Re: [PATCH v4 04/13] media: nxp: imx8-isi: Use devm_clk_bulk_get_all() to fetch clocks

[Rob Herring <robh@kernel.org>]

On Wed, Jun 11, 2025 at 05:14:49PM +0300, Laurent Pinchart wrote:
> Hi Rob,
> 
> On Thu, May 08, 2025 at 08:35:53AM -0400, Frank Li wrote:
> > On Fri, May 02, 2025 at 06:57:47PM +0300, Laurent Pinchart wrote:
> > > On Thu, May 01, 2025 at 09:02:04PM -0400, Frank Li wrote:
> > > > On Tue, Apr 22, 2025 at 12:14:38AM +0300, Laurent Pinchart wrote:
> > > > > On Tue, Apr 08, 2025 at 05:53:02PM -0400, Frank Li wrote:
> > > > > > Use devm_clk_bulk_get_all() helper to simplify clock handle code.
> > > > > >
> > > > > > No functional changes intended.
> > > > > >
> > > > > > Signed-off-by: Frank Li <Frank.Li@nxp.com>
> > > > > > ---
> > > > > >  .../media/platform/nxp/imx8-isi/imx8-isi-core.c    | 46 +++-------------------
> > > > > >  .../media/platform/nxp/imx8-isi/imx8-isi-core.h    |  3 +-
> > > > > >  2 files changed, 6 insertions(+), 43 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.c b/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.c
> > > > > > index ecfc95882f903..015350c6f2784 100644
> > > > > > --- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.c
> > > > > > +++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.c
> > > > > > @@ -275,11 +275,6 @@ static const struct mxc_isi_set_thd mxc_imx8_isi_thd_v1 = {
> > > > > >  	.panic_set_thd_v = { .mask = 0xf0000, .offset = 16, .threshold = 0x7 },
> > > > > >  };
> > > > > >
> > > > > > -static const struct clk_bulk_data mxc_imx8mn_clks[] = {
> > > > > > -	{ .id = "axi" },
> > > > > > -	{ .id = "apb" },
> > > > > > -};
> > > > > > -
> > > > > >  static const struct mxc_isi_plat_data mxc_imx8mn_data = {
> > > > > >  	.model			= MXC_ISI_IMX8MN,
> > > > > >  	.num_ports		= 1,
> > > > > > @@ -287,8 +282,6 @@ static const struct mxc_isi_plat_data mxc_imx8mn_data = {
> > > > > >  	.reg_offset		= 0,
> > > > > >  	.ier_reg		= &mxc_imx8_isi_ier_v1,
> > > > > >  	.set_thd		= &mxc_imx8_isi_thd_v1,
> > > > > > -	.clks			= mxc_imx8mn_clks,
> > > > > > -	.num_clks		= ARRAY_SIZE(mxc_imx8mn_clks),
> > > > > >  	.buf_active_reverse	= false,
> > > > > >  	.gasket_ops		= &mxc_imx8_gasket_ops,
> > > > > >  	.has_36bit_dma		= false,
> > > > > > @@ -301,8 +294,6 @@ static const struct mxc_isi_plat_data mxc_imx8mp_data = {
> > > > > >  	.reg_offset		= 0x2000,
> > > > > >  	.ier_reg		= &mxc_imx8_isi_ier_v2,
> > > > > >  	.set_thd		= &mxc_imx8_isi_thd_v1,
> > > > > > -	.clks			= mxc_imx8mn_clks,
> > > > > > -	.num_clks		= ARRAY_SIZE(mxc_imx8mn_clks),
> > > > > >  	.buf_active_reverse	= true,
> > > > > >  	.gasket_ops		= &mxc_imx8_gasket_ops,
> > > > > >  	.has_36bit_dma		= true,
> > > > > > @@ -315,8 +306,6 @@ static const struct mxc_isi_plat_data mxc_imx8ulp_data = {
> > > > > >  	.reg_offset		= 0x0,
> > > > > >  	.ier_reg		= &mxc_imx8_isi_ier_v2,
> > > > > >  	.set_thd		= &mxc_imx8_isi_thd_v1,
> > > > > > -	.clks			= mxc_imx8mn_clks,
> > > > > > -	.num_clks		= ARRAY_SIZE(mxc_imx8mn_clks),
> > > > > >  	.buf_active_reverse	= true,
> > > > > >  	.has_36bit_dma		= false,
> > > > > >  };
> > > > > > @@ -328,8 +317,6 @@ static const struct mxc_isi_plat_data mxc_imx93_data = {
> > > > > >  	.reg_offset		= 0,
> > > > > >  	.ier_reg		= &mxc_imx8_isi_ier_v2,
> > > > > >  	.set_thd		= &mxc_imx8_isi_thd_v1,
> > > > > > -	.clks			= mxc_imx8mn_clks,
> > > > > > -	.num_clks		= ARRAY_SIZE(mxc_imx8mn_clks),
> > > > > >  	.buf_active_reverse	= true,
> > > > > >  	.gasket_ops		= &mxc_imx93_gasket_ops,
> > > > > >  	.has_36bit_dma		= false,
> > > > > > @@ -386,7 +373,7 @@ static int mxc_isi_runtime_suspend(struct device *dev)
> > > > > >  {
> > > > > >  	struct mxc_isi_dev *isi = dev_get_drvdata(dev);
> > > > > >
> > > > > > -	clk_bulk_disable_unprepare(isi->pdata->num_clks, isi->clks);
> > > > > > +	clk_bulk_disable_unprepare(isi->num_clks, isi->clks);
> > > > > >
> > > > > >  	return 0;
> > > > > >  }
> > > > > > @@ -396,7 +383,7 @@ static int mxc_isi_runtime_resume(struct device *dev)
> > > > > >  	struct mxc_isi_dev *isi = dev_get_drvdata(dev);
> > > > > >  	int ret;
> > > > > >
> > > > > > -	ret = clk_bulk_prepare_enable(isi->pdata->num_clks, isi->clks);
> > > > > > +	ret = clk_bulk_prepare_enable(isi->num_clks, isi->clks);
> > > > > >  	if (ret) {
> > > > > >  		dev_err(dev, "Failed to enable clocks (%d)\n", ret);
> > > > > >  		return ret;
> > > > > > @@ -414,27 +401,6 @@ static const struct dev_pm_ops mxc_isi_pm_ops = {
> > > > > >   * Probe, remove & driver
> > > > > >   */
> > > > > >
> > > > > > -static int mxc_isi_clk_get(struct mxc_isi_dev *isi)
> > > > > > -{
> > > > > > -	unsigned int size = isi->pdata->num_clks
> > > > > > -			  * sizeof(*isi->clks);
> > > > > > -	int ret;
> > > > > > -
> > > > > > -	isi->clks = devm_kmemdup(isi->dev, isi->pdata->clks, size, GFP_KERNEL);
> > > > > > -	if (!isi->clks)
> > > > > > -		return -ENOMEM;
> > > > > > -
> > > > > > -	ret = devm_clk_bulk_get(isi->dev, isi->pdata->num_clks,
> > > > > > -				isi->clks);
> > > > > > -	if (ret < 0) {
> > > > > > -		dev_err(isi->dev, "Failed to acquire clocks: %d\n",
> > > > > > -			ret);
> > > > > > -		return ret;
> > > > > > -	}
> > > > > > -
> > > > > > -	return 0;
> > > > > > -}
> > > > > > -
> > > > > >  static int mxc_isi_probe(struct platform_device *pdev)
> > > > > >  {
> > > > > >  	struct device *dev = &pdev->dev;
> > > > > > @@ -457,11 +423,9 @@ static int mxc_isi_probe(struct platform_device *pdev)
> > > > > >  	if (!isi->pipes)
> > > > > >  		return -ENOMEM;
> > > > > >
> > > > > > -	ret = mxc_isi_clk_get(isi);
> > > > > > -	if (ret < 0) {
> > > > > > -		dev_err(dev, "Failed to get clocks\n");
> > > > > > -		return ret;
> > > > > > -	}
> > > > > > +	isi->num_clks = devm_clk_bulk_get_all(dev, &isi->clks);
> > > > >
> > > > > This prevents validating that the DT contains the expected clocks, which
> > > > > could cause hard to debug issues. Isn't it a problem ?
> > > >
> > > > It is checked by dt-binding. Now no warning by DTB_CHECK under arm64 freecale.
> > > > CHECK_DTB should be enough to find expected clocks.
> > >
> > > Yes, the DTB check will catch issues at build time, but the driver will
> > > not enforce that. I'm not sure if there's a clear policy here, and if
> > > ensuring at runtime in drivers that the expected clocks are present is
> > > considered as a good practice by the DT maintainers. Rob, Krzysztof,
> > > Conor, do you have an opinion ?
> > 
> > Rob:
> > 	can you comment this?
> 
> Rob, any comment on this ?

My preference is to not do validation of the DT in the kernel. Unless 
you need greater control of the clocks, I would use 
devm_clk_bulk_get_all(). 

Rob