RE: [PATCH v4] clk: imx7ulp: do not export out IMX7ULP_CLK_MIPI_PLL clock

[Fancy Fang]

> -----Original Message-----
> From: Shawn Guo <shawnguo@xxxxxxxxxx>
> Sent: Monday, October 28, 2019 6:51 PM
> To: Fancy Fang <chen.fang@xxxxxxx>
> Cc: sboyd@xxxxxxxxxx; linux-clk@xxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> mturquette@xxxxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx;
> dl-linux-imx <linux-imx@xxxxxxx>
> Subject: Re: [PATCH v4] clk: imx7ulp: do not export out IMX7ULP_CLK_MIPI_PLL
> clock
> 
> On Mon, Oct 28, 2019 at 08:07:59AM +0000, Fancy Fang wrote:
> > The mipi pll clock comes from the MIPI PHY PLL output, so
> > it should not be a fixed clock.
> >
> > MIPI PHY PLL is in the MIPI DSI space, and it is used as
> > the bit clock for transferring the pixel data out and its
> > output clock is configured according to the display mode.
> >
> > So it should be used only for MIPI DSI and not be exported
> > out for other usages.
> >
> > Signed-off-by: Fancy Fang <chen.fang@xxxxxxx>
> > ---
> > ChangeLog v3->v4:
> >  * Add some comments to 'IMX7ULP_CLK_MIPI_PLL'
> >    clock.
> >
> >  Documentation/devicetree/bindings/clock/imx7ulp-clock.txt | 1 -
> >  drivers/clk/imx/clk-imx7ulp.c                             | 3 +--
> >  include/dt-bindings/clock/imx7ulp-clock.h                 | 6 ++++++
> >  3 files changed, 7 insertions(+), 3 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/clock/imx7ulp-clock.txt
> b/Documentation/devicetree/bindings/clock/imx7ulp-clock.txt
> > index a4f8cd478f92..93d89adb7afe 100644
> > --- a/Documentation/devicetree/bindings/clock/imx7ulp-clock.txt
> > +++ b/Documentation/devicetree/bindings/clock/imx7ulp-clock.txt
> > @@ -82,7 +82,6 @@ pcc2: pcc2@403f0000 {
> >  		 <&scg1 IMX7ULP_CLK_APLL_PFD0>,
> >  		 <&scg1 IMX7ULP_CLK_UPLL>,
> >  		 <&scg1 IMX7ULP_CLK_SOSC_BUS_CLK>,
> > -		 <&scg1 IMX7ULP_CLK_MIPI_PLL>,
> >  		 <&scg1 IMX7ULP_CLK_FIRC_BUS_CLK>,
> >  		 <&scg1 IMX7ULP_CLK_ROSC>,
> >  		 <&scg1 IMX7ULP_CLK_SPLL_BUS_CLK>;
> > diff --git a/drivers/clk/imx/clk-imx7ulp.c b/drivers/clk/imx/clk-imx7ulp.c
> > index 2022d9bead91..459b120b71d5 100644
> > --- a/drivers/clk/imx/clk-imx7ulp.c
> > +++ b/drivers/clk/imx/clk-imx7ulp.c
> > @@ -28,7 +28,7 @@ static const char * const scs_sels[]		= { "dummy",
> "sosc", "sirc", "firc", "dumm
> >  static const char * const ddr_sels[]		= { "apll_pfd_sel", "upll", };
> >  static const char * const nic_sels[]		= { "firc", "ddr_clk", };
> >  static const char * const periph_plat_sels[]	= { "dummy", "nic1_bus_clk",
> "nic1_clk", "ddr_clk", "apll_pfd2", "apll_pfd1", "apll_pfd0", "upll", };
> > -static const char * const periph_bus_sels[]	= { "dummy", "sosc_bus_clk",
> "mpll", "firc_bus_clk", "rosc", "nic1_bus_clk", "nic1_clk", "spll_bus_clk", };
> > +static const char * const periph_bus_sels[]	= { "dummy", "sosc_bus_clk",
> "dummy", "firc_bus_clk", "rosc", "nic1_bus_clk", "nic1_clk", "spll_bus_clk", };
> >  static const char * const arm_sels[]		= { "divcore", "dummy", "dummy",
> "hsrun_divcore", };
> >
> >  /* used by sosc/sirc/firc/ddr/spll/apll dividers */
> > @@ -75,7 +75,6 @@ static void __init imx7ulp_clk_scg1_init(struct
> device_node *np)
> >  	clks[IMX7ULP_CLK_SOSC]		= imx_obtain_fixed_clk_hw(np, "sosc");
> >  	clks[IMX7ULP_CLK_SIRC]		= imx_obtain_fixed_clk_hw(np, "sirc");
> >  	clks[IMX7ULP_CLK_FIRC]		= imx_obtain_fixed_clk_hw(np, "firc");
> > -	clks[IMX7ULP_CLK_MIPI_PLL]	= imx_obtain_fixed_clk_hw(np, "mpll");
> >  	clks[IMX7ULP_CLK_UPLL]		= imx_obtain_fixed_clk_hw(np, "upll");
> >
> >  	/* SCG1 */
> > diff --git a/include/dt-bindings/clock/imx7ulp-clock.h
> b/include/dt-bindings/clock/imx7ulp-clock.h
> > index 6f66f9005c81..e9ef62f211fe 100644
> > --- a/include/dt-bindings/clock/imx7ulp-clock.h
> > +++ b/include/dt-bindings/clock/imx7ulp-clock.h
> > @@ -49,7 +49,13 @@
> >  #define IMX7ULP_CLK_NIC1_DIV		36
> >  #define IMX7ULP_CLK_NIC1_BUS_DIV	37
> >  #define IMX7ULP_CLK_NIC1_EXT_DIV	38
> > +
> > +/* mpll clock is a special clock comes from
> > + * mipi DPHY PLL and should be used only for
> > + * mipi dsi instead of any other peripheral.
> > + */
> >  #define IMX7ULP_CLK_MIPI_PLL		39
> > +
> 
> The point of comment is to tell that the clock ID is unsupported and
> shouldn't be used in DT.
> 
> I reworded the comment and applied the patch.

OK. Thank you.

Best regards,
Fancy Fang
> 
> Shawn
> 
> >  #define IMX7ULP_CLK_SIRC		40
> >  #define IMX7ULP_CLK_SOSC_BUS_CLK	41
> >  #define IMX7ULP_CLK_FIRC_BUS_CLK	42
> > --
> > 2.17.1
> >