Thread (6 messages) flat view 6 messages, 3 authors, 2014-09-10

RE: [PATCH V2 3/3] ARM: imx: source gpt per clk from OSC for system timer

From: Anson.Huang-KZfg59tc24xl57MIdRCFDg@public.gmane.org <hidden>
Date: 2014-09-10 07:45:53
Also in: linux-arm-kernel


Best regards!
Anson Huang


-----Original Message-----
From: Shawn Guo [mailto:shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org] 
Sent: 2014-09-10 3:37 PM
To: Huang Yongcai-B20788
Cc: festevam-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org; kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org; devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH V2 3/3] ARM: imx: source gpt per clk from OSC for system timer

On Fri, Sep 05, 2014 at 11:26:46AM +0800, Anson Huang wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/arm/mach-imx/time.c b/arch/arm/mach-imx/time.c index 
bf92e5a..a3ecb4a 100644
--- a/arch/arm/mach-imx/time.c
+++ b/arch/arm/mach-imx/time.c
@@ -60,17 +60,23 @@
 #define MX2_TSTAT_CAPT		(1 << 1)
 #define MX2_TSTAT_COMP		(1 << 0)
 
-/* MX31, MX35, MX25, MX5 */
+/* MX31, MX35, MX25, MX5, MX6 */
 #define V2_TCTL_WAITEN		(1 << 3) /* Wait enable mode */
 #define V2_TCTL_CLK_IPG		(1 << 6)
 #define V2_TCTL_CLK_PER		(2 << 6)
+#define V2_TCTL_CLK_OSC_DIV8	(5 << 6)
+#define V2_TCTL_CLK_OSC		(7 << 6)
This one is unused?
[Anson] Yes, will remove it in V3.
 #define V2_TCTL_FRR		(1 << 9)
+#define V2_TCTL_24MEN		(1 << 10)
+#define V2_TPRER_PRE24M		12
 #define V2_IR			0x0c
 #define V2_TSTAT		0x08
 #define V2_TSTAT_OF1		(1 << 0)
 #define V2_TCN			0x24
 #define V2_TCMP			0x10
 
+#define	V2_TIMER_RATE_OSC_DIV8	3000000
A space instead of tab should be used right after '#define'.
[Anson] Accepted.
quoted hunk ↗ jump to hunk
+
 #define timer_is_v1()	(cpu_is_mx1() || cpu_is_mx21() || cpu_is_mx27())
 #define timer_is_v2()	(!timer_is_v1())
 
@@ -293,7 +299,7 @@ static int __init mxc_clockevent_init(struct clk 
*timer_clk)  static void __init _mxc_timer_init(int irq,
 				   struct clk *clk_per, struct clk *clk_ipg)  {
-	uint32_t tctl_val;
+	uint32_t tctl_val, tprer_val;
The variable tprer_val does not seem really needed.
[Anson] Will remove it and write the value directly to the register.

Shawn
quoted hunk ↗ jump to hunk
 
 	if (IS_ERR(clk_per)) {
 		pr_err("i.MX timer: unable to get clk\n");
@@ -312,10 +318,26 @@ static void __init _mxc_timer_init(int irq,
 	__raw_writel(0, timer_base + MXC_TCTL);
 	__raw_writel(0, timer_base + MXC_TPRER); /* see datasheet note */
 
-	if (timer_is_v2())
-		tctl_val = V2_TCTL_CLK_PER | V2_TCTL_FRR | V2_TCTL_WAITEN | MXC_TCTL_TEN;
-	else
+	if (timer_is_v2()) {
+		if (((cpu_is_imx6q() && imx_get_soc_revision() >
+			IMX_CHIP_REVISION_1_0) || cpu_is_imx6dl() ||
+			cpu_is_imx6sx()) && (clk_get_rate(clk_per) ==
+			V2_TIMER_RATE_OSC_DIV8)) {
+			tctl_val = V2_TCTL_CLK_OSC_DIV8 | V2_TCTL_FRR |
+				V2_TCTL_WAITEN | MXC_TCTL_TEN;
+			if (cpu_is_imx6dl() || cpu_is_imx6sx()) {
+				/* 24 / 8 = 3 MHz */
+				tprer_val = 7 << V2_TPRER_PRE24M;
+				__raw_writel(tprer_val, timer_base + MXC_TPRER);
+				tctl_val |= V2_TCTL_24MEN;
+			}
+		} else {
+			tctl_val = V2_TCTL_CLK_PER | V2_TCTL_FRR |
+				V2_TCTL_WAITEN | MXC_TCTL_TEN;
+		}
+	} else {
 		tctl_val = MX1_2_TCTL_FRR | MX1_2_TCTL_CLK_PCLK1 | MXC_TCTL_TEN;
+	}
 
 	__raw_writel(tctl_val, timer_base + MXC_TCTL);
 
@@ -339,7 +361,7 @@ void __init mxc_timer_init(void __iomem *base, int irq)
 
 static void __init mxc_timer_init_dt(struct device_node *np)
 {
-	struct clk *clk_per, *clk_ipg;
+	struct clk *clk_per, *clk_ipg, *clk_osc_per;
 	int irq;
 
 	if (timer_base)
@@ -352,6 +374,13 @@ static void __init mxc_timer_init_dt(struct device_node *np)
 	clk_per = of_clk_get_by_name(np, "per");
 	clk_ipg = of_clk_get_by_name(np, "ipg");
 
+	if ((cpu_is_imx6q() && imx_get_soc_revision() >
+		IMX_CHIP_REVISION_1_0) || cpu_is_imx6dl()) {
+		clk_osc_per = of_clk_get_by_name(np, "osc_per");
+		if (!IS_ERR(clk_osc_per))
+			clk_per = clk_osc_per;
+	}
+
 	_mxc_timer_init(irq, clk_per, clk_ipg);
 }
 CLOCKSOURCE_OF_DECLARE(mx1_timer, "fsl,imx1-gpt", mxc_timer_init_dt);
-- 
1.7.9.5
--
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