clk: imx6: Make the LDB_DI0 and LDB_DI1 clocks read-only
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@pengutronix.de>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
index 3799ff8..4afad3b 100644
--- a/drivers/clk/imx/clk.h
+++ b/drivers/clk/imx/clk.h
@@ -75,6 +75,14 @@ static inline struct clk *imx_clk_fixed(const char *name, int rate)
return clk_register_fixed_rate(NULL, name, NULL, 0, rate);
}
+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_register_mux(NULL, name, parents, num_parents,
+ CLK_SET_RATE_NO_REPARENT | CLK_SET_RATE_PARENT, reg,
+ shift, width, CLK_MUX_READ_ONLY, &imx_ccm_lock);
+}
+
static inline struct clk *imx_clk_fixed_factor(const char *name,
const char *parent, unsigned int mult, unsigned int div)
{