[PATCH V2 15/20] i3c: mipi-i3c-hci: Factor out IO mode setting into helper

[Frank Li]

On Thu, Jan 08, 2026 at 10:05:53AM +0200, Adrian Hunter wrote:
> Prepare for future reuse.  Move the IO mode setting logic from
> i3c_hci_init() into a dedicated helper function, i3c_hci_set_io_mode().
>
> Signed-off-by: Adrian Hunter <adrian.hunter at intel.com>
> ---

Reviewed-by: Frank Li <Frank.Li at nxp.com>

>
>
> Changes in V2:
>
> 	New patch
>
>
>  drivers/i3c/master/mipi-i3c-hci/core.c | 45 ++++++++++++++++++--------
>  1 file changed, 31 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
> index 3b0609cb7da7..569c8584045a 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/core.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/core.c
> @@ -613,9 +613,35 @@ static int i3c_hci_software_reset(struct i3c_hci *hci)
>  	return 0;
>  }
>
> +static inline bool is_version_1_1_or_newer(struct i3c_hci *hci)
> +{
> +	return hci->version_major > 1 || (hci->version_major == 1 && hci->version_minor > 0);
> +}
> +
> +static int i3c_hci_set_io_mode(struct i3c_hci *hci, bool dma)
> +{
> +	bool pio_mode;
> +
> +	if (dma)
> +		reg_clear(HC_CONTROL, HC_CONTROL_PIO_MODE);
> +	else
> +		reg_set(HC_CONTROL, HC_CONTROL_PIO_MODE);
> +
> +	if (!is_version_1_1_or_newer(hci))
> +		return 0;
> +
> +	pio_mode = reg_read(HC_CONTROL) & HC_CONTROL_PIO_MODE;
> +	if ((dma && pio_mode) || (!dma && !pio_mode)) {
> +		dev_err(&hci->master.dev, "%s mode is stuck\n", pio_mode ? "PIO" : "DMA");
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
>  static int i3c_hci_init(struct i3c_hci *hci)
>  {
> -	bool size_in_dwords, mode_selector;
> +	bool size_in_dwords;
>  	u32 regval, offset;
>  	int ret;
>
> @@ -732,20 +758,14 @@ static int i3c_hci_init(struct i3c_hci *hci)
>  		return -EINVAL;
>  	}
>
> -	mode_selector = hci->version_major > 1 ||
> -				(hci->version_major == 1 && hci->version_minor > 0);
> -
>  	/* Quirk for HCI_QUIRK_PIO_MODE on AMD platforms */
>  	if (hci->quirks & HCI_QUIRK_PIO_MODE)
>  		hci->RHS_regs = NULL;
>
>  	/* Try activating DMA operations first */
>  	if (hci->RHS_regs) {
> -		reg_clear(HC_CONTROL, HC_CONTROL_PIO_MODE);
> -		if (mode_selector && (reg_read(HC_CONTROL) & HC_CONTROL_PIO_MODE)) {
> -			dev_err(&hci->master.dev, "PIO mode is stuck\n");
> -			ret = -EIO;
> -		} else {
> +		ret = i3c_hci_set_io_mode(hci, true);
> +		if (!ret) {
>  			hci->io = &mipi_i3c_hci_dma;
>  			dev_dbg(&hci->master.dev, "Using DMA\n");
>  		}
> @@ -753,11 +773,8 @@ static int i3c_hci_init(struct i3c_hci *hci)
>
>  	/* If no DMA, try PIO */
>  	if (!hci->io && hci->PIO_regs) {
> -		reg_set(HC_CONTROL, HC_CONTROL_PIO_MODE);
> -		if (mode_selector && !(reg_read(HC_CONTROL) & HC_CONTROL_PIO_MODE)) {
> -			dev_err(&hci->master.dev, "DMA mode is stuck\n");
> -			ret = -EIO;
> -		} else {
> +		ret = i3c_hci_set_io_mode(hci, false);
> +		if (!ret) {
>  			hci->io = &mipi_i3c_hci_pio;
>  			dev_dbg(&hci->master.dev, "Using PIO\n");
>  		}
> --
> 2.51.0
>
>
> --
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