From: "Pandey, Radhey Shyam" <radheys@amd•com>
To: Thinh Nguyen <Thinh.Nguyen@synopsys•com>,
Radhey Shyam Pandey <radhey.shyam.pandey@amd•com>
Cc: "gregkh@linuxfoundation•org" <gregkh@linuxfoundation•org>,
"michal.simek@amd•com" <michal.simek@amd•com>,
"p.zabel@pengutronix•de" <p.zabel@pengutronix•de>,
"linux-usb@vger•kernel.org" <linux-usb@vger•kernel.org>,
"linux-arm-kernel@lists•infradead.org"
<linux-arm-kernel@lists•infradead.org>,
"linux-kernel@vger•kernel.org" <linux-kernel@vger•kernel.org>,
"git@amd•com" <git@amd•com>
Subject: Re: [PATCH 2/3] usb: dwc3: xilinx: use reset_control_reset() in versal init
Date: Mon, 18 May 2026 19:58:58 +0530 [thread overview]
Message-ID: <95361d3a-34b6-4f0f-935e-9e1b45698e81@amd.com> (raw)
In-Reply-To: <agUltzvDFgJtPa6j@vbox>
On 5/14/2026 7:04 AM, Thinh Nguyen wrote:
> On Mon, May 11, 2026, Radhey Shyam Pandey wrote:
>> Replace separate reset_control_assert() and reset_control_deassert() calls
>> with reset_control_reset(), which pulses the reset in one step. Report
>> failures with dev_err_probe() and a single message. No functional change.
>>
>
> The behavior of reset_control_reset() is a little different. I wouldn't
> call this "No functional change". However, I assumed this was tested.
> Please provide a proper reason for this change in the change log.
In the dwc3-xilinx case, reset_control_reset() routes through the
zynqmp reset driver and invokes PM_RESET_ACTION_PULSE. This triggers
the Xilinx firmware reset implementation, which performs both assert
and deassert. Effectively, reset() issues a single SMC call for a
reset pulse instead of separate assert and deassert calls and moves
IP out of reset.
Yes this new reset sequence is validated on HW. I will include
above description and respin v2..
>
>> Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd•com>
>> ---
>> drivers/usb/dwc3/dwc3-xilinx.c | 16 ++++------------
>> 1 file changed, 4 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/usb/dwc3/dwc3-xilinx.c b/drivers/usb/dwc3/dwc3-xilinx.c
>> index a3c7dc258c7d..94458b3da1a0 100644
>> --- a/drivers/usb/dwc3/dwc3-xilinx.c
>> +++ b/drivers/usb/dwc3/dwc3-xilinx.c
>> @@ -98,18 +98,10 @@ static int dwc3_xlnx_init_versal(struct dwc3_xlnx *priv_data)
>>
>> dwc3_xlnx_mask_phy_rst(priv_data, false);
>>
>> - /* Assert and De-assert reset */
>> - ret = reset_control_assert(crst);
>> - if (ret < 0) {
>> - dev_err_probe(dev, ret, "failed to assert Reset\n");
>> - return ret;
>> - }
>> -
>> - ret = reset_control_deassert(crst);
>> - if (ret < 0) {
>> - dev_err_probe(dev, ret, "failed to De-assert Reset\n");
>> - return ret;
>> - }
>> + /* assert and deassert reset */
>> + ret = reset_control_reset(crst);
>> + if (ret)
>> + return dev_err_probe(dev, ret, "failed to assert and deassert reset\n");
>>
>> dwc3_xlnx_mask_phy_rst(priv_data, true);
>> dwc3_xlnx_set_coherency(priv_data, XLNX_USB2_TRAFFIC_ROUTE_CONFIG);
>> --
>> 2.44.4
next prev parent reply other threads:[~2026-05-18 14:29 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-11 16:08 [PATCH 0/3] usb: dwc3: xilinx: minor fixes for dwc3-xilinx glue driver Radhey Shyam Pandey
2026-05-11 16:08 ` [PATCH 1/3] usb: dwc3: xilinx: fix missing space before closing comment delimiter Radhey Shyam Pandey
2026-05-14 1:23 ` Thinh Nguyen
2026-05-11 16:08 ` [PATCH 2/3] usb: dwc3: xilinx: use reset_control_reset() in versal init Radhey Shyam Pandey
2026-05-14 1:34 ` Thinh Nguyen
2026-05-18 14:28 ` Pandey, Radhey Shyam [this message]
2026-05-19 22:39 ` Thinh Nguyen
2026-05-11 16:08 ` [PATCH 3/3] usb: dwc3: xilinx: fix error handling in zynqmp init error paths Radhey Shyam Pandey
2026-05-14 1:43 ` Thinh Nguyen
2026-05-14 12:52 ` Pandey, Radhey Shyam
2026-05-16 0:04 ` Thinh Nguyen
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