Thread (9 messages) flat view 9 messages, 2 authors, 2014-01-06

[PATCHv8 1/4] pwm: Add Freescale FTM PWM driver support

From: arnd@arndb.de (Arnd Bergmann)
Date: 2014-01-02 11:12:57
Also in: linux-pwm, lkml

On Thursday 02 January 2014 17:57:01 Xiubo Li wrote:
+static inline u32 ftm_readl(bool big_endian, const void __iomem *addr)
+{
+       u32 val;
+
+       val = __raw_readl(addr);
+
+       if (likely(big_endian))
+               val = be32_to_cpu((__force __be32)val);
+       else
+               val = le32_to_cpu((__force __le32)val);
+       rmb();
+
+       return val;
+}
+
+static inline void ftm_writel(bool big_endian, u32 val, void __iomem *addr)
+{
+       wmb();
+       if (likely(big_endian))
+               val = (__force u32)cpu_to_be32(val);
+       else
+               val = (__force u32)cpu_to_le32(val);
+
+       __raw_writel(val, addr);
These functions definitely need some comments regarding why this is necessary.
I assume that after 8 rounds of review (that I did not read) this has been
discussed already, so please explain above the functions why you don't just
use ioread32be/ioread32 and iowrite32be/iowrite32 here.

Also all callers seem to be of the style

       val = ftm_readl(fpc->big_endian, fpc->base + FTM_SC);

so I wonder why you don't just pass the fpc pointer to the function
and make it

static inline void ftm_readl(struct fsl_pwm_chip *fpc, unsigned long reg, u32 val)
{
	if (fpc->big_endian)
		iowrite32be(val, fpc->base + reg);
	else
		iowrite32(val, fpc->base + reg);
}

	Arnd
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