> -----Original Message----- > From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> > Sent: 24 November 2022 20:24 > To: Vivek Yadav <vivek.2311@xxxxxxxxxxx> > Cc: rcsekar@xxxxxxxxxxx; krzysztof.kozlowski+dt@xxxxxxxxxx; > wg@xxxxxxxxxxxxxx; davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; > kuba@xxxxxxxxxx; pabeni@xxxxxxxxxx; pankaj.dubey@xxxxxxxxxxx; > ravi.patel@xxxxxxxxxxx; alim.akhtar@xxxxxxxxxxx; linux-fsd@xxxxxxxxx; > robh+dt@xxxxxxxxxx; linux-can@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux- > samsung-soc@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; > aswani.reddy@xxxxxxxxxxx; sriranjani.p@xxxxxxxxxxx > Subject: Re: RE: [PATCH v3 1/2] can: m_can: Move mram init to mcan device > setup > > On 24.11.2022 14:36:48, Vivek Yadav wrote: > > > Why not call the RAM init directly from m_can_chip_config()? > > > > > m_can_chip_config function is called from m_can open. > > > > Configuring RAM init every time we open the CAN instance is not > > needed, I think only once during the probe is enough. > > That probably depends on you power management. If I add a regulator to > power the external tcan4x5x chip and power it up during open(), I need to > initialize the RAM. > Thanks for the clarification, There is one doubt for which I need clarity if I add ram init in m_can_chip_config. In the current implementation, m_can_ram_init is added in the probe and m_can_class_resume function. If I add the ram init function in chip_config which is getting called from m_can_start, then m_can_init_ram will be called two times, once in resume and next from m_can_start also. Can we add ram init inside the m_can_open function itself? Because it is independent of m_can resume functionality. > > If message RAM init failed then fifo Transmit and receive will fail > > and there will be no communication. So there is no point to "open and > > Configure CAN chip". > > For mmio devices the RAM init will probably not fail. There are return values > and error checking for the SPI attached devices. Where the SPI > communication will fail. However if this is problem, I assume the chip will not > be detected in the first place. > > > From my understanding it's better to keep RAM init inside the probe > > and if there is a failure happened goes to CAN probe failure. > > Marc > > -- > Pengutronix e.K. | Marc Kleine-Budde | > Embedded Linux | > https://protect2.fireeye.com/v1/url?k=2053d9ab-7fc8e0b4-205252e4- > 000babdfecba-a8c309c53e3358f5&q=1&e=c0cfd0e2-a422-4821-a49d- > 113cfa4da9cb&u=https%3A%2F%2Fwww.pengutronix.de%2F | > Vertretung West/Dortmund | Phone: +49-231-2826-924 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
