Re: [PATCH v2 2/3] phy: phy-mtk-tphy: add configurable parameters for slew rate calibrate

[Chunfeng Yun]

On Wed, 2018-03-14 at 00:21 +0100, Matthias Brugger wrote:
> 
> On 03/12/2018 06:25 AM, Chunfeng Yun wrote:
> > There are two parameters, ref_clk and coefficient, for U2 slew rate
> > calibrate which may vary on different SoCs, here allow them to be
> > configurable
> > 
> > Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
> 
> Reviewed-by: Matthias Brugger <matthias.bgg@xxxxxxxxx>
> 
Thanks
> 
> > ---
> >  drivers/phy/mediatek/phy-mtk-tphy.c | 20 +++++++++++++++-----
> >  1 file changed, 15 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/phy/mediatek/phy-mtk-tphy.c b/drivers/phy/mediatek/phy-mtk-tphy.c
> > index 6073c25..38c281b 100644
> > --- a/drivers/phy/mediatek/phy-mtk-tphy.c
> > +++ b/drivers/phy/mediatek/phy-mtk-tphy.c
> > @@ -306,6 +306,8 @@ struct mtk_tphy {
> >  	const struct mtk_phy_pdata *pdata;
> >  	struct mtk_phy_instance **phys;
> >  	int nphys;
> > +	int src_ref_clk; /* MHZ, reference clock for slew rate calibrate */
> > +	int src_coef; /* coefficient for slew rate calibrate */
> >  };
> >  
> >  static void hs_slew_rate_calibrate(struct mtk_tphy *tphy,
> > @@ -360,16 +362,17 @@ static void hs_slew_rate_calibrate(struct mtk_tphy *tphy,
> >  	writel(tmp, fmreg + U3P_U2FREQ_FMMONR1);
> >  
> >  	if (fm_out) {
> > -		/* ( 1024 / FM_OUT ) x reference clock frequency x 0.028 */
> > -		tmp = U3P_FM_DET_CYCLE_CNT * U3P_REF_CLK * U3P_SLEW_RATE_COEF;
> > -		tmp /= fm_out;
> > +		/* ( 1024 / FM_OUT ) x reference clock frequency x coef */
> > +		tmp = tphy->src_ref_clk * tphy->src_coef;
> > +		tmp = (tmp * U3P_FM_DET_CYCLE_CNT) / fm_out;
> >  		calibration_val = DIV_ROUND_CLOSEST(tmp, U3P_SR_COEF_DIVISOR);
> >  	} else {
> >  		/* if FM detection fail, set default value */
> >  		calibration_val = 4;
> >  	}
> > -	dev_dbg(tphy->dev, "phy:%d, fm_out:%d, calib:%d\n",
> > -		instance->index, fm_out, calibration_val);
> > +	dev_dbg(tphy->dev, "phy:%d, fm_out:%d, calib:%d (clk:%d, coef:%d)\n",
> > +		instance->index, fm_out, calibration_val,
> > +		tphy->src_ref_clk, tphy->src_coef);
> >  
> >  	/* set HS slew rate */
> >  	tmp = readl(com + U3P_USBPHYACR5);
> > @@ -1041,6 +1044,13 @@ static int mtk_tphy_probe(struct platform_device *pdev)
> >  		tphy->u3phya_ref = NULL;
> >  	}
> >  
> > +	tphy->src_ref_clk = U3P_REF_CLK;
> > +	tphy->src_coef = U3P_SLEW_RATE_COEF;
> > +	/* update parameters of slew rate calibrate if exist */
> > +	device_property_read_u32(dev, "mediatek,src-ref-clk-mhz",
> > +		&tphy->src_ref_clk);
> > +	device_property_read_u32(dev, "mediatek,src-coef", &tphy->src_coef);
> > +
> >  	port = 0;
> >  	for_each_child_of_node(np, child_np) {
> >  		struct mtk_phy_instance *instance;
> >