From: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
To: Jisheng Zhang <jszhang@marvell.com>
Cc: linux-mmc@vger.kernel.org, ulf.hansson@linaro.org,
linus.walleij@linaro.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC 2/3] mmc: sdhci: add host_ops->voltage_switch callback for all other voltages
Date: Wed, 2 Sep 2015 17:13:57 +0530 [thread overview]
Message-ID: <55E6E0FD.7000806@linaro.org> (raw)
In-Reply-To: <20150902162627.682cdedf@xhacker>
On Wednesday 02 September 2015 01:56 PM, Jisheng Zhang wrote:
> On Wed, 2 Sep 2015 13:49:53 +0530
> Vaibhav Hiremath <vaibhav.hiremath@linaro.org> wrote:
>
>>
>>
>> On Wednesday 02 September 2015 12:34 PM, Jisheng Zhang wrote:
>>> On Wed, 2 Sep 2015 01:02:17 +0530
>>> Vaibhav Hiremath <vaibhav.hiremath@linaro.org> wrote:
>>>
>>>> Currently, the sdhci_do_start_signal_voltage_switch() function invokes
>>>> controller specific voltage switch configuration only for 1.8v usecase;
>>>> but it is required for others as well.
>>>>
>>>> For example, in case of PXA1928 SDH controller, we need to set different
>>>> configuration for 3.3, 1.8 and 1.2 volt support (I/O domain power
>>>> control register).
>>>>
>>>> Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
>>>> ---
>>>> Note:
>>>> Currently ->voltage_switch() callback is only supported
>>>> in f_sdh30 driver. And I am not sure on the dependency of execution
>>>> sequence for that device. I could have moved ->voltage_switch() call
>>>> at one common place (above/below), but was not quite sure about it.
>>>> So, replicated/duplicated the call for other voltages.
>>>>
>>>> drivers/mmc/host/sdhci.c | 8 ++++++++
>>>> 1 file changed, 8 insertions(+)
>>>>
>>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>>> index 3dd295f..b59b76d 100644
>>>> --- a/drivers/mmc/host/sdhci.c
>>>> +++ b/drivers/mmc/host/sdhci.c
>>>> @@ -1753,6 +1753,10 @@ static int sdhci_do_start_signal_voltage_switch(struct sdhci_host *host,
>>>> /* Wait for 5ms */
>>>> usleep_range(5000, 5500);
>>>>
>>>> + /* Some controller need to do more when switching */
>>>> + if (host->ops->voltage_switch)
>>>> + host->ops->voltage_switch(host, MMC_SIGNAL_VOLTAGE_330);
>>>
>>> Could this be implemented by regulator API? From patch set 3/3, the pxa1928
>>> voltage_switch hook is to operate the IO pad registers, this seems not belong
>>> to the SDHC IP core.
>>>
>>
>> Not quite sure whether regulator would be right fit for this.
>
> From the patche[3/3], this can be achieved by abstracting the IO PAD as regulators
> then, we may not need to touch the core sdhci.c. But I'm not sure whether this
> is the good solution or not.
Exactly...
> sdhci Maintainers and experts may have better
> suggestions.
>
Thats is the reason I stamped it as a RFC :)
Thanks,
Vaibhav
WARNING: multiple messages have this Message-ID (diff)
From: vaibhav.hiremath@linaro.org (Vaibhav Hiremath)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC 2/3] mmc: sdhci: add host_ops->voltage_switch callback for all other voltages
Date: Wed, 2 Sep 2015 17:13:57 +0530 [thread overview]
Message-ID: <55E6E0FD.7000806@linaro.org> (raw)
In-Reply-To: <20150902162627.682cdedf@xhacker>
On Wednesday 02 September 2015 01:56 PM, Jisheng Zhang wrote:
> On Wed, 2 Sep 2015 13:49:53 +0530
> Vaibhav Hiremath <vaibhav.hiremath@linaro.org> wrote:
>
>>
>>
>> On Wednesday 02 September 2015 12:34 PM, Jisheng Zhang wrote:
>>> On Wed, 2 Sep 2015 01:02:17 +0530
>>> Vaibhav Hiremath <vaibhav.hiremath@linaro.org> wrote:
>>>
>>>> Currently, the sdhci_do_start_signal_voltage_switch() function invokes
>>>> controller specific voltage switch configuration only for 1.8v usecase;
>>>> but it is required for others as well.
>>>>
>>>> For example, in case of PXA1928 SDH controller, we need to set different
>>>> configuration for 3.3, 1.8 and 1.2 volt support (I/O domain power
>>>> control register).
>>>>
>>>> Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
>>>> ---
>>>> Note:
>>>> Currently ->voltage_switch() callback is only supported
>>>> in f_sdh30 driver. And I am not sure on the dependency of execution
>>>> sequence for that device. I could have moved ->voltage_switch() call
>>>> at one common place (above/below), but was not quite sure about it.
>>>> So, replicated/duplicated the call for other voltages.
>>>>
>>>> drivers/mmc/host/sdhci.c | 8 ++++++++
>>>> 1 file changed, 8 insertions(+)
>>>>
>>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>>> index 3dd295f..b59b76d 100644
>>>> --- a/drivers/mmc/host/sdhci.c
>>>> +++ b/drivers/mmc/host/sdhci.c
>>>> @@ -1753,6 +1753,10 @@ static int sdhci_do_start_signal_voltage_switch(struct sdhci_host *host,
>>>> /* Wait for 5ms */
>>>> usleep_range(5000, 5500);
>>>>
>>>> + /* Some controller need to do more when switching */
>>>> + if (host->ops->voltage_switch)
>>>> + host->ops->voltage_switch(host, MMC_SIGNAL_VOLTAGE_330);
>>>
>>> Could this be implemented by regulator API? From patch set 3/3, the pxa1928
>>> voltage_switch hook is to operate the IO pad registers, this seems not belong
>>> to the SDHC IP core.
>>>
>>
>> Not quite sure whether regulator would be right fit for this.
>
> From the patche[3/3], this can be achieved by abstracting the IO PAD as regulators
> then, we may not need to touch the core sdhci.c. But I'm not sure whether this
> is the good solution or not.
Exactly...
> sdhci Maintainers and experts may have better
> suggestions.
>
Thats is the reason I stamped it as a RFC :)
Thanks,
Vaibhav
next prev parent reply other threads:[~2015-09-02 11:44 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-01 19:32 [RFC 0/3] mmc: sdhci: pass signal voltage as an argument to ->voltage_switch() Vaibhav Hiremath
2015-09-01 19:32 ` Vaibhav Hiremath
2015-09-01 19:32 ` [RFC 1/3] mmc: sdhci: pass signal_voltage as an argument to voltage_switch callback Vaibhav Hiremath
2015-09-01 19:32 ` Vaibhav Hiremath
2015-09-01 19:32 ` [RFC 2/3] mmc: sdhci: add host_ops->voltage_switch callback for all other voltages Vaibhav Hiremath
2015-09-01 19:32 ` Vaibhav Hiremath
2015-09-02 7:04 ` Jisheng Zhang
2015-09-02 7:04 ` Jisheng Zhang
2015-09-02 7:04 ` Jisheng Zhang
2015-09-02 8:19 ` Vaibhav Hiremath
2015-09-02 8:19 ` Vaibhav Hiremath
2015-09-02 8:26 ` Jisheng Zhang
2015-09-02 8:26 ` Jisheng Zhang
2015-09-02 8:26 ` Jisheng Zhang
2015-09-02 11:43 ` Vaibhav Hiremath [this message]
2015-09-02 11:43 ` Vaibhav Hiremath
2015-09-14 9:30 ` Ulf Hansson
2015-09-14 9:30 ` Ulf Hansson
2015-09-14 9:42 ` Vaibhav Hiremath
2015-09-14 9:42 ` Vaibhav Hiremath
2015-09-14 10:34 ` Ulf Hansson
2015-09-14 10:34 ` Ulf Hansson
2015-09-14 12:41 ` Vaibhav Hiremath
2015-09-14 12:41 ` Vaibhav Hiremath
2015-09-14 12:47 ` Vaibhav Hiremath
2015-09-14 12:47 ` Vaibhav Hiremath
2015-10-02 10:00 ` Linus Walleij
2015-10-02 10:00 ` Linus Walleij
2015-09-01 19:32 ` [RFC 3/3] mmc: sdhci-pxav3: Add ->voltage_switch callback support Vaibhav Hiremath
2015-09-01 19:32 ` Vaibhav Hiremath
2015-09-02 13:51 ` Shawn Lin
2015-09-02 14:32 ` Vaibhav Hiremath
2015-09-02 14:32 ` Vaibhav Hiremath
2015-09-03 18:35 ` Vaibhav Hiremath
2015-09-03 18:35 ` Vaibhav Hiremath
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