Subject: Re: [PATCH 3/6] clk: stm32f4: Add post divisor for I2S & SAI PLLs and
 Add lcd-tft clock
To: gabriel.fernandez@st.com, Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Russell King <linux@armlinux.org.uk>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@st.com>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@codeaurora.org>, Nicolas Pitre <nico@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>, andrea.merello@gmail.com
References: <1478523943-23142-1-git-send-email-gabriel.fernandez@st.com>
 <1478523943-23142-4-git-send-email-gabriel.fernandez@st.com>
Cc: devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org,
        kernel@stlinux.com, ludovic.barre@st.com, olivier.bideau@st.com,
        amelie.delaunay@st.com
From: Daniel Thompson <daniel.thompson@linaro.org>
Message-ID: <860ce6a2-066f-2b44-3cf5-2d73720ed588@linaro.org>
Date: Mon, 7 Nov 2016 13:58:40 +0000
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On 07/11/16 13:05, gabriel.fernandez@st.com wrote:
> From: Gabriel Fernandez <gabriel.fernandez@st.com>
>
> This patch adds post dividers of I2S & SAI PLLs.
> These dividers are managed by a dedicated register (RCC_DCKCFGR).
> The PLL should be off before a set rate.
> This patch also introduces the lcd-tft clock.
>
> Signed-off-by: Gabriel Fernandez <gabriel.fernandez@st.com>
> ---
>  drivers/clk/clk-stm32f4.c | 27 +++++++++++++++++++++++++--
>  1 file changed, 25 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/clk/clk-stm32f4.c b/drivers/clk/clk-stm32f4.c
> index dda15bc..5fa5d51 100644
> --- a/drivers/clk/clk-stm32f4.c
> +++ b/drivers/clk/clk-stm32f4.c
> @@ -215,6 +215,7 @@ struct stm32f4_gate_data {
>  enum {
>  	SYSTICK, FCLK, CLK_LSI, CLK_LSE, CLK_HSE_RTC, CLK_RTC,
>  	PLL_VCO_I2S, PLL_VCO_SAI,
> +	CLK_LCD,
>  	END_PRIMARY_CLK
>  };
>
> @@ -599,6 +600,9 @@ static struct clk_hw *clk_register_pll_div(const char *name,
>  static const struct clk_div_table pll_divp_table[] = {
>  	{ 0, 2 }, { 1, 4 }, { 2, 6 }, { 3, 8 },
>  };
> +static const struct clk_div_table pll_lcd_div_table[] = {
> +	{ 0, 2 }, { 1, 4 }, { 2, 8 }, { 3, 16 },
> +};
>
>  /*
>   * Decode current PLL state and (statically) model the state we inherit from
> @@ -659,16 +663,35 @@ static struct clk_hw *stm32f4_rcc_register_pll(const char *pllsrc,
>  		clk_register_pll_div(data->p_name, data->vco_name, 0, reg,
>  				16, 2, 0, pll_divp_table, pll_hw, lock);
>
> -	if (data->q_name)
> +	if (data->q_name) {
>  		clk_register_pll_div(data->q_name, data->vco_name, 0, reg,
>  				24, 4, CLK_DIVIDER_ONE_BASED, NULL,
>  				pll_hw, lock);
>
> -	if (data->r_name)
> +		if (data->pll_num == PLL_I2S)
> +			clk_register_pll_div("plli2s-q-div", data->q_name,
> +				0, base + STM32F4_RCC_DCKCFGR,
> +				0, 5, 0, NULL, pll_hw, &stm32f4_clk_lock);
> +
> +		if (data->pll_num == PLL_SAI)
> +			clk_register_pll_div("pllsai-q-div", data->q_name,
> +				0, base + STM32F4_RCC_DCKCFGR,
> +				8, 5, 0, NULL, pll_hw, &stm32f4_clk_lock);
> +	}

Shouldn't this be in the config structures?

It seems very odd to me to allow the config structures to control 
whether we take the branch or not and then add these hard coded hacks.


Daniel.