[PATCH 2/3] i2c: Add special case for detecting LEGO devices

From: David Lechner
Date: Mon Sep 05 2016 - 16:44:21 EST


LEGO chose to ignore the I2C specification and has created devices with
I2C addresses of 0x01 and 0x02. i2c_check_7bit_addr_validity_strict()
disallows these addresses, so we need a special case to skip this for
LEGO sensors.

Furthermore, LEGO devices do not respond to i2c_default_probe(), so we
skip this as a special case as well.

Signed-off-by: David Lechner <david@xxxxxxxxxxxxxx>
---
drivers/i2c/i2c-core.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index da3a02e..28436d9 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -2591,12 +2591,14 @@ static int i2c_detect_address(struct i2c_client *temp_client,
int addr = temp_client->addr;
int err;

- /* Make sure the address is valid */
- err = i2c_check_7bit_addr_validity_strict(addr);
- if (err) {
- dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
- addr);
- return err;
+ /* Make sure the address is valid - LEGO devices break the rules */
+ if (!(driver->class & I2C_CLASS_LEGO)) {
+ err = i2c_check_7bit_addr_validity_strict(addr);
+ if (err) {
+ dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
+ addr);
+ return err;
+ }
}

/* Skip if already in use (7 bit, no need to encode flags) */
@@ -2604,7 +2606,8 @@ static int i2c_detect_address(struct i2c_client *temp_client,
return 0;

/* Make sure there is something at this address */
- if (!i2c_default_probe(adapter, addr))
+ if (!(driver->class & I2C_CLASS_LEGO) &&
+ !i2c_default_probe(adapter, addr))
return 0;

/* Finally call the custom detection function */
--
2.7.4