RE: [PATCHv7 1/4] pwm: Add Freescale FTM PWM driver support

From: Li.Xiubo@xxxxxxxxxxxxx
Date: Wed Dec 18 2013 - 04:44:23 EST



> On Tue, Dec 17, 2013 at 01:54:35PM +0100, Tomasz Figa wrote:
> > On Tuesday 17 of December 2013 13:45:06 Thierry Reding wrote:
> > > I fail to see how that would eliminate the problem with the types.
> > > That said I don't actually see sparse complaining about any type
> mismatches.
> > > That's probably because the various macros implicitly cast to u32.
> >
> > Well, in BE variant you would read the register using __raw_readl()
> > into a __be32 and then get an u32 from be32_to_cpu() and return it.
> > Similarly for writes
>
> __raw_readl() returns a u32, so you'll get a warning trying to assign a
> u32 to a __be32.
>

If all are ok about this method.
How about the following:

+static inline u32 fsl_pwm_readl(struct fsl_pwm_chip *fpc,
+ const void __iomem *addr)
+{
+ u32 val;
+
+ val = __raw_readl(addr);
+
+ if (likely(fpc->big_endian))
+ val = be32_to_cpu((__force __be32)val);
+ else
+ val = le32_to_cpu((__force __le32)val);
+ rmb();
+
+ return val;
+}
+
+static inline void fsl_pwm_writel(struct fsl_pwm_chip *fpc,
+ u32 val, void __iomem *addr)
+{
+ wmb();
+ if (likely(fpc->big_endian))
+ val = (__force u32)cpu_to_be32(val);
+ else
+ val = (__force u32)cpu_to_le32(val);
+
+ __raw_writel(val, addr);
+}

Best Regards,
Xiubo
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