[PATCH v7 2/5] media: imx8mq-mipi-csi2: Use devm_clk_bulk_get_all() to fetch clocks

[G.N. Zhou (OSS)]

Hi Laurent,

Thanks for your review.

> -----Original Message-----
> From: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Sent: Monday, October 27, 2025 8:12 AM
> To: G.N. Zhou (OSS) <guoniu.zhou at oss.nxp.com>
> Cc: Rui Miguel Silva <rmfrfs at gmail.com>; Martin Kepplinger
> <martink at posteo.de>; Purism Kernel Team <kernel at puri.sm>; Mauro
> Carvalho Chehab <mchehab at kernel.org>; Rob Herring <robh at kernel.org>;
> Krzysztof Kozlowski <krzk+dt at kernel.org>; Conor Dooley
> <conor+dt at kernel.org>; Shawn Guo <shawnguo at kernel.org>; Sascha Hauer
> <s.hauer at pengutronix.de>; Pengutronix Kernel Team
> <kernel at pengutronix.de>; Fabio Estevam <festevam at gmail.com>; Philipp
> Zabel <p.zabel at pengutronix.de>; Frank Li <frank.li at nxp.com>; linux-
> media at vger.kernel.org; devicetree at vger.kernel.org; imx at lists.linux.dev; linux-
> arm-kernel at lists.infradead.org; linux-kernel at vger.kernel.org; G.N. Zhou
> <guoniu.zhou at nxp.com>
> Subject: Re: [PATCH v7 2/5] media: imx8mq-mipi-csi2: Use
> devm_clk_bulk_get_all() to fetch clocks
> 
> On Thu, Oct 23, 2025 at 05:19:43PM +0800, Guoniu Zhou wrote:
> > From: Guoniu Zhou <guoniu.zhou at nxp.com>
> >
> > Use devm_clk_bulk_get_all() helper to simplify clock handle code.
> >
> > No functional changes intended.
> >
> > Reviewed-by: Frank Li <Frank.Li at nxp.com>
> > Signed-off-by: Guoniu Zhou <guoniu.zhou at nxp.com>
> > ---
> >  drivers/media/platform/nxp/imx8mq-mipi-csi2.c | 52
> > ++++++++-------------------
> >  1 file changed, 15 insertions(+), 37 deletions(-)
> >
> > diff --git a/drivers/media/platform/nxp/imx8mq-mipi-csi2.c
> > b/drivers/media/platform/nxp/imx8mq-mipi-csi2.c
> > index
> >
> d333ff43539f061b8b9cf88af2cda8c44b3ec2a9..fd202601d401145da8be23df4
> 451
> > f6af660642c5 100644
> > --- a/drivers/media/platform/nxp/imx8mq-mipi-csi2.c
> > +++ b/drivers/media/platform/nxp/imx8mq-mipi-csi2.c
> > @@ -71,21 +71,6 @@ enum {
> >  	ST_SUSPENDED	= 4,
> >  };
> >
> > -enum imx8mq_mipi_csi_clk {
> > -	CSI2_CLK_CORE,
> > -	CSI2_CLK_ESC,
> > -	CSI2_CLK_UI,
> > -	CSI2_NUM_CLKS,
> > -};
> > -
> > -static const char * const imx8mq_mipi_csi_clk_id[CSI2_NUM_CLKS] = {
> > -	[CSI2_CLK_CORE] = "core",
> > -	[CSI2_CLK_ESC] = "esc",
> > -	[CSI2_CLK_UI] = "ui",
> > -};
> > -
> > -#define CSI2_NUM_CLKS	ARRAY_SIZE(imx8mq_mipi_csi_clk_id)
> > -
> >  struct imx8mq_plat_data {
> >  	int (*enable)(struct csi_state *state, u32 hs_settle);
> >  	void (*disable)(struct csi_state *state); @@ -111,7 +96,8 @@ struct
> > csi_state {
> >  	struct device *dev;
> >  	const struct imx8mq_plat_data *pdata;
> >  	void __iomem *regs;
> > -	struct clk_bulk_data clks[CSI2_NUM_CLKS];
> > +	struct clk_bulk_data *clks;
> > +	int num_clks;
> >  	struct reset_control *rst;
> >  	struct regulator *mipi_phy_regulator;
> >
> > @@ -384,24 +370,16 @@ static void imx8mq_mipi_csi_set_params(struct
> csi_state *state)
> >  			      CSI2RX_SEND_LEVEL);
> >  }
> >
> > -static int imx8mq_mipi_csi_clk_enable(struct csi_state *state) -{
> > -	return clk_bulk_prepare_enable(CSI2_NUM_CLKS, state->clks);
> > -}
> > -
> > -static void imx8mq_mipi_csi_clk_disable(struct csi_state *state)
> > +static struct clk *find_esc_clk(struct csi_state *state)
> 
> This is one of the reasons why I don't like devm_clk_bulk_get_all(). I won't
> object to this patch, but I don't like it. At the very lest, you should look up the
> clock at probe time and cache it in the imx8mq_plat_data structure, to avoid
> looking it up multiple times at runtime.

Ok, but could we cache the clock in the csi_state structure? Because the imx8mq_plat_data
structure instance is const.

> 
> >  {
> > -	clk_bulk_disable_unprepare(CSI2_NUM_CLKS, state->clks);
> > -}
> > -
> > -static int imx8mq_mipi_csi_clk_get(struct csi_state *state) -{
> > -	unsigned int i;
> > +	int i;
> >
> > -	for (i = 0; i < CSI2_NUM_CLKS; i++)
> > -		state->clks[i].id = imx8mq_mipi_csi_clk_id[i];
> > +	for (i = 0; i < state->num_clks; i++) {
> 
> Make state->num_clks unsigned instead of making i signed.
> 
> > +		if (!strcmp(state->clks[i].id, "esc"))
> > +			return state->clks[i].clk;
> > +	}
> >
> > -	return devm_clk_bulk_get(state->dev, CSI2_NUM_CLKS, state->clks);
> > +	return NULL;
> 
> This needs to become a probe error.

Got it, will update in next version.

> 
> >  }
> >
> >  static int imx8mq_mipi_csi_calc_hs_settle(struct csi_state *state, @@
> > -456,7 +434,7 @@ static int imx8mq_mipi_csi_calc_hs_settle(struct csi_state
> *state,
> >  	 * documentation recommends picking a value away from the
> boundaries.
> >  	 * Let's pick the average.
> >  	 */
> > -	esc_clk_rate = clk_get_rate(state->clks[CSI2_CLK_ESC].clk);
> > +	esc_clk_rate = clk_get_rate(find_esc_clk(state));
> >  	if (!esc_clk_rate) {
> >  		dev_err(state->dev, "Could not get esc clock rate.\n");
> >  		return -EINVAL;
> > @@ -783,7 +761,7 @@ static void imx8mq_mipi_csi_pm_suspend(struct
> > device *dev)
> >
> >  	if (state->state & ST_POWERED) {
> >  		imx8mq_mipi_csi_stop_stream(state);
> > -		imx8mq_mipi_csi_clk_disable(state);
> > +		clk_bulk_disable_unprepare(state->num_clks, state->clks);
> >  		state->state &= ~ST_POWERED;
> >  	}
> >
> > @@ -801,7 +779,7 @@ static int imx8mq_mipi_csi_pm_resume(struct
> device
> > *dev)
> >
> >  	if (!(state->state & ST_POWERED)) {
> >  		state->state |= ST_POWERED;
> > -		ret = imx8mq_mipi_csi_clk_enable(state);
> > +		ret = clk_bulk_prepare_enable(state->num_clks, state->clks);
> >  	}
> >  	if (state->state & ST_STREAMING) {
> >  		sd_state = v4l2_subdev_lock_and_get_active_state(sd);
> > @@ -1027,9 +1005,9 @@ static int imx8mq_mipi_csi_probe(struct
> platform_device *pdev)
> >  	if (IS_ERR(state->regs))
> >  		return PTR_ERR(state->regs);
> >
> > -	ret = imx8mq_mipi_csi_clk_get(state);
> > -	if (ret < 0)
> > -		return ret;
> > +	state->num_clks = devm_clk_bulk_get_all(dev, &state->clks);
> > +	if (state->num_clks < 0)
> > +		return dev_err_probe(dev, state->num_clks, "Failed to get
> > +clocks\n");
> >
> >  	platform_set_drvdata(pdev, &state->sd);
> >
> 
> --
> Regards,
> 
> Laurent Pinchart