Increasing build coverage for drivers/spi/spi-ppc4xx.c

["Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>]

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Hello,

recently the spi-ppc4xx.c driver suffered from build errors and warnings
that were undetected for longer than I expected. I think it would be
very beneficial if this driver was enabled in (at least) a powerpc
allmodconfig build.

The challenge to do so is that spi-ppc4xx.c uses dcri_clrset() which is
only defined for 4xx (as these select PPC_DCR_NATIVE).

I wonder if dcri_clrset() could be defined for the PPC_DCR_MMIO case,
too. I tried and failed. The best I came up without extensive doc
reading is:

diff --git a/arch/powerpc/include/asm/dcr-native.h b/arch/powerpc/include/asm/dcr-native.h
index a92059964579..159ab7abfe46 100644
--- a/arch/powerpc/include/asm/dcr-native.h
+++ b/arch/powerpc/include/asm/dcr-native.h
@@ -115,15 +115,11 @@ static inline void __dcri_clrset(int base_addr, int base_data, int reg,
 	unsigned int val;
 
 	spin_lock_irqsave(&dcr_ind_lock, flags);
-	if (cpu_has_feature(CPU_FTR_INDEXED_DCR)) {
-		mtdcrx(base_addr, reg);
-		val = (mfdcrx(base_data) & ~clr) | set;
-		mtdcrx(base_data, val);
-	} else {
-		__mtdcr(base_addr, reg);
-		val = (__mfdcr(base_data) & ~clr) | set;
-		__mtdcr(base_data, val);
-	}
+
+	mtdcr(base_addr, reg);
+	val = (mfdcr(base_data) & ~clr) | set;
+	mtdcr(base_data, val);
+
 	spin_unlock_irqrestore(&dcr_ind_lock, flags);
 }
 
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index bc7021da2fe9..9a0a5e8c70c8 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -810,7 +810,8 @@ config SPI_PL022
 
 config SPI_PPC4xx
 	tristate "PPC4xx SPI Controller"
-	depends on PPC32 && 4xx
+	depends on 4xx || COMPILE_TEST
+	depends on PPC32 || PPC64
 	select SPI_BITBANG
 	help
 	  This selects a driver for the PPC4xx SPI Controller.

While this is a step in the right direction (I think) it's not enough to
make the driver build (but maybe make it easier to define
dcri_clrset()?)

Could someone with more powerpc knowledge jump in and help (for the
benefit of better compile coverage of the spi driver and so less
breakage)? (If you do so based on my changes above, you don't need to
credit me for my effort, claim it as your's. I'm happy enough if the
situation improves.)

Thanks
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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