[linux-keystone] Re: [PATCH] arm:davinci: clk - migrate to new common clock API
Turquette, Mike
mturquette at ti.com
Mon Aug 13 17:44:24 EDT 2012
On Mon, Aug 13, 2012 at 2:13 PM, Karicheri, Muralidharan
<m-karicheri2 at ti.com> wrote:
>>> -----Original Message-----
>>> From: Turquette, Mike
>>> Sent: Thursday, August 02, 2012 5:20 PM
>>> To: Karicheri, Muralidharan
>>> Cc: linux-arm-kernel at lists.infradead.org; davinci-linux-open-
>>> source at linux.davincidsp.com; linux-keystone at list.ti.com - Linux developers for Keystone
>>> family of devices (May contain non-TIers); Chemparathy, Cyril; Nori, Sekhar;
>>> linux at arm.linux.org.uk
>>> Subject: [linux-keystone] Re: [PATCH] arm:davinci: clk - migrate to new common clock
>>> API
>>>
>>> On 20120802-12:53, Murali Karicheri wrote:
>>> > As a first step towards migrating davinci platforms to use common clock
>>> > framework, replace all instances of clk_enable() with clk_prepare_enable()
>>> > and clk_disable() with clk_disable_unprepare(). Until the platform is
>>> > switched to use the CONFIG_HAVE_CLK_PREPARE Kconfig variable, this just
>>> > adds a might_sleep() call and would work without any issues.
>>> >
>>> > This will make it easy later to switch to common clk based implementation
>>> > of clk driver from DaVinci specific driver.
>>> >
>>> > Signed-off-by: Murali Karicheri <m-karicheri2 at ti.com>
>>>
>>> Murali,
>>>
>>> The important thing to know about clk_prepare is that it might sleep.
>>> All of the functions below look like initialization functions for code
>>> that is never run in interrupt context. If you can confirm that this is
>>> true then feel free to add my,
>>>
>
> Mike,
>
> I believe they are. I will double check and then post the patch again. If they are called under
> interrupt context, basically I need to make two API calls instead as below right?
>
> clk_prepare()
> clk_enable()
>
This is correct. You must insure that clk_prepare is called (and will
complete) before clk_enable is called. clk_prepare must be run from
process context. It is still OK to call clk_enable/clk_disable from
interrupt context as needed.
Regards,
Mike
> Murali Karicheri
> Software Design Engineer
>
>
>>> Reviewed-by: Mike Turquette <mturquette at linaro.org>
>>>
>>> Regards,
>>> Mike
>>>
>>> > ---
>>> > arch/arm/mach-davinci/board-dm355-evm.c | 2 +-
>>> > arch/arm/mach-davinci/board-dm355-leopard.c | 2 +-
>>> > arch/arm/mach-davinci/board-dm365-evm.c | 4 ++--
>>> > arch/arm/mach-davinci/board-dm644x-evm.c | 2 +-
>>> > arch/arm/mach-davinci/board-neuros-osd2.c | 2 +-
>>> > arch/arm/mach-davinci/devices-da8xx.c | 6 +++---
>>> > arch/arm/mach-davinci/serial.c | 2 +-
>>> > arch/arm/mach-davinci/time.c | 4 ++--
>>> > 8 files changed, 12 insertions(+), 12 deletions(-)
>>> >
>>> > diff --git a/arch/arm/mach-davinci/board-dm355-evm.c b/arch/arm/mach-
>>> davinci/board-dm355-evm.c
>>> > index 1c7b1f4..4821fba 100644
>>> > --- a/arch/arm/mach-davinci/board-dm355-evm.c
>>> > +++ b/arch/arm/mach-davinci/board-dm355-evm.c
>>> > @@ -324,7 +324,7 @@ static __init void dm355_evm_init(void)
>>> > if (IS_ERR(aemif))
>>> > WARN("%s: unable to get AEMIF clock\n", __func__);
>>> > else
>>> > - clk_enable(aemif);
>>> > + clk_prepare_enable(aemif);
>>> >
>>> > platform_add_devices(davinci_evm_devices,
>>> > ARRAY_SIZE(davinci_evm_devices));
>>> > diff --git a/arch/arm/mach-davinci/board-dm355-leopard.c b/arch/arm/mach-
>>> davinci/board-dm355-leopard.c
>>> > index 8e77032..b754ccf 100644
>>> > --- a/arch/arm/mach-davinci/board-dm355-leopard.c
>>> > +++ b/arch/arm/mach-davinci/board-dm355-leopard.c
>>> > @@ -246,7 +246,7 @@ static __init void dm355_leopard_init(void)
>>> > if (IS_ERR(aemif))
>>> > WARN("%s: unable to get AEMIF clock\n", __func__);
>>> > else
>>> > - clk_enable(aemif);
>>> > + clk_prepare_enable(aemif);
>>> >
>>> > platform_add_devices(davinci_leopard_devices,
>>> > ARRAY_SIZE(davinci_leopard_devices));
>>> > diff --git a/arch/arm/mach-davinci/board-dm365-evm.c b/arch/arm/mach-
>>> davinci/board-dm365-evm.c
>>> > index 2830692..3a4743b 100644
>>> > --- a/arch/arm/mach-davinci/board-dm365-evm.c
>>> > +++ b/arch/arm/mach-davinci/board-dm365-evm.c
>>> > @@ -481,7 +481,7 @@ static void __init evm_init_cpld(void)
>>> > aemif_clk = clk_get(NULL, "aemif");
>>> > if (IS_ERR(aemif_clk))
>>> > return;
>>> > - clk_enable(aemif_clk);
>>> > + clk_prepare_enable(aemif_clk);
>>> >
>>> > if (request_mem_region(DM365_ASYNC_EMIF_DATA_CE1_BASE, SECTION_SIZE,
>>> > "cpld") == NULL)
>>> > @@ -492,7 +492,7 @@ static void __init evm_init_cpld(void)
>>> > SECTION_SIZE);
>>> > fail:
>>> > pr_err("ERROR: can't map CPLD\n");
>>> > - clk_disable(aemif_clk);
>>> > + clk_disable_unprepare(aemif_clk);
>>> > return;
>>> > }
>>> >
>>> > diff --git a/arch/arm/mach-davinci/board-dm644x-evm.c b/arch/arm/mach-
>>> davinci/board-dm644x-evm.c
>>> > index d34ed55..04ef708 100644
>>> > --- a/arch/arm/mach-davinci/board-dm644x-evm.c
>>> > +++ b/arch/arm/mach-davinci/board-dm644x-evm.c
>>> > @@ -775,7 +775,7 @@ static __init void davinci_evm_init(void)
>>> > struct davinci_soc_info *soc_info = &davinci_soc_info;
>>> >
>>> > aemif_clk = clk_get(NULL, "aemif");
>>> > - clk_enable(aemif_clk);
>>> > + clk_prepare_enable(aemif_clk);
>>> >
>>> > if (HAS_ATA) {
>>> > if (HAS_NAND || HAS_NOR)
>>> > diff --git a/arch/arm/mach-davinci/board-neuros-osd2.c b/arch/arm/mach-
>>> davinci/board-neuros-osd2.c
>>> > index 5de69f2..7fdd0a7b 100644
>>> > --- a/arch/arm/mach-davinci/board-neuros-osd2.c
>>> > +++ b/arch/arm/mach-davinci/board-neuros-osd2.c
>>> > @@ -221,7 +221,7 @@ static __init void davinci_ntosd2_init(void)
>>> > int status;
>>> >
>>> > aemif_clk = clk_get(NULL, "aemif");
>>> > - clk_enable(aemif_clk);
>>> > + clk_prepare_enable(aemif_clk);
>>> >
>>> > if (HAS_ATA) {
>>> > if (HAS_NAND)
>>> > diff --git a/arch/arm/mach-davinci/devices-da8xx.c b/arch/arm/mach-davinci/devices-
>>> da8xx.c
>>> > index d1624a3..20141f5 100644
>>> > --- a/arch/arm/mach-davinci/devices-da8xx.c
>>> > +++ b/arch/arm/mach-davinci/devices-da8xx.c
>>> > @@ -905,7 +905,7 @@ static int da850_sata_init(struct device *dev, void __iomem
>>> *addr)
>>> > if (IS_ERR(da850_sata_clk))
>>> > return PTR_ERR(da850_sata_clk);
>>> >
>>> > - ret = clk_enable(da850_sata_clk);
>>> > + ret = clk_prepare_enable(da850_sata_clk);
>>> > if (ret)
>>> > goto err0;
>>> >
>>> > @@ -936,7 +936,7 @@ static int da850_sata_init(struct device *dev, void __iomem
>>> *addr)
>>> > return 0;
>>> >
>>> > err1:
>>> > - clk_disable(da850_sata_clk);
>>> > + clk_disable_unprepare(da850_sata_clk);
>>> > err0:
>>> > clk_put(da850_sata_clk);
>>> > return ret;
>>> > @@ -944,7 +944,7 @@ err0:
>>> >
>>> > static void da850_sata_exit(struct device *dev)
>>> > {
>>> > - clk_disable(da850_sata_clk);
>>> > + clk_disable_unprepare(da850_sata_clk);
>>> > clk_put(da850_sata_clk);
>>> > }
>>> >
>>> > diff --git a/arch/arm/mach-davinci/serial.c b/arch/arm/mach-davinci/serial.c
>>> > index 1875740..24ddb0d 100644
>>> > --- a/arch/arm/mach-davinci/serial.c
>>> > +++ b/arch/arm/mach-davinci/serial.c
>>> > @@ -95,7 +95,7 @@ int __init davinci_serial_init(struct davinci_uart_config *info)
>>> > continue;
>>> > }
>>> >
>>> > - clk_enable(uart_clk);
>>> > + clk_prepare_enable(uart_clk);
>>> > p->uartclk = clk_get_rate(uart_clk);
>>> >
>>> > if (!p->membase && p->mapbase) {
>>> > diff --git a/arch/arm/mach-davinci/time.c b/arch/arm/mach-davinci/time.c
>>> > index 75da315..9847938 100644
>>> > --- a/arch/arm/mach-davinci/time.c
>>> > +++ b/arch/arm/mach-davinci/time.c
>>> > @@ -379,7 +379,7 @@ static void __init davinci_timer_init(void)
>>> >
>>> > timer_clk = clk_get(NULL, "timer0");
>>> > BUG_ON(IS_ERR(timer_clk));
>>> > - clk_enable(timer_clk);
>>> > + clk_prepare_enable(timer_clk);
>>> >
>>> > /* init timer hw */
>>> > timer_init();
>>> > @@ -429,7 +429,7 @@ void davinci_watchdog_reset(struct platform_device *pdev)
>>> > wd_clk = clk_get(&pdev->dev, NULL);
>>> > if (WARN_ON(IS_ERR(wd_clk)))
>>> > return;
>>> > - clk_enable(wd_clk);
>>> > + clk_prepare_enable(wd_clk);
>>> >
>>> > /* disable, internal clock source */
>>> > __raw_writel(0, base + TCR);
>>> > --
>>> > 1.7.9.5
>>> >
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