From 8efaf5ed4d442068a1b76f218c0a90e6a5989f11 Mon Sep 17 00:00:00 2001 From: Anson Huang Date: Thu, 6 Aug 2015 22:13:56 +0800 Subject: [PATCH] clk: imx: increase AXI clock rate to 264MHz for i.MX6UL On i.MX6UL, AXI clock rate's design target is 264MHz, but by default it is only set to 198MHz which is NOT good enough for performance, this patch increases AXI clock rate from 198MHz to 264MHz to meet the design target, this is done by switching its parent clock "periph" from 396MHz PFD to 528MHz PLL. Signed-off-by: Anson Huang Signed-off-by: Shawn Guo --- drivers/clk/imx/clk-imx6ul.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/clk/imx/clk-imx6ul.c b/drivers/clk/imx/clk-imx6ul.c index aaa36650695f..01718d05e952 100644 --- a/drivers/clk/imx/clk-imx6ul.c +++ b/drivers/clk/imx/clk-imx6ul.c @@ -407,6 +407,24 @@ static void __init imx6ul_clocks_init(struct device_node *ccm_node) clk_data.clk_num = ARRAY_SIZE(clks); of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data); + /* + * Lower the AHB clock rate before changing the parent clock source, + * as AHB clock rate can NOT be higher than 133MHz, but its parent + * will be switched from 396MHz PFD to 528MHz PLL in order to increase + * AXI clock rate, so we need to lower AHB rate first to make sure at + * any time, AHB rate is <= 133MHz. + */ + clk_set_rate(clks[IMX6UL_CLK_AHB], 99000000); + + /* Change periph_pre clock to pll2_bus to adjust AXI rate to 264MHz */ + clk_set_parent(clks[IMX6UL_CLK_PERIPH_CLK2_SEL], clks[IMX6UL_CLK_PLL3_USB_OTG]); + clk_set_parent(clks[IMX6UL_CLK_PERIPH], clks[IMX6UL_CLK_PERIPH_CLK2]); + clk_set_parent(clks[IMX6UL_CLK_PERIPH_PRE], clks[IMX6UL_CLK_PLL2_BUS]); + clk_set_parent(clks[IMX6UL_CLK_PERIPH], clks[IMX6UL_CLK_PERIPH_PRE]); + + /* Make sure AHB rate is 132MHz */ + clk_set_rate(clks[IMX6UL_CLK_AHB], 132000000); + /* set perclk to from OSC */ clk_set_parent(clks[IMX6UL_CLK_PERCLK_SEL], clks[IMX6UL_CLK_OSC]); -- 2.39.5