Re: [PATCH v3 19/24] drm/sun4i: Add support for second clock parent to DW HDMI PHY clk driver

Chen-Yu Tsai
2018-06-28T02:30:27Z

On Mon, Jun 25, 2018 at 8:02 PM, Jernej Skrabec <jernej.skrabec-gGgVlfcn5nU@public.gmane.org> wrote:
> Expand HDMI PHY clock driver to support second clock parent.
>
> Signed-off-by: Jernej Skrabec <jernej.skrabec-gGgVlfcn5nU@public.gmane.org>

Reviewed-by: Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org>

> ---
> drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h | 4 +-
> drivers/gpu/drm/sun4i/sun8i_hdmi_phy.c | 3 +-
> drivers/gpu/drm/sun4i/sun8i_hdmi_phy_clk.c | 90 ++++++++++++++++------
> 3 files changed, 73 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h
> index 46a3aa6a53a9..aadbe0a10b0c 100644
> --- a/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h
> +++ b/drivers/gpu/drm/sun4i/sun8i_dw_hdmi.h
> @@ -99,6 +99,7 @@
> #define SUN8I_HDMI_PHY_PLL_CFG1_LDO1_EN BIT(28)
> #define SUN8I_HDMI_PHY_PLL_CFG1_HV_IS_33 BIT(27)
> #define SUN8I_HDMI_PHY_PLL_CFG1_CKIN_SEL_MSK BIT(26)
> +#define SUN8I_HDMI_PHY_PLL_CFG1_CKIN_SEL_SHIFT 26
> #define SUN8I_HDMI_PHY_PLL_CFG1_PLLEN BIT(25)
> #define SUN8I_HDMI_PHY_PLL_CFG1_LDO_VSET(x) ((x) << 22)
> #define SUN8I_HDMI_PHY_PLL_CFG1_UNKNOWN(x) ((x) << 20)
> @@ -190,6 +191,7 @@ void sun8i_hdmi_phy_remove(struct sun8i_dw_hdmi *hdmi);
> void sun8i_hdmi_phy_init(struct sun8i_hdmi_phy *phy);
> const struct dw_hdmi_phy_ops *sun8i_hdmi_phy_get_ops(void);
>
> -int sun8i_phy_clk_create(struct sun8i_hdmi_phy *phy, struct device *dev);
> +int sun8i_phy_clk_create(struct sun8i_hdmi_phy *phy, struct device *dev,
> + bool second_parent);
>
> #endif /* _SUN8I_DW_HDMI_H_ */
> diff --git a/drivers/gpu/drm/sun4i/sun8i_hdmi_phy.c b/drivers/gpu/drm/sun4i/sun8i_hdmi_phy.c
> index f0877b3f67e7..aea46b08f127 100644
> --- a/drivers/gpu/drm/sun4i/sun8i_hdmi_phy.c
> +++ b/drivers/gpu/drm/sun4i/sun8i_hdmi_phy.c
> @@ -491,7 +491,8 @@ int sun8i_hdmi_phy_probe(struct sun8i_dw_hdmi *hdmi, struct device_node *node)
> }
> }
>
> - ret = sun8i_phy_clk_create(phy, dev);
> + ret = sun8i_phy_clk_create(phy, dev,
> + phy->variant->has_second_pll);
> if (ret) {
> dev_err(dev, "Couldn't create the PHY clock\n");
> goto err_put_clk_pll1;
> diff --git a/drivers/gpu/drm/sun4i/sun8i_hdmi_phy_clk.c b/drivers/gpu/drm/sun4i/sun8i_hdmi_phy_clk.c
> index faea449812f8..a4d31fe3abff 100644
> --- a/drivers/gpu/drm/sun4i/sun8i_hdmi_phy_clk.c
> +++ b/drivers/gpu/drm/sun4i/sun8i_hdmi_phy_clk.c
> @@ -22,35 +22,45 @@ static int sun8i_phy_clk_determine_rate(struct clk_hw *hw,
> {
> unsigned long rate = req->rate;
> unsigned long best_rate = 0;
> + struct clk_hw *best_parent = NULL;
> struct clk_hw *parent;
> int best_div = 1;
> - int i;
> + int i, p;
>
> - parent = clk_hw_get_parent(hw);
> -
> - for (i = 1; i <= 16; i++) {
> - unsigned long ideal = rate * i;
> - unsigned long rounded;
> -
> - rounded = clk_hw_round_rate(parent, ideal);
> + for (p = 0; p < clk_hw_get_num_parents(hw); p++) {
> + parent = clk_hw_get_parent_by_index(hw, p);
> + if (!parent)
> + continue;
>
> - if (rounded == ideal) {
> - best_rate = rounded;
> - best_div = i;
> - break;
> + for (i = 1; i <= 16; i++) {
> + unsigned long ideal = rate * i;
> + unsigned long rounded;
> +
> + rounded = clk_hw_round_rate(parent, ideal);
> +
> + if (rounded == ideal) {
> + best_rate = rounded;
> + best_div = i;
> + best_parent = parent;
> + break;
> + }
> +
> + if (!best_rate ||
> + abs(rate - rounded / i) <
> + abs(rate - best_rate / best_div)) {
> + best_rate = rounded;
> + best_div = i;
> + best_parent = parent;
> + }
> }
>
> - if (!best_rate ||
> - abs(rate - rounded / i) <
> - abs(rate - best_rate / best_div)) {
> - best_rate = rounded;
> - best_div = i;
> - }
> + if (best_rate / best_div == rate)
> + break;
> }
>
> req->rate = best_rate / best_div;
> req->best_parent_rate = best_rate;
> - req->best_parent_hw = parent;
> + req->best_parent_hw = best_parent;
>
> return 0;
> }
> @@ -95,22 +105,58 @@ static int sun8i_phy_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> return 0;
> }
>
> +static u8 sun8i_phy_clk_get_parent(struct clk_hw *hw)
> +{
> + struct sun8i_phy_clk *priv = hw_to_phy_clk(hw);
> + u32 reg;
> +
> + regmap_read(priv->phy->regs, SUN8I_HDMI_PHY_PLL_CFG1_REG, &reg);
> + reg = (reg & SUN8I_HDMI_PHY_PLL_CFG1_CKIN_SEL_MSK) >>
> + SUN8I_HDMI_PHY_PLL_CFG1_CKIN_SEL_SHIFT;
> +
> + return reg;
> +}
> +
> +static int sun8i_phy_clk_set_parent(struct clk_hw *hw, u8 index)
> +{
> + struct sun8i_phy_clk *priv = hw_to_phy_clk(hw);
> +
> + if (index > 1)
> + return -EINVAL;
> +
> + regmap_update_bits(priv->phy->regs, SUN8I_HDMI_PHY_PLL_CFG1_REG,
> + SUN8I_HDMI_PHY_PLL_CFG1_CKIN_SEL_MSK,
> + index << SUN8I_HDMI_PHY_PLL_CFG1_CKIN_SEL_SHIFT);
> +
> + return 0;
> +}
> +
> static const struct clk_ops sun8i_phy_clk_ops = {
> .determine_rate = sun8i_phy_clk_determine_rate,
> .recalc_rate = sun8i_phy_clk_recalc_rate,
> .set_rate = sun8i_phy_clk_set_rate,
> +
> + .get_parent = sun8i_phy_clk_get_parent,
> + .set_parent = sun8i_phy_clk_set_parent,
> };
>
> -int sun8i_phy_clk_create(struct sun8i_hdmi_phy *phy, struct device *dev)
> +int sun8i_phy_clk_create(struct sun8i_hdmi_phy *phy, struct device *dev,
> + bool second_parent)
> {
> struct clk_init_data init;
> struct sun8i_phy_clk *priv;
> - const char *parents[1];
> + const char *parents[2];
>
> parents[0] = __clk_get_name(phy->clk_pll0);
> if (!parents[0])
> return -ENODEV;
>
> + if (second_parent) {
> + parents[1] = __clk_get_name(phy->clk_pll1);

Like I mentioned in the TCON TOP patch, you don't actually need a reference
if all you want is just the clock name.

ChenYu

> + if (!parents[1])
> + return -ENODEV;
> + }
> +
> priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> if (!priv)
> return -ENOMEM;
> @@ -118,7 +164,7 @@ int sun8i_phy_clk_create(struct sun8i_hdmi_phy *phy, struct device *dev)
> init.name = "hdmi-phy-clk";
> init.ops = &sun8i_phy_clk_ops;
> init.parent_names = parents;
> - init.num_parents = 1;
> + init.num_parents = second_parent ? 2 : 1;
> init.flags = CLK_SET_RATE_PARENT;
>
> priv->phy = phy;
> --
> 2.18.0
>
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