On Wed, Jun 26, 2013 at 4:53 PM, Jonas Jensen <[email protected]> wrote:
> This patch adds an clocksource driver for the main timer(s) > found on MOXA ART SoCs. > > Changes since v2: > > 1. use clocksource/clockevents infrastructures > 2. clock frequency read from system clock > > Applies to next-20130619 > > Signed-off-by: Jonas Jensen <[email protected]> This is starting to look good :-) > +/* TIMER_CR flags: > + TIMEREG_CR_1_CLOCK 0: PCLK, 1: EXT1CLK > + TIMEREG_CR_1_INT over flow interrupt enable bit */ /* * Usually we use this comment style, one star at the beginning * of every comment line and a closing star-slash sitting lonley * on a single line to close it. */ > + case CLOCK_EVT_MODE_RESUME: > + case CLOCK_EVT_MODE_ONESHOT: > + u |= TIMEREG_CR_1_ENABLE; > + writel(u, timer_base + TIMER_CR); > + writel(~0, timer_base + TIMER1_LOAD); Should you not write the load value *before* enabling the timer? > + pr_debug("%s: CLOCK_EVT_MODE_ONESHOT\n", __func__); > + break; This looks like you're enabling a tick far ahead in the future. For oneshot you should just trigger new events in .next_event(), I would just disable the timer for oneshot and enable it for each new event in .next_event() instead. > + case CLOCK_EVT_MODE_PERIODIC: > + u |= TIMEREG_CR_1_ENABLE; > + writel(u, timer_base + TIMER_CR); > + writel(clock_frequency / HZ, timer_base + TIMER1_LOAD); Use DIV_ROUND_CLOSEST(clock_frequency, HZ) > + pr_debug("%s: CLOCK_EVT_MODE_PERIODIC\n", __func__); > + break; > + case CLOCK_EVT_MODE_UNUSED: > + case CLOCK_EVT_MODE_SHUTDOWN: > + default: > + u &= ~TIMEREG_CR_1_ENABLE; I would do this also for Oneshot. Then enable it in .next_event(). > + writel(u, timer_base + TIMER_CR); > + break; > +static int moxart_clkevt_next_event(unsigned long cycles, > + struct clock_event_device *unused) > +{ > + u32 alarm = readl(timer_base + TIMER1_COUNT) - cycles; > + writel(alarm, timer_base + TIMER1_MATCH1); I would write TIMEREG_CR_1_ENABLE *here*. This way the timer is only strictly triggered when an event is queued. > +static struct irqaction moxart_timer_irq = { > + .name = "moxart-timer", > + .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, IRQF_DISABLED is pointless, remove it. Nowadays all IRQ handlers are called with interrupts disabled. Why do you need IRQF_IRQPOLL? That seems like more copy/paste luggade. > + clock_frequency = APB_CLK; > + /* it might be a good idea to have a default other than 0 for > + clock_frequency, should any attempt at getting a valid > + frequency fail, not that i see how it could, it probably could.. > + having it APB_CLK can certainly be wrong on some hardware, > + why it is set again with the DT specific property: */ Seems overkill. > + ret = of_property_read_u32(node, "clock-frequency", &clock_frequency); > + if (ret) > + pr_err("%s: can't read clock-frequency DT property\n", > + node->full_name); I don't think it's apropriate to put clock frequencies into the device tree node as u32:s. Please use the clock framework exclusively. Now it's like three ways to get this frequency... what if all three are different :-P > + clk = of_clk_get(node, 0); > + if (IS_ERR(clk)) > + pr_err("%s: of_clk_get failed\n", __func__); bail out here? > + else { > + clock_frequency = clk_get_rate(clk); > + pr_debug("%s: clk_get_rate=%u success\n", __func__, > + clock_frequency); > + } Then you can remove the else clause and de-indent this. The rest looks OK... Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
