On 28.06.2024 17:46, Bartosz Golaszewski wrote:

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On Fri, Jun 28, 2024 at 4:17 PM [off-list ref] wrote:

quoted

On 28.06.2024 11:30, Bartosz Golaszewski wrote:

quoted

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On Fri, Jun 28, 2024 at 10:02 AM Andrei Simion
[off-list ref] wrote:

quoted

From: Claudiu Beznea <redacted>

The EEPROMs could be used only for MAC storage. In this case the
EEPROM areas where MACs resides could be modeled as NVMEM cells
(directly via DT bindings) such that the already available networking
infrastructure to read properly the MAC addresses (via
of_get_mac_address()). The previously available compatibles needs the
offset adjustment probably for compatibility w/ old DT bindings.
Add "microchip,24aa025e48", "microchip,24aa025e64" compatible for the
usage w/ 24AA025E{48, 64} type of EEPROMs where "24aa025e48" stands
for EUI-48 address and "24aa025e64" stands for EUI-64 address.

Signed-off-by: Claudiu Beznea <redacted>
[andrei.simion@microchip.com: Add extended macros to initialize the structure
with explicit value to adjusting offset. Add extra description for the commit
message.]
Signed-off-by: Andrei Simion <andrei.simion@microchip.com>
---
v2 -> v3:
- add specific compatible names according with
https://ww1.microchip.com/downloads/en/DeviceDoc/24AA02E48-24AA025E48-24AA02E64-24AA025E64-Data-Sheet-20002124H.pdf
- add extended macros to initialize the structure with explicit value for adjoff
- drop co-developed-by to maintain the commit history
 (chronological order of modifications)

v1 -> v2:
- no change
---
 drivers/misc/eeprom/at24.c | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 4bd4f32bcdab..e2ac08f656cf 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c

@@ -121,20 +121,29 @@ struct at24_chip_data {
        u32 byte_len;
        u8 flags;
        u8 bank_addr_shift;
+       u8 adjoff;
        void (*read_post)(unsigned int off, char *buf, size_t count);
 };

-#define AT24_CHIP_DATA(_name, _len, _flags)                            \
+#define AT24_CHIP_DATA_AO(_name, _len, _flags, _ao)                    \

Please, don't try to save space on a few letters, call it
AT24_CHIP_DATA_ADJOFF() for better readability.

I will change in next the version.

quoted

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        static const struct at24_chip_data _name = {                    \
                .byte_len = _len, .flags = _flags,                      \
+               .adjoff = _ao                                           \
        }

-#define AT24_CHIP_DATA_CB(_name, _len, _flags, _read_post)             \
+#define AT24_CHIP_DATA(_name, _len, _flags)                            \
+       AT24_CHIP_DATA_AO(_name, _len, _flags, 0)
+
+#define AT24_CHIP_DATA_CB_AO(_name, _len, _flags, _ao, _read_post)     \
        static const struct at24_chip_data _name = {                    \
                .byte_len = _len, .flags = _flags,                      \
+               .adjoff = _ao,                                          \
                .read_post = _read_post,                                \
        }

+#define AT24_CHIP_DATA_CB(_name, _len, _flags, _read_post)             \
+       AT24_CHIP_DATA_CB_AO(_name, _len, _flags, 0, _read_post)
+
 #define AT24_CHIP_DATA_BS(_name, _len, _flags, _bank_addr_shift)       \
        static const struct at24_chip_data _name = {                    \
                .byte_len = _len, .flags = _flags,                      \

@@ -170,9 +179,13 @@ AT24_CHIP_DATA(at24_data_24cs01, 16,
 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_CHIP_DATA_AO(at24_data_24mac402, 48 / 8,
+       AT24_FLAG_MAC | AT24_FLAG_READONLY, 1);

And this will not break existing users? I guess you refer to these
changes in your commit message but it's not very clear what you're
doing and why.

For those types of eeprom 24AA025E{48, 64} adjusting offset is not required (at24_get_offset_adj()).
So, indeed, it is an entanglement in logic.
To keep the implementation as it is:
adjoff (which is a flag that indicates when to use the adjusting offset) needs to be 1 for old compatibles but for these new ones needs to be 0.

I think that is enough not to break the existing users. What are your thoughts?

Wait... is the adjoff field effectively a boolean? Why u8?

struct at24_data contains offset_adj which will get value calling at24_get_offset_adj()) if adjoff is true (1).
Yes, adjoff needs to be treated as a boolean. I will change it in the next version.

Best Regards,
Andrei

Bart

quoted

Best Regards,
Andrei Simion

quoted

quoted

+AT24_CHIP_DATA_AO(at24_data_24mac602, 64 / 8,
+       AT24_FLAG_MAC | AT24_FLAG_READONLY, 1);
+AT24_CHIP_DATA(at24_data_24aa025e48, 48 / 8,
        AT24_FLAG_MAC | AT24_FLAG_READONLY);
-AT24_CHIP_DATA(at24_data_24mac602, 64 / 8,
+AT24_CHIP_DATA(at24_data_24aa025e64, 64 / 8,
        AT24_FLAG_MAC | AT24_FLAG_READONLY);
 /* spd is a 24c02 in memory DIMMs */
 AT24_CHIP_DATA(at24_data_spd, 2048 / 8,

@@ -218,6 +231,8 @@ static const struct i2c_device_id at24_ids[] = {
        { "24cs02",     (kernel_ulong_t)&at24_data_24cs02 },
        { "24mac402",   (kernel_ulong_t)&at24_data_24mac402 },
        { "24mac602",   (kernel_ulong_t)&at24_data_24mac602 },
+       { "24aa025e48", (kernel_ulong_t)&at24_data_24aa025e48 },
+       { "24aa025e64", (kernel_ulong_t)&at24_data_24aa025e64 },
        { "spd",        (kernel_ulong_t)&at24_data_spd },
        { "24c02-vaio", (kernel_ulong_t)&at24_data_24c02_vaio },
        { "24c04",      (kernel_ulong_t)&at24_data_24c04 },

@@ -270,6 +285,8 @@ static const struct of_device_id __maybe_unused at24_of_match[] = {
        { .compatible = "atmel,24c1024",        .data = &at24_data_24c1024 },
        { .compatible = "atmel,24c1025",        .data = &at24_data_24c1025 },
        { .compatible = "atmel,24c2048",        .data = &at24_data_24c2048 },
+       { .compatible = "microchip,24aa025e48", .data = &at24_data_24aa025e48 },
+       { .compatible = "microchip,24aa025e64", .data = &at24_data_24aa025e64 },
        { /* END OF LIST */ },
 };
 MODULE_DEVICE_TABLE(of, at24_of_match);

@@ -690,7 +707,8 @@ static int at24_probe(struct i2c_client *client)
        at24->read_post = cdata->read_post;
        at24->bank_addr_shift = cdata->bank_addr_shift;
        at24->num_addresses = num_addresses;
-       at24->offset_adj = at24_get_offset_adj(flags, byte_len);
+       at24->offset_adj = cdata->adjoff ?
+                               at24_get_offset_adj(flags, byte_len) : 0;
        at24->client_regmaps[0] = regmap;

        at24->vcc_reg = devm_regulator_get(dev, "vcc");
--

2.34.1

Bart