Some hardware designs have a GPIO used to control the reset of all the
devices on and I2C bus. It's not possible for every child node to
declare a reset-gpios property as only the first device probed would be
able to successfully request it (the others will get -EBUSY). Represent
this kind of hardware design by associating the reset-gpios with the
parent I2C bus. The reset line will be released prior to the child I2C
devices being probed.
Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-mv64xxx.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index efd28bbecf61..b2ca31857cbd 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -160,6 +160,7 @@ struct mv64xxx_i2c_data {
bool clk_n_base_0;
struct i2c_bus_recovery_info rinfo;
bool atomic;
+ struct gpio_desc *reset_gpio;
};
static struct mv64xxx_i2c_regs mv64xxx_i2c_regs_mv64xxx = {
@@ -1083,6 +1084,10 @@ mv64xxx_i2c_probe(struct platform_device *pd)
if (drv_data->irq < 0)
return drv_data->irq;
+ drv_data->reset_gpio = devm_gpiod_get_optional(&pd->dev, "reset", GPIOD_OUT_HIGH);
+ if (IS_ERR(drv_data->reset_gpio))
+ return PTR_ERR(drv_data->reset_gpio);
+
if (pdata) {
drv_data->freq_m = pdata->freq_m;
drv_data->freq_n = pdata->freq_n;
@@ -1121,6 +1126,12 @@ mv64xxx_i2c_probe(struct platform_device *pd)
goto exit_disable_pm;
}
+ if (drv_data->reset_gpio) {
+ udelay(1);
+ gpiod_set_value_cansleep(drv_data->reset_gpio, 0);
+ udelay(1);
+ }
+
rc = request_irq(drv_data->irq, mv64xxx_i2c_intr, 0,
MV64XXX_I2C_CTLR_NAME, drv_data);
if (rc) {
--
2.42.0
