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Message-ID: <24f55e7d-2f2d-2181-2265-7365d648be8f@molgen.mpg.de>
Date:   Tue, 26 Oct 2021 08:10:18 +0200
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Subject: Re: [PATCH 01/10] clk: aspeed: ast2600: Porting sdhci clock source
Content-Language: en-US
To:     Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>
Cc:     robh+dt@kernel.org, joel@jms.id.au, mturquette@baylibre.com,
        sboyd@kernel.org, adrian.hunter@intel.com,
        linux-aspeed@lists.ozlabs.org, openbmc@lists.ozlabs.org,
        linux-mmc@vger.kernel.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-clk@vger.kernel.org, andrew@aj.id.au, BMC-SW@aspeedtech.com,
        steven_lee@aspeedtech.com
References: <20210922103116.30652-1-chin-ting_kuo@aspeedtech.com>
 <20210922103116.30652-2-chin-ting_kuo@aspeedtech.com>
From:   Paul Menzel <pmenzel@molgen.mpg.de>
In-Reply-To: <20210922103116.30652-2-chin-ting_kuo@aspeedtech.com>
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Precedence: bulk

Dear Chin-Ting,


Thank you for your patch. Some small things.

Please use imperative mood in the commit messages summary [1]:

clk: aspeed: ast2600: Port SDHCI clock source

On 22.09.21 12:31, Chin-Ting Kuo 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.

Please reference the datasheet name and version, and please reflow the 
commit message for 75 characters per line.

> 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[] = {
> +	{ 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[] = {
> +	{ 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);
> +	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) {
> +		/* 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 */
> 

Does Linux already log, if A1 or A2/A3 is detected?

Should a debug message be added, what clock divisor is used?


Kind regards,

Paul