From: Caesar Wang <caesar.upstream@gmail.com>
To: Javier Martinez Canillas <javier@osg.samsung.com>
Cc: Heiko Stuebner <heiko@sntech.de>,
Ulf Hansson <ulf.hansson@linaro.org>,
linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-rockchip@lists.infradead.org, leecam@google.com,
keescook@google.com, NeilBrown <neil@brown.name>,
Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
Alexandre Courbot <acourbot@nvidia.com>,
leozwang@google.com, Caesar Wang <wxt@rock-chips.com>
Subject: Re: [PATCH v2 06/12] mmc: pwrseq: add support for power-on sequencing through DT
Date: Fri, 15 Jan 2016 17:15:21 +0800 [thread overview]
Message-ID: <5698B8A9.9040002@gmail.com> (raw)
In-Reply-To: <5693D226.2000307@osg.samsung.com>
Hi Javier,
在 2016年01月12日 00:02, Javier Martinez Canillas 写道:
> Hello Heiko,
>
> On 01/08/2016 11:42 PM, Heiko Stuebner wrote:
>> Am Freitag, 8. Januar 2016, 09:22:31 schrieb Javier Martinez Canillas:
>>>> For example:
>>>> we need enable wifi module power to via the WL_REG_ON
>>>> pin, we need enable it as the regulator if this pin is connected to
>>>> the gpio of cpu.
>>> This part confuses me, so does your chip have an actual regulator that
>>> needs to be enabled or is just a fake regulator whose gpio property is
>>> used not to enable the regulator but to toggle the WL_REG_ON pin of
>>> the WiFi chip?
>> another option would be to use the reset-gpio-handles. rk3288-veyron and I
>> think some Exynos as well use it that way.
>>
> Yes I know, my point was that the reset-gpios property should be used
> instead of a fake regulator if what's needed is to toggle a chip pin.
>
>>>> Maybe, someone will say that can pull up/down from dts.
>>>> Unfortunately some SoCs can't support pinctrl pull up/down in
>>>> internal.
>>> Can you please elaborate on this? AFAIU this limitation is the reason
>>> why you went with the regulator approach so I think it deserve a more
>>> deep explanation.
>> On the rk3036 each pin has an individual unchangable pull direction. So it's
>> either no bias or pulling in the predefined direction (the pin_default bias
>> option).
>>
> I think each change has to be justified on its own so I would say that
> having a regulator enabled as a part of a SDIO chip's power sequencing
> is something needed for many platforms, and that this provider should
> be extended to support that (something like commit msg in patch 05/12).
>
> And then in the kylin DTS change (patch 08/12), I would explain why a
> chained regulators approach is used/needed instead of the reset-gpios
> due any platform limitations.
Okay,
I 'm agreed with your points in here.
The reset-gpios/pwrsq can meet the demand of some wlan chips trigger
condition.
No matter whatever is the BT_EN or WL_EN triggers pin.
>> Heiko
>>
> Best regards,
--
Thanks,
Caesar
next prev parent reply other threads:[~2016-01-15 9:16 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-07 8:25 [PATCH v2 00/12] Add the family patches to support for kylin board Caesar Wang
2016-01-07 8:25 ` [PATCH v2 01/12] ARM: dts: rockchip: set the pinctrl default setting for rk3036 i2s Caesar Wang
2016-01-09 2:17 ` Heiko Stuebner
2016-01-07 8:25 ` [PATCH v2 02/12] ARM: dts: rockchip: add the sound codec for kylin board Caesar Wang
2016-01-09 2:39 ` Heiko Stuebner
2016-01-07 8:25 ` [PATCH v2 03/12] ARM: dts: rockchip: override the clocks in i2s " Caesar Wang
2016-01-09 2:31 ` Heiko Stuebner
2016-01-11 13:38 ` Caesar Wang
2016-01-07 8:25 ` [PATCH v2 04/12] clk: rockchip: rk3036: enable the CLK_IGNORE_UNUSED flag for sclk_i2s_out Caesar Wang
2016-01-07 10:05 ` Heiko Stuebner
2016-01-08 9:26 ` Caesar Wang
2016-01-08 9:46 ` Heiko Stuebner
2016-01-13 8:10 ` Caesar Wang
2016-01-07 8:25 ` [PATCH v2 05/12] mmc: pwrseq: Document optional exteral vcc for the simple power sequence Caesar Wang
2016-01-08 12:13 ` Javier Martinez Canillas
2016-01-07 8:25 ` [PATCH v2 06/12] mmc: pwrseq: add support for power-on sequencing through DT Caesar Wang
2016-01-08 12:22 ` Javier Martinez Canillas
2016-01-09 2:42 ` Heiko Stuebner
2016-01-11 16:02 ` Javier Martinez Canillas
2016-01-15 9:15 ` Caesar Wang [this message]
2016-01-07 8:25 ` [PATCH v2 07/12] ARM: dts: rockchip: enable the high speed on sdio for kylin board Caesar Wang
2016-01-07 8:25 ` [PATCH v2 08/12] ARM: dts: rockchip: add the wifi/bt regulator " Caesar Wang
2016-01-07 8:25 ` [PATCH v2 09/12] ARM: dts: rockchip: enable the uart0 " Caesar Wang
2016-01-07 8:25 ` [PATCH v2 10/12] ARM: dts: rockchip: add the sdmmc " Caesar Wang
2016-01-07 8:25 ` [PATCH v2 11/12] ARM: dts: rockchip: add the lcdc and hdmi node for rk3036 Caesar Wang
2016-01-07 8:25 ` [PATCH v2 12/12] ARM: dts: Add pl330-broken-no-flushp quirk for rk3036 SoCs Caesar Wang
2016-01-07 10:44 ` [PATCH v2 00/12] Add the family patches to support for kylin board Heiko Stuebner
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