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From: mkl@pengutronix.de (Marc Kleine-Budde)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 2/2] ARM i.MX5: set CAN peripheral clock to 24 MHz parent
Date: Mon, 25 Nov 2013 22:15:21 +0100	[thread overview]
Message-ID: <1385414121-21493-3-git-send-email-mkl@pengutronix.de> (raw)
In-Reply-To: <1385414121-21493-1-git-send-email-mkl@pengutronix.de>

This patch sets the parent of CAN peripheral clock (a.k.a. CPI clock) to the
lp_apm clock, which has a rate of 24 MHz.

In the CAN world a base clock with multiple of 8 MHz is suited best for all CIA
recommented bit rates. Without this patch the CAN peripheral clock on i.MX53
has a rate of 66.666 MHz which produces quite large bit rate errors.

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 arch/arm/mach-imx/clk-imx51-imx53.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm/mach-imx/clk-imx51-imx53.c b/arch/arm/mach-imx/clk-imx51-imx53.c
index e349fd5..dff5ca9 100644
--- a/arch/arm/mach-imx/clk-imx51-imx53.c
+++ b/arch/arm/mach-imx/clk-imx51-imx53.c
@@ -584,6 +584,9 @@ static void __init mx53_clocks_init(struct device_node *np)
 	clk_set_rate(clk[IMX5_CLK_ESDHC_A_PODF], 200000000);
 	clk_set_rate(clk[IMX5_CLK_ESDHC_B_PODF], 200000000);
 
+	/* move can bus clk to 24MHz */
+	clk_set_parent(clk[IMX5_CLK_CAN_SEL], clk[IMX5_CLK_LP_APM]);
+
 	clk_prepare_enable(clk[IMX5_CLK_IIM_GATE]);
 	imx_print_silicon_rev("i.MX53", mx53_revision());
 	clk_disable_unprepare(clk[IMX5_CLK_IIM_GATE]);
-- 
1.8.4.2

  parent reply	other threads:[~2013-11-25 21:15 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-25 21:15 [PATCH v2 1/2] can + ARM i.MX53: use 24 MHz clock parent on i.MX53 Marc Kleine-Budde
2013-11-25 21:15 ` [PATCH v2 1/2] can: flexcan: use correct clock as base for bit rate calculation Marc Kleine-Budde
2013-11-26  8:27   ` Marc Kleine-Budde
2013-11-26  8:35     ` Marc Kleine-Budde
2013-11-25 21:15 ` Marc Kleine-Budde [this message]
2013-11-26  4:53 ` [PATCH v2 1/2] can + ARM i.MX53: use 24 MHz clock parent on i.MX53 Shawn Guo
2013-11-26  8:26   ` Marc Kleine-Budde
2013-11-26 14:33     ` Shawn Guo
2013-11-26 14:35       ` Marc Kleine-Budde
2013-12-03 10:54       ` Marc Kleine-Budde
2013-12-03 11:46         ` Shawn Guo
2013-12-09  5:59         ` Shawn Guo

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