linux-kernel - RE: [PATCH 1/1] clk: aspeed: Fix APLL calculate formula for ast2600-A2

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Date:   Tue, 19 Jan 2021 03:04:13 +0000
From:   Ryan Chen <ryan_chen@...eedtech.com>
To:     Joel Stanley <joel@...ux.ibm.com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        "linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "andrewrj@....ibm.com" <andrewrj@....ibm.com>,
        BMC-SW <BMC-SW@...eedtech.com>
CC:     "joel@....id.au" <joel@....id.au>, Andrew Jeffery <andrew@...id.au>
Subject: RE: [PATCH 1/1] clk: aspeed: Fix APLL calculate formula for
 ast2600-A2

> -----Original Message-----
> From: Joel Stanley <joel@...ux.ibm.com>
> Sent: Tuesday, January 19, 2021 10:20 AM
> To: Ryan Chen <ryan_chen@...eedtech.com>; Michael Turquette
> <mturquette@...libre.com>; Stephen Boyd <sboyd@...nel.org>;
> linux-clk@...r.kernel.org; linux-kernel@...r.kernel.org;
> andrewrj@....ibm.com; BMC-SW <BMC-SW@...eedtech.com>
> Cc: joel@....id.au; Andrew Jeffery <andrew@...id.au>
> Subject: Re: [PATCH 1/1] clk: aspeed: Fix APLL calculate formula for ast2600-A2
> 
> On Mon, 2021-01-18 at 18:08 +0800, Ryan Chen wrote:
> > AST2600A1/A2 have different pll calculate formula.
> 
> To clarify, only the A0 has the old calculation, and all subsequent revisions use
> the new calculation?
> 
> If this is the case, do we need to support A0 in mainline linux, or should we
> drop support for A0 and only support A1, A2 and onwards?
> 
A0/A1 is use older calculate formula
After A2 is new calculate formula as the patch. 

> You should add a line to indicate this is a fix:
> 
> Fixes: d3d04f6c330a ("clk: Add support for AST2600 SoC")
> 
Got it. so should I send new patch? 

> Also, when sending single patches you do not need to include the cover letter.
> You should include all of the relevant information in the patch's commit
> message.
> 
> >
> > Signed-off-by: Ryan Chen <ryan_chen@...eedtech.com>
> > ---
> >  drivers/clk/clk-ast2600.c | 37 +++++++++++++++++++++++++++----------
> >  1 file changed, 27 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/clk/clk-ast2600.c b/drivers/clk/clk-ast2600.c
> > index bbacaccad554..8933bd1506b3 100644
> > --- a/drivers/clk/clk-ast2600.c
> > +++ b/drivers/clk/clk-ast2600.c
> > @@ -17,7 +17,8 @@
> >
> >  #define ASPEED_G6_NUM_CLKS             71
> >
> > -#define ASPEED_G6_SILICON_REV          0x004
> > +#define ASPEED_G6_SILICON_REV          0x014 #define
> CHIP_REVISION_ID
> > +GENMASK(23, 16)
> >
> >  #define ASPEED_G6_RESET_CTRL           0x040
> >  #define ASPEED_G6_RESET_CTRL2          0x050 @@ -190,18
> +191,34 @@
> > static struct clk_hw *ast2600_calc_pll(const char *name, u32 val)
> >  static struct clk_hw *ast2600_calc_apll(const char *name, u32 val)
> >  {
> >         unsigned int mult, div;
> > +       u32 chip_id = readl(scu_g6_base + ASPEED_G6_SILICON_REV);
> >
> > -       if (val & BIT(20)) {
> > -               /* Pass through mode */
> > -               mult = div = 1;
> > +       if (((chip_id & CHIP_REVISION_ID) >> 16) >= 2) {
> > +               if (val & BIT(24)) {
> > +                       /* Pass through mode */
> > +                       mult = div = 1;
> > +               } else {
> > +                       /* F = 25Mhz * [(m + 1) / (n + 1)] / (p +
> 1)
> > */
> > +                       u32 m = val & 0x1fff;
> > +                       u32 n = (val >> 13) & 0x3f;
> > +                       u32 p = (val >> 19) & 0xf;
> > +
> > +                       mult = (m + 1);
> > +                       div = (n + 1) * (p + 1);
> > +               }
> >         } else {
> > -               /* F = 25Mhz * (2-od) * [(m + 2) / (n + 1)] */
> > -               u32 m = (val >> 5) & 0x3f;
> > -               u32 od = (val >> 4) & 0x1;
> > -               u32 n = val & 0xf;
> > +               if (val & BIT(20)) {
> > +                       /* Pass through mode */
> > +                       mult = div = 1;
> > +               } else {
> > +                       /* F = 25Mhz * (2-od) * [(m + 2) / (n +
> 1)]
> > */
> > +                       u32 m = (val >> 5) & 0x3f;
> > +                       u32 od = (val >> 4) & 0x1;
> > +                       u32 n = val & 0xf;
> >
> > -               mult = (2 - od) * (m + 2);
> > -               div = n + 1;
> > +                       mult = (2 - od) * (m + 2);
> > +                       div = n + 1;
> > +               }
> >         }
> >         return clk_hw_register_fixed_factor(NULL, name, "clkin", 0,
> >                         mult, div);
>