Both the i.MX8M Mini and Nano have a video_pll which can be used
to source a clock which feeds the lcdif interface. This interface
currently fixes video_pll and divides down the clock feeding LCDIF.
However, when connected to an HDMI bridge chip that supports a
variety of video resolutions and refresh rates, the only settings
that properly sync are ones that evenly divide from the video_pll_out
clock.
This series adds the ability for the clk-compolsite-8m to
request a better parent clock rate if the proper clock flag is
enable and sets that flag in the corresponding imx8mm and
imx8mn video_pll clocks to increase the number of resolutions
and refresh rates timings that the LCDIF can produce.
This also has a side benefit of allowing the video-pll to run
at a lower clock speed which can potentially save some power
depending on the requested resolution and refresh rate.
V3: Change the name of clk_divider_determine_rate to
imx8m_clk_divider_determine_rate
V2: Split off the new imx8m_clk_hw_composite_flags definition
into its own patch and re-order to fix build error.
Adam Ford (3):
clk: imx: composite-8m: Add support to determine_rate
clk: imx8mm: Let IMX8MM_CLK_LCDIF_PIXEL set parent rate
clk: imx: Let IMX8MN_CLK_DISP_PIXEL set parent rate
drivers/clk/imx/clk-composite-8m.c | 7 +++++++
drivers/clk/imx/clk-imx8mm.c | 2 +-
drivers/clk/imx/clk-imx8mn.c | 2 +-
drivers/clk/imx/clk.h | 4 ++++
4 files changed, 13 insertions(+), 2 deletions(-)
--
2.34.1
Similar to imx/clk-composite-93 and imx/clk-divider-gate, the
imx8m_clk_composite_divider_ops can support determine_rate.
Without this the parent clocks are set to a fixed value, and
if a consumer needs a slower reate, the clock is divided, but
the division is only as good as the parent clock rate.
With this added, the system can attempt to adjust the parent rate
if the proper flags are set which can lead to a more precise clock
value.
Signed-off-by: Adam Ford <[email protected]>
Reviewed-by: Peng Fan <[email protected]>
Reviewed-by: Fabio Estevam <[email protected]>
---
V3: Change name clk_divider_determine_rate to
imx8m_clk_divider_determine_rate to match naming convention
V2: No Change
diff --git a/drivers/clk/imx/clk-composite-8m.c b/drivers/clk/imx/clk-composite-8m.c
index cbf0d7955a00..3b63e47f088f 100644
--- a/drivers/clk/imx/clk-composite-8m.c
+++ b/drivers/clk/imx/clk-composite-8m.c
@@ -119,10 +119,17 @@ static int imx8m_clk_composite_divider_set_rate(struct clk_hw *hw,
return ret;
}
+static int clk_divider_determine_rate(struct clk_hw *hw,
+ struct clk_rate_request *req)
+{
+ return clk_divider_ops.determine_rate(hw, req);
+}
+
static const struct clk_ops imx8m_clk_composite_divider_ops = {
.recalc_rate = imx8m_clk_composite_divider_recalc_rate,
.round_rate = imx8m_clk_composite_divider_round_rate,
.set_rate = imx8m_clk_composite_divider_set_rate,
+ .determine_rate = clk_divider_determine_rate,
};
static u8 imx8m_clk_composite_mux_get_parent(struct clk_hw *hw)
--
2.34.1
In order to set custom flags to imx8m_clk_hw_composite,
split it off into a separate macro which can accept additional
flags.
Signed-off-by: Adam Ford <[email protected]>
Reviewed-by: Fabio Estevam <[email protected]>
diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
index 3d94722bbf99..621b0e84ef27 100644
--- a/drivers/clk/imx/clk.h
+++ b/drivers/clk/imx/clk.h
@@ -417,6 +417,10 @@ struct clk_hw *__imx8m_clk_hw_composite(const char *name,
_imx8m_clk_hw_composite(name, parent_names, reg, \
0, IMX_COMPOSITE_CLK_FLAGS_DEFAULT)
+#define imx8m_clk_hw_composite_flags(name, parent_names, reg, flags) \
+ _imx8m_clk_hw_composite(name, parent_names, reg, \
+ 0, IMX_COMPOSITE_CLK_FLAGS_DEFAULT | flags)
+
#define imx8m_clk_hw_composite_critical(name, parent_names, reg) \
_imx8m_clk_hw_composite(name, parent_names, reg, \
0, IMX_COMPOSITE_CLK_FLAGS_CRITICAL)
--
2.34.1
By default the display pixel clock needs to be evenly divide
down from 594MHz which rules out a significant number of
resolution and refresh rates.
The current clock tree looks something like:
video_pll1 594000000
video_pll1_bypass 594000000
video_pll1_out 594000000
lcdif_pixel 148500000
Now that composite-8m supports determine_rate, we can allow
lcdif_pixel to set the parent rate which then switches
every clock in the chain to a new frequency when lcdif_pixel
cannot evenly divide from video_pll1_out.
Signed-off-by: Adam Ford <[email protected]>
Reviewed-by: Fabio Estevam <[email protected]>
diff --git a/drivers/clk/imx/clk-imx8mm.c b/drivers/clk/imx/clk-imx8mm.c
index b618892170f2..075f643e3f35 100644
--- a/drivers/clk/imx/clk-imx8mm.c
+++ b/drivers/clk/imx/clk-imx8mm.c
@@ -468,7 +468,7 @@ static int imx8mm_clocks_probe(struct platform_device *pdev)
hws[IMX8MM_CLK_PCIE1_PHY] = imx8m_clk_hw_composite("pcie1_phy", imx8mm_pcie1_phy_sels, base + 0xa380);
hws[IMX8MM_CLK_PCIE1_AUX] = imx8m_clk_hw_composite("pcie1_aux", imx8mm_pcie1_aux_sels, base + 0xa400);
hws[IMX8MM_CLK_DC_PIXEL] = imx8m_clk_hw_composite("dc_pixel", imx8mm_dc_pixel_sels, base + 0xa480);
- hws[IMX8MM_CLK_LCDIF_PIXEL] = imx8m_clk_hw_composite("lcdif_pixel", imx8mm_lcdif_pixel_sels, base + 0xa500);
+ hws[IMX8MM_CLK_LCDIF_PIXEL] = imx8m_clk_hw_composite_flags("lcdif_pixel", imx8mm_lcdif_pixel_sels, base + 0xa500, CLK_SET_RATE_PARENT);
hws[IMX8MM_CLK_SAI1] = imx8m_clk_hw_composite("sai1", imx8mm_sai1_sels, base + 0xa580);
hws[IMX8MM_CLK_SAI2] = imx8m_clk_hw_composite("sai2", imx8mm_sai2_sels, base + 0xa600);
hws[IMX8MM_CLK_SAI3] = imx8m_clk_hw_composite("sai3", imx8mm_sai3_sels, base + 0xa680);
--
2.34.1
By default the display pixel clock needs to be evenly divide
down from the video_pll_out clock which rules out a significant
number of resolution and refresh rates.
The current clock tree looks something like:
video_pll 594000000
video_pll_bypass 594000000
video_pll_out 594000000
disp_pixel 148500000
disp_pixel_clk 148500000
Now that composite-8m supports determine_rate, we can allow
disp_pixel to set the parent rate which then switches
every clock in the chain to a new frequency when disp_pixel
cannot evenly divide from video_pll_out.
Signed-off-by: Adam Ford <[email protected]>
Reviewed-by: Fabio Estevam <[email protected]>
diff --git a/drivers/clk/imx/clk-imx8mn.c b/drivers/clk/imx/clk-imx8mn.c
index a042ed3a9d6c..4b23a4648600 100644
--- a/drivers/clk/imx/clk-imx8mn.c
+++ b/drivers/clk/imx/clk-imx8mn.c
@@ -470,7 +470,7 @@ static int imx8mn_clocks_probe(struct platform_device *pdev)
hws[IMX8MN_CLK_DRAM_ALT] = imx8m_clk_hw_fw_managed_composite("dram_alt", imx8mn_dram_alt_sels, base + 0xa000);
hws[IMX8MN_CLK_DRAM_APB] = imx8m_clk_hw_fw_managed_composite_critical("dram_apb", imx8mn_dram_apb_sels, base + 0xa080);
- hws[IMX8MN_CLK_DISP_PIXEL] = imx8m_clk_hw_composite("disp_pixel", imx8mn_disp_pixel_sels, base + 0xa500);
+ hws[IMX8MN_CLK_DISP_PIXEL] = imx8m_clk_hw_composite_flags("disp_pixel", imx8mn_disp_pixel_sels, base + 0xa500, CLK_SET_RATE_PARENT);
hws[IMX8MN_CLK_SAI2] = imx8m_clk_hw_composite("sai2", imx8mn_sai2_sels, base + 0xa600);
hws[IMX8MN_CLK_SAI3] = imx8m_clk_hw_composite("sai3", imx8mn_sai3_sels, base + 0xa680);
hws[IMX8MN_CLK_SAI5] = imx8m_clk_hw_composite("sai5", imx8mn_sai5_sels, base + 0xa780);
--
2.34.1