On Fri, Sep 5, 2014 at 12:26 AM, Anson Huang <b20788@xxxxxxxxxxxxx> wrote:
> On i.MX6Q TO > 1.0, i.MX6DL and i.MX6SX, gpt per clock
> can be from OSC instead of ipg_per, as ipg_per's rate
> may be scaled when system enter low bus mode, to keep
> system timer NOT drift, better to make gpt per clock
> at fixed rate, here add support for gpt per clock to
> be from OSC which is at fixed rate always.
>
> There are some difference on this implementation of
> gpt per clock source, see below for details:
>
> i.MX6Q TO > 1.0: GPT_CR_CLKSRC, 3b'101 selects fix clock
> of OSC / 8 for gpt per clk;
You mean "5b'101 selects fix clock..."
> i.MX6DL and i.MX6SX: GPT_CR_CLKSRC, 3b'101 selects OSC
Same here: "5b'101"
> @@ -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;
>
> 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;
> + }
Can this block be rearranged a bit so that it becomes easier to read?
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