linux-kernel - Re: [PATCH 3/5] clk: meson-gxbb: Add GXL/GXM GP0 Variant

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Message-ID: <149023325102.54062.9484584718973106363@resonance>
Date:   Wed, 22 Mar 2017 18:40:51 -0700
From:   Michael Turquette <mturquette@...libre.com>
To:     Neil Armstrong <narmstrong@...libre.com>, sboyd@...eaurora.org,
        carlo@...one.org, khilman@...libre.com
Cc:     linux-clk@...r.kernel.org, linux-amlogic@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/5] clk: meson-gxbb: Add GXL/GXM GP0 Variant

Quoting Neil Armstrong (2017-03-22 02:22:57)
> On 03/22/2017 12:49 AM, Michael Turquette wrote:
> > Hi Neil,
> > 
> > Quoting Neil Armstrong (2017-03-13 06:26:42)
> >> @@ -821,6 +893,7 @@ struct pll_params_table gxbb_gp0_params_table[] = {
> >>         &gxbb_hdmi_pll,
> >>         &gxbb_sys_pll,
> >>         &gxbb_gp0_pll,
> >> +       &gxl_gp0_pll,
> 
> Yes, because this is the table used to change the register base, this won't harm in any way
> to add SoC variant clocks, since they they are initialized using the gxbb_hw_onecell_data table.
> 
> > 
> > Is there a reason for adding the pointer to this array here? It seems to
> > me that the gxbb_gp0_pll and gxl_gp0_pll are mutually exclusive, so
> > perhaps two different tables should be used?
> > 
> >>  };
> >>  
> >>  static struct meson_clk_mpll *const gxbb_clk_mplls[] = {
> >> @@ -923,6 +996,10 @@ static int gxbb_clkc_probe(struct platform_device *pdev)
> >>         struct clk *parent_clk;
> >>         struct device *dev = &pdev->dev;
> >>  
> >> +       /* Override GP0 clock for GXL/GXM */
> >> +       if (of_device_is_compatible(dev->of_node, "amlogic,gxl-clkc"))
> >> +               gxbb_hw_onecell_data.hws[CLKID_GP0_PLL] = &gxl_gp0_pll.hw;
> > 
> > Similarly, this above is a little ugly compared to dedicated tables for
> > each variant.
> 
> Here is the true uglyness, but would you like to have the exact same gxbb_hw_onecell_data
> duplicated for only two different clocks ?
> The gxbb_hw_onecell_data table is 105 lines, and when adding new clocks, we will need to
> make sure they are still synchronized.
> 
> If you have a better idea... I can still push a v2 with such table with also a
> separate gxbb_clk_plls table stored in a struct given from of_device_get_match_data()

I was not thinking of duplicating all of the clock data table, but
breaking out the parts with variation into separate tables. E.g. a
common table, a gxbb table and a gp0 table.

But on second look your original solution is fine, especially since
those two new tables I mentioned would only have a single element in
them, which is silly.

Ack.

Regards,
Mike

> 
> Neil
> 
> > 
> > Regards,
> > Mike
> > 
> >> +
> >>         /*  Generic clocks and PLLs */
> >>         clk_base = of_iomap(dev->of_node, 0);
> >>         if (!clk_base) {
> >> @@ -996,6 +1073,7 @@ static int gxbb_clkc_probe(struct platform_device *pdev)
> >>  
> >>  static const struct of_device_id gxbb_clkc_match_table[] = {
> >>         { .compatible = "amlogic,gxbb-clkc" },
> >> +       { .compatible = "amlogic,gxl-clkc" },
> >>         { }
> >>  };
> >>  
> >> diff --git a/drivers/clk/meson/gxbb.h b/drivers/clk/meson/gxbb.h
> >> index 8ee2022..7f99bf6 100644
> >> --- a/drivers/clk/meson/gxbb.h
> >> +++ b/drivers/clk/meson/gxbb.h
> >> @@ -71,6 +71,8 @@
> >>  #define HHI_GP0_PLL_CNTL2              0x44 /* 0x11 offset in data sheet */
> >>  #define HHI_GP0_PLL_CNTL3              0x48 /* 0x12 offset in data sheet */
> >>  #define HHI_GP0_PLL_CNTL4              0x4c /* 0x13 offset in data sheet */
> >> +#define        HHI_GP0_PLL_CNTL5               0x50 /* 0x14 offset in data sheet */
> >> +#define        HHI_GP0_PLL_CNTL1               0x58 /* 0x16 offset in data sheet */
> >>  
> >>  #define HHI_XTAL_DIVN_CNTL             0xbc /* 0x2f offset in data sheet */
> >>  #define HHI_TIMER90K                   0xec /* 0x3b offset in data sheet */
> >> -- 
> >> 1.9.1
> >>
>