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

[ Upstream commit c3083124e6a1c0d6cd4fe3b3f627b488bd3b10c4 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Sean Nyekjaer 2019-12-11 14:58:51 +01:00 committed by Greg Kroah-Hartman
parent 68d199fc8e
commit db10c64764
1 changed files with 26 additions and 1 deletions
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27
drivers/net/can/m_can/tcan4x5x.c
View File

@ -164,6 +164,28 @@ 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)
@ -341,6 +363,7 @@ static int tcan4x5x_init(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);
@ -354,7 +377,9 @@ 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",