clk: imx6: retain early UART clocks during kernel init

Make sure to keep UART clocks enabled during kernel init if
earlyprintk or earlycon are active.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

3 files changed, 24 insertions, 0 deletions

diff --git a/drivers/clk/imx/clk-imx6q.c b/drivers/clk/imx/clk-imx6q.c
index b2c1c047dc94..e9ba018ac6a3 100644
--- a/drivers/clk/imx/clk-imx6q.c
+++ b/drivers/clk/imx/clk-imx6q.c
@@ -130,6 +130,12 @@ static inline int clk_on_imx6dl(void)
         return of_machine_is_compatible("fsl,imx6dl");
 }
 
+static struct clk ** const uart_clks[] __initconst = {
+        &clk[IMX6QDL_CLK_UART_IPG],
+        &clk[IMX6QDL_CLK_UART_SERIAL],
+        NULL
+};
+
 static void __init imx6q_clocks_init(struct device_node *ccm_node)
 {
         struct device_node *np;
@@ -541,5 +547,7 @@ static void __init imx6q_clocks_init(struct device_node *ccm_node)
         /* All existing boards with PCIe use LVDS1 */
         if (IS_ENABLED(CONFIG_PCI_IMX6))
                 clk_set_parent(clk[IMX6QDL_CLK_LVDS1_SEL], clk[IMX6QDL_CLK_SATA_REF_100M]);
+
+        imx_register_uart_clocks(uart_clks);
 }
 CLK_OF_DECLARE(imx6q, "fsl,imx6q-ccm", imx6q_clocks_init);
diff --git a/drivers/clk/imx/clk-imx6sl.c b/drivers/clk/imx/clk-imx6sl.c
index a0d4cf26cfa9..3c3333faae8e 100644
--- a/drivers/clk/imx/clk-imx6sl.c
+++ b/drivers/clk/imx/clk-imx6sl.c
@@ -184,6 +184,12 @@ void imx6sl_set_wait_clk(bool enter)
                 imx6sl_enable_pll_arm(false);
 }
 
+static struct clk ** const uart_clks[] __initconst = {
+        &clks[IMX6SL_CLK_UART],
+        &clks[IMX6SL_CLK_UART_SERIAL],
+        NULL
+};
+
 static void __init imx6sl_clocks_init(struct device_node *ccm_node)
 {
         struct device_node *np;
@@ -439,5 +445,7 @@ static void __init imx6sl_clocks_init(struct device_node *ccm_node)
 
         clk_set_parent(clks[IMX6SL_CLK_LCDIF_AXI_SEL],
                        clks[IMX6SL_CLK_PLL2_PFD2]);
+
+        imx_register_uart_clocks(uart_clks);
 }
 CLK_OF_DECLARE(imx6sl, "fsl,imx6sl-ccm", imx6sl_clocks_init);
diff --git a/drivers/clk/imx/clk-imx6sx.c b/drivers/clk/imx/clk-imx6sx.c
index 5b95c2c2bf52..f0ad8bbc12f8 100644
--- a/drivers/clk/imx/clk-imx6sx.c
+++ b/drivers/clk/imx/clk-imx6sx.c
@@ -135,6 +135,12 @@ static u32 share_count_ssi1;
 static u32 share_count_ssi2;
 static u32 share_count_ssi3;
 
+static struct clk ** const uart_clks[] __initconst = {
+        &clks[IMX6SX_CLK_UART_IPG],
+        &clks[IMX6SX_CLK_UART_SERIAL],
+        NULL
+};
+
 static void __init imx6sx_clocks_init(struct device_node *ccm_node)
 {
         struct device_node *np;
@@ -557,5 +563,7 @@ static void __init imx6sx_clocks_init(struct device_node *ccm_node)
 
         clk_set_parent(clks[IMX6SX_CLK_QSPI1_SEL], clks[IMX6SX_CLK_PLL2_BUS]);
         clk_set_parent(clks[IMX6SX_CLK_QSPI2_SEL], clks[IMX6SX_CLK_PLL2_BUS]);
+
+        imx_register_uart_clocks(uart_clks);
 }
 CLK_OF_DECLARE(imx6sx, "fsl,imx6sx-ccm", imx6sx_clocks_init);