[PATCH] crypto: atmel-sha204a - Fix error codes in OTP reads

[Lothar Rubusch]

Hi, the change works (doesn't break behavior at least) verified on
hardware, LGTM.

I remember that time we had a small discussion on what is the right
approach with the return
handling, and at least me was unsure about it. If this puts it
straight I'll take it for me as take
away. Thank you Thorsten, and sorry for the fuzz.

Reviewed-by: Lothar Rubusch <l.rubusch at gmail.com>

Best,
L

On Sun, Feb 15, 2026 at 9:52 PM Thorsten Blum <thorsten.blum at linux.dev> wrote:
>
> Return -EINVAL from atmel_i2c_init_read_otp_cmd() on invalid addresses
> instead of -1. Since the OTP zone is accessed in 4-byte blocks, valid
> addresses range from 0 to OTP_ZONE_SIZE / 4 - 1. Fix the bounds check
> accordingly.
>
> In atmel_sha204a_otp_read(), propagate the actual error code from
> atmel_i2c_init_read_otp_cmd() instead of -1. Also, return -EIO instead
> of -EINVAL when the device is not ready.
>
> Cc: stable at vger.kernel.org
> Fixes: e05ce444e9e5 ("crypto: atmel-sha204a - add reading from otp zone")
> Signed-off-by: Thorsten Blum <thorsten.blum at linux.dev>
> ---
> Compile-tested only.
> ---
>  drivers/crypto/atmel-i2c.c     | 4 ++--
>  drivers/crypto/atmel-sha204a.c | 7 ++++---
>  2 files changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/crypto/atmel-i2c.c b/drivers/crypto/atmel-i2c.c
> index 9688d116d07e..ba9d3f593601 100644
> --- a/drivers/crypto/atmel-i2c.c
> +++ b/drivers/crypto/atmel-i2c.c
> @@ -72,8 +72,8 @@ EXPORT_SYMBOL(atmel_i2c_init_read_config_cmd);
>
>  int atmel_i2c_init_read_otp_cmd(struct atmel_i2c_cmd *cmd, u16 addr)
>  {
> -       if (addr < 0 || addr > OTP_ZONE_SIZE)
> -               return -1;
> +       if (addr >= OTP_ZONE_SIZE / 4)
> +               return -EINVAL;
>
>         cmd->word_addr = COMMAND;
>         cmd->opcode = OPCODE_READ;
> diff --git a/drivers/crypto/atmel-sha204a.c b/drivers/crypto/atmel-sha204a.c
> index 0fcf4a39de27..6b4e2764523e 100644
> --- a/drivers/crypto/atmel-sha204a.c
> +++ b/drivers/crypto/atmel-sha204a.c
> @@ -94,9 +94,10 @@ static int atmel_sha204a_rng_read(struct hwrng *rng, void *data, size_t max,
>  static int atmel_sha204a_otp_read(struct i2c_client *client, u16 addr, u8 *otp)
>  {
>         struct atmel_i2c_cmd cmd;
> -       int ret = -1;
> +       int ret;
>
> -       if (atmel_i2c_init_read_otp_cmd(&cmd, addr) < 0) {
> +       ret = atmel_i2c_init_read_otp_cmd(&cmd, addr);
> +       if (ret < 0) {
>                 dev_err(&client->dev, "failed, invalid otp address %04X\n",
>                         addr);
>                 return ret;
> @@ -106,7 +107,7 @@ static int atmel_sha204a_otp_read(struct i2c_client *client, u16 addr, u8 *otp)
>
>         if (cmd.data[0] == 0xff) {
>                 dev_err(&client->dev, "failed, device not ready\n");
> -               return -EINVAL;
> +               return -EIO;
>         }
>
>         memcpy(otp, cmd.data+1, 4);
> --
> Thorsten Blum <thorsten.blum at linux.dev>
> GPG: 1D60 735E 8AEF 3BE4 73B6  9D84 7336 78FD 8DFE EAD4
>