Re: [PATCH 03/17] i3c: renesas: Restore STDBR and EXTBR registers on resume

[Frank Li <Frank.li@nxp.com>]

On Fri, May 22, 2026 at 01:18:01PM +0300, Claudiu Beznea wrote:
> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>
> The Renesas RZ/G3S supports a power saving state where power to the most
> SoC componentes (including I3C) is lost.
>
> The STDBR and EXTBR are configured in initialization phase though the
> struct i3c_master_controller_ops::bus_init. Set them on resume function
> as well to keep the same state of the controller after a suspend with
> power loss and a similar initialization sequence as in bus_init.
>
> Fixes: e7218986319b ("i3c: renesas: Add suspend/resume support")
> Cc: stable@vger.kernel.org
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> ---
>  drivers/i3c/master/renesas-i3c.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/i3c/master/renesas-i3c.c b/drivers/i3c/master/renesas-i3c.c
> index 1917549cf6d5..6c23f956ad2a 100644
> --- a/drivers/i3c/master/renesas-i3c.c
> +++ b/drivers/i3c/master/renesas-i3c.c
> @@ -260,6 +260,7 @@ struct renesas_i3c {
>  	u32 dyn_addr;
>  	u32 i2c_STDBR;
>  	u32 i3c_STDBR;
> +	u32 extbr;

can you keep consisent with above 2 register, use upcase EXTBR,

Frank
>  	unsigned long rate;
>  	u8 addrs[RENESAS_I3C_MAX_DEVS];
>  	struct renesas_i3c_xferqueue xferqueue;
> @@ -607,10 +608,9 @@ static int renesas_i3c_bus_init(struct i3c_master_controller *m)
>  	renesas_writel(i3c->regs, STDBR, i3c->i3c_STDBR);
>
>  	/* Extended Bit Rate setting */
> -	renesas_writel(i3c->regs, EXTBR, EXTBR_EBRLO(od_low_ticks) |
> -					   EXTBR_EBRHO(od_high_ticks) |
> -					   EXTBR_EBRLP(pp_low_ticks) |
> -					   EXTBR_EBRHP(pp_high_ticks));
> +	i3c->extbr = EXTBR_EBRLO(od_low_ticks) | EXTBR_EBRHO(od_high_ticks) |
> +		     EXTBR_EBRLP(pp_low_ticks) | EXTBR_EBRHP(pp_high_ticks);
> +	renesas_writel(i3c->regs, EXTBR, i3c->extbr);
>
>  	renesas_writel(i3c->regs, REFCKCTL, REFCKCTL_IREFCKS(cks));
>  	i3c->refclk_div = cks;
> @@ -1447,6 +1447,8 @@ static int renesas_i3c_resume_noirq(struct device *dev)
>  		goto err_tresetn;
>
>  	/* Re-store I3C registers value. */
> +	renesas_writel(i3c->regs, STDBR, i3c->i3c_STDBR);
> +	renesas_writel(i3c->regs, EXTBR, i3c->extbr);
>  	renesas_writel(i3c->regs, REFCKCTL,
>  		       REFCKCTL_IREFCKS(i3c->refclk_div));
>  	renesas_writel(i3c->regs, MSDVAD, MSDVAD_MDYADV |
> --
> 2.43.0
>