MLK-11459 ARM: imx: add uart clk parent from OSC support

when kernel command line has "uart_from_osc" defined, set uart1
parent clock to OSC for low power case.

Signed-off-by: Fugang Duan <B38611@freescale.com>

4 files changed, 27 insertions, 1 deletions

diff --git a/arch/arm/mach-imx/clk-imx6sl.c b/arch/arm/mach-imx/clk-imx6sl.c
index 524039d05a4a..fe9fb733c921 100644
--- a/arch/arm/mach-imx/clk-imx6sl.c
+++ b/arch/arm/mach-imx/clk-imx6sl.c
@@ -56,7 +56,7 @@ static const char *lcdif_pix_sels[]	= { "pll2_bus", "pll3_usb_otg", "pll5_video_
 static const char *epdc_pix_sels[]	= { "pll2_bus", "pll3_usb_otg", "pll5_video_div", "pll2_pfd0", "pll2_pfd1", "pll3_pfd1", };
 static const char *audio_sels[]		= { "pll4_audio_div", "pll3_pfd2", "pll3_pfd3", "pll3_usb_otg", };
 static const char *ecspi_sels[]		= { "pll3_60m", "osc", };
-static const char *uart_sels[]		= { "pll3_80m", "osc", };
+static const char *uart_sels[]		= { "pll3_80m", "uart_osc_4m", };
 static const char *lvds_sels[]		= {
 	"pll1_sys", "pll2_bus", "pll2_pfd0", "pll2_pfd1", "pll2_pfd2", "dummy", "pll4_audio", "pll5_video",
 	"dummy", "enet_ref", "dummy", "dummy", "pll3_usb_otg", "pll7_usb_host", "pll3_pfd0", "pll3_pfd1",
@@ -283,6 +283,7 @@ static void __init imx6sl_clocks_init(struct device_node *ccm_node)
 	clks[IMX6SL_CLK_PLL3_120M] = imx_clk_fixed_factor("pll3_120m", "pll3_usb_otg",   1, 4);
 	clks[IMX6SL_CLK_PLL3_80M]  = imx_clk_fixed_factor("pll3_80m",  "pll3_usb_otg",   1, 6);
 	clks[IMX6SL_CLK_PLL3_60M]  = imx_clk_fixed_factor("pll3_60m",  "pll3_usb_otg",   1, 8);
+	clks[IMX6SL_CLK_UART_OSC_4M] = imx_clk_fixed_factor("uart_osc_4m",  "osc",   1, 6);
 
 	np = ccm_node;
 	base = of_iomap(np, 0);
@@ -446,6 +447,10 @@ 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]);
 
+        /* Set the UART parent if needed */
+        if (uart_from_osc)
+		imx_clk_set_parent(clks[IMX6SL_CLK_UART_SEL], clks[IMX6SL_CLK_UART_OSC_4M]);
+
 	/* Set initial power mode */
 	imx6q_set_lpm(WAIT_CLOCKED);
 }
diff --git a/arch/arm/mach-imx/clk-imx6sx.c b/arch/arm/mach-imx/clk-imx6sx.c
index 0bf98ce592c2..146b3e1ea122 100644
--- a/arch/arm/mach-imx/clk-imx6sx.c
+++ b/arch/arm/mach-imx/clk-imx6sx.c
@@ -551,6 +551,12 @@ static void __init imx6sx_clocks_init(struct device_node *ccm_node)
 	clk_set_parent(clks[IMX6SX_CLK_ESAI_SEL], clks[IMX6SX_CLK_PLL4_AUDIO_DIV]);
 	clk_set_rate(clks[IMX6SX_CLK_ESAI_PODF], 24576000);
 
+        /* Set the UART parent if needed. */
+        if (uart_from_osc)
+		clk_set_parent(clks[IMX6SX_CLK_UART_SEL], clks[IMX6SX_CLK_OSC]);
+        else
+		clk_set_parent(clks[IMX6SX_CLK_UART_SEL], clks[IMX6SX_CLK_PLL3_80M]);
+
 	/* Set parent clock for vadc */
 	clk_set_parent(clks[IMX6SX_CLK_VID_SEL], clks[IMX6SX_CLK_PLL3_USB_OTG]);
 
diff --git a/arch/arm/mach-imx/clk-imx6ul.c b/arch/arm/mach-imx/clk-imx6ul.c
index d5dd67cf5ef0..9fcedf22ff55 100644
--- a/arch/arm/mach-imx/clk-imx6ul.c
+++ b/arch/arm/mach-imx/clk-imx6ul.c
@@ -413,6 +413,12 @@ static void __init imx6ul_clocks_init(struct device_node *ccm_node)
 	/* set perclk to from OSC */
 	clk_set_parent(clks[IMX6UL_CLK_PERCLK_SEL], clks[IMX6UL_CLK_OSC]);
 
+        /* Set the UART parent if needed */
+        if (uart_from_osc)
+		imx_clk_set_parent(clks[IMX6UL_CLK_UART_SEL], clks[IMX6UL_CLK_OSC]);
+        else
+		imx_clk_set_parent(clks[IMX6UL_CLK_UART_SEL], clks[IMX6UL_CLK_PLL3_80M]);
+
 	clk_set_rate(clks[IMX6UL_CLK_ENET_REF], 50000000);
 	clk_set_rate(clks[IMX6UL_CLK_ENET2_REF], 50000000);
 	clk_set_rate(clks[IMX6UL_CLK_CSI], 24000000);
diff --git a/arch/arm/mach-imx/clk.c b/arch/arm/mach-imx/clk.c
index df12b5307175..1967733409b6 100644
--- a/arch/arm/mach-imx/clk.c
+++ b/arch/arm/mach-imx/clk.c
@@ -7,6 +7,8 @@
 
 DEFINE_SPINLOCK(imx_ccm_lock);
 
+bool uart_from_osc;
+
 void __init imx_check_clocks(struct clk *clks[], unsigned int count)
 {
 	unsigned i;
@@ -73,3 +75,10 @@ void imx_cscmr1_fixup(u32 *val)
 	*val ^= CSCMR1_FIXUP;
 	return;
 }
+
+static int __init setup_uart_clk(char *uart_rate)
+{
+       uart_from_osc = true;
+       return 1;
+}
+__setup("uart_from_osc", setup_uart_clk);