On exynos5250-spring the battery and tps65090 regulator are sitting on an i2c bus behind the EC (much like on exynos5420-peach-pit). However on spring we don't have the full EC_CMD_I2C_PASSTHRU command.
For the production kernel of spring we used a solution like this: - Fork the tps65090 driver and make a version that talks straight to the cros_ec MFD driver and sends special EC commands for talking to the regulator. - Add code into the i2c tunnel to look for i2c transfers and convert them into special EC commands for talking to the battery. For reference: * http://crosreview.com/66116 * https://chromium.googlesource.com/chromiumos/third_party/kernel/+/chromeos-3.8/drivers/regulator/cros_ec-tps65090.c The above solution works great but is a bunch of code. It appears that we can make do with the limited i2c passthrough commands that actually happened to be present on the exynos5250-spring EC. Doing this we can present ourselves as supporting a small subset of smbus. We might need to do a few extra transfers here and there but we don't need any extra code. Seriss-cc: linux-samsung-soc Signed-off-by: Doug Anderson <[email protected]> --- drivers/i2c/busses/i2c-cros-ec-tunnel.c | 92 ++++++++++++++++++++++++++++++++- 1 file changed, 91 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-cros-ec-tunnel.c b/drivers/i2c/busses/i2c-cros-ec-tunnel.c index 6d7d009..c52c491 100644 --- a/drivers/i2c/busses/i2c-cros-ec-tunnel.c +++ b/drivers/i2c/busses/i2c-cros-ec-tunnel.c @@ -38,6 +38,76 @@ struct ec_i2c_device { u8 response_buf[256]; }; +static int ec_smbus_xfer(struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, union i2c_smbus_data *data) +{ + struct ec_i2c_device *bus = adap->algo_data; + struct cros_ec_command msg = {}; + int result; + + if (read_write == I2C_SMBUS_WRITE) { + struct ec_params_i2c_write params; + + params.addr = addr << 1; + params.port = bus->remote_bus; + params.offset = command; + + if (size == I2C_SMBUS_WORD_DATA) { + params.data = data->word; + params.write_size = 16; + } else if (size == I2C_SMBUS_BYTE_DATA) { + params.data = data->byte; + params.write_size = 8; + } else { + return -EINVAL; + } + + msg.command = EC_CMD_I2C_WRITE; + msg.outdata = (uint8_t *)¶ms; + msg.outsize = sizeof(params); + + result = bus->ec->cmd_xfer(bus->ec, &msg); + if (result < 0) + return -EIO; + + return 0; + } else if (read_write == I2C_SMBUS_READ) { + struct ec_params_i2c_read params; + struct ec_response_i2c_read response; + + params.addr = addr << 1; + params.port = bus->remote_bus; + params.offset = command; + + if (size == I2C_SMBUS_WORD_DATA) + params.read_size = 16; + else if (size == I2C_SMBUS_BYTE_DATA) + params.read_size = 8; + else + return -EINVAL; + + msg.command = EC_CMD_I2C_READ; + msg.outdata = (uint8_t *)¶ms; + msg.outsize = sizeof(params); + msg.indata = (uint8_t *)&response; + msg.insize = sizeof(response); + + result = bus->ec->cmd_xfer(bus->ec, &msg); + if (result < 0) + return -EIO; + + if (size == I2C_SMBUS_WORD_DATA) + data->word = response.data; + else + data->byte = response.data; + + return 0; + } + + return -EINVAL; +} + /** * ec_i2c_count_message - Count bytes needed for ec_i2c_construct_message * @@ -233,6 +303,11 @@ static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[], if (result < 0) goto exit; + if (msg.result == EC_RES_INVALID_COMMAND) { + result = -EINVAL; + goto exit; + } + result = ec_i2c_parse_response(response, i2c_msgs, &num); if (result < 0) goto exit; @@ -258,6 +333,16 @@ static const struct i2c_algorithm ec_i2c_algorithm = { .functionality = ec_i2c_functionality, }; +static u32 ec_smbus_functionality(struct i2c_adapter *adap) +{ + return I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA; +} + +static const struct i2c_algorithm ec_i2c_limited_algorithm = { + .smbus_xfer = ec_smbus_xfer, + .functionality = ec_smbus_functionality, +}; + static int ec_i2c_probe(struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node; @@ -288,11 +373,16 @@ static int ec_i2c_probe(struct platform_device *pdev) bus->adap.owner = THIS_MODULE; strlcpy(bus->adap.name, "cros-ec-i2c-tunnel", sizeof(bus->adap.name)); - bus->adap.algo = &ec_i2c_algorithm; bus->adap.algo_data = bus; bus->adap.dev.parent = &pdev->dev; bus->adap.dev.of_node = np; + /* Test if we can support full passthrough or just limited */ + if (ec_i2c_xfer(&bus->adap, NULL, 0) == 0) + bus->adap.algo = &ec_i2c_algorithm; + else + bus->adap.algo = &ec_i2c_limited_algorithm; + err = i2c_add_adapter(&bus->adap); if (err) { dev_err(dev, "cannot register i2c adapter\n"); -- 2.0.0.526.g5318336 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
