From: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Due to incorrect placement of the clock gate cell in the ldb_di[x]_clk
tree, the glitchy parent mux of ldb_di[x]_clk can cause a glitch to
enter the ldb_di_ipu_div divider. If the divider gets locked up, no
ldb_di[x]_clk is generated, and the LVDS display will hang when the
ipu_di_clk is sourced from ldb_di_clk.
To fix the problem, both the new and current parent of the ldb_di_clk
should be disabled before the switch. As this can not be guaranteed by
the clock framework during runtime, make the ldb_di[x]_sel muxes read-only.
A workaround to set the muxes once during boot could be added to the
kernel or bootloader.
Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Signed-off-by: Fabio Estevam <fabio.estevam@xxxxxxx>
Signed-off-by: Shawn Guo <shawnguo@xxxxxxxxxx>
[afa: ported from Linux kernel commit 03d576f202]
[afa: added exception for i.MX6QP, see kernel commit f4a0a6c309]
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
drivers/clk/imx/clk-imx6.c | 9 ++++++---
drivers/clk/imx/clk.h | 8 ++++++++
2 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/drivers/clk/imx/clk-imx6.c b/drivers/clk/imx/clk-imx6.c
index f527d1d5e565..65d8f4cd89be 100644
--- a/drivers/clk/imx/clk-imx6.c
+++ b/drivers/clk/imx/clk-imx6.c
@@ -601,10 +601,13 @@ static void imx6_add_video_clks(void __iomem *anab, void __iomem *cb, struct dev
* ldb_di_sel clocks.
*/
init_ldb_clks(ccm_np, cb);
- }
- clks[IMX6QDL_CLK_LDB_DI0_SEL] = imx_clk_mux_p("ldb_di0_sel", cb + 0x2c, 9, 3, ldb_di_sels, ARRAY_SIZE(ldb_di_sels));
- clks[IMX6QDL_CLK_LDB_DI1_SEL] = imx_clk_mux_p("ldb_di1_sel", cb + 0x2c, 12, 3, ldb_di_sels, ARRAY_SIZE(ldb_di_sels));
+ clks[IMX6QDL_CLK_LDB_DI0_SEL] = imx_clk_mux_ldb("ldb_di0_sel", cb + 0x2c, 9, 3, ldb_di_sels, ARRAY_SIZE(ldb_di_sels));
+ clks[IMX6QDL_CLK_LDB_DI1_SEL] = imx_clk_mux_ldb("ldb_di1_sel", cb + 0x2c, 12, 3, ldb_di_sels, ARRAY_SIZE(ldb_di_sels));
+ } else {
+ clks[IMX6QDL_CLK_LDB_DI0_SEL] = imx_clk_mux_p("ldb_di0_sel", cb + 0x2c, 9, 3, ldb_di_sels, ARRAY_SIZE(ldb_di_sels));
+ clks[IMX6QDL_CLK_LDB_DI1_SEL] = imx_clk_mux_p("ldb_di1_sel", cb + 0x2c, 12, 3, ldb_di_sels, ARRAY_SIZE(ldb_di_sels));
+ }
clks[IMX6QDL_CLK_IPU1_DI0_PRE_SEL] = imx_clk_mux_p("ipu1_di0_pre_sel", cb + 0x34, 6, 3, ipu_di_pre_sels, ARRAY_SIZE(ipu_di_pre_sels));
clks[IMX6QDL_CLK_IPU1_DI1_PRE_SEL] = imx_clk_mux_p("ipu1_di1_pre_sel", cb + 0x34, 15, 3, ipu_di_pre_sels, ARRAY_SIZE(ipu_di_pre_sels));
clks[IMX6QDL_CLK_IPU2_DI0_PRE_SEL] = imx_clk_mux_p("ipu2_di0_pre_sel", cb + 0x38, 6, 3, ipu_di_pre_sels, ARRAY_SIZE(ipu_di_pre_sels));
diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
index 875c76a8b3e4..04286f03f727 100644
--- a/drivers/clk/imx/clk.h
+++ b/drivers/clk/imx/clk.h
@@ -39,6 +39,14 @@ static inline struct clk *imx_clk_divider_table(const char *name,
width, table, 0);
}
+static inline struct clk *imx_clk_mux_ldb(const char *name, void __iomem *reg,
+ u8 shift, u8 width, const char **parents, int num_parents)
+{
+ return clk_mux(name, CLK_SET_RATE_NO_REPARENT | CLK_SET_RATE_PARENT, reg,
+ shift, width, parents, num_parents, CLK_MUX_READ_ONLY);
+}
+
+
static inline struct clk *imx_clk_fixed_factor(const char *name,
const char *parent, unsigned int mult, unsigned int div)
{
--
2.20.1
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