Re: [PATCH v2 3/7] spmi: apple: check transaction status

On Tue, Jul 28, 2026 at 11:28:09AM +0200, Sasha Finkelstein wrote:
> From: Alba Mendez <[email protected]>
> 
> Check for parity errors and missing command ACKs
> 
> Signed-off-by: Alba Mendez <[email protected]>
> Signed-off-by: Sasha Finkelstein <[email protected]>
> ---
>  drivers/spmi/spmi-apple-controller.c | 23 ++++++++++++++++++-----
>  1 file changed, 18 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/spmi/spmi-apple-controller.c b/drivers/spmi/spmi-apple-controller.c
> index b4f442d0b4ad..4678a9e5270a 100644
> --- a/drivers/spmi/spmi-apple-controller.c
> +++ b/drivers/spmi/spmi-apple-controller.c
> @@ -22,6 +22,12 @@
>  #define SPMI_CMD_REG 0x4
>  #define SPMI_RSP_REG 0x8
>  
> +/* SPMI_RSP_REG reply word */
> +#define SPMI_REPLY_FRAME_PARITY_OFFSET 16

SPMI_REPLY_FRAME_PARITY_STATUS GENMASK(31, 16)

> +#define SPMI_REPLY_ACK BIT(15)
> +#define SPMI_REPLY_SLAVE_ID GENMASK(14, 8)
> +#define SPMI_REPLY_CMD GENMASK(7, 0)
> +
>  #define SPMI_RX_FIFO_EMPTY BIT(24)
>  
>  #define REG_POLL_INTERVAL_US 10000
> @@ -62,7 +68,7 @@ static int spmi_read_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
>  {
>  	struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
>  	u32 spmi_cmd = apple_spmi_pack_cmd(opc, sid, saddr, len);
> -	u32 rsp;
> +	u32 reply, rsp;
>  	size_t len_read = 0;
>  	u8 i;
>  	int ret;
> @@ -73,8 +79,7 @@ static int spmi_read_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
>  	if (ret)
>  		return ret;
>  
> -	/* Discard SPMI reply status */
> -	readl(spmi->regs + SPMI_RSP_REG);
> +	reply = readl(spmi->regs + SPMI_RSP_REG);
>  
>  	/* Read SPMI data reply */
>  	while (len_read < len) {
> @@ -93,6 +98,10 @@ static int spmi_read_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
>  	if (!(readl(spmi->regs + SPMI_STATUS_REG) & SPMI_RX_FIFO_EMPTY))
>  		dev_warn(&ctrl->dev, "FIFO has extra data\n");
>  
> +	if ((~reply >> SPMI_REPLY_FRAME_PARITY_OFFSET) & ((1 << len) - 1)) {

if (~GET_FIELD(SPMI_REPLY_FRAME_PARITY_STATUS, reply) & ((1 << len) - 1)) {

not sure this is clear improvement

> +		dev_err(&ctrl->dev, "some frames failed parity check\n");
> +		return -EIO;
> +	}
>  	return 0;
>  }
>  
> @@ -101,6 +110,7 @@ static int spmi_write_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
>  {
>  	struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
>  	u32 spmi_cmd = apple_spmi_pack_cmd(opc, sid, saddr, len);
> +	u32 reply;
>  	size_t i = 0, j;
>  	int ret;
>  
> @@ -119,12 +129,15 @@ static int spmi_write_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
>  	if (ret)
>  		return ret;
>  
> -	/* Discard */
> -	readl(spmi->regs + SPMI_RSP_REG);
> +	reply = readl(spmi->regs + SPMI_RSP_REG);
>  
>  	if (!(readl(spmi->regs + SPMI_STATUS_REG) & SPMI_RX_FIFO_EMPTY))
>  		dev_warn(&ctrl->dev, "FIFO has extra data\n");
>  
> +	if (!(reply & SPMI_REPLY_ACK)) {

if (!GET_FIELD(SPMI_REPLY_ACK, reply)) {

> +		dev_err(&ctrl->dev, "command not acknowledged\n");
> +		return -EIO;
> +	}
>  	return 0;
>  }

Janne