RE: [PATCH 01/10] clk: aspeed: ast2600: Porting sdhci clock source

[Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>]

Hi Joel,

Thanks for the review.

> -----Original Message-----
> From: Joel Stanley <joel@jms.id.au>
> Sent: Thursday, September 23, 2021 8:02 AM
> To: Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>
> Subject: Re: [PATCH 01/10] clk: aspeed: ast2600: Porting sdhci clock source
> 
> On Wed, 22 Sept 2021 at 10:31, Chin-Ting Kuo
> <chin-ting_kuo@aspeedtech.com> wrote:
> >
> > - There are two clock sources used to generate
> >   SD/SDIO clock, APLL clock and HCLK (200MHz).
> >   User can select which clock source should be used
> >   by configuring SCU310[8].
> > - The SD/SDIO clock divider selection table SCU310[30:28]
> >   is different between AST2600-A1 and AST2600-A2/A3.
> >   For AST2600-A1, 200MHz SD/SDIO clock cannot be
> >   gotten by the dividers in SCU310[30:28] if APLL
> >   is not the multiple of 200MHz and HCLK is 200MHz.
> >   For AST2600-A2/A3, a new divider, "1", is added and
> >   200MHz SD/SDIO clock can be obtained by adopting HCLK
> >   as clock source and setting SCU310[30:28] to 3b'111.
> >
> > Signed-off-by: Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>
> > ---
> >  drivers/clk/clk-ast2600.c | 69
> > ++++++++++++++++++++++++++++++++++-----
> >  1 file changed, 61 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/clk/clk-ast2600.c b/drivers/clk/clk-ast2600.c
> > index bc3be5f3eae1..a6778c18274a 100644
> > --- a/drivers/clk/clk-ast2600.c
> > +++ b/drivers/clk/clk-ast2600.c
> > @@ -168,6 +168,30 @@ static const struct clk_div_table ast2600_div_table[]
> = {
> >         { 0 }
> >  };
> >
> > +static const struct clk_div_table ast2600_sd_div_a1_table[] = {
> 
> Let's put the revision next to the ast2600 like the other tables:
> 
> ast2600_a1_sd_div_table
> 
> > +       { 0x0, 2 },
> > +       { 0x1, 4 },
> > +       { 0x2, 6 },
> > +       { 0x3, 8 },
> > +       { 0x4, 10 },
> > +       { 0x5, 12 },
> > +       { 0x6, 14 },
> > +       { 0x7, 16 },
> > +       { 0 }
> > +};
> > +
> > +static const struct clk_div_table ast2600_sd_div_a2_table[] = {
> 

Okay, this will be updated in the next patch version.

> For naming; can I propose we omit the revision for the A2/A3+ case? So this
> one would be called:
> 
> ast2600_sd_div_table
> 

Okay, this will also be updated in the next patch version.

> > +       { 0x0, 2 },
> > +       { 0x1, 4 },
> > +       { 0x2, 6 },
> > +       { 0x3, 8 },
> > +       { 0x4, 10 },
> > +       { 0x5, 12 },
> > +       { 0x6, 14 },
> > +       { 0x7, 1 },
> > +       { 0 }
> > +};
> > +
> >  /* For hpll/dpll/epll/mpll */
> >  static struct clk_hw *ast2600_calc_pll(const char *name, u32 val)  {
> > @@ -424,6 +448,11 @@ static const char *const
> emmc_extclk_parent_names[] = {
> >         "mpll",
> >  };
> >
> > +static const char *const sd_extclk_parent_names[] = {
> > +       "hclk",
> > +       "apll",
> > +};
> > +
> >  static const char * const vclk_parent_names[] = {
> >         "dpll",
> >         "d1pll",
> > @@ -523,18 +552,42 @@ static int aspeed_g6_clk_probe(struct
> platform_device *pdev)
> >                 return PTR_ERR(hw);
> >         aspeed_g6_clk_data->hws[ASPEED_CLK_EMMC] = hw;
> >
> > -       /* SD/SDIO clock divider and gate */
> > -       hw = clk_hw_register_gate(dev, "sd_extclk_gate", "hpll", 0,
> > -                       scu_g6_base + ASPEED_G6_CLK_SELECTION4,
> 31, 0,
> > -                       &aspeed_g6_clk_lock);
> > +       clk_hw_register_fixed_rate(NULL, "hclk", NULL, 0, 200000000);
> > +
> > +       regmap_read(map, 0x310, &val);
> 
> Use the #defines for the register number.

Okay.

> 
> > +       hw = clk_hw_register_mux(dev, "sd_extclk_mux",
> > +                                sd_extclk_parent_names,
> > +
> ARRAY_SIZE(sd_extclk_parent_names), 0,
> > +                                scu_g6_base +
> ASPEED_G6_CLK_SELECTION4, 8, 1,
> > +                                0, &aspeed_g6_clk_lock);
> >         if (IS_ERR(hw))
> >                 return PTR_ERR(hw);
> > -       hw = clk_hw_register_divider_table(dev, "sd_extclk",
> "sd_extclk_gate",
> > -                       0, scu_g6_base + ASPEED_G6_CLK_SELECTION4,
> 28, 3, 0,
> > -                       ast2600_div_table,
> > -                       &aspeed_g6_clk_lock);
> > +
> > +       hw = clk_hw_register_gate(dev, "sd_extclk_gate", "sd_extclk_mux",
> > +                                 0, scu_g6_base +
> ASPEED_G6_CLK_SELECTION4,
> > +                                 31, 0, &aspeed_g6_clk_lock);
> >         if (IS_ERR(hw))
> >                 return PTR_ERR(hw);
> > +
> > +       regmap_read(map, 0x14, &val);
> > +       /* AST2600-A2/A3 clock divisor is different from AST2600-A1 */
> > +       if (((val & GENMASK(23, 16)) >> 16) >= 2) {
> 
> I've got a little patch that I recommend you base your series on (feel free to
> include it in your series when posting v2 to make it
> self-contained):
> 
> https://lore.kernel.org/all/20210922235449.213631-1-joel@jms.id.au/
> 
> With this one you can do:
> 
> const struct clk_div_table* table;
> 
>  if (soc_rev >= 2)
>    table = ast2600_sd_div_table;
> else
>    table = ast2600_a1_sd_div_table;
> 
> Then you don't need to duplicate the registration for each case:
> 
>                hw = clk_hw_register_divider_table(dev, "sd_extclk",
> "sd_extclk_gate",
>                                        0, scu_g6_base +
> ASPEED_G6_CLK_SELECTION4, 28, 3, 0,
>                                        table,
>                                        &aspeed_g6_clk_lock);
>                if (IS_ERR(hw))
>                        return PTR_ERR(hw);
> 

Okay, I will include your patch into this patch series when posting v2.

> > +               /* AST2600-A2/A3 */
> > +               hw = clk_hw_register_divider_table(dev, "sd_extclk",
> "sd_extclk_gate",
> > +                                       0, scu_g6_base +
> ASPEED_G6_CLK_SELECTION4, 28, 3, 0,
> > +                                       ast2600_sd_div_a2_table,
> > +                                       &aspeed_g6_clk_lock);
> > +               if (IS_ERR(hw))
> > +                       return PTR_ERR(hw);
> > +       } else {
> > +               /* AST2600-A1 */
> > +               hw = clk_hw_register_divider_table(dev, "sd_extclk",
> "sd_extclk_gate",
> > +                                       0, scu_g6_base +
> ASPEED_G6_CLK_SELECTION4, 28, 3, 0,
> > +                                       ast2600_sd_div_a1_table,
> > +                                       &aspeed_g6_clk_lock);
> > +               if (IS_ERR(hw))
> > +                       return PTR_ERR(hw);
> > +       }
> >         aspeed_g6_clk_data->hws[ASPEED_CLK_SDIO] = hw;
> >
> >         /* MAC1/2 RMII 50MHz RCLK */
> > --
> > 2.17.1
> >