On 20-03-16 18:20, Stefan Lengfeld wrote: > Hi Michał, > > On Mon, Mar 16, 2020 at 03:42:21PM +0100, Michał Mirosław wrote: > > On Sun, Mar 15, 2020 at 11:46:33PM +0300, Dmitry Osipenko wrote: > > > 15.03.2020 21:27, Michał Mirosław пишет: > > > > Implement basic support for atomic write - enough to get a simple > > > > write to PMIC on shutdown. Only for chips having ALT_CMD register, > > > > eg. SAMA5D2. > > > > > > > > Signed-off-by: Michał Mirosław <mirq-linux@xxxxxxxxxxxx> > > > > --- > > > > > > Hello Michał, > > > > > > ... > > > > + ret = pm_runtime_get_sync(dev->dev); > > > > + if (ret < 0) > > > > + goto out; > > > > > > Runtime PM can't be used while interrupts are disabled, unless > > > pm_runtime_irq_safe() is used and driver's RPM callback is IRQ-safe. > > > > I didn't get any warnings from lockdep and friends, but I'll double > > check if this is by luck. > > You can have a look at the I2C atomic patch for the imx-driver. See > > https://patchwork.ozlabs.org/patch/1225802/ > > In that patch Marco Felsch is using clk_enable() and clk_disable() calls. Yep because we need to handle the runtime_pm stuff by our-self. So for the imx case we need to handle the clk en-/disable stuff. Runtime pm is using a workqueue which can't be used in that late case. Regards, Marco > > > ... > > > > + timeout = jiffies + (2 + msg->len) * HZ/1000; > > > > + for (;;) { > > > > + stat = at91_twi_read(dev, AT91_TWI_SR); > > > > + if (stat & AT91_TWI_TXCOMP) > > > > + break; > > > > + if (time_after(jiffies, timeout)) { > > > > + ret = -ETIMEDOUT; > > > > + goto out; > > > > + } > > > > + udelay(100); > > > > + } > > > > > > Jiffies can't be used with the disabled interrupts because jiffies are > > > updated by timer's interrupt. > > > > > > Either ktime() API or iterator-based loop should be used. > > > > Thanks for the pointers. In my use-case power is cut from the CPU at this > > point so it didn't matter that the loop was infinite. > > Here again you can have a look at Marco Felsch's patch. He used the > function readb_poll_timeout_atomic(). So the loop can potentially > replaced by a single line. > > Kind regards, > Stefan > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
