clk: imx27: 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>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/clk/imx/clk-imx27.c b/drivers/clk/imx/clk-imx27.c
index d9d50d54ef2a..0d7b8df04dfa 100644
--- a/drivers/clk/imx/clk-imx27.c
+++ b/drivers/clk/imx/clk-imx27.c
@@ -47,6 +47,17 @@ static const char *ssi_sel_clks[] = { "spll_gate", "mpll", };
 static struct clk *clk[IMX27_CLK_MAX];
 static struct clk_onecell_data clk_data;
 
+static struct clk ** const uart_clks[] __initconst = {
+        &clk[IMX27_CLK_PER1_GATE],
+        &clk[IMX27_CLK_UART1_IPG_GATE],
+        &clk[IMX27_CLK_UART2_IPG_GATE],
+        &clk[IMX27_CLK_UART3_IPG_GATE],
+        &clk[IMX27_CLK_UART4_IPG_GATE],
+        &clk[IMX27_CLK_UART5_IPG_GATE],
+        &clk[IMX27_CLK_UART6_IPG_GATE],
+        NULL
+};
+
 static void __init _mx27_clocks_init(unsigned long fref)
 {
         BUG_ON(!ccm);
@@ -163,6 +174,8 @@ static void __init _mx27_clocks_init(unsigned long fref)
 
         clk_prepare_enable(clk[IMX27_CLK_EMI_AHB_GATE]);
 
+        imx_register_uart_clocks(uart_clks);
+
         imx_print_silicon_rev("i.MX27", mx27_revision());
 }