linux-kernel - Re: [PATCH v5 3/9] clk: mediatek: Add configurable pcwibits and fmin to mtk_pll

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Message-ID: <1551768411.22671.3.camel@mtksdaap41>
Date:   Tue, 5 Mar 2019 14:46:51 +0800
From:   James Liao <jamesjj.liao@...iatek.com>
To:     Weiyi Lu <weiyi.lu@...iatek.com>
CC:     Nicolas Boichat <drinkcat@...omium.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Stephen Boyd <sboyd@...eaurora.org>,
        Rob Herring <robh@...nel.org>,
        Fan Chen <fan.chen@...iatek.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-mediatek@...ts.infradead.org>, <linux-clk@...r.kernel.org>,
        <srv_heupstream@...iatek.com>, <stable@...r.kernel.org>,
        Owen Chen <owen.chen@...iatek.com>
Subject: Re: [PATCH v5 3/9] clk: mediatek: Add configurable pcwibits and
 fmin to mtk_pll_data

On Tue, 2019-03-05 at 13:05 +0800, Weiyi Lu wrote:
> From: Owen Chen <owen.chen@...iatek.com>
> 
> 1. pcwibits: The integer bits of pcw for plls is extend to 8 bits,
>    add a variable to indicate this change and
>    backward-compatible.
> 2. fmin: The pll freqency lower-bound is vary from 1GMhz to
>    1.5Ghz, add a variable to indicate platform-dependent.
> 
> Signed-off-by: Owen Chen <owen.chen@...iatek.com>
> Signed-off-by: Weiyi Lu <weiyi.lu@...iatek.com>
> Acked-by: Sean Wang <sean.wang@...nel.org>

Reviewed-by: James Liao <jamesjj.liao@...iatek.com>

> ---
>  drivers/clk/mediatek/clk-mtk.h |  2 ++
>  drivers/clk/mediatek/clk-pll.c | 15 +++++++++++----
>  2 files changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/clk/mediatek/clk-mtk.h b/drivers/clk/mediatek/clk-mtk.h
> index f83c2bbb677e..11b5517903d0 100644
> --- a/drivers/clk/mediatek/clk-mtk.h
> +++ b/drivers/clk/mediatek/clk-mtk.h
> @@ -214,8 +214,10 @@ struct mtk_pll_data {
>  	unsigned int flags;
>  	const struct clk_ops *ops;
>  	u32 rst_bar_mask;
> +	unsigned long fmin;
>  	unsigned long fmax;
>  	int pcwbits;
> +	int pcwibits;
>  	uint32_t pcw_reg;
>  	int pcw_shift;
>  	const struct mtk_pll_div_table *div_table;
> diff --git a/drivers/clk/mediatek/clk-pll.c b/drivers/clk/mediatek/clk-pll.c
> index 18842d660317..67aaa3082d9b 100644
> --- a/drivers/clk/mediatek/clk-pll.c
> +++ b/drivers/clk/mediatek/clk-pll.c
> @@ -32,6 +32,8 @@
>  #define AUDPLL_TUNER_EN		BIT(31)
>  
>  #define POSTDIV_MASK		0x7
> +
> +/* default 7 bits integer, can be overridden with pcwibits. */
>  #define INTEGER_BITS		7
>  
>  /*
> @@ -68,12 +70,15 @@ static unsigned long __mtk_pll_recalc_rate(struct mtk_clk_pll *pll, u32 fin,
>  		u32 pcw, int postdiv)
>  {
>  	int pcwbits = pll->data->pcwbits;
> -	int pcwfbits;
> +	int pcwfbits = 0;
> +	int ibits;
>  	u64 vco;
>  	u8 c = 0;
>  
>  	/* The fractional part of the PLL divider. */
> -	pcwfbits = pcwbits > INTEGER_BITS ? pcwbits - INTEGER_BITS : 0;
> +	ibits = pll->data->pcwibits ? pll->data->pcwibits : INTEGER_BITS;
> +	if (pcwbits > ibits)
> +		pcwfbits = pcwbits - ibits;
>  
>  	vco = (u64)fin * pcw;
>  
> @@ -170,9 +175,10 @@ static void mtk_pll_set_rate_regs(struct mtk_clk_pll *pll, u32 pcw,
>  static void mtk_pll_calc_values(struct mtk_clk_pll *pll, u32 *pcw, u32 *postdiv,
>  		u32 freq, u32 fin)
>  {
> -	unsigned long fmin = 1000 * MHZ;
> +	unsigned long fmin = pll->data->fmin ? pll->data->fmin : (1000 * MHZ);
>  	const struct mtk_pll_div_table *div_table = pll->data->div_table;
>  	u64 _pcw;
> +	int ibits;
>  	u32 val;
>  
>  	if (freq > pll->data->fmax)
> @@ -196,7 +202,8 @@ static void mtk_pll_calc_values(struct mtk_clk_pll *pll, u32 *pcw, u32 *postdiv,
>  	}
>  
>  	/* _pcw = freq * postdiv / fin * 2^pcwfbits */
> -	_pcw = ((u64)freq << val) << (pll->data->pcwbits - INTEGER_BITS);
> +	ibits = pll->data->pcwibits ? pll->data->pcwibits : INTEGER_BITS;
> +	_pcw = ((u64)freq << val) << (pll->data->pcwbits - ibits);
>  	do_div(_pcw, fin);
>  
>  	*pcw = (u32)_pcw;