be handled with this generic entry! */
AT24_CHIP_DATA(at24_data_24c01, 1024 / 8, 0);
AT24_CHIP_DATA(at24_data_24cs01, 16,
AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
AT24_CHIP_DATA(at24_data_24c02, 2048 / 8, 0);
AT24_CHIP_DATA(at24_data_24cs02, 16,
AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
AT24_CHIP_DATA(at24_data_24mac402, 48 / 8,
AT24_FLAG_MAC | AT24_FLAG_READONLY);
AT24_CHIP_DATA(at24_data_24mac602, 64 / 8,
AT24_FLAG_MAC | AT24_FLAG_READONLY);
/* spd is a 24c02 in memory DIMMs */
AT24_CHIP_DATA(at24_data_spd, 2048 / 8,
AT24_FLAG_READONLY | AT24_FLAG_IRUGO);
AT24_CHIP_DATA(at24_data_24c04, 4096 / 8, 0);
AT24_CHIP_DATA(at24_data_24cs04, 16,
AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
/* 24rf08 quirk is handled at i2c-core */
AT24_CHIP_DATA(at24_data_24c08, 8192 / 8, 0);
AT24_CHIP_DATA(at24_data_24cs08, 16,
AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
AT24_CHIP_DATA(at24_data_24c16, 16384 / 8, 0);
AT24_CHIP_DATA(at24_data_24cs16, 16,
AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
AT24_CHIP_DATA(at24_data_24c32, 32768 / 8, AT24_FLAG_ADDR16);
AT24_CHIP_DATA(at24_data_24cs32, 16,
AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
AT24_CHIP_DATA(at24_data_24c64, 65536 / 8, AT24_FLAG_ADDR16);
AT24_CHIP_DATA(at24_data_24cs64, 16,
AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
AT24_CHIP_DATA(at24_data_24c128, 131072 / 8, AT24_FLAG_ADDR16);
AT24_CHIP_DATA(at24_data_24c256, 262144 / 8, AT24_FLAG_ADDR16);
AT24_CHIP_DATA(at24_data_24c512, 524288 / 8, AT24_FLAG_ADDR16);
AT24_CHIP_DATA(at24_data_24c1024, 1048576 / 8, AT24_FLAG_ADDR16);
/* identical to 24c08 ? */
AT24_CHIP_DATA(at24_data_INT3499, 8192 / 8, 0);

static const struct i2c_device_id at24_ids[] = {
/* needs 8 addresses as A0-A2 are ignored */
{ "24c00", AT24_DEVICE_MAGIC(128 / 8, AT24_FLAG_TAKE8ADDR) },
/* old variants can't be handled with this generic entry! */
{ "24c01", AT24_DEVICE_MAGIC(1024 / 8, 0) },
{ "24cs01", AT24_DEVICE_MAGIC(16,
AT24_FLAG_SERIAL | AT24_FLAG_READONLY) },
{ "24c02", AT24_DEVICE_MAGIC(2048 / 8, 0) },
{ "24cs02", AT24_DEVICE_MAGIC(16,
AT24_FLAG_SERIAL | AT24_FLAG_READONLY) },
{ "24mac402", AT24_DEVICE_MAGIC(48 / 8,
AT24_FLAG_MAC | AT24_FLAG_READONLY) },
{ "24mac602", AT24_DEVICE_MAGIC(64 / 8,
AT24_FLAG_MAC | AT24_FLAG_READONLY) },
/* spd is a 24c02 in memory DIMMs */
{ "spd", AT24_DEVICE_MAGIC(2048 / 8,
AT24_FLAG_READONLY | AT24_FLAG_IRUGO) },
{ "24c04", AT24_DEVICE_MAGIC(4096 / 8, 0) },
{ "24cs04", AT24_DEVICE_MAGIC(16,
AT24_FLAG_SERIAL | AT24_FLAG_READONLY) },
/* 24rf08 quirk is handled at i2c-core */
{ "24c08", AT24_DEVICE_MAGIC(8192 / 8, 0) },
{ "24cs08", AT24_DEVICE_MAGIC(16,
AT24_FLAG_SERIAL | AT24_FLAG_READONLY) },
{ "24c16", AT24_DEVICE_MAGIC(16384 / 8, 0) },
{ "24cs16", AT24_DEVICE_MAGIC(16,
AT24_FLAG_SERIAL | AT24_FLAG_READONLY) },
{ "24c32", AT24_DEVICE_MAGIC(32768 / 8, AT24_FLAG_ADDR16) },
{ "24cs32", AT24_DEVICE_MAGIC(16,
AT24_FLAG_ADDR16 |
AT24_FLAG_SERIAL |
AT24_FLAG_READONLY) },
{ "24c64", AT24_DEVICE_MAGIC(65536 / 8, AT24_FLAG_ADDR16) },
{ "24cs64", AT24_DEVICE_MAGIC(16,
AT24_FLAG_ADDR16 |
AT24_FLAG_SERIAL |
AT24_FLAG_READONLY) },
{ "24c128", AT24_DEVICE_MAGIC(131072 / 8, AT24_FLAG_ADDR16) },
{ "24c256", AT24_DEVICE_MAGIC(262144 / 8, AT24_FLAG_ADDR16) },
{ "24c512", AT24_DEVICE_MAGIC(524288 / 8, AT24_FLAG_ADDR16) },
{ "24c1024", AT24_DEVICE_MAGIC(1048576 / 8, AT24_FLAG_ADDR16) },
{ "at24", 0 },
{ "24c00", (kernel_ulong_t)&at24_data_24c00 },
{ "24c01", (kernel_ulong_t)&at24_data_24c01 },
{ "24cs01", (kernel_ulong_t)&at24_data_24cs01 },
{ "24c02", (kernel_ulong_t)&at24_data_24c02 },
{ "24cs02", (kernel_ulong_t)&at24_data_24cs02 },
{ "24mac402", (kernel_ulong_t)&at24_data_24mac402 },
{ "24mac602", (kernel_ulong_t)&at24_data_24mac602 },
{ "spd", (kernel_ulong_t)&at24_data_spd },
{ "24c04", (kernel_ulong_t)&at24_data_24c04 },
{ "24cs04", (kernel_ulong_t)&at24_data_24cs04 },
{ "24c08", (kernel_ulong_t)&at24_data_24c08 },
{ "24cs08", (kernel_ulong_t)&at24_data_24cs08 },
{ "24c16", (kernel_ulong_t)&at24_data_24c16 },
{ "24cs16", (kernel_ulong_t)&at24_data_24cs16 },
{ "24c32", (kernel_ulong_t)&at24_data_24c32 },
{ "24cs32", (kernel_ulong_t)&at24_data_24cs32 },
{ "24c64", (kernel_ulong_t)&at24_data_24c64 },
{ "24cs64", (kernel_ulong_t)&at24_data_24cs64 },
{ "24c128", (kernel_ulong_t)&at24_data_24c128 },
{ "24c256", (kernel_ulong_t)&at24_data_24c256 },
{ "24c512", (kernel_ulong_t)&at24_data_24c512 },
{ "24c1024", (kernel_ulong_t)&at24_data_24c1024 },
{ "at24", 0 },
{ /* END OF LIST */ }
};
MODULE_DEVICE_TABLE(i2c, at24_ids);

static const struct of_device_id at24_of_match[] = {
{
.compatible = "atmel,24c00",
.data = (void *)AT24_DEVICE_MAGIC(128 / 8, AT24_FLAG_TAKE8ADDR)
},
{
.compatible = "atmel,24c01",
.data = (void *)AT24_DEVICE_MAGIC(1024 / 8, 0)
},
{
.compatible = "atmel,24c02",
.data = (void *)AT24_DEVICE_MAGIC(2048 / 8, 0)
},
{
.compatible = "atmel,spd",
.data = (void *)AT24_DEVICE_MAGIC(2048 / 8,
AT24_FLAG_READONLY | AT24_FLAG_IRUGO)
},
{
.compatible = "atmel,24c04",
.data = (void *)AT24_DEVICE_MAGIC(4096 / 8, 0)
},
{
.compatible = "atmel,24c08",
.data = (void *)AT24_DEVICE_MAGIC(8192 / 8, 0)
},
{
.compatible = "atmel,24c16",
.data = (void *)AT24_DEVICE_MAGIC(16384 / 8, 0)
},
{
.compatible = "atmel,24c32",
.data = (void *)AT24_DEVICE_MAGIC(32768 / 8, AT24_FLAG_ADDR16)
},
{
.compatible = "atmel,24c64",
.data = (void *)AT24_DEVICE_MAGIC(65536 / 8, AT24_FLAG_ADDR16)
},
{
.compatible = "atmel,24c128",
.data = (void *)AT24_DEVICE_MAGIC(131072 / 8, AT24_FLAG_ADDR16)
},
{
.compatible = "atmel,24c256",
.data = (void *)AT24_DEVICE_MAGIC(262144 / 8, AT24_FLAG_ADDR16)
},
{
.compatible = "atmel,24c512",
.data = (void *)AT24_DEVICE_MAGIC(524288 / 8, AT24_FLAG_ADDR16)
},
{
.compatible = "atmel,24c1024",
.data = (void *)AT24_DEVICE_MAGIC(1048576 / 8, AT24_FLAG_ADDR16)
},
{ },
{ .compatible = "atmel,24c00", .data = &at24_data_24c00 },
{ .compatible = "atmel,24c01", .data = &at24_data_24c01 },
{ .compatible = "atmel,24c02", .data = &at24_data_24c02 },
{ .compatible = "atmel,spd", .data = &at24_data_spd },
{ .compatible = "atmel,24c04", .data = &at24_data_24c04 },
{ .compatible = "atmel,24c08", .data = &at24_data_24c08 },
{ .compatible = "atmel,24c16", .data = &at24_data_24c16 },
{ .compatible = "atmel,24c32", .data = &at24_data_24c32 },
{ .compatible = "atmel,24c64", .data = &at24_data_24c64 },
{ .compatible = "atmel,24c128", .data = &at24_data_24c128 },
{ .compatible = "atmel,24c256", .data = &at24_data_24c256 },
{ .compatible = "atmel,24c512", .data = &at24_data_24c512 },
{ .compatible = "atmel,24c1024", .data = &at24_data_24c1024 },
{ /* END OF LIST */ },
};
MODULE_DEVICE_TABLE(of, at24_of_match);

static const struct acpi_device_id at24_acpi_ids[] = {
{ "INT3499", AT24_DEVICE_MAGIC(8192 / 8, 0) },
{ }
{ "INT3499", (kernel_ulong_t)&at24_data_INT3499 },
{ /* END OF LIST */ }
};
MODULE_DEVICE_TABLE(acpi, at24_acpi_ids);

Expand Down Expand Up @@ -516,8 +501,8 @@ static unsigned int at24_get_offset_adj(u8 flags, unsigned int byte_len)

static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
struct at24_platform_data chip;
kernel_ulong_t magic = 0;
struct at24_platform_data chip = { 0 };
const struct at24_chip_data *cd = NULL;
bool writable;
struct at24_data *at24;
int err;
Expand All @@ -535,28 +520,22 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
*/
if (client->dev.of_node &&
of_match_device(at24_of_match, &client->dev)) {
magic = (kernel_ulong_t)
of_device_get_match_data(&client->dev);
cd = of_device_get_match_data(&client->dev);
} else if (id) {
magic = id->driver_data;
cd = (void *)id->driver_data;
} else {
const struct acpi_device_id *aid;

aid = acpi_match_device(at24_acpi_ids, &client->dev);
if (aid)
magic = aid->driver_data;
cd = (void *)aid->driver_data;
}
if (!magic)
if (!cd)
return -ENODEV;

chip.byte_len = BIT(magic & AT24_BITMASK(AT24_SIZE_BYTELEN));
magic >>= AT24_SIZE_BYTELEN;
chip.flags = magic & AT24_BITMASK(AT24_SIZE_FLAGS);

chip.byte_len = cd->byte_len;
chip.flags = cd->flags;
at24_get_pdata(&client->dev, &chip);

chip.setup = NULL;
chip.context = NULL;
}

if (!is_power_of_2(chip.byte_len))
Expand Down

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