Messages in this thread | | | From | Roger Tseng <> | Date | Wed, 8 Jan 2014 15:56:05 +0800 | Subject | RE: [PATCH 1/3] mfd: Add realtek USB card reader driver |
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Hi Dan,
>> +int rtsx_usb_ep0_write_register(struct rtsx_ucr *ucr, u16 addr, >> + u8 mask, u8 data) >> +{ >> + u16 value = 0, index = 0; >> + >> + value |= (u16)(3 & 0x03) << 14; >> + value |= (u16)(addr & 0x3FFF); > >Don't do pointless things: > > value |= 0x03 << 14; > value |= addr & 0x3FFF; > >> + value = ((value << 8) & 0xFF00) | ((value >> 8) & 0x00FF); > >This is an endian conversion? It is buggy. Use the kernel endian >conversion functions cpu_to_le16().
This is not a conversion for endianess with respect to CPU but for command format of the device. It should always be performed regardless of platform.
In other words, it could be equivalent to: value |= 0x03 << 6; // lower byte value |= (addr & 0x3F00) >> 8; // lower byte value |= (addr & 0xFF) << 8; //higher byte
We think the previous form is easier to read. Should we keep it or change to the later one?
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