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Message-ID: <ce42bb5f-c77e-e882-0579-2bbf95d7b1a5@linaro.org>
Date: Mon, 8 Apr 2019 14:35:05 +0200
From: Daniel Lezcano <daniel.lezcano@...aro.org>
To: Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc: Claudiu.Beznea@...rochip.com, robh+dt@...nel.org,
mark.rutland@....com, Nicolas.Ferre@...rochip.com,
Ludovic.Desroches@...rochip.com, tglx@...utronix.de,
devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/5] clocksource/drivers/timer-microchip-pit64b: add
Microchip PIT64B support
On 08/04/2019 14:11, Alexandre Belloni wrote:
> Hi Daniel,
>
> On 08/04/2019 10:43:26+0200, Daniel Lezcano wrote:
>> Hi Claudiu,
>>
>> On 14/03/2019 17:26, Claudiu.Beznea@...rochip.com wrote:
>>> From: Claudiu Beznea <claudiu.beznea@...rochip.com>
>>>
>>> Add driver for Microchip PIT64B timer. Timer could be used in continuous
>>> mode or oneshot mode. The hardware has 2x32 bit registers for period
>>> emulating a 64 bit timer. The LSB_PR and MSB_PR registers are used to set
>>> the period value (compare value). TLSB and TMSB keeps the current value
>>> of the counter. After a compare the TLSB and TMSB register resets. Apart
>>> from this the hardware has SMOD bit in mode register that allow to
>>> reconfigure the timer without reset and start commands (start command
>>> while timer is active is ignored).
>>> The driver uses PIT64B timer as clocksource or clockevent. First requested
>>> timer would be registered as clockevent, second one would be registered as
>>> clocksource.
>>
>> Even if that was done this way before, assuming the DT describes the
>> clockevent at the first place and then the clocksource, it is a fragile
>> approach.
>>
>> What about using one of these approach?
>>
>> eg.
>>
>> arch/arm/boot/dts/at91sam9261ek.dts
>>
>> chosen {
>> bootargs = "rootfstype=ubifs ubi.mtd=5 root=ubi0:rootfs rw";
>> stdout-path = "serial0:115200n8";
>>
>> clocksource {
>> timer = <&timer0>;
>> };
>>
>> clockevent {
>> timer = <&timer1>;
>> };
>> };
>>
>
> I suggested and implemented exactly that back in 2017 and it was shot
> down by both Rob and Mark:
>
> https://lore.kernel.org/lkml/20171213185313.20017-1-alexandre.belloni@free-electrons.com/
>
> At the time, you didn't do *anything* to get it accepted, you stayed
> silent.
What about commit 51f0aeb2d21f1 ?
Author: Alexandre Belloni <alexandre.belloni@...e-electrons.com>
Date: Wed Jun 8 17:08:57 2016 +0200
ARM: dts: at91: at91sam9261ek: use TCB0 as timers
Use tcb0 for timers as selected in at91_dt_defconfig.
Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@...e-electrons.com>
diff --git a/arch/arm/boot/dts/at91sam9261ek.dts
b/arch/arm/boot/dts/at91sam9261ek.dts
index 9733db3f739b..a29fc0494076 100644
--- a/arch/arm/boot/dts/at91sam9261ek.dts
+++ b/arch/arm/boot/dts/at91sam9261ek.dts
@@ -15,6 +15,14 @@
chosen {
bootargs = "rootfstype=ubifs ubi.mtd=5 root=ubi0:rootfs rw";
stdout-path = "serial0:115200n8";
+
+ clocksource {
+ timer = <&timer0>;
+ };
+
+ clockevent {
+ timer = <&timer1>;
+ };
};
memory {
@@ -125,6 +133,18 @@
};
apb {
+ tcb0: timer@...a0000 {
+ timer0: timer@0 {
+ compatible = "atmel,tcb-timer";
+ reg = <0>, <1>;
+ };
+
+ timer1: timer@2 {
+ compatible = "atmel,tcb-timer";
+ reg = <2>;
+ };
+ };
+
usb1: gadget@...a4000 {
atmel,vbus-gpio = <&pioB 29
GPIO_ACTIVE_HIGH>;
status = "okay";
> I can respin the series but then I see two options:
> - either you back up the series and really push for it
> - or you simply take this driver as it is. There is nothing in it that
> couldn't be reworked later once you reached a conclusion with the DT
> maintainers.
>
>> or
>>
>> arch/arm/boot/dts/integratorap.dts
>>
>> aliases {
>> arm,timer-primary = &timer2;
>> arm,timer-secondary = &timer1;
>> };
>>
>> So we can have control of what is the clocksource or the clockevent.
>> That is particulary handy in case of multiple channels.
>>
>> Not sure if we can replace the 'arm,timer_primary' to 'clocksource'.
>>
>> Rob? What is your opinion?
>>
>>> Individual PIT64B hardware resources were used for clocksource
>>> and clockevent to be able to support high resolution timers with this
>>> hardware implementation.
>>>
>>> Signed-off-by: Claudiu Beznea <claudiu.beznea@...rochip.com>
>>> ---
>>> drivers/clocksource/Kconfig | 6 +
>>> drivers/clocksource/Makefile | 1 +
>>> drivers/clocksource/timer-microchip-pit64b.c | 464 +++++++++++++++++++++++++++
>>> 3 files changed, 471 insertions(+)
>>> create mode 100644 drivers/clocksource/timer-microchip-pit64b.c
>>>
>>> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
>>> index 5d93e580e5dc..2ad6f881a0bb 100644
>>> --- a/drivers/clocksource/Kconfig
>>> +++ b/drivers/clocksource/Kconfig
>>> @@ -448,6 +448,12 @@ config OXNAS_RPS_TIMER
>>> config SYS_SUPPORTS_SH_CMT
>>> bool
>>>
>>> +config MICROCHIP_PIT64B
>>> + bool "Microchip PIT64B support"
>>> + depends on OF || COMPILE_TEST
>>> + help
>>> + This option enables Microchip PIT64B timer.
>>> +
>>> config MTK_TIMER
>>> bool "Mediatek timer driver" if COMPILE_TEST
>>> depends on HAS_IOMEM
>>> diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
>>> index c4a8e9ef932a..c53fa12b9b94 100644
>>> --- a/drivers/clocksource/Makefile
>>> +++ b/drivers/clocksource/Makefile
>>> @@ -35,6 +35,7 @@ obj-$(CONFIG_U300_TIMER) += timer-u300.o
>>> obj-$(CONFIG_SUN4I_TIMER) += timer-sun4i.o
>>> obj-$(CONFIG_SUN5I_HSTIMER) += timer-sun5i.o
>>> obj-$(CONFIG_MESON6_TIMER) += timer-meson6.o
>>> +obj-$(CONFIG_MICROCHIP_PIT64B) += timer-microchip-pit64b.o
>>> obj-$(CONFIG_TEGRA_TIMER) += timer-tegra20.o
>>> obj-$(CONFIG_VT8500_TIMER) += timer-vt8500.o
>>> obj-$(CONFIG_NSPIRE_TIMER) += timer-zevio.o
>>> diff --git a/drivers/clocksource/timer-microchip-pit64b.c b/drivers/clocksource/timer-microchip-pit64b.c
>>> new file mode 100644
>>> index 000000000000..6787aa98ef01
>>> --- /dev/null
>>> +++ b/drivers/clocksource/timer-microchip-pit64b.c
>>> @@ -0,0 +1,464 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +//
>>> +// Copyright (C) 2019 Microchip Technology Inc.
>>> +// Copyright (C) 2019 Claudiu Beznea (claudiu.beznea@...rochip.com)
>>> +
>>> +#include <linux/clk.h>
>>> +#include <linux/clockchips.h>
>>> +#include <linux/interrupt.h>
>>> +#include <linux/of_address.h>
>>> +#include <linux/of_irq.h>
>>> +#include <linux/sched_clock.h>
>>> +#include <linux/slab.h>
>>> +
>>> +#define MCHP_PIT64B_CR 0x00 /* Control Register */
>>> +#define MCHP_PIT64B_CR_START BIT(0)
>>> +#define MCHP_PIT64B_CR_SWRST BIT(8)
>>> +
>>> +#define MCHP_PIT64B_MR 0x04 /* Mode Register */
>>> +#define MCHP_PIT64B_MR_CONT BIT(0)
>>> +#define MCHP_PIT64B_MR_SGCLK BIT(3)
>>> +#define MCHP_PIT64B_MR_SMOD BIT(4)
>>> +#define MCHP_PIT64B_MR_PRES GENMASK(11, 8)
>>> +
>>> +#define MCHP_PIT64B_LSB_PR 0x08 /* LSB Period Register */
>>> +
>>> +#define MCHP_PIT64B_MSB_PR 0x0C /* MSB Period Register */
>>> +
>>> +#define MCHP_PIT64B_IER 0x10 /* Interrupt Enable Register */
>>> +#define MCHP_PIT64B_IER_PERIOD BIT(0)
>>> +
>>> +#define MCHP_PIT64B_ISR 0x1C /* Interrupt Status Register */
>>> +#define MCHP_PIT64B_ISR_PERIOD BIT(0)
>>> +
>>> +#define MCHP_PIT64B_TLSBR 0x20 /* Timer LSB Register */
>>> +
>>> +#define MCHP_PIT64B_TMSBR 0x24 /* Timer MSB Register */
>>> +
>>> +#define MCHP_PIT64B_PRES_MAX 0x10
>>> +#define MCHP_PIT64B_DEF_FREQ 2500000UL /* 2.5 MHz */
>>> +#define MCHP_PIT64B_LSBMASK GENMASK_ULL(31, 0)
>>> +#define MCHP_PIT64B_PRESCALER(p) (MCHP_PIT64B_MR_PRES & ((p) << 8))
>>> +
>>> +#define MCHP_PIT64B_NAME "pit64b"
>>> +
>>> +struct mchp_pit64b_common_data {
>>> + void __iomem *base;
>>> + struct clk *pclk;
>>> + struct clk *gclk;
>>> + u64 cycles;
>>> + u8 pres;
>>> +};
>>> +
>>> +struct mchp_pit64b_clksrc_data {
>>> + struct clocksource *clksrc;
>>> + struct mchp_pit64b_common_data *cd;
>>> +};
>>> +
>>> +struct mchp_pit64b_clkevt_data {
>>> + struct clock_event_device *clkevt;
>>> + struct mchp_pit64b_common_data *cd;
>>> +};
>>> +
>>> +static struct mchp_pit64b_data {
>>> + struct mchp_pit64b_clksrc_data *csd;
>>> + struct mchp_pit64b_clkevt_data *ced;
>>> +} data;
>>> +
>>> +static inline u32 mchp_pit64b_read(void __iomem *base, u32 offset)
>>> +{
>>> + return readl_relaxed(base + offset);
>>> +}
>>> +
>>> +static inline void mchp_pit64b_write(void __iomem *base, u32 offset, u32 val)
>>> +{
>>> + writel_relaxed(val, base + offset);
>>> +}
>>> +
>>> +static inline u64 mchp_pit64b_get_period(void __iomem *base)
>>> +{
>>> + u32 lsb, msb;
>>> +
>>> + /* LSB must be read first to guarantee an atomic read of the 64 bit
>>> + * timer.
>>> + */
>>> + lsb = mchp_pit64b_read(base, MCHP_PIT64B_TLSBR);
>>> + msb = mchp_pit64b_read(base, MCHP_PIT64B_TMSBR);
>>> +
>>> + return (((u64)msb << 32) | lsb);
>>> +}
>>> +
>>> +static inline void mchp_pit64b_set_period(void __iomem *base, u64 cycles)
>>> +{
>>> + u32 lsb, msb;
>>> +
>>> + lsb = cycles & MCHP_PIT64B_LSBMASK;
>>> + msb = cycles >> 32;
>>> +
>>> + /* LSB must be write last to guarantee an atomic update of the timer
>>> + * even when SMOD=1.
>>> + */
>>> + mchp_pit64b_write(base, MCHP_PIT64B_MSB_PR, msb);
>>> + mchp_pit64b_write(base, MCHP_PIT64B_LSB_PR, lsb);
>>> +}
>>> +
>>> +static inline void mchp_pit64b_reset(struct mchp_pit64b_common_data *data,
>>> + u32 mode, bool irq_ena)
>>> +{
>>> + mode |= MCHP_PIT64B_PRESCALER(data->pres);
>>> + if (data->gclk)
>>> + mode |= MCHP_PIT64B_MR_SGCLK;
>>> +
>>> + mchp_pit64b_write(data->base, MCHP_PIT64B_CR, MCHP_PIT64B_CR_SWRST);
>>> + mchp_pit64b_write(data->base, MCHP_PIT64B_MR, mode);
>>> + mchp_pit64b_set_period(data->base, data->cycles);
>>> + if (irq_ena)
>>> + mchp_pit64b_write(data->base, MCHP_PIT64B_IER,
>>> + MCHP_PIT64B_IER_PERIOD);
>>> + mchp_pit64b_write(data->base, MCHP_PIT64B_CR, MCHP_PIT64B_CR_START);
>>> +}
>>> +
>>> +static u64 mchp_pit64b_read_clk(struct clocksource *cs)
>>> +{
>>> + return mchp_pit64b_get_period(data.csd->cd->base);
>>> +}
>>> +
>>> +static u64 mchp_sched_read_clk(void)
>>> +{
>>> + return mchp_pit64b_get_period(data.csd->cd->base);
>>> +}
>>> +
>>> +static struct clocksource mchp_pit64b_clksrc = {
>>> + .name = MCHP_PIT64B_NAME,
>>> + .mask = CLOCKSOURCE_MASK(64),
>>> + .flags = CLOCK_SOURCE_IS_CONTINUOUS,
>>> + .rating = 210,
>>> + .read = mchp_pit64b_read_clk,
>>> +};
>>> +
>>> +static int mchp_pit64b_clkevt_shutdown(struct clock_event_device *cedev)
>>> +{
>>> + mchp_pit64b_write(data.ced->cd->base, MCHP_PIT64B_CR,
>>> + MCHP_PIT64B_CR_SWRST);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int mchp_pit64b_clkevt_set_periodic(struct clock_event_device *cedev)
>>> +{
>>> + mchp_pit64b_reset(data.ced->cd, MCHP_PIT64B_MR_CONT, true);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int mchp_pit64b_clkevt_set_oneshot(struct clock_event_device *cedev)
>>> +{
>>> + mchp_pit64b_reset(data.ced->cd, MCHP_PIT64B_MR_SMOD, true);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int mchp_pit64b_clkevt_set_next_event(unsigned long evt,
>>> + struct clock_event_device *cedev)
>>> +{
>>> + mchp_pit64b_set_period(data.ced->cd->base, evt);
>>> + mchp_pit64b_write(data.ced->cd->base, MCHP_PIT64B_CR,
>>> + MCHP_PIT64B_CR_START);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static void mchp_pit64b_clkevt_suspend(struct clock_event_device *cedev)
>>> +{
>>> + mchp_pit64b_write(data.ced->cd->base, MCHP_PIT64B_CR,
>>> + MCHP_PIT64B_CR_SWRST);
>>> + if (data.ced->cd->gclk)
>>> + clk_disable_unprepare(data.ced->cd->gclk);
>>> + clk_disable_unprepare(data.ced->cd->pclk);
>>> +}
>>> +
>>> +static void mchp_pit64b_clkevt_resume(struct clock_event_device *cedev)
>>> +{
>>> + u32 mode = MCHP_PIT64B_MR_SMOD;
>>> +
>>> + clk_prepare_enable(data.ced->cd->pclk);
>>> + if (data.ced->cd->gclk)
>>> + clk_prepare_enable(data.ced->cd->gclk);
>>> +
>>> + if (clockevent_state_periodic(data.ced->clkevt))
>>> + mode = MCHP_PIT64B_MR_CONT;
>>> +
>>> + mchp_pit64b_reset(data.ced->cd, mode, true);
>>> +}
>>> +
>>> +static struct clock_event_device mchp_pit64b_clkevt = {
>>> + .name = MCHP_PIT64B_NAME,
>>> + .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
>>> + .rating = 150,
>>> + .set_state_shutdown = mchp_pit64b_clkevt_shutdown,
>>> + .set_state_periodic = mchp_pit64b_clkevt_set_periodic,
>>> + .set_state_oneshot = mchp_pit64b_clkevt_set_oneshot,
>>> + .set_next_event = mchp_pit64b_clkevt_set_next_event,
>>> + .suspend = mchp_pit64b_clkevt_suspend,
>>> + .resume = mchp_pit64b_clkevt_resume,
>>> +};
>>> +
>>> +static irqreturn_t mchp_pit64b_interrupt(int irq, void *dev_id)
>>> +{
>>> + struct mchp_pit64b_clkevt_data *irq_data = dev_id;
>>> +
>>> + if (data.ced != irq_data)
>>> + return IRQ_NONE;
>>> +
>>> + if (mchp_pit64b_read(irq_data->cd->base, MCHP_PIT64B_ISR) &
>>> + MCHP_PIT64B_ISR_PERIOD) {
>>> + irq_data->clkevt->event_handler(irq_data->clkevt);
>>> + return IRQ_HANDLED;
>>> + }
>>> +
>>> + return IRQ_NONE;
>>> +}
>>> +
>>> +static int __init mchp_pit64b_pres_compute(u32 *pres, u32 clk_rate,
>>> + u32 max_rate)
>>> +{
>>> + u32 tmp;
>>> +
>>> + for (*pres = 0; *pres < MCHP_PIT64B_PRES_MAX; (*pres)++) {
>>> + tmp = clk_rate / (*pres + 1);
>>> + if (tmp <= max_rate)
>>> + break;
>>> + }
>>> +
>>> + if (*pres == MCHP_PIT64B_PRES_MAX)
>>> + return -EINVAL;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int __init mchp_pit64b_pres_prepare(struct mchp_pit64b_common_data *cd,
>>> + unsigned long max_rate)
>>> +{
>>> + unsigned long pclk_rate, diff = 0, best_diff = ULONG_MAX;
>>> + long gclk_round = 0;
>>> + u32 pres, best_pres;
>>> + int ret = 0;
>>> +
>>> + pclk_rate = clk_get_rate(cd->pclk);
>>> + if (!pclk_rate)
>>> + return -EINVAL;
>>> +
>>> + if (cd->gclk) {
>>> + gclk_round = clk_round_rate(cd->gclk, max_rate);
>>> + if (gclk_round < 0)
>>> + goto pclk;
>>> +
>>> + if (pclk_rate / gclk_round < 3)
>>> + goto pclk;
>>> +
>>> + ret = mchp_pit64b_pres_compute(&pres, gclk_round, max_rate);
>>> + if (ret)
>>> + best_diff = abs(gclk_round - max_rate);
>>> + else
>>> + best_diff = abs(gclk_round / (pres + 1) - max_rate);
>>> + best_pres = pres;
>>> + }
>>> +
>>> +pclk:
>>> + /* Check if requested rate could be obtained using PCLK. */
>>> + ret = mchp_pit64b_pres_compute(&pres, pclk_rate, max_rate);
>>> + if (ret)
>>> + diff = abs(pclk_rate - max_rate);
>>> + else
>>> + diff = abs(pclk_rate / (pres + 1) - max_rate);
>>> +
>>> + if (best_diff > diff) {
>>> + /* Use PCLK. */
>>> + cd->gclk = NULL;
>>> + best_pres = pres;
>>> + } else {
>>> + clk_set_rate(cd->gclk, gclk_round);
>>> + }
>>> +
>>> + cd->pres = best_pres;
>>> +
>>> + pr_info("PIT64B: using clk=%s with prescaler %u, freq=%lu [Hz]\n",
>>> + cd->gclk ? "gclk" : "pclk", cd->pres,
>>> + cd->gclk ? gclk_round / (cd->pres + 1)
>>> + : pclk_rate / (cd->pres + 1));
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int __init mchp_pit64b_dt_init_clksrc(struct mchp_pit64b_common_data *cd)
>>> +{
>>> + struct mchp_pit64b_clksrc_data *csd;
>>> + unsigned long clk_rate;
>>> + int ret;
>>> +
>>> + csd = kzalloc(sizeof(*csd), GFP_KERNEL);
>>> + if (!csd)
>>> + return -ENOMEM;
>>> +
>>> + csd->cd = cd;
>>> +
>>> + if (csd->cd->gclk)
>>> + clk_rate = clk_get_rate(csd->cd->gclk);
>>> + else
>>> + clk_rate = clk_get_rate(csd->cd->pclk);
>>> +
>>> + clk_rate = clk_rate / (cd->pres + 1);
>>> + csd->cd->cycles = ULLONG_MAX;
>>> + mchp_pit64b_reset(csd->cd, MCHP_PIT64B_MR_CONT, false);
>>> +
>>> + data.csd = csd;
>>> +
>>> + csd->clksrc = &mchp_pit64b_clksrc;
>>> +
>>> + ret = clocksource_register_hz(csd->clksrc, clk_rate);
>>> + if (ret) {
>>> + pr_debug("clksrc: Failed to register PIT64B clocksource!\n");
>>> + goto free;
>>> + }
>>> +
>>> + sched_clock_register(mchp_sched_read_clk, 64, clk_rate);
>>> +
>>> + return 0;
>>> +
>>> +free:
>>> + kfree(csd);
>>> + data.csd = NULL;
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +static int __init mchp_pit64b_dt_init_clkevt(struct mchp_pit64b_common_data *cd,
>>> + u32 irq)
>>> +{
>>> + struct mchp_pit64b_clkevt_data *ced;
>>> + unsigned long clk_rate;
>>> + int ret;
>>> +
>>> + ced = kzalloc(sizeof(*ced), GFP_KERNEL);
>>> + if (!ced)
>>> + return -ENOMEM;
>>> +
>>> + ced->cd = cd;
>>> +
>>> + if (ced->cd->gclk)
>>> + clk_rate = clk_get_rate(ced->cd->gclk);
>>> + else
>>> + clk_rate = clk_get_rate(ced->cd->pclk);
>>> +
>>> + clk_rate = clk_rate / (ced->cd->pres + 1);
>>> + ced->cd->cycles = DIV_ROUND_CLOSEST(clk_rate, HZ);
>>> +
>>> + ret = request_irq(irq, mchp_pit64b_interrupt, IRQF_TIMER, "pit64b_tick",
>>> + ced);
>>> + if (ret) {
>>> + pr_debug("clkevt: Failed to setup PIT64B IRQ\n");
>>> + goto free;
>>> + }
>>> +
>>> + data.ced = ced;
>>> +
>>> + /* Set up and register clockevents. */
>>> + ced->clkevt = &mchp_pit64b_clkevt;
>>> + ced->clkevt->cpumask = cpumask_of(0);
>>> + ced->clkevt->irq = irq;
>>> + clockevents_config_and_register(ced->clkevt, clk_rate, 1, ULONG_MAX);
>>> +
>>> + return 0;
>>> +
>>> +free:
>>> + kfree(ced);
>>> + data.ced = NULL;
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +static int __init mchp_pit64b_dt_init(struct device_node *node)
>>> +{
>>> + struct mchp_pit64b_common_data *cd;
>>> + u32 irq, freq = MCHP_PIT64B_DEF_FREQ;
>>> + int ret;
>>> +
>>> + if (data.csd && data.ced)
>>> + return -EBUSY;
>>> +
>>> + cd = kzalloc(sizeof(*cd), GFP_KERNEL);
>>> + if (!cd)
>>> + return -ENOMEM;
>>> +
>>> + cd->pclk = of_clk_get_by_name(node, "pclk");
>>> + if (IS_ERR(cd->pclk)) {
>>> + ret = PTR_ERR(cd->pclk);
>>> + goto free;
>>> + }
>>> +
>>> + cd->gclk = of_clk_get_by_name(node, "gclk");
>>> + if (IS_ERR(cd->gclk))
>>> + cd->gclk = NULL;
>>> +
>>> + ret = of_property_read_u32(node, "clock-frequency", &freq);
>>> + if (ret)
>>> + pr_debug("PIT64B: failed to read clock frequency. Using default!\n");
>>> +
>>> + ret = mchp_pit64b_pres_prepare(cd, freq);
>>> + if (ret)
>>> + goto free;
>>> +
>>> + cd->base = of_iomap(node, 0);
>>> + if (!cd->base) {
>>> + pr_debug("%s: Could not map PIT64B address!\n",
>>> + MCHP_PIT64B_NAME);
>>> + ret = -ENXIO;
>>> + goto free;
>>> + }
>>> +
>>> + ret = clk_prepare_enable(cd->pclk);
>>> + if (ret)
>>> + goto unmap;
>>> +
>>> + if (cd->gclk) {
>>> + ret = clk_prepare_enable(cd->gclk);
>>> + if (ret)
>>> + goto pclk_unprepare;
>>> + }
>>> +
>>> + if (!data.ced) {
>>> + irq = irq_of_parse_and_map(node, 0);
>>> + if (!irq) {
>>> + pr_debug("%s: Failed to get PIT64B clockevent IRQ!\n",
>>> + MCHP_PIT64B_NAME);
>>> + ret = -ENODEV;
>>> + goto gclk_unprepare;
>>> + }
>>> + ret = mchp_pit64b_dt_init_clkevt(cd, irq);
>>> + if (ret)
>>> + goto irq_unmap;
>>> + } else {
>>> + ret = mchp_pit64b_dt_init_clksrc(cd);
>>> + if (ret)
>>> + goto gclk_unprepare;
>>> + }
>>> +
>>> + return 0;
>>> +
>>> +irq_unmap:
>>> + irq_dispose_mapping(irq);
>>> +gclk_unprepare:
>>> + if (cd->gclk)
>>> + clk_disable_unprepare(cd->gclk);
>>> +pclk_unprepare:
>>> + clk_disable_unprepare(cd->pclk);
>>> +unmap:
>>> + iounmap(cd->base);
>>> +free:
>>> + kfree(cd);
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +TIMER_OF_DECLARE(mchp_pit64b_clksrc, "microchip,sam9x60-pit64b",
>>> + mchp_pit64b_dt_init);
>>>
>>
>>
>> --
>> <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs
>>
>> Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook |
>> <http://twitter.com/#!/linaroorg> Twitter |
>> <http://www.linaro.org/linaro-blog/> Blog
>>
>
--
<http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs
Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog
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