[PATCH] i2c: add pmic_reg_read() for PBL use

[Ahmad Fatoum]

Hello Bastian,

On 19.12.23 17:11, Bastian Krause wrote:
> Add a common PMIC read function to PBL which allows easy porting of
> U-Boot's pmic_reg_read() in lowlevel board code.
> 
> Signed-off-by: Bastian Krause <bst at pengutronix.de>
> ---
>  include/pbl/pmic.h | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/include/pbl/pmic.h b/include/pbl/pmic.h
> index 0f882c5649d..bd0583370ec 100644
> --- a/include/pbl/pmic.h
> +++ b/include/pbl/pmic.h
> @@ -9,6 +9,27 @@ struct pmic_config {
>  	u8 val;
>  };
>  
> +static void pmic_reg_read(struct pbl_i2c *i2c, int addr, u8 reg, void *buf)

This should be static inline to avoid warnings for boards that don't use it.

> +{
> +	int ret;
> +	struct i2c_msg msg[] = {
> +		{
> +			.addr = addr,
> +			.buf = &reg,
> +			.len = 1,
> +		}, {
> +			.addr = addr,
> +			.flags = I2C_M_RD,
> +			.buf = buf,

U-Boot has buf of type u32 *. In your barebox implementation, only the
first byte is written, so this leaves 3 bytes potentially uninitialized.

You likely want to change void *buf to u32 *val and then

  u8 buf[1];
  /* i2c_xfer... */
  *val = buf[0];

> +			.len = 1,
> +		},
> +	};
> +
> +	ret = pbl_i2c_xfer(i2c, msg, ARRAY_SIZE(msg));
> +	if (ret != ARRAY_SIZE(msg))
> +		pr_err("Failed to read from pmic@%x: %d\n", addr, ret);
> +}

Cheers,
Ahmad

> +
>  static void pmic_reg_write(struct pbl_i2c *i2c, int addr, u8 reg, u8 val)
>  {
>  	int ret;

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