linux-kernel - Re: [PATCH v4] clk: axs10x: introduce AXS10X pll driver

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Date:   Tue, 11 Jul 2017 22:25:35 -0700
From:   Stephen Boyd <sboyd@...eaurora.org>
To:     Eugeniy Paltsev <Eugeniy.Paltsev@...opsys.com>
Cc:     linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-snps-arc@...ts.infradead.org, Jose.Abreu@...opsys.com,
        Michael Turquette <mturquette@...libre.com>
Subject: Re: [PATCH v4] clk: axs10x: introduce AXS10X pll driver

On 06/21, Eugeniy Paltsev wrote:
> AXS10X boards manages it's clocks using various PLLs. These PLL has same
> dividers and corresponding control registers mapped to different addresses.
> So we add one common driver for such PLLs.
> 
> Each PLL on AXS10X board consist of three dividers: IDIV, FBDIV and
> ODIV. Output clock value is managed using these dividers.
> 
> We add pre-defined tables with supported rate values and appropriate
> configurations of IDIV, FBDIV and ODIV for each value.
> 
> As of today we add support for PLLs that generate clock for the
> following devices:
>  * ARC core on AXC CPU tiles.
>  * ARC PGU on ARC SDP Mainboard.
> and more to come later.
> 
> By this patch we add support for two plls (arc core pll and pgu pll),
> so we had to use two different init types: CLK_OF_DECLARE for arc core pll and
> regular probing for pgu pll.
> 
> Acked-by: Rob Herring <robh@...nel.org>
> Acked-by: Jose Abreu <joabreu@...opsys.com>
> 
> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@...opsys.com>
> Signed-off-by: Vlad Zakharov <vzakhar@...opsys.com>
> Signed-off-by: Jose Abreu <joabreu@...opsys.com>

Sorry this missed the cutoff for new code for v4.13. Should be in
clk-next next week though.

> +}
> +
> +static inline struct axs10x_pll_clk *to_axs10x_pll_clk(struct clk_hw *hw)
> +{
> +	return container_of(hw, struct axs10x_pll_clk, hw);
> +}
> +
> +static inline u32 axs10x_div_get_value(u32 reg)
> +{
> +	if (PLL_REG_GET_BYPASS(reg))
> +		return 1;
> +
> +	return PLL_REG_GET_HIGH(reg) + PLL_REG_GET_LOW(reg);
> +}
> +
> +static inline u32 axs10x_encode_div(unsigned int id, int upd)
> +{
> +	u32 div = 0;
> +
> +	PLL_REG_SET_LOW(div, (id % 2 == 0) ? id >> 1 : (id >> 1) + 1);
> +	PLL_REG_SET_HIGH(div, id >> 1);
> +	PLL_REG_SET_EDGE(div, id % 2);
> +	PLL_REG_SET_BYPASS(div, id == 1 ? 1 : 0);
> +	PLL_REG_SET_NOUPD(div, !upd);

So sparse complains here about a "dubious !x & y". Perhaps this
can be changed to

	PLL_REG_SET_NOUPD(div, upd == 0 ? 1 : 0);

That way sparse doesn't complain. I can make the change when
applying if you agree.

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