diff options
| author | Wolfram Sang <wsa+renesas@sang-engineering.com> | 2018-07-11 00:24:22 +0200 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2018-07-17 10:46:51 +0200 |
| commit | 7ca5f6be7900ca753ed01c0202dc5f998a41f4ee (patch) | |
| tree | 3648c63c59b230dfcd24f7fef705e77cf90ef39f | |
| parent | 0b71026c69caa10261218528326721828d29a481 (diff) | |
| download | linux-7ca5f6be7900ca753ed01c0202dc5f998a41f4ee.tar.gz linux-7ca5f6be7900ca753ed01c0202dc5f998a41f4ee.tar.bz2 linux-7ca5f6be7900ca753ed01c0202dc5f998a41f4ee.zip | |
i2c: recovery: add get_bus_free callback
Some IP cores have an internal 'bus free' logic which may be more
advanced than just checking if SDA is high. Add a separate callback to
get this status. Filling it is optional.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
| -rw-r--r-- | drivers/i2c/i2c-core-base.c | 27 | ||||
| -rw-r--r-- | include/linux/i2c.h | 3 |
2 files changed, 26 insertions, 4 deletions
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index c7995efd58ea..59f8dfc5be36 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -158,6 +158,22 @@ static void set_sda_gpio_value(struct i2c_adapter *adap, int val) gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val); } +static int i2c_generic_bus_free(struct i2c_adapter *adap) +{ + struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; + int ret = -EOPNOTSUPP; + + if (bri->get_bus_free) + ret = bri->get_bus_free(adap); + else if (bri->get_sda) + ret = bri->get_sda(adap); + + if (ret < 0) + return ret; + + return ret ? 0 : -EBUSY; +} + /* * We are generating clock pulses. ndelay() determines durating of clk pulses. * We will generate clock with rate 100 KHz and so duration of both clock levels @@ -169,7 +185,7 @@ static void set_sda_gpio_value(struct i2c_adapter *adap, int val) int i2c_generic_scl_recovery(struct i2c_adapter *adap) { struct i2c_bus_recovery_info *bri = adap->bus_recovery_info; - int i = 0, val = 1, ret = 0; + int i = 0, val = 1, ret; if (bri->prepare_recovery) bri->prepare_recovery(adap); @@ -207,14 +223,17 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) bri->set_sda(adap, val); ndelay(RECOVERY_NDELAY / 2); - /* Break if SDA is high */ - if (val && bri->get_sda) { - ret = bri->get_sda(adap) ? 0 : -EBUSY; + if (val) { + ret = i2c_generic_bus_free(adap); if (ret == 0) break; } } + /* If we can't check bus status, assume recovery worked */ + if (ret == -EOPNOTSUPP) + ret = 0; + if (bri->unprepare_recovery) bri->unprepare_recovery(adap); diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 4c4360f94786..bc8d42f8544f 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -587,6 +587,8 @@ struct i2c_timings { * @set_sda: This sets/clears the SDA line. This or get_sda() is mandatory for * generic SCL recovery. Populated internally, if sda_gpio is a valid GPIO, * for generic GPIO recovery. + * @get_bus_free: Returns the bus free state as seen from the IP core in case it + * has a more complex internal logic than just reading SDA. Optional. * @prepare_recovery: This will be called before starting recovery. Platform may * configure padmux here for SDA/SCL line or something else they want. * @unprepare_recovery: This will be called after completing recovery. Platform @@ -601,6 +603,7 @@ struct i2c_bus_recovery_info { void (*set_scl)(struct i2c_adapter *adap, int val); int (*get_sda)(struct i2c_adapter *adap); void (*set_sda)(struct i2c_adapter *adap, int val); + int (*get_bus_free)(struct i2c_adapter *adap); void (*prepare_recovery)(struct i2c_adapter *adap); void (*unprepare_recovery)(struct i2c_adapter *adap); |