On Tue, Jul 26, 2016 at 10:47:16PM +0800, Caesar Wang wrote: > > On 2016年07月26日 21:39, Guenter Roeck wrote: > > > >>static int rockchip_saradc_probe(struct platform_device *pdev) > >>{ > >>struct rockchip_saradc *info = NULL; > >>@@ -218,6 +231,21 @@ static int rockchip_saradc_probe(struct > >>platform_device *pdev) > >>if (IS_ERR(info->regs)) > >>return PTR_ERR(info->regs); > >> > >>+ /* > >>+ * The reset should be an optional property, as it should work > >>+ * with old devicetrees as well > >>+ */ > >>+ info->reset = devm_reset_control_get_optional(&pdev->dev, > >>+ "saradc-apb"); > > > >Does anyone know what the _optional API is for ? It seems to be exactly > >the same > >as devm_reset_control_get(). > > “ > As far as I see, the difference is WARN_ON(1) > when CONFIG_RESET_CONTROLLER is not defined. > > > The _optional functions were introduced by the following commit: > > ----------------->8----------------- > commit b424080a9e086e683ad5fdc624a7cf3c024e0c0f > Author: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> > Date: Fri Mar 7 15:18:47 2014 +0100 > > reset: Add optional resets and stubs > > This patch adds device_reset_optional and (devm_)reset_control_get_optional > variants that drivers can use to indicate they can function without control > over the reset line. For those functions, stubs are added so the drivers can > be compiled with CONFIG_RESET_CONTROLLER disabled. > Also, device_reset is annotated with __must_check. Drivers > ignoring the return > value should use device_reset_optional instead. > Is that really what we are looking for here ? CONFIG_RESET_CONTROLLER is required for other functions of rk3399, isn't it ? Guenter > Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> > ------------------8<----------------------------- > ” > > for more information on http://www.spinics.net/lists/kernel/msg2306677.html > :-) > > > > >Guenter > > > >>+ if (IS_ERR(info->reset)) { > >>+ ret = PTR_ERR(info->reset); > >>+ if (ret != -ENOENT) > >>+ return ret; > >>+ > >>+ dev_dbg(&pdev->dev, "no reset control found\n"); > >>+ info->reset = NULL; > >>+ } > >>+ > >>init_completion(&info->completion); > >> > >>irq = platform_get_irq(pdev, 0); > >>@@ -252,6 +280,9 @@ static int rockchip_saradc_probe(struct > >>platform_device *pdev) > >>return PTR_ERR(info->vref); > >>} > >> > >>+ if (info->reset) > >>+ rockchip_saradc_reset_controller(info->reset); > >>+ > >>/* > >>* Use a default value for the converter clock. > >>* This may become user-configurable in the future. > >> > > > > > >_______________________________________________ > >Linux-rockchip mailing list > >Linux-rockchip@xxxxxxxxxxxxxxxxxxx > >http://lists.infradead.org/mailman/listinfo/linux-rockchip > > > -- > caesar wang | software engineer | wxt@xxxxxxxxxxxxx > > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html