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Message-ID: <20251121024714.GD11519@pendragon.ideasonboard.com>
Date: Fri, 21 Nov 2025 11:47:14 +0900
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: "G.N. Zhou (OSS)" <guoniu.zhou@....nxp.com>
Cc: Rui Miguel Silva <rmfrfs@...il.com>,
Martin Kepplinger <martink@...teo.de>,
Purism Kernel Team <kernel@...i.sm>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>, Shawn Guo <shawnguo@...nel.org>,
Sascha Hauer <s.hauer@...gutronix.de>,
Pengutronix Kernel Team <kernel@...gutronix.de>,
Fabio Estevam <festevam@...il.com>,
Philipp Zabel <p.zabel@...gutronix.de>, Frank Li <frank.li@....com>,
"linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"imx@...ts.linux.dev" <imx@...ts.linux.dev>,
"linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"G.N. Zhou" <guoniu.zhou@....com>
Subject: Re: [PATCH v7 2/5] media: imx8mq-mipi-csi2: Use
devm_clk_bulk_get_all() to fetch clocks
On Fri, Nov 21, 2025 at 02:21:23AM +0000, G.N. Zhou (OSS) wrote:
> On Monday, October 27, 2025 8:12 AM, Laurent Pinchart wrote:
> > On Thu, Oct 23, 2025 at 05:19:43PM +0800, Guoniu Zhou wrote:
> > > From: Guoniu Zhou <guoniu.zhou@....com>
> > >
> > > Use devm_clk_bulk_get_all() helper to simplify clock handle code.
> > >
> > > No functional changes intended.
> > >
> > > Reviewed-by: Frank Li <Frank.Li@....com>
> > > Signed-off-by: Guoniu Zhou <guoniu.zhou@....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..fd202601d401145da8be23df4451f6af660642c5 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.
> >
> > > {
> > > - 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.
>
> I address the comment in v8(https://lore.kernel.org/all/20251113-csi2_imx8ulp-v8-0-2ebe378f7111@nxp.com/),
> but Media CI robot detected some issues as bellow.
>
> # Test static:test-smatch
> drivers/media/platform/nxp/imx8mq-mipi-csi2.c:1006 imx8mq_mipi_csi_probe() warn: unsigned 'state->num_clks' is never less than zero.
>
> # Test static:test-coccinelle
> ./platform/nxp/imx8mq-mipi-csi2.c:1006:5-20: WARNING: Unsigned expression compared with zero: state -> num_clks < 0
>
> I checked the parameters type of all functions which will refer to
> num_clks, their type is int, so I plan to drop the changes in v8 and
> will send v9.
You can address the issue in the probe function as follows:
ret = devm_clk_bulk_get_all(dev, &state->clks);
if (ret < 0)
return dev_err_probe(dev, ret, "Failed to get clocks\n");
state->num_clks = ret;
> > > + 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.
> >
> > > }
> > >
> > > 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
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