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 <[email protected]> Cc: Wolfram Sang <[email protected]> Cc: Viresh Kumar <[email protected]> --- v2: - Removed parenthesis for single-statement block - Moved "swab" and "access_16bit" into "accessor_flags" drivers/i2c/busses/i2c-designware-core.c | 27 ++++++++++++++++++++++----- drivers/i2c/busses/i2c-designware-core.h | 5 ++++- 2 files changed, 26 insertions(+), 6 deletions(-) diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c index df87992..b3c5cfa 100644 --- a/drivers/i2c/busses/i2c-designware-core.c +++ b/drivers/i2c/busses/i2c-designware-core.c @@ -164,9 +164,15 @@ static char *abort_sources[] = { u32 dw_readl(struct dw_i2c_dev *dev, int offset) { - u32 value = readl(dev->base + offset); + u32 value; - if (dev->swab) + if (dev->accessor_flags & ACCESS_16BIT) + value = readw(dev->base + offset) | + (readw(dev->base + offset + 2) << 16); + else + value = readl(dev->base + offset); + + if (dev->accessor_flags & ACCESS_SWAP) return swab32(value); else return value; @@ -174,10 +180,15 @@ u32 dw_readl(struct dw_i2c_dev *dev, int offset) void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset) { - if (dev->swab) + if (dev->accessor_flags & ACCESS_SWAP) b = swab32(b); - writel(b, dev->base + offset); + if (dev->accessor_flags & ACCESS_16BIT) { + writew((u16)b, dev->base + offset); + writew((u16)(b >> 16), dev->base + offset + 2); + } else { + writel(b, dev->base + offset); + } } static u32 @@ -254,7 +265,13 @@ int i2c_dw_init(struct dw_i2c_dev *dev) /* Configure register endianess access */ reg = dw_readl(dev, DW_IC_COMP_TYPE); if (reg == ___constant_swab32(DW_IC_COMP_TYPE_VALUE)) { - dev->swab = 1; + dev->accessor_flags |= ACCESS_SWAP; + reg = DW_IC_COMP_TYPE_VALUE; + } + + /* Configure register access mode 16bit */ + if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) { + dev->accessor_flags |= ACCESS_16BIT; reg = DW_IC_COMP_TYPE_VALUE; } diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h index 02d1a2d..9c1840e 100644 --- a/drivers/i2c/busses/i2c-designware-core.h +++ b/drivers/i2c/busses/i2c-designware-core.h @@ -82,7 +82,7 @@ struct dw_i2c_dev { unsigned int status; u32 abort_source; int irq; - int swab; + u32 accessor_flags; struct i2c_adapter adapter; u32 functionality; u32 master_cfg; @@ -90,6 +90,9 @@ struct dw_i2c_dev { unsigned int rx_fifo_depth; }; +#define ACCESS_SWAP 0x00000001 +#define ACCESS_16BIT 0x00000002 + extern u32 dw_readl(struct dw_i2c_dev *dev, int offset); extern void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset); extern int i2c_dw_init(struct dw_i2c_dev *dev); -- 1.7.10 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
