Hi Stefan, > -----Original Message----- > From: Stefan Roese [mailto:sr@xxxxxxx] > Sent: Tuesday, March 13, 2012 9:24 PM > To: linux-i2c@xxxxxxxxxxxxxxx > Cc: spear-devel; ben-linux@xxxxxxxxx > Subject: [PATCH] i2c: designware: Add support for 16bit register access > > The STM SPEAr platform can only access the i2c controller register > via 16bit read/write functions. This patch adds support to > automatically detect this 16bit access mode. > > Signed-off-by: Stefan Roese <sr@xxxxxxx> > --- > drivers/i2c/busses/i2c-designware-core.c | 22 ++++++++++++++++++++-- > drivers/i2c/busses/i2c-designware-core.h | 1 + > 2 files changed, 21 insertions(+), 2 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-designware-core.c > b/drivers/i2c/busses/i2c-designware-core.c > index df87992..d1facbc 100644 > --- a/drivers/i2c/busses/i2c-designware-core.c > +++ b/drivers/i2c/busses/i2c-designware-core.c > @@ -164,7 +164,14 @@ static char *abort_sources[] = { > > u32 dw_readl(struct dw_i2c_dev *dev, int offset) > { > - u32 value = readl(dev->base + offset); > + u32 value; > + > + if (dev->access_16bit) { > + value = readw(dev->base + offset) | > + (readw(dev->base + offset + 2) << 16); > + } else { > + value = readl(dev->base + offset); > + } We can do away with '{' parenthesis as these are single line of code inside both the 'if-else' blocks. > if (dev->swab) > return swab32(value); > @@ -177,7 +184,12 @@ void dw_writel(struct dw_i2c_dev *dev, u32 b, int > offset) > if (dev->swab) > b = swab32(b); > > - writel(b, dev->base + offset); > + if (dev->access_16bit) { > + writew((u16)b, dev->base + offset); > + writew((u16)(b >> 16), dev->base + offset + 2); > + } else { > + writel(b, dev->base + offset); > + } > } > > static u32 > @@ -258,6 +270,12 @@ int i2c_dw_init(struct dw_i2c_dev *dev) > reg = DW_IC_COMP_TYPE_VALUE; > } > > + /* Configure register access mode 16bit */ > + if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) { > + dev->access_16bit = 1; Can we use a suitable macro for 0x0000ffff? Also, if dev->access_16bit is bool we can simply set: dev->access_16bit = true; more on that below... > + reg = DW_IC_COMP_TYPE_VALUE; > + } > + > if (reg != DW_IC_COMP_TYPE_VALUE) { > dev_err(dev->dev, "Unknown Synopsys component type: " > "0x%08x\n", reg); > diff --git a/drivers/i2c/busses/i2c-designware-core.h > b/drivers/i2c/busses/i2c-designware-core.h > index 02d1a2d..f5af101 100644 > --- a/drivers/i2c/busses/i2c-designware-core.h > +++ b/drivers/i2c/busses/i2c-designware-core.h > @@ -83,6 +83,7 @@ struct dw_i2c_dev { > u32 abort_source; > int irq; > int swab; > + int access_16bit; ... int?? Probably we are better off with making this as bool. > struct i2c_adapter adapter; > u32 functionality; > u32 master_cfg; > -- Regards, Bhupesh -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
