Re: [PATCH 2/3] drm/msm/dsi: Use "ref" fw clock instead of global name for VCO parent

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

Hi,

On Sun, 29 Aug 2021 at 23:30, Marijn Suijten
<marijn.suijten@somainline.org> wrote:
>
> All DSI PHY/PLL drivers were referencing their VCO parent clock by a
> global name, most of which don't exist or have been renamed.  These
> clock drivers seem to function fine without that except the 14nm driver
> for the sdm6xx [1].
>
> At the same time all DTs provide a "ref" clock as per the requirements
> of dsi-phy-common.yaml, but the clock is never used.  This patchset puts
> that clock to use without relying on a global clock name, so that all
> dependencies are explicitly defined in DT (the firmware) in the end.

msm8974 (28nm-hpm) does not define the "ref" clock. So you'd have to:
1) add ref clock to the dtsi (should come in a separate patch).
2) add .name = "xo" as a fallback to the 28nm driver (to be compatible
with older devices)

Other than that this looks good to me.

>
> [1]: https://lore.kernel.org/linux-arm-msm/386db1a6-a1cd-3c7d-a88e-dc83f8a1be96@somainline.org/
>
> Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
> Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
> ---
>  drivers/gpu/drm/msm/dsi/phy/dsi_phy_10nm.c      | 4 +++-
>  drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c      | 4 +++-
>  drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c      | 4 +++-
>  drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm_8960.c | 4 +++-
>  drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c       | 4 +++-
>  5 files changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_10nm.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_10nm.c
> index e46b10fc793a..3cbb1f1475e8 100644
> --- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_10nm.c
> +++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_10nm.c
> @@ -562,7 +562,9 @@ static int pll_10nm_register(struct dsi_pll_10nm *pll_10nm, struct clk_hw **prov
>         char clk_name[32], parent[32], vco_name[32];
>         char parent2[32], parent3[32], parent4[32];
>         struct clk_init_data vco_init = {
> -               .parent_names = (const char *[]){ "xo" },
> +               .parent_data = &(const struct clk_parent_data) {
> +                       .fw_name = "ref",
> +               },
>                 .num_parents = 1,
>                 .name = vco_name,
>                 .flags = CLK_IGNORE_UNUSED,
> diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c
> index bb31230721bd..406470265408 100644
> --- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c
> +++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c
> @@ -804,7 +804,9 @@ static int pll_14nm_register(struct dsi_pll_14nm *pll_14nm, struct clk_hw **prov
>  {
>         char clk_name[32], parent[32], vco_name[32];
>         struct clk_init_data vco_init = {
> -               .parent_names = (const char *[]){ "xo" },
> +               .parent_data = &(const struct clk_parent_data) {
> +                       .fw_name = "ref",
> +               },
>                 .num_parents = 1,
>                 .name = vco_name,
>                 .flags = CLK_IGNORE_UNUSED,
> diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c
> index 2da673a2add6..8ee9c9c0548d 100644
> --- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c
> +++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c
> @@ -521,7 +521,9 @@ static int pll_28nm_register(struct dsi_pll_28nm *pll_28nm, struct clk_hw **prov
>  {
>         char clk_name[32], parent1[32], parent2[32], vco_name[32];
>         struct clk_init_data vco_init = {
> -               .parent_names = (const char *[]){ "xo" },
> +               .parent_data = &(const struct clk_parent_data) {
> +                       .fw_name = "ref",
> +               },
>                 .num_parents = 1,
>                 .name = vco_name,
>                 .flags = CLK_IGNORE_UNUSED,
> diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm_8960.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm_8960.c
> index aaa37456f4ee..9662cb236468 100644
> --- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm_8960.c
> +++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm_8960.c
> @@ -385,7 +385,9 @@ static int pll_28nm_register(struct dsi_pll_28nm *pll_28nm, struct clk_hw **prov
>  {
>         char *clk_name, *parent_name, *vco_name;
>         struct clk_init_data vco_init = {
> -               .parent_names = (const char *[]){ "pxo" },
> +               .parent_data = &(const struct clk_parent_data) {
> +                       .fw_name = "ref",
> +               },
>                 .num_parents = 1,
>                 .flags = CLK_IGNORE_UNUSED,
>                 .ops = &clk_ops_dsi_pll_28nm_vco,
> diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
> index 7c23d4c47338..c77c30628cca 100644
> --- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
> +++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
> @@ -590,7 +590,9 @@ static int pll_7nm_register(struct dsi_pll_7nm *pll_7nm, struct clk_hw **provide
>         char clk_name[32], parent[32], vco_name[32];
>         char parent2[32], parent3[32], parent4[32];
>         struct clk_init_data vco_init = {
> -               .parent_names = (const char *[]){ "bi_tcxo" },
> +               .parent_data = &(const struct clk_parent_data) {
> +                       .fw_name = "ref",
> +               },
>                 .num_parents = 1,
>                 .name = vco_name,
>                 .flags = CLK_IGNORE_UNUSED,
> --
> 2.33.0
>


-- 
With best wishes
Dmitry