> -----Original Message----- > From: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> > Sent: Friday, December 20, 2024 1:33 PM > To: Carlos Song <carlos.song@xxxxxxx> > Cc: Andi Shyti <andi.shyti@xxxxxxxxxx>; Frank Li <frank.li@xxxxxxx>; > kernel@xxxxxxxxxxxxxx; shawnguo@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx; > festevam@xxxxxxxxx; linux-i2c@xxxxxxxxxxxxxxx; imx@xxxxxxxxxxxxxxx; > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Clark Wang > <xiaoning.wang@xxxxxxx>; Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx> > Subject: [EXT] Re: [PATCH v5] i2c: imx: support DMA defer probing > > Caution: This is an external email. Please take care when clicking links or > opening attachments. When in doubt, report the message using the 'Report this > email' button > > > On Fri, Dec 20, 2024 at 02:45:09AM +0000, Carlos Song wrote: > > > > > > > -----Original Message----- > > > From: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> > > > Sent: Thursday, December 19, 2024 8:23 PM > > > To: Andi Shyti <andi.shyti@xxxxxxxxxx> > > > Cc: Carlos Song <carlos.song@xxxxxxx>; Frank Li <frank.li@xxxxxxx>; > > > kernel@xxxxxxxxxxxxxx; shawnguo@xxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx; > > > festevam@xxxxxxxxx; linux-i2c@xxxxxxxxxxxxxxx; imx@xxxxxxxxxxxxxxx; > > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > > > Clark Wang <xiaoning.wang@xxxxxxx>; Ahmad Fatoum > > > <a.fatoum@xxxxxxxxxxxxxx> > > > Subject: [EXT] Re: [PATCH v5] i2c: imx: support DMA defer probing > > > > > > Caution: This is an external email. Please take care when clicking > > > links or opening attachments. When in doubt, report the message > > > using the 'Report this email' button > > > > > > > > > On Thu, Dec 19, 2024 at 01:02:29PM +0100, Andi Shyti wrote: > > > > Hi Carlos, > > > > > > > > > + /* > > > > > + * Init DMA config if supported, -ENODEV means DMA not enabled > at > > > > > + * this platform, that is not a real error, so just remind "only > > > > > + * PIO mode is used". If DMA is enabled, but meet error when > request > > > > > + * DMA channel, error should be showed in probe error log. PIO > mode > > > > > + * should be available regardless of DMA. > > > > > + */ > > > > > + ret = i2c_imx_dma_request(i2c_imx, phy_addr); > > > > > + if (ret) { > > > > > + if (ret == -EPROBE_DEFER) > > > > > + goto clk_notifier_unregister; > > > > > + else if (ret == -ENODEV) > > > > > + dev_dbg(&pdev->dev, "Only use PIO mode\n"); > > > > > + else > > > > > + dev_err_probe(&pdev->dev, ret, "Failed to > > > > > + setup DMA, only use PIO mode\n"); > > > > > > > > Just for understanding, should we quit in this last case, as well? > > > > > > > > Before we were ignoring ENODEV and EPROBE_DEFER, but now you are > > > > making it clear that other failures like ENOMEM might happen. > > > > > > Good point, dev_err_probe() would not print an error in case of > > > EPROBE_DEFER, but in this case we should only print error and continue with > PIO. > > > > > Hi, > > > > Thank you all very much! As I comment at previous mail: > > DMA mode should be optional for i2c-imx, because i2c-imx can accept > > DMA mode not enabled, because it still can work in CPU mode.[1] > > [1]https://l/ > > > ore.kernel.org%2Fimx%2FAM0PR0402MB39374E34FD6133B5E3D414D7E82F2 > %40AM0P > > > R0402MB3937.eurprd04.prod.outlook.com%2F&data=05%7C02%7Ccarlos.song > %40 > > > nxp.com%7C5bfbfc0a74184fa1620808dd20b7c4db%7C686ea1d3bc2b4c6fa92c > d99c5 > > > c301635%7C0%7C0%7C638702695851431182%7CUnknown%7CTWFpbGZsb3d > 8eyJFbXB0e > > > U1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIl > d > > > UIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=F28DC7RUwlqd5OIyh5QMVyqa1%2 > F%2BcX2p%2 > > FsFWftgDaliA%3D&reserved=0 > > > > Also we don't want to annoy current user without DMA[2] [2] > > https://lore/ > > .kernel.org%2Fimx%2F20241127-analytic-azure-hamster-727fd8-mkl%40peng > u > > > tronix.de%2F&data=05%7C02%7Ccarlos.song%40nxp.com%7C5bfbfc0a74184fa > 162 > > > 0808dd20b7c4db%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C638 > 7026958 > > > 51449521%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiI > wLjAuM > > > DAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C% > 7C&s > > > data=y6pkewfVx7Mb0ZrPfRwDdAo69TV1eHOkRMnRq91Ec9Q%3D&reserved=0 > > > > So we make this logic. Anyway we let the I2C controller registered whether > DMA is available or not(except defer probe). > > Ignoring ENODEV and EPROBE_DEFER makes it looks like nothing happened if > DMA is defer probed or not enabled(This is an expected). > > However we still need i2c DMA status is known when meet an unexpected > error, so we use dev_err_probe() to print error. > > Why dev_err_probe() instead of dev_err()? > Hi, In patch V2 discussion, Marc suggested just return dev_err_probe(), but I don't accept it so I choose to use dev_err_probe() to print error in V3.[1] In this case, the two APIs have the same function, do you mean dev_err() is more suitable? [1]https://lore.kernel.org/imx/AM0PR0402MB39374E34FD6133B5E3D414D7E82F2@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/#t > -- > Pengutronix e.K. | > | > Steuerwalder Str. 21 | > http://www.pen/ > gutronix.de%2F&data=05%7C02%7Ccarlos.song%40nxp.com%7C5bfbfc0a7418 > 4fa1620808dd20b7c4db%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0% > 7C638702695851464654%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiO > nRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ% > 3D%3D%7C0%7C%7C%7C&sdata=X2AuLskzqYH9g34wfb4%2B%2Bs2OdZEW3q5 > i49V8OwKmgtw%3D&reserved=0 | > 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 > | > Amtsgericht Hildesheim, HRA 2686 | Fax: > +49-5121-206917-5555 |