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i2c: recovery: add get_bus_free callback

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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>
This commit is contained in:
Wolfram Sang
2018-07-11 00:24:22 +02:00
committed by Wolfram Sang
parent 0b71026c69
commit 7ca5f6be79
2 changed files with 26 additions and 4 deletions
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27
drivers/i2c/i2c-core-base.c
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@@ -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);