[PATCH v4 3/6] spmi: apple: check transaction status

[Janne Grunau]

On Wed, Aug 05, 2026 at 12:11:13PM +0200, Sasha Finkelstein wrote:
> From: Alba Mendez <me at alba.sh>
> 
> Check for parity errors and missing command ACKs
> 
> Signed-off-by: Alba Mendez <me at alba.sh>
> Signed-off-by: Sasha Finkelstein <k at chaosmail.tech>
> ---
>  drivers/spmi/spmi-apple-controller.c | 26 +++++++++++++++++++++-----
>  1 file changed, 21 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/spmi/spmi-apple-controller.c b/drivers/spmi/spmi-apple-controller.c
> index 4d5356bf9bbf..7ebf899edf17 100644
> --- a/drivers/spmi/spmi-apple-controller.c
> +++ b/drivers/spmi/spmi-apple-controller.c
> @@ -11,6 +11,8 @@
>   *		spmi-pmic-arb.c Copyright (c) 2021, The Linux Foundation.
>   */
>  
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
>  #include <linux/io.h>
>  #include <linux/iopoll.h>
>  #include <linux/module.h>
> @@ -23,6 +25,12 @@
>  #define SPMI_RSP_REG 0x8
>  #define SPMI_ACT_REG 0xa4
>  
> +/* SPMI_RSP_REG reply word */
> +#define 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_ACT_FIFO_FLUSH BIT(0)
>  #define SPMI_RX_FIFO_EMPTY BIT(24)
>  
> @@ -66,7 +74,7 @@ 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;
> @@ -82,12 +90,12 @@ 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) {
>  		if (readl(spmi->regs + SPMI_STATUS_REG) & SPMI_RX_FIFO_EMPTY) {
> +			spmi->prev_fail = true;

should this have been in the previous patch? Not sure if the flush helps
in this case but the line looks in this change out-of-place

>  			dev_err_ratelimited(&ctrl->dev,
>  					    "FIFO lacks reply data, controller stuck?\n");
>  			return -EIO;
> @@ -105,6 +113,10 @@ static int spmi_read_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
>  		spmi->prev_fail = true;
>  	}
>  
> +	if (~FIELD_GET(SPMI_REPLY_FRAME_PARITY_STATUS, reply) & ((1 << len) - 1)) {
> +		dev_err(&ctrl->dev, "some frames failed parity check\n");
> +		return -EIO;
> +	}
>  	return 0;
>  }
>  
> @@ -113,6 +125,7 @@ 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;
>  
> @@ -136,14 +149,17 @@ 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");
>  		spmi->prev_fail = true;
>  	}
>  
> +	if (!FIELD_GET(SPMI_REPLY_ACK, reply)) {
> +		dev_err(&ctrl->dev, "command not acknowledged\n");
> +		return -EIO;
> +	}
>  	return 0;
>  }

besides the single misplaced line

Reviewed-by: Janne Grunau <j at jannau.net>

Janne