From: Nagarjuna Kristam <nkristam@nvidia.com>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: <balbi@kernel.org>, <gregkh@linuxfoundation.org>,
<jonathanh@nvidia.com>, <mark.rutland@arm.com>,
<robh+dt@kernel.org>, <kishon@ti.com>,
<devicetree@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
<linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH V2 6/8] phy: tegra: xusb: Add support for charger detect
Date: Mon, 11 May 2020 08:49:37 +0530 [thread overview]
Message-ID: <229333de-8dd6-2d09-c8ad-99afdcec703f@nvidia.com> (raw)
In-Reply-To: <20200504155029.GB614153@ulmo>
On 04-05-2020 21:20, Thierry Reding wrote:
>
> On Mon, May 04, 2020 at 02:32:51PM +0530, Nagarjuna Kristam wrote:
>>> On 28-04-2020 16:25, Thierry Reding wrote:
>>>> On Wed, Apr 15, 2020 at 01:55:06PM +0530, Nagarjuna Kristam wrote:
> [...]
>>>> diff --git a/drivers/phy/tegra/xusb-tegra-cd.c b/drivers/phy/tegra/xusb-tegra-cd.c
>>>> +static void tegra_xusb_padctl_utmi_pad_dcd(struct tegra_xusb_padctl *padctl,
>>>> + u32 index)
>>>> +{
>>>> + u32 value;
>>>> + int dcd_timeout_ms = 0;
>>>> + bool ret = false;
>>>> +
>>>> + /* Turn on IDP_SRC */
>>>> + value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>>>> + value |= OP_I_SRC_EN;
>>>> + padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL0(index));
>>>> +
>>>> + /* Turn on D- pull-down resistor */
>>>> + value = padctl_readl(padctl, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
>>>> + value |= USBON_RPD_OVRD_VAL;
>>>> + padctl_writel(padctl, value, USB2_BATTERY_CHRG_OTGPADX_CTL1(index));
>>>> +
>>>> + /* Wait for TDCD_DBNC */
>>>> + usleep_range(10000, 120000);
>>> From the comment this looks like we're waiting for some hardware
>>> condition. Can we somehow obtain this rather than implementing a fixed
>>> sleep? Especially since the range here is so large.
>>>
>> As per data sheet we need to wait for 10 micro seconds as settle time.
> Okay, so TDCD_DBNC is a value that comes from a timing diagram in a
> datasheet? Seems fine to leave it as-is then. Perhaps add parentheses
> and mention which exact datasheet that's from, and perhaps which figure
> so that people can more easily reference it. Provided there is a
> publicly available datasheet, of course.
>
Will update reference to table in the data sheet where these values are
recommended. ITs part of BC 1.2 spec from USB.
> Actually, one other thing: If the data sheet says to wait 10 us, why do
> you use an upper range of 120 us? Shouldn't a range of 10-20 us be good
> enough?
> Yes, will reduce it to 20ms.
-Nagarjuna
next prev parent reply other threads:[~2020-05-11 3:17 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-15 8:25 [PATCH V2 0/8] Tegra XUSB charger detect support Nagarjuna Kristam
2020-04-15 8:25 ` [PATCH V2 1/8] dt-bindings: phy: tegra-xusb: Add charger-detect property Nagarjuna Kristam
2020-04-28 9:57 ` Thierry Reding
2020-04-15 8:25 ` [PATCH V2 2/8] usb: gadget: tegra-xudc: Add vbus_draw support Nagarjuna Kristam
2020-04-28 9:59 ` Thierry Reding
2020-05-04 4:10 ` Nagarjuna Kristam
2020-04-15 8:25 ` [PATCH V2 3/8] phy: tegra: xusb: Add support for UTMI pad power control Nagarjuna Kristam
2020-04-28 10:04 ` Thierry Reding
2020-04-28 10:16 ` Thierry Reding
2020-04-15 8:25 ` [PATCH V2 4/8] phy: tegra: xusb: Add USB2 pad power control support for Tegra210 Nagarjuna Kristam
2020-04-28 10:06 ` Thierry Reding
2020-04-28 10:17 ` Thierry Reding
2020-04-15 8:25 ` [PATCH V2 5/8] phy: tegra: xusb: Add soc ops API to enable UTMI PAD protection Nagarjuna Kristam
2020-04-28 10:15 ` Thierry Reding
2020-05-04 10:26 ` Nagarjuna Kristam
2020-04-15 8:25 ` [PATCH V2 6/8] phy: tegra: xusb: Add support for charger detect Nagarjuna Kristam
2020-04-28 10:55 ` Thierry Reding
2020-05-04 9:02 ` Nagarjuna Kristam
2020-05-04 15:50 ` Thierry Reding
2020-05-11 3:19 ` Nagarjuna Kristam [this message]
2020-04-15 8:25 ` [PATCH V2 7/8] phy: tegra: xusb: Enable charger detect for Tegra186 Nagarjuna Kristam
2020-04-28 10:56 ` Thierry Reding
2020-04-15 8:25 ` [PATCH V2 8/8] phy: tegra: xusb: Enable charger detect for Tegra210 Nagarjuna Kristam
2020-04-28 10:56 ` Thierry Reding
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