On Tue, Mar 29, 2016 at 2:37 PM, Arnd Bergmann <a...@arndb.de> wrote: > On Tuesday 29 March 2016 13:23:00 Rob Herring wrote: >> Drivers shouldn't have to care about HAS_IOMEM to compile and having to >> causes a Kconfig mess: >> >> warning: (MEDIA_SUBDRV_AUTOSELECT && VIDEO_CX231XX && INV_MPU6050_I2C) >> selects I2C_MUX which has unmet direct dependencies (I2C && HAS_IOMEM) >> warning: (ST_IRQCHIP && STMMAC_PLATFORM && DWMAC_IPQ806X && DWMAC_LPC18XX && >> DWMAC_ROCKCHIP && DWMAC_SOCFPGA && DWMAC_STI && TI_CPSW && PINCTRL_ROCKCHIP >> && PINCTRL_DOVE && POWER_RESET_KEYSTONE && S3C2410_WATCHDOG && VIDEO_OMAP3 >> && VIDEO_S5P_FIMC && USB_XHCI_MTK && RTC_DRV_AT91SAM9 && LPC18XX_DMAMUX && >> VIDEO_OMAP4 && HWSPINLOCK_QCOM && ATMEL_ST && QCOM_GSBI && PHY_HI6220_USB) >> selects MFD_SYSCON which has unmet direct dependencies (HAS_IOMEM) >> >> Reuse the !MMU variants for !HAS_IOMEM as they are sufficient for our >> needs. This fixes build errors for UM allyesconfig: >> >> drivers/mfd/syscon.c:89:2: error: implicit declaration of function 'iounmap' >> [-Werror=implicit-function-declaration] >> iounmap(base); >> >> Reported-by: Fengguang Wu <fengguang...@intel.com> >> Cc: Arnd Bergmann <a...@arndb.de> >> Cc: linux-a...@vger.kernel.org >> Signed-off-by: Rob Herring <r...@kernel.org> > > (adding Richard and the UML list to cc) > > I actually prototyped a patch that did the opposite: remove the > readl/writel/... > definitions when HAS_IOMEM is unset. I didn't get far enough to submit it, > but see below for what I did.
Ewww. Why do the opposite of what we do for every other Kconfig symbol which is provide empty functions? It really only functions as a disable on UML flag which runs counter to enabling drivers to build for all arches. I actually started a patch to remove the HAS_IOMEM dependency everywhere (or just the per driver cases). It didn't break as bad as I expected, but became more than I wanted to fix. Mainly, all the devm_ variants also need empty versions or to be always enabled. Rob
