[PATCH 4/8] clk: imx31: retain early UART clocks during kernel init

[Lucas Stach]

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

Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
---
 drivers/clk/imx/clk-imx31.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/clk/imx/clk-imx31.c b/drivers/clk/imx/clk-imx31.c
index fe66c40b7be2..c8da3b31f24d 100644
--- a/drivers/clk/imx/clk-imx31.c
+++ b/drivers/clk/imx/clk-imx31.c
@@ -62,6 +62,16 @@ enum mx31_clks {
 static struct clk *clk[clk_max];
 static struct clk_onecell_data clk_data;
 
+static void __init imx31_uart_disable_cb(void)
+{
+	clk_disable_unprepare(clk[ipg]);
+	clk_disable_unprepare(clk[uart1_gate]);
+	clk_disable_unprepare(clk[uart2_gate]);
+	clk_disable_unprepare(clk[uart3_gate]);
+	clk_disable_unprepare(clk[uart4_gate]);
+	clk_disable_unprepare(clk[uart5_gate]);
+}
+
 int __init mx31_clocks_init(unsigned long fref)
 {
 	void __iomem *base;
@@ -199,6 +209,16 @@ int __init mx31_clocks_init(unsigned long fref)
 	mx31_revision();
 	clk_disable_unprepare(clk[iim_gate]);
 
+	if (imx_clk_keep_uart()) {
+		clk_prepare_enable(clk[ipg]);
+		clk_prepare_enable(clk[uart1_gate]);
+		clk_prepare_enable(clk[uart2_gate]);
+		clk_prepare_enable(clk[uart3_gate]);
+		clk_prepare_enable(clk[uart4_gate]);
+		clk_prepare_enable(clk[uart5_gate]);
+		imx_clk_set_uart_disable_callback(imx31_uart_disable_cb);
+	}
+
 	mxc_timer_init(MX31_GPT1_BASE_ADDR, MX31_INT_GPT, GPT_TYPE_IMX31);
 
 	return 0;
-- 
2.5.0