From: Tomas Menzl <[email protected]> Add master_xfer / I2C_FUNC_I2C by simply reusing existing FSM scx200_acb_machine. This adds possibility to do direct read/write on an i2c device or use I2C_RDWR ioctl in addition to existing SM Bus API.
Signed-off-by: Tomas Menzl <[email protected]> ---- Added plain I2C interface so that one can use plain read/write (among others). Needed plain I2C multibyte read which is not possible with SM bus. Tested on Voyage Linux 0.75 (http://linux.voyage.hk/, based on Debian Squeeze, 2.6.38, this module is original/vanilla - i.e. patch applicable to any current version) on PC Engine WRAP 2C with Microchip ADC MCP3421. SM BUS interface intact, read/write worked for me (only tested single message transactions, do not have HW to test combined transaction but they are there...). --- linux-source-2.6.38-voyage/drivers/i2c/busses/scx200_acb.c 2011-08-05 19:44:11.000000000 +0200 +++ linux-source-2.6.38-voyage.new/drivers/i2c/busses/scx200_acb.c 2011-08-05 22:06:18.000000000 +0200 @@ -86,6 +86,7 @@ struct scx200_acb_iface { u8 *ptr; char needs_reset; unsigned len; + char skip_stop; }; /* Register Definitions */ @@ -130,6 +131,7 @@ static void scx200_acb_machine(struct sc scx200_acb_state_name[iface->state]); iface->state = state_idle; + iface->skip_stop = 0; iface->result = -ENXIO; outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1); @@ -191,7 +193,8 @@ static void scx200_acb_machine(struct sc if (iface->len == 1) { iface->result = 0; iface->state = state_idle; - outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1); + if (!iface->skip_stop) + outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1); } *iface->ptr++ = inb(ACBSDA); @@ -203,7 +206,8 @@ static void scx200_acb_machine(struct sc if (iface->len == 0) { iface->result = 0; iface->state = state_idle; - outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1); + if (!iface->skip_stop) + outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1); break; } @@ -222,6 +226,7 @@ static void scx200_acb_machine(struct sc iface->len, status); iface->state = state_idle; + iface->skip_stop = 0; iface->result = -EIO; iface->needs_reset = 1; } @@ -277,6 +282,104 @@ static void scx200_acb_reset(struct scx2 outb(inb(ACBCST) | ACBCST_BB, ACBCST); } +/* + * Generic i2c master transfer entrypoint. + * + * Basically copy of part of scx200_acb_smbus_xfer where we use existing + * scx200_acb_machine which already supports simple i2c with any data length + * (not only 0 and 1 as used by smbus) by using: + * + * state_quick -> ( state_read | state_write )+ -> state_idle + * + * Added flag skip_stop to support multimessage ops in scx200_acb_machine + * to be able skip stop bit between messages in state_read/state_write: + * + * S Addr Rd [A] [Data] NA S Addr Wr [A] Data [A] P + * ^--- no stop bit! ^--- stop bit + * + * Still missing 10b address, pec, etc... + */ +static int scx200_acb_i2c_master_xfer(struct i2c_adapter *adapter, + struct i2c_msg *msgs, + int num) +{ + struct scx200_acb_iface *iface = i2c_get_adapdata(adapter); + int rc = 0; + char rw; + int len; + u8 *buffer; + u16 address; + + mutex_lock(&iface->mutex); + while (num > 0) { + if (msgs->flags & I2C_M_TEN) { + dev_err(&adapter->dev, + "10b i2c address supported\n"); + rc = -EINVAL; + break; + } + + rw = (msgs->flags & I2C_M_RD) != 0; + address = (msgs->addr << 1) | rw; + len = msgs->len; + buffer = msgs->buf; + + dev_dbg(&adapter->dev, + "address=0x%x, len=%d, read=%d\n", msgs->addr, len, rw); + + if (!len && rw == I2C_SMBUS_READ) { + dev_dbg(&adapter->dev, "zero length read\n"); + rc = -EINVAL; + break; + } + + iface->address_byte = address; + iface->command = 0; + iface->ptr = buffer; + iface->len = len; + iface->result = -EINVAL; + iface->needs_reset = 0; + if (num > 1) + iface->skip_stop = 1; + else + iface->skip_stop = 0; + + /* send start */ + outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1); + + /* no command */ + iface->state = state_quick; + + while (iface->state != state_idle) + scx200_acb_poll(iface); + + if (iface->needs_reset) + scx200_acb_reset(iface); + + if (iface->result) + break; + +#ifdef DEBUG + dev_dbg(&adapter->dev, "transfer done, result: %d", rc); + if (buffer) { + int i; + printk(KERN_DEBUG " data:"); + for (i = 0; i < len; ++i) + printk(KERN_DEBUG " %02x", buffer[i]); + } + printk(KERN_DEBUG "\n"); +#endif + ++rc; + --num; + ++msgs; + } + mutex_unlock(&iface->mutex); + + iface->skip_stop = 0; + return rc; +} + + static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter, u16 address, unsigned short flags, char rw, u8 command, int size, @@ -338,6 +441,7 @@ static s32 scx200_acb_smbus_xfer(struct iface->len = len; iface->result = -EINVAL; iface->needs_reset = 0; + iface->skip_stop = 0; outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1); @@ -377,12 +481,13 @@ static u32 scx200_acb_func(struct i2c_ad { return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | - I2C_FUNC_SMBUS_I2C_BLOCK; + I2C_FUNC_SMBUS_I2C_BLOCK | I2C_FUNC_I2C; } /* For now, we only handle combined mode (smbus) */ static const struct i2c_algorithm scx200_acb_algorithm = { .smbus_xfer = scx200_acb_smbus_xfer, + .master_xfer = scx200_acb_i2c_master_xfer, .functionality = scx200_acb_func, }; -- 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
