linux-kernel - Re: [PATCH 1/2] clk: imx: pllv4: Fix SPLL2 MULT range

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Message-ID: <ZL98Tgpb29HLXYDr@linaro.org>
Date:   Tue, 25 Jul 2023 10:39:58 +0300
From:   Abel Vesa <abel.vesa@...aro.org>
To:     "Peng Fan (OSS)" <peng.fan@....nxp.com>
Cc:     abelvesa@...nel.org, mturquette@...libre.com, sboyd@...nel.org,
        shawnguo@...nel.org, s.hauer@...gutronix.de, kernel@...gutronix.de,
        festevam@...il.com, linux-imx@....com, linux-clk@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Ye Li <ye.li@....com>, Peng Fan <peng.fan@....com>,
        Jacky Bai <ping.bai@....com>
Subject: Re: [PATCH 1/2] clk: imx: pllv4: Fix SPLL2 MULT range

On 23-06-25 20:33:39, Peng Fan (OSS) wrote:
> From: Ye Li <ye.li@....com>
> 
> The SPLL2 on iMX8ULP is different with other frac PLLs, it can
> support VCO from 650Mhz to 1Ghz. According to RM, the MULT is
> using a range from 27 to 54, not some fixed values. If using
> current PLL implementation, some clock rate can't be supported.
> 
> Fix the issue by adding new type for the SPLL2 and use MULT range
> to replace MULT table
> 
> Fixes: 5f0601c47c33 ("clk: imx: Update the pllv4 to support imx8ulp")
> Reviewed-by: Peng Fan <peng.fan@....com>
> Reviewed-by: Jacky Bai <ping.bai@....com>
> Signed-off-by: Ye Li <ye.li@....com>
> Signed-off-by: Peng Fan <peng.fan@....com>

LGTM.

Reviewed-by: Abel Vesa <abel.vesa@...aro.org>

> ---
>  drivers/clk/imx/clk-pllv4.c | 46 +++++++++++++++++++++++++++++--------
>  drivers/clk/imx/clk.h       |  1 +
>  2 files changed, 37 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/clk/imx/clk-pllv4.c b/drivers/clk/imx/clk-pllv4.c
> index 6e7e34571fc8..9b136c951762 100644
> --- a/drivers/clk/imx/clk-pllv4.c
> +++ b/drivers/clk/imx/clk-pllv4.c
> @@ -44,11 +44,15 @@ struct clk_pllv4 {
>  	u32		cfg_offset;
>  	u32		num_offset;
>  	u32		denom_offset;
> +	bool		use_mult_range;
>  };
>  
>  /* Valid PLL MULT Table */
>  static const int pllv4_mult_table[] = {33, 27, 22, 20, 17, 16};
>  
> +/* Valid PLL MULT range, (max, min) */
> +static const int pllv4_mult_range[] = {54, 27};
> +
>  #define to_clk_pllv4(__hw) container_of(__hw, struct clk_pllv4, hw)
>  
>  #define LOCK_TIMEOUT_US		USEC_PER_MSEC
> @@ -94,17 +98,30 @@ static unsigned long clk_pllv4_recalc_rate(struct clk_hw *hw,
>  static long clk_pllv4_round_rate(struct clk_hw *hw, unsigned long rate,
>  				 unsigned long *prate)
>  {
> +	struct clk_pllv4 *pll = to_clk_pllv4(hw);
>  	unsigned long parent_rate = *prate;
>  	unsigned long round_rate, i;
>  	u32 mfn, mfd = DEFAULT_MFD;
>  	bool found = false;
>  	u64 temp64;
> -
> -	for (i = 0; i < ARRAY_SIZE(pllv4_mult_table); i++) {
> -		round_rate = parent_rate * pllv4_mult_table[i];
> -		if (rate >= round_rate) {
> +	u32 mult;
> +
> +	if (pll->use_mult_range) {
> +		temp64 = (u64)rate;
> +		do_div(temp64, parent_rate);
> +		mult = temp64;
> +		if (mult >= pllv4_mult_range[1] &&
> +		    mult <= pllv4_mult_range[0]) {
> +			round_rate = parent_rate * mult;
>  			found = true;
> -			break;
> +		}
> +	} else {
> +		for (i = 0; i < ARRAY_SIZE(pllv4_mult_table); i++) {
> +			round_rate = parent_rate * pllv4_mult_table[i];
> +			if (rate >= round_rate) {
> +				found = true;
> +				break;
> +			}
>  		}
>  	}
>  
> @@ -138,14 +155,20 @@ static long clk_pllv4_round_rate(struct clk_hw *hw, unsigned long rate,
>  	return round_rate + (u32)temp64;
>  }
>  
> -static bool clk_pllv4_is_valid_mult(unsigned int mult)
> +static bool clk_pllv4_is_valid_mult(struct clk_pllv4 *pll, unsigned int mult)
>  {
>  	int i;
>  
>  	/* check if mult is in valid MULT table */
> -	for (i = 0; i < ARRAY_SIZE(pllv4_mult_table); i++) {
> -		if (pllv4_mult_table[i] == mult)
> +	if (pll->use_mult_range) {
> +		if (mult >= pllv4_mult_range[1] &&
> +		    mult <= pllv4_mult_range[0])
>  			return true;
> +	} else {
> +		for (i = 0; i < ARRAY_SIZE(pllv4_mult_table); i++) {
> +			if (pllv4_mult_table[i] == mult)
> +				return true;
> +		}
>  	}
>  
>  	return false;
> @@ -160,7 +183,7 @@ static int clk_pllv4_set_rate(struct clk_hw *hw, unsigned long rate,
>  
>  	mult = rate / parent_rate;
>  
> -	if (!clk_pllv4_is_valid_mult(mult))
> +	if (!clk_pllv4_is_valid_mult(pll, mult))
>  		return -EINVAL;
>  
>  	if (parent_rate <= MAX_MFD)
> @@ -227,10 +250,13 @@ struct clk_hw *imx_clk_hw_pllv4(enum imx_pllv4_type type, const char *name,
>  
>  	pll->base = base;
>  
> -	if (type == IMX_PLLV4_IMX8ULP) {
> +	if (type == IMX_PLLV4_IMX8ULP ||
> +	    type == IMX_PLLV4_IMX8ULP_1GHZ) {
>  		pll->cfg_offset = IMX8ULP_PLL_CFG_OFFSET;
>  		pll->num_offset = IMX8ULP_PLL_NUM_OFFSET;
>  		pll->denom_offset = IMX8ULP_PLL_DENOM_OFFSET;
> +		if (type == IMX_PLLV4_IMX8ULP_1GHZ)
> +			pll->use_mult_range = true;
>  	} else {
>  		pll->cfg_offset = PLL_CFG_OFFSET;
>  		pll->num_offset = PLL_NUM_OFFSET;
> diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
> index af19d9f6aed0..adb7ad649a0d 100644
> --- a/drivers/clk/imx/clk.h
> +++ b/drivers/clk/imx/clk.h
> @@ -45,6 +45,7 @@ enum imx_pll14xx_type {
>  enum imx_pllv4_type {
>  	IMX_PLLV4_IMX7ULP,
>  	IMX_PLLV4_IMX8ULP,
> +	IMX_PLLV4_IMX8ULP_1GHZ,
>  };
>  
>  enum imx_pfdv2_type {
> -- 
> 2.37.1
>