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can: tcan4x5x: tcan4x5x_parse_config(): reset device before register access 

It's a good idea to reset a ip-block/spi device before using it, this
patch will reset the device.

And a generic reset function if needed elsewhere.

Signed-off-by: Sean Nyekjaer <sean@geanix.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Sean Nyekjaer 2019-12-11 14:58:51 +01:00 committed by Marc Kleine-Budde
parent 3814ca3a10
commit c3083124e6
1 changed files with 26 additions and 1 deletions
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27
drivers/net/can/m_can/tcan4x5x.c
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@ -166,6 +166,28 @@ static void tcan4x5x_check_wake(struct tcan4x5x_priv *priv)
}
}
static int tcan4x5x_reset(struct tcan4x5x_priv *priv)
{
int ret = 0;
if (priv->reset_gpio) {
gpiod_set_value(priv->reset_gpio, 1);
/* tpulse_width minimum 30us */
usleep_range(30, 100);
gpiod_set_value(priv->reset_gpio, 0);
} else {
ret = regmap_write(priv->regmap, TCAN4X5X_CONFIG,
TCAN4X5X_SW_RESET);
if (ret)
return ret;
}
usleep_range(700, 1000);
return ret;
}
static int regmap_spi_gather_write(void *context, const void *reg,
size_t reg_len, const void *val,
size_t val_len)
@ -351,6 +373,7 @@ static int tcan4x5x_disable_wake(struct m_can_classdev *cdev)
static int tcan4x5x_parse_config(struct m_can_classdev *cdev)
{
struct tcan4x5x_priv *tcan4x5x = cdev->device_data;
int ret;
tcan4x5x->device_wake_gpio = devm_gpiod_get(cdev->dev, "device-wake",
GPIOD_OUT_HIGH);
@ -366,7 +389,9 @@ static int tcan4x5x_parse_config(struct m_can_classdev *cdev)
if (IS_ERR(tcan4x5x->reset_gpio))
tcan4x5x->reset_gpio = NULL;
usleep_range(700, 1000);
ret = tcan4x5x_reset(tcan4x5x);
if (ret)
return ret;
tcan4x5x->device_state_gpio = devm_gpiod_get_optional(cdev->dev,
"device-state",