Re: [PATCH v4 1/4] i3c: renesas: Switch to clk_bulk API and store clocks in private data

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

On Tue, Jan 06, 2026 at 03:01:49PM +0000, Biju Das wrote:
> Hi Frank Li,
>
> Thanks for the feedback.
>
> > -----Original Message-----
> > From: Frank Li <Frank.li@nxp.com>
> > Sent: 06 January 2026 14:49
> > Subject: Re: [PATCH v4 1/4] i3c: renesas: Switch to clk_bulk API and store clocks in private data
> >
> > On Mon, Jan 05, 2026 at 06:06:19PM +0000, Biju Das wrote:
> > > Hi Frank Li,
> > >
> > > > -----Original Message-----
> > > > From: Frank Li <Frank.li@nxp.com>
> > > > Sent: 05 January 2026 17:12
> > > > Subject: Re: [PATCH v4 1/4] i3c: renesas: Switch to clk_bulk API and
> > > > store clocks in private data
> > > >
> > > > On Mon, Jan 05, 2026 at 11:49:59AM +0100, Tommaso Merciai wrote:
> > > > > Replace individual devm_clk_get_enabled() calls with the clk_bulk
> > > > > API and store the clock handles in the driver's private data structure.
> > > > >
> > > > > All clocks required by the controller are now acquired and enabled
> > > > > using devm_clk_bulk_get_all_enabled(), removing the need for
> > > > > per-SoC clock handling and the renesas_i3c_config data.
> > > > > The TCLK is accessed via a fixed index in the bulk clock array.
> > > > >
> > > > > Simplify the code and prepare the driver for upcoming
> > > > > suspend/resume support.
> > > > >
> > > > > No functional change intended.
> > > > >
> > > > > Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
> > > > > Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
> > > > > ---
> > > > > v3->v4:
> > > > >  - Collected Biju Das tag.
> > > > >
> > > > > v2->v3:
> > > > >  - Added define for TCLK index.
> > > > >  - Use devm_clk_bulk_get_all_enabled() into renesas_i3c_probe().
> > > > >  - Improved commit body.
> > > > >  - Dropped unnecessary static const char * const renesas_i3c_clks[].
> > > > >  - Removed the need for per-SoC clock handling and the renesas_i3c_config data.
> > > > >
> > > > > v1->v2:
> > > > >  - New patch.
> > > > >
> > > > >  drivers/i3c/master/renesas-i3c.c | 43
> > > > > ++++++++------------------------
> > > > >  1 file changed, 11 insertions(+), 32 deletions(-)
> > > > >
> > > > > diff --git a/drivers/i3c/master/renesas-i3c.c
> > > > > b/drivers/i3c/master/renesas-i3c.c
> > > > > index 426a418f29b6..1b8f4be9ad67 100644
> > > > > --- a/drivers/i3c/master/renesas-i3c.c
> > > > > +++ b/drivers/i3c/master/renesas-i3c.c
> > > > > @@ -198,6 +198,8 @@
> > > > >  #define RENESAS_I3C_MAX_DEVS	8
> > > > >  #define I2C_INIT_MSG		-1
> > > > >
> > > > > +#define RENESAS_I3C_TCLK_IDX	1
> > > > > +
> > > > >  enum i3c_internal_state {
> > > > >  	I3C_INTERNAL_STATE_DISABLED,
> > > > >  	I3C_INTERNAL_STATE_CONTROLLER_IDLE,
> > > > > @@ -259,7 +261,8 @@ struct renesas_i3c {
> > > > >  	u8 addrs[RENESAS_I3C_MAX_DEVS];
> > > > >  	struct renesas_i3c_xferqueue xferqueue;
> > > > >  	void __iomem *regs;
> > > > > -	struct clk *tclk;
> > > > > +	struct clk_bulk_data *clks;
> > > > > +	u8 num_clks;
> > > > >  };
> > > > >
> > > > >  struct renesas_i3c_i2c_dev_data { @@ -272,10 +275,6 @@ struct
> > > > > renesas_i3c_irq_desc {
> > > > >  	const char *desc;
> > > > >  };
> > > > >
> > > > > -struct renesas_i3c_config {
> > > > > -	unsigned int has_pclkrw:1;
> > > > > -};
> > > > > -
> > > > >  static inline void renesas_i3c_reg_update(void __iomem *reg, u32
> > > > > mask, u32 val)  {
> > > > >  	u32 data = readl(reg);
> > > > > @@ -489,7 +488,7 @@ static int renesas_i3c_bus_init(struct i3c_master_controller *m)
> > > > >  	int od_high_ticks, od_low_ticks, i2c_total_ticks;
> > > > >  	int ret;
> > > > >
> > > > > -	rate = clk_get_rate(i3c->tclk);
> > > > > +	rate = clk_get_rate(i3c->clks[RENESAS_I3C_TCLK_IDX].clk);
> > > > >  	if (!rate)
> > > > >  		return -EINVAL;
> > > > >
> > > > > @@ -1302,13 +1301,8 @@ static int renesas_i3c_probe(struct
> > > > > platform_device *pdev)  {
> > > > >  	struct renesas_i3c *i3c;
> > > > >  	struct reset_control *reset;
> > > > > -	struct clk *clk;
> > > > > -	const struct renesas_i3c_config *config = of_device_get_match_data(&pdev->dev);
> > > > >  	int ret, i;
> > > > >
> > > > > -	if (!config)
> > > > > -		return -ENODATA;
> > > > > -
> > > > >  	i3c = devm_kzalloc(&pdev->dev, sizeof(*i3c), GFP_KERNEL);
> > > > >  	if (!i3c)
> > > > >  		return -ENOMEM;
> > > > > @@ -1317,19 +1311,11 @@ static int renesas_i3c_probe(struct platform_device *pdev)
> > > > >  	if (IS_ERR(i3c->regs))
> > > > >  		return PTR_ERR(i3c->regs);
> > > > >
> > > > > -	clk = devm_clk_get_enabled(&pdev->dev, "pclk");
> > > > > -	if (IS_ERR(clk))
> > > > > -		return PTR_ERR(clk);
> > > > > -
> > > > > -	if (config->has_pclkrw) {
> > > > > -		clk = devm_clk_get_enabled(&pdev->dev, "pclkrw");
> > > > > -		if (IS_ERR(clk))
> > > > > -			return PTR_ERR(clk);
> > > > > -	}
> > > > > +	ret = devm_clk_bulk_get_all_enabled(&pdev->dev, &i3c->clks);
> > > > > +	if (ret < 0)
> > > > > +		return ret;
> > > > >
> > > > > -	i3c->tclk = devm_clk_get_enabled(&pdev->dev, "tclk");
> > > > > -	if (IS_ERR(i3c->tclk))
> > > > > -		return PTR_ERR(i3c->tclk);
> > > > > +	i3c->num_clks = ret;
> > > >
> > > > Need check num_clks > RENESAS_I3C_TCLK_IDX to avoid outbound access
> > > > at
> > > > i3c->clks[RENESAS_I3C_TCLK_IDX].clk
> > >
> > > I guess dt binding check validate this as well. Eg: a single clk
> > > defined in the DT instead of minimum 2, will give DT warnings.
> > >
> > > Do you expect additional check in C code as well?
> >
> > Yes, worry about a wrong dtb cause kernel crash. Direct access
> > i3c->clks[RENESAS_I3C_TCLK_IDX] without check is risk.  if clock wrong
> > i3c->in
> > dtb,generally, it just impact function. but this may cause crash. So I suggest add addtional check
> > here.
>
> OK, to avoid a crash num_clks > RENESAS_I3C_TCLK_IDX check is sufficient

Yes,

> But it does not check whether tclk in 0th entry or first entry.
>
> >
> > Or search 'tclk' in array i3c->clks.
> > for (i = 0; i < i3c->num_clks; i++)
> > 	if (!strcmp("tclk", i3c->clks[i]->id))
> > 		break;
>
> But this returns correct index of the "tclk"

This is just more flexiable for clk schema. If your schema is simple enough
check num_clks > RENESAS_I3C_TCLK_IDX should be enough.

Frank

>
> Cheers,
> Biju