Re: [PATCH v4 3/8] drm/msm/dsi: 28nm PHY: Get ref clock from the DT

[Matthias Kaehlcke <mka@chromium.org>]

Hi Niklas,

On Wed, Dec 12, 2018 at 11:07:17PM +0100, Niklas Cassel wrote:
> On Tue, Dec 04, 2018 at 02:42:29PM -0800, Matthias Kaehlcke wrote:
> > Get the ref clock of the PHY from the device tree instead of
> > hardcoding its name and rate.
> > 
> > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > ---
> > Changes in v4:
> > - always use parent rate in dsi_pll_28nm_clk_set_rate() and
> >    dsi_pll_28nm_clk_recalc_rate()
> > - pass name of VCO ref clock to pll_28nm_register() instead of
> >   storing it in a struct field
> > - updated commit message
> > 
> > Changes in v3:
> > - use default name and rate if the ref clock is not specified
> >   in the DT
> > - store vco_ref_clk_name instead of vco_ref_clk
> > - dsi_pll_28nm_clk_set_rate: changed data type of ref_clk_rate to
> >   unsigned long
> > - fixed check for EPROBE_DEFER
> > - renamed VCO_REF_CLK_RATE to VCO_REF_CLK_DEFAULT_RATE
> > 
> > Changes in v2:
> > - patch added to the series
> > ---
> >  drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c | 36 +++++++++++++++-------
> >  1 file changed, 25 insertions(+), 11 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c b/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c
> > index 26e3a01a99c2b..7777340b03e8d 100644
> > --- a/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c
> > +++ b/drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm.c
> > @@ -40,7 +40,6 @@
> >  
> >  #define NUM_PROVIDED_CLKS		2
> >  
> > -#define VCO_REF_CLK_RATE		19200000
> >  #define VCO_MIN_RATE			350000000
> >  #define VCO_MAX_RATE			750000000
> >  
> > @@ -166,17 +165,17 @@ static int dsi_pll_28nm_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> >  	pll_write(base + REG_DSI_28nm_PHY_PLL_LPFC1_CFG, 0x70);
> >  	pll_write(base + REG_DSI_28nm_PHY_PLL_LPFC2_CFG, 0x15);
> >  
> > -	rem = rate % VCO_REF_CLK_RATE;
> > +	rem = rate % parent_rate;
> >  	if (rem) {
> >  		refclk_cfg = DSI_28nm_PHY_PLL_REFCLK_CFG_DBLR;
> >  		frac_n_mode = 1;
> > -		div_fbx1000 = rate / (VCO_REF_CLK_RATE / 500);
> > -		gen_vco_clk = div_fbx1000 * (VCO_REF_CLK_RATE / 500);
> > +		div_fbx1000 = rate / (parent_rate / 500);
> > +		gen_vco_clk = div_fbx1000 * (parent_rate / 500);
> >  	} else {
> >  		refclk_cfg = 0x0;
> >  		frac_n_mode = 0;
> > -		div_fbx1000 = rate / (VCO_REF_CLK_RATE / 1000);
> > -		gen_vco_clk = div_fbx1000 * (VCO_REF_CLK_RATE / 1000);
> > +		div_fbx1000 = rate / (parent_rate / 1000);
> > +		gen_vco_clk = div_fbx1000 * (parent_rate / 1000);
> >  	}
> >  
> >  	DBG("refclk_cfg = %d", refclk_cfg);
> > @@ -265,7 +264,7 @@ static unsigned long dsi_pll_28nm_clk_recalc_rate(struct clk_hw *hw,
> >  	void __iomem *base = pll_28nm->mmio;
> >  	u32 sdm0, doubler, sdm_byp_div;
> >  	u32 sdm_dc_off, sdm_freq_seed, sdm2, sdm3;
> > -	u32 ref_clk = VCO_REF_CLK_RATE;
> > +	u32 ref_clk = parent_rate;
> >  	unsigned long vco_rate;
> >  
> >  	VERB("parent_rate=%lu", parent_rate);
> > @@ -273,7 +272,7 @@ static unsigned long dsi_pll_28nm_clk_recalc_rate(struct clk_hw *hw,
> >  	/* Check to see if the ref clk doubler is enabled */
> >  	doubler = pll_read(base + REG_DSI_28nm_PHY_PLL_REFCLK_CFG) &
> >  			DSI_28nm_PHY_PLL_REFCLK_CFG_DBLR;
> > -	ref_clk += (doubler * VCO_REF_CLK_RATE);
> > +	ref_clk += (doubler * ref_clk);
> >  
> >  	/* see if it is integer mode or sdm mode */
> >  	sdm0 = pll_read(base + REG_DSI_28nm_PHY_PLL_SDM_CFG0);
> > @@ -514,11 +513,12 @@ static void dsi_pll_28nm_destroy(struct msm_dsi_pll *pll)
> >  	pll_28nm->clk_data.clk_num = 0;
> >  }
> >  
> > -static int pll_28nm_register(struct dsi_pll_28nm *pll_28nm)
> > +static int pll_28nm_register(struct dsi_pll_28nm *pll_28nm,
> > +			     const char *ref_clk_name)
> >  {
> >  	char clk_name[32], parent1[32], parent2[32], vco_name[32];
> >  	struct clk_init_data vco_init = {
> > -		.parent_names = (const char *[]){ "xo" },
> > +		.parent_names = &ref_clk_name,
> >  		.num_parents = 1,
> >  		.name = vco_name,
> >  		.flags = CLK_IGNORE_UNUSED,
> > @@ -593,6 +593,8 @@ struct msm_dsi_pll *msm_dsi_pll_28nm_init(struct platform_device *pdev,
> >  {
> >  	struct dsi_pll_28nm *pll_28nm;
> >  	struct msm_dsi_pll *pll;
> > +	struct clk *vco_ref_clk;
> > +	const char *vco_ref_clk_name;
> >  	int ret;
> >  
> >  	if (!pdev)
> > @@ -605,6 +607,18 @@ struct msm_dsi_pll *msm_dsi_pll_28nm_init(struct platform_device *pdev,
> >  	pll_28nm->pdev = pdev;
> >  	pll_28nm->id = id;
> >  
> > +	vco_ref_clk = devm_clk_get(&pdev->dev, "ref");
> > +	if (!IS_ERR(vco_ref_clk)) {
> > +		vco_ref_clk_name = __clk_get_name(vco_ref_clk);
> > +	} else {
> > +		ret = PTR_ERR(vco_ref_clk);
> > +		if (ret == -EPROBE_DEFER)
> > +			ERR_PTR(ret);
> 
> It looks like you are missing the return keyword here.

Indeed, thanks for pointing that out!

Cheers

Matthias