Hi Philipp: > -----Original Message----- > From: Hongxing Zhu > Sent: 2022年4月15日 15:33 > To: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>; l.stach@xxxxxxxxxxxxxx; > bhelgaas@xxxxxxxxxx; lorenzo.pieralisi@xxxxxxx; robh@xxxxxxxxxx; > shawnguo@xxxxxxxxxx; vkoul@xxxxxxxxxx; alexander.stein@xxxxxxxxxxxxxxx > Cc: linux-phy@xxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; > linux-pci@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; dl-linux-imx > <linux-imx@xxxxxxx> > Subject: RE: [PATCH v2 1/7] reset: imx7: Add the iMX8MP PCIe PHY PERST > support > > Hi Philipp: > > > -----Original Message----- > > From: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> > > Sent: 2022年4月4日 17:34 > > To: Hongxing Zhu <hongxing.zhu@xxxxxxx>; l.stach@xxxxxxxxxxxxxx; > > bhelgaas@xxxxxxxxxx; lorenzo.pieralisi@xxxxxxx; robh@xxxxxxxxxx; > > shawnguo@xxxxxxxxxx; vkoul@xxxxxxxxxx; alexander.stein@xxxxxxxxxxxxxxx > > Cc: linux-phy@xxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; > > linux-pci@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > > linux-kernel@xxxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; dl-linux-imx > > <linux-imx@xxxxxxx> > > Subject: Re: [PATCH v2 1/7] reset: imx7: Add the iMX8MP PCIe PHY PERST > > support > > > > Hi Richard, > > > > On Mo, 2022-03-07 at 17:07 +0800, Richard Zhu wrote: > > > Add the i.MX8MP PCIe PHY PERST support. > > > > > > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx> > > > --- > > > drivers/reset/reset-imx7.c | 1 + > > > 1 file changed, 1 insertion(+) > > > > > > diff --git a/drivers/reset/reset-imx7.c b/drivers/reset/reset-imx7.c > > > index 185a333df66c..d2408725eb2c 100644 > > > --- a/drivers/reset/reset-imx7.c > > > +++ b/drivers/reset/reset-imx7.c > > > @@ -329,6 +329,7 @@ static int imx8mp_reset_set(struct > > > reset_controller_dev *rcdev, > > > break; > > > > > > case IMX8MP_RESET_PCIE_CTRL_APPS_EN: > > > + case IMX8MP_RESET_PCIEPHY_PERST: > > > value = assert ? 0 : bit; > > > break; > > > } > > > > This doesn't do what the commit description says. > > > > The PCIEPHY_PERST bit is already supported by the driver (albeit > > incorrectly?) - this patch just inverts the bit. > > > > Since this bit is not inverted on the other platforms, and the i.MX8MP > > reference manual says nothing about this, please explicitly state why > > this needs to be inverted and call it a fix in the commit description. > Thanks for your comments, and sorry for replying late. > I didn't get more details about this bit difference between i.MX8MP and > others. > Let me consult with design team again, and back to you later. I got some details of this PERST bit(BIT3) of SRC_PCIEPHY_RCR. The initialized default value of this bit is 1b'1 on i.MX7/iMX8MM/iMX8MQ. But unfortunately, the i.MX8MP has one inverted default value 1b'0 of this bit. And this bit should be kept 1b'1 after power and clocks are stable. So, I assert/de-assert this bit on i.MX8MP only. Best Regards Richard Zhu > > Best Regards > Richard Zhu > > > > > regards > > Philipp
