From: Sekhar Nori <nsekhar@ti•com>
To: Mike Turquette <mturquette@linaro•org>
Cc: "David S. Miller" <davem@davemloft•net>, <netdev@vger•kernel.org>,
<davinci-linux-open-source@linux•davincidsp.com>,
"Rafael J. Wysocki" <rjw@sisk•pl>
Subject: Re: [PATCH net-next 2/2] net/davinci_emac: use clk_{prepare|unprepare}
Date: Tue, 26 Mar 2013 15:35:43 +0530 [thread overview]
Message-ID: <515172F7.3050600@ti.com> (raw)
In-Reply-To: <20130325161654.4014.68401@quantum>
On 3/25/2013 9:46 PM, Mike Turquette wrote:
> Quoting Sekhar Nori (2013-03-25 02:25:47)
>> Use clk_prepare()/clk_unprepare() in the driver since common
>> clock framework needs these to be called before clock is enabled.
>>
>> This is in preparation of common clock framework migration
>> for DaVinci.
>>
>> Cc: Mike Turquette <mturquette@linaro•org>
>> Signed-off-by: Sekhar Nori <nsekhar@ti•com>
>> ---
>> drivers/net/ethernet/ti/davinci_emac.c | 19 +++++++++++++++++--
>> 1 file changed, 17 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/ti/davinci_emac.c b/drivers/net/ethernet/ti/davinci_emac.c
>> index b1349b5..436296c 100644
>> --- a/drivers/net/ethernet/ti/davinci_emac.c
>> +++ b/drivers/net/ethernet/ti/davinci_emac.c
>> @@ -350,6 +350,7 @@ struct emac_priv {
>> /*platform specific members*/
>> void (*int_enable) (void);
>> void (*int_disable) (void);
>> + struct clk *clk;
>> };
>>
>> /* EMAC TX Host Error description strings */
>> @@ -1870,19 +1871,29 @@ static int davinci_emac_probe(struct platform_device *pdev)
>> dev_err(&pdev->dev, "failed to get EMAC clock\n");
>> return -EBUSY;
>> }
>> +
>> + rc = clk_prepare(emac_clk);
>> + if (rc) {
>> + dev_err(&pdev->dev, "emac clock prepare failed.\n");
>> + return rc;
>> + }
>> +
>
> Is clk_enable ever called for emac_clk here? I don't see it in the
> diff. clk_prepare and clk_enable should usually be paired, even if
> simply calling clk_prepare generates the clock signal that your device
> needs.
clk_enable() is called by pm_runtime framework. Without this patch, the
clk_enable() call from pm_clk_resume() will result in a warning when
using common clock framework. This issue can actually be fixed by patch
below which fixes this in drivers/base/power/clock_ops.c so
individual drivers don't have to do this, but we need to careful since
will break for callers who intend to use the pm_runtime apis from atomic
context.
Anyway, its probably much better to fix this in pm_runtime framework so I will
work with Rafael to see if I can come up with something acceptable.
This patch can then be dropped for now, but 1/2 can still be applied.
That one is pretty harmless!
Thanks,
Sekhar
diff --git a/drivers/base/power/clock_ops.c b/drivers/base/power/clock_ops.c
index 9d8fde7..60d389a 100644
--- a/drivers/base/power/clock_ops.c
+++ b/drivers/base/power/clock_ops.c
@@ -230,7 +230,7 @@ int pm_clk_suspend(struct device *dev)
list_for_each_entry_reverse(ce, &psd->clock_list, node) {
if (ce->status < PCE_STATUS_ERROR) {
if (ce->status == PCE_STATUS_ENABLED)
- clk_disable(ce->clk);
+ clk_disable_unprepare(ce->clk);
ce->status = PCE_STATUS_ACQUIRED;
}
}
@@ -259,7 +259,7 @@ int pm_clk_resume(struct device *dev)
list_for_each_entry(ce, &psd->clock_list, node) {
if (ce->status < PCE_STATUS_ERROR) {
- clk_enable(ce->clk);
+ clk_prepare_enable(ce->clk);
ce->status = PCE_STATUS_ENABLED;
}
}
next prev parent reply other threads:[~2013-03-26 10:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-25 9:25 [PATCH net-next 0/2] net/davinci_emac updates Sekhar Nori
2013-03-25 9:25 ` [PATCH net-next 1/2] net/davinci_emac: use devres APIs Sekhar Nori
2013-03-25 9:25 ` [PATCH net-next 2/2] net/davinci_emac: use clk_{prepare|unprepare} Sekhar Nori
2013-03-25 16:16 ` Mike Turquette
2013-03-26 10:05 ` Sekhar Nori [this message]
2013-03-26 16:29 ` David Miller
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