Re: [PATCH v3 4/4] i3c: renesas: Add suspend/resume support

[Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>]

Hi Biju,

On Mon, Jan 05, 2026 at 09:35:46AM +0000, Biju Das wrote:
> 
> 
> > -----Original Message-----
> > From: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
> > Sent: 05 January 2026 09:33
> > To: Biju Das <biju.das.jz@bp.renesas.com>
> > Cc: Tommaso Merciai <tomm.merciai@gmail.com>; linux-renesas-soc@vger.kernel.org; wsa+renesas
> > <wsa+renesas@sang-engineering.com>; Alexandre Belloni <alexandre.belloni@bootlin.com>; Frank Li
> > <Frank.Li@nxp.com>; Philipp Zabel <p.zabel@pengutronix.de>; Geert Uytterhoeven
> > <geert+renesas@glider.be>; magnus.damm <magnus.damm@gmail.com>; linux-i3c@lists.infradead.org; linux-
> > kernel@vger.kernel.org
> > Subject: Re: [PATCH v3 4/4] i3c: renesas: Add suspend/resume support
> > 
> > Hi Biju,
> > Thanks for your review!
> > 
> > On Wed, Dec 31, 2025 at 09:04:16AM +0000, Biju Das wrote:
> > >
> > >
> > > > -----Original Message-----
> > > > From: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
> > > > Sent: 31 December 2025 08:23
> > > > To: Tommaso Merciai <tomm.merciai@gmail.com>
> > > > Cc: linux-renesas-soc@vger.kernel.org; Biju Das
> > > > <biju.das.jz@bp.renesas.com>; Tommaso Merciai
> > > > <tommaso.merciai.xr@bp.renesas.com>; wsa+renesas
> > > > <wsa+renesas@sang-engineering.com>; Alexandre Belloni
> > > > <alexandre.belloni@bootlin.com>; Frank Li <Frank.Li@nxp.com>;
> > > > Philipp Zabel <p.zabel@pengutronix.de>; Geert Uytterhoeven
> > > > <geert+renesas@glider.be>; magnus.damm <magnus.damm@gmail.com>;
> > > > linux- i3c@lists.infradead.org; linux-kernel@vger.kernel.org
> > > > Subject: [PATCH v3 4/4] i3c: renesas: Add suspend/resume support
> > > >
> > > > The Renesas I3C controller does not retain its register state across
> > > > system suspend, requiring the driver to explicitly save and restore hardware configuration.
> > > >
> > > > Add suspend and resume NOIRQ callbacks to handle system sleep transitions.
> > > >
> > > > During suspend, save the Device Address Table (DAT) entries, assert
> > > > reset lines, and disable all related clocks to allow the controller to enter a low-power state.
> > > >
> > > > On resume, re-enable clocks and reset lines in the proper order.
> > > > Restore the REFCKCTL register, master dynamic address, and all DAT entries, then reinitialize the
> > controller.
> > > >
> > > > Store the REFCLK divider value, and the master dynamic address to
> > > > restore timing and addressing configuration after resume.
> > > >
> > > > Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
> > > > ---
> > > > v2->v3:
> > > >  - Fixed error path into renesas_i3c_resume_noirq() and
> > > >    renesas_i3c_suspend_noirq() function.
> > > >  - Moved up one line sizeof(u32) * i3c->maxdevs into devm_kzalloc() call.
> > > >
> > > > v1->v2:
> > > >  - Updated commit as v1 has been split into smaller patches.
> > > >  - Use clock bulk API into renesas_i3c_suspend_noirq() and
> > > >    renesas_i3c_resume_noirq().
> > > >
> > > >  drivers/i3c/master/renesas-i3c.c | 89
> > > > ++++++++++++++++++++++++++++++++
> > > >  1 file changed, 89 insertions(+)
> > > >
> > > > diff --git a/drivers/i3c/master/renesas-i3c.c
> > > > b/drivers/i3c/master/renesas-i3c.c
> > > > index b065b8d4b138..e33ff16efdb3 100644
> > > > --- a/drivers/i3c/master/renesas-i3c.c
> > > > +++ b/drivers/i3c/master/renesas-i3c.c
> > > > @@ -256,16 +256,19 @@ struct renesas_i3c {
> > > >  	enum i3c_internal_state internal_state;
> > > >  	u16 maxdevs;
> > > >  	u32 free_pos;
> > > > +	u32 dyn_addr;
> > > >  	u32 i2c_STDBR;
> > > >  	u32 i3c_STDBR;
> > > >  	unsigned long rate;
> > > >  	u8 addrs[RENESAS_I3C_MAX_DEVS];
> > > >  	struct renesas_i3c_xferqueue xferqueue;
> > > >  	void __iomem *regs;
> > > > +	u32 *DATBASn;
> > > >  	struct clk_bulk_data *clks;
> > > >  	u8 num_clks;
> > > >  	struct reset_control *presetn;
> > > >  	struct reset_control *tresetn;
> > > > +	u8 refclk_div;
> > > >  };
> > > >
> > > >  struct renesas_i3c_i2c_dev_data {
> > > > @@ -609,6 +612,7 @@ static int renesas_i3c_bus_init(struct i3c_master_controller *m)
> > > >  					   EXTBR_EBRHP(pp_high_ticks));
> > > >
> > > >  	renesas_writel(i3c->regs, REFCKCTL, REFCKCTL_IREFCKS(cks));
> > > > +	i3c->refclk_div = cks;
> > > >
> > > >  	/* I3C hw init*/
> > > >  	renesas_i3c_hw_init(i3c);
> > > > @@ -617,6 +621,7 @@ static int renesas_i3c_bus_init(struct i3c_master_controller *m)
> > > >  	if (ret < 0)
> > > >  		return ret;
> > > >
> > > > +	i3c->dyn_addr = ret;
> > > >  	renesas_writel(i3c->regs, MSDVAD, MSDVAD_MDYAD(ret) |
> > > > MSDVAD_MDYADV);
> > > >
> > > >  	memset(&info, 0, sizeof(info));
> > > > @@ -1362,6 +1367,12 @@ static int renesas_i3c_probe(struct platform_device *pdev)
> > > >  	i3c->maxdevs = RENESAS_I3C_MAX_DEVS;
> > > >  	i3c->free_pos = GENMASK(i3c->maxdevs - 1, 0);
> > > >
> > > > +	/* Allocate dynamic Device Address Table backup. */
> > > > +	i3c->DATBASn = devm_kzalloc(&pdev->dev, sizeof(u32) * i3c->maxdevs,
> > > > +				    GFP_KERNEL);
> > > > +	if (!i3c->DATBASn)
> > > > +		return -ENOMEM;
> > > > +
> > > >  	return i3c_master_register(&i3c->base, &pdev->dev,
> > > > &renesas_i3c_ops, false);  }
> > > >
> > > > @@ -1372,6 +1383,83 @@ static void renesas_i3c_remove(struct platform_device *pdev)
> > > >  	i3c_master_unregister(&i3c->base);
> > > >  }
> > > >
> > > > +static int renesas_i3c_suspend_noirq(struct device *dev) {
> > > > +	struct renesas_i3c *i3c = dev_get_drvdata(dev);
> > > > +	int i, ret;
> > > > +
> > > > +	i2c_mark_adapter_suspended(&i3c->base.i2c);
> > > > +
> > > > +	/* Store Device Address Table values. */
> > > > +	for (i = 0; i < i3c->maxdevs; i++)
> > > > +		i3c->DATBASn[i] = renesas_readl(i3c->regs, DATBAS(i));
> > > > +
> > > > +	ret = reset_control_assert(i3c->presetn);
> > > > +	if (ret)
> > > > +		goto err_mark_resumed;
> > > > +
> > > > +	ret = reset_control_assert(i3c->tresetn);
> > > > +	if (ret)
> > > > +		goto err_presetn;
> > > > +
> > > > +	clk_bulk_disable_unprepare(i3c->num_clks, i3c->clks);
> > >
> > > Why can't you use unlocked version clk_bulk_disable/enable(num_clks,
> > > clks); for suspend()/resume()?
> > 
> > I'm seeing the same calls into:
> > 
> >  - svc_i3c_runtime_suspend()
> 
> 
> Are they doing in  suspend_noirq callback(), if yes you could fix that driver as well.

Yes, but unfortunally I can't test the fix on this platform.
I will send v4 using:

	clk_bulk_disable(i3c->num_clks, i3c->clks) into renesas_i3c_suspend_noirq()

and 

	ret = clk_bulk_enable(i3c->num_clks, i3c->clks) into renesas_i3c_resume_noirq()

As you suggested, Thanks.

Kind Regards,
Tommaso

> 
> Cheers,
> Biju
> 
> > 
> > Into drivers/i3c/master/svc-i3c-master.c
> > 
> > >
> > > > +
> > > > +	return 0;
> > > > +
> > > > +err_presetn:
> > > > +	reset_control_deassert(i3c->presetn);
> > > > +err_mark_resumed:
> > > > +	i2c_mark_adapter_resumed(&i3c->base.i2c);
> > > > +
> > > > +	return ret;
> > > > +}
> > > > +
> > > > +static int renesas_i3c_resume_noirq(struct device *dev) {
> > > > +	struct renesas_i3c *i3c = dev_get_drvdata(dev);
> > > > +	int i, ret;
> > > > +
> > > > +	ret = reset_control_deassert(i3c->presetn);
> > > > +	if (ret)
> > > > +		return ret;
> > > > +
> > > > +	ret = reset_control_deassert(i3c->tresetn);
> > > > +	if (ret)
> > > > +		goto err_presetn;
> > > > +
> > > > +	ret = clk_bulk_prepare_enable(i3c->num_clks, i3c->clks);
> > >
> > > Same here.
> > 
> > Same here.
> > 
> > 
> > Thanks & Regards,
> > Tommaso
> > 
> > >
> > > > +	if (ret)
> > > > +		goto err_tresetn;
> > > > +
> > > > +	/* Re-store I3C registers value. */
> > > > +	renesas_writel(i3c->regs, REFCKCTL,
> > > > +		       REFCKCTL_IREFCKS(i3c->refclk_div));
> > > > +	renesas_writel(i3c->regs, MSDVAD, MSDVAD_MDYADV |
> > > > +		       MSDVAD_MDYAD(i3c->dyn_addr));
> > > > +
> > > > +	/* Restore Device Address Table values. */
> > > > +	for (i = 0; i < i3c->maxdevs; i++)
> > > > +		renesas_writel(i3c->regs, DATBAS(i), i3c->DATBASn[i]);
> > > > +
> > > > +	/* I3C hw init. */
> > > > +	renesas_i3c_hw_init(i3c);
> > > > +
> > > > +	i2c_mark_adapter_resumed(&i3c->base.i2c);
> > > > +
> > > > +	return 0;
> > > > +
> > > > +err_tresetn:
> > > > +	reset_control_assert(i3c->tresetn);
> > > > +err_presetn:
> > > > +	reset_control_assert(i3c->presetn);
> > > > +	return ret;
> > > > +}
> > > > +
> > > > +static const struct dev_pm_ops renesas_i3c_pm_ops = {
> > > > +	NOIRQ_SYSTEM_SLEEP_PM_OPS(renesas_i3c_suspend_noirq,
> > > > +				  renesas_i3c_resume_noirq)
> > > > +};
> > > > +
> > > >  static const struct of_device_id renesas_i3c_of_ids[] = {
> > > >  	{ .compatible = "renesas,r9a08g045-i3c" },
> > > >  	{ .compatible = "renesas,r9a09g047-i3c" }, @@ -1385,6 +1473,7 @@
> > > > static struct platform_driver renesas_i3c = {
> > > >  	.driver = {
> > > >  		.name = "renesas-i3c",
> > > >  		.of_match_table = renesas_i3c_of_ids,
> > > > +		.pm = pm_sleep_ptr(&renesas_i3c_pm_ops),
> > > >  	},
> > > >  };
> > > >  module_platform_driver(renesas_i3c);
> > > > --
> > > > 2.43.0
> > >

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