diff mbox series

[RESEND,1/6] clk: imx6ul: disable gpmi_io clock before changing parent clock

Message ID 20220125144441.17750-2-ceggers@arri.de (mailing list archive)
State New, archived
Headers show
Series clk: imx6*: avoid GPMI clock glitches on reparenting/divider change | expand

Commit Message

Christian Eggers Jan. 25, 2022, 2:44 p.m. UTC 
gpmi_io clock may have been enabled by the boot loader. All children of
enfc_clk_root must be gated in order to prevent glitches during parent
change.

Signed-off-by: Christian Eggers <ceggers@arri.de>
---
 drivers/clk/imx/clk-imx6ul.c | 9 +++++++++
 1 file changed, 9 insertions(+)
diff mbox series

Patch

diff --git a/drivers/clk/imx/clk-imx6ul.c b/drivers/clk/imx/clk-imx6ul.c
index 520b100bff4b..f599ae50dd9f 100644
--- a/drivers/clk/imx/clk-imx6ul.c
+++ b/drivers/clk/imx/clk-imx6ul.c
@@ -514,6 +514,15 @@  static void __init imx6ul_clocks_init(struct device_node *ccm_node)
 	else if (clk_on_imx6ull())
 		clk_set_parent(hws[IMX6ULL_CLK_EPDC_PRE_SEL]->clk, hws[IMX6UL_CLK_PLL3_PFD2]->clk);
 
+	/*
+	 * gpmi_io clock may have been enabled by the boot loader. All children of
+	 * enfc_clk_root must be gated in order to prevent glitches during parent
+	 * change. The task of re-enabling is left to the gpmi-nand driver.
+	 */
+	if (clk_hw_is_enabled(hws[IMX6UL_CLK_GPMI_IO])) {
+		clk_prepare_enable(hws[IMX6UL_CLK_GPMI_IO]->clk);
+		clk_disable_unprepare(hws[IMX6UL_CLK_GPMI_IO]->clk);
+	}
 	clk_set_parent(hws[IMX6UL_CLK_ENFC_SEL]->clk, hws[IMX6UL_CLK_PLL2_PFD2]->clk);
 }