Add support for resetting the device using a reset controller,
complementing the existing GPIO reset functionality (reset-gpios).
Although the reset is optional and the driver performs a soft reset
during setup, if the initial reset pin state was asserted, the driver
will not detect the device until the reset is deasserted.
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
drivers/net/dsa/realtek/realtek.h | 2 ++
drivers/net/dsa/realtek/rtl83xx.c | 46 ++++++++++++++++++++++++++++++++++-----
drivers/net/dsa/realtek/rtl83xx.h | 2 ++
3 files changed, 45 insertions(+), 5 deletions(-)
diff --git a/drivers/net/dsa/realtek/realtek.h b/drivers/net/dsa/realtek/realtek.h
index b80bfde1ad04..e0b1aa01337b 100644
--- a/drivers/net/dsa/realtek/realtek.h
+++ b/drivers/net/dsa/realtek/realtek.h
@@ -12,6 +12,7 @@
#include <linux/platform_device.h>
#include <linux/gpio/consumer.h>
#include <net/dsa.h>
+#include <linux/reset.h>
#define REALTEK_HW_STOP_DELAY 25 /* msecs */
#define REALTEK_HW_START_DELAY 100 /* msecs */
@@ -48,6 +49,7 @@ struct rtl8366_vlan_4k {
struct realtek_priv {
struct device *dev;
+ struct reset_control *reset_ctl;
struct gpio_desc *reset;
struct gpio_desc *mdc;
struct gpio_desc *mdio;
diff --git a/drivers/net/dsa/realtek/rtl83xx.c b/drivers/net/dsa/realtek/rtl83xx.c
index 801873754df2..8262ec5032a4 100644
--- a/drivers/net/dsa/realtek/rtl83xx.c
+++ b/drivers/net/dsa/realtek/rtl83xx.c
@@ -184,6 +184,13 @@ rtl83xx_probe(struct device *dev,
"realtek,disable-leds");
/* TODO: if power is software controlled, set up any regulators here */
+ priv->reset_ctl = devm_reset_control_get_optional(dev, NULL);
+ if (IS_ERR(priv->reset_ctl)) {
+ ret = PTR_ERR(priv->reset_ctl);
+ dev_err_probe(dev, ret, "failed to get reset control\n");
+ return ERR_CAST(priv->reset_ctl);
+ }
+
priv->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
if (IS_ERR(priv->reset)) {
dev_err(dev, "failed to get RESET GPIO\n");
@@ -192,11 +199,11 @@ rtl83xx_probe(struct device *dev,
dev_set_drvdata(dev, priv);
- if (priv->reset) {
- gpiod_set_value(priv->reset, 1);
+ if (priv->reset_ctl || priv->reset) {
+ rtl83xx_reset_assert(priv);
dev_dbg(dev, "asserted RESET\n");
msleep(REALTEK_HW_STOP_DELAY);
- gpiod_set_value(priv->reset, 0);
+ rtl83xx_reset_deassert(priv);
msleep(REALTEK_HW_START_DELAY);
dev_dbg(dev, "deasserted RESET\n");
}
@@ -292,11 +299,40 @@ EXPORT_SYMBOL_NS_GPL(rtl83xx_shutdown, REALTEK_DSA);
void rtl83xx_remove(struct realtek_priv *priv)
{
/* leave the device reset asserted */
- if (priv->reset)
- gpiod_set_value(priv->reset, 1);
+ rtl83xx_reset_assert(priv);
}
EXPORT_SYMBOL_NS_GPL(rtl83xx_remove, REALTEK_DSA);
+void rtl83xx_reset_assert(struct realtek_priv *priv)
+{
+ int ret;
+
+ ret = reset_control_assert(priv->reset_ctl);
+ if (!ret)
+ return;
+
+ dev_warn(priv->dev,
+ "Failed to assert the switch reset control: %pe\n",
+ ERR_PTR(ret));
+
+ gpiod_set_value(priv->reset, true);
+}
+
+void rtl83xx_reset_deassert(struct realtek_priv *priv)
+{
+ int ret;
+
+ ret = reset_control_deassert(priv->reset_ctl);
+ if (!ret)
+ return;
+
+ dev_warn(priv->dev,
+ "Failed to deassert the switch reset control: %pe\n",
+ ERR_PTR(ret));
+
+ gpiod_set_value(priv->reset, false);
+}
+
MODULE_AUTHOR("Luiz Angelo Daros de Luca <luizluca@gmail.com>");
MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
MODULE_DESCRIPTION("Realtek DSA switches common module");
diff --git a/drivers/net/dsa/realtek/rtl83xx.h b/drivers/net/dsa/realtek/rtl83xx.h
index 0ddff33df6b0..c8a0ff8fd75e 100644
--- a/drivers/net/dsa/realtek/rtl83xx.h
+++ b/drivers/net/dsa/realtek/rtl83xx.h
@@ -18,5 +18,7 @@ int rtl83xx_register_switch(struct realtek_priv *priv);
void rtl83xx_unregister_switch(struct realtek_priv *priv);
void rtl83xx_shutdown(struct realtek_priv *priv);
void rtl83xx_remove(struct realtek_priv *priv);
+void rtl83xx_reset_assert(struct realtek_priv *priv);
+void rtl83xx_reset_deassert(struct realtek_priv *priv);
#endif /* _RTL83XX_H */
--
2.43.0On Mon, Feb 19, 2024 at 08:44:42PM -0300, Luiz Angelo Daros de Luca wrote:
> +void rtl83xx_reset_assert(struct realtek_priv *priv)
> +{
> + int ret;
> +
> + ret = reset_control_assert(priv->reset_ctl);
> + if (!ret)
> + return;
If priv->reset_ctl is NULL - i.e. if no DT property is specified - then
this will always return early and the GPIO will not be asserted.
> +
> + dev_warn(priv->dev,
> + "Failed to assert the switch reset control: %pe\n",
> + ERR_PTR(ret));
You only log an error if the reset controller assert fails, but not if
the GPIO assert fails. Why the unequal treatment?
I suggest keeping it simple:
void rtl83xx_reset_assert(struct realtek_priv *priv)
{
int ret;
ret = reset_control_assert(priv->reset_ctl);
if (ret)
dev_warn(priv->dev, "failed to assert reset control: %d\n", ret);
ret = gpiod_set_value(priv->reset, false);
if (ret)
dev_warn(priv->dev, "failed to assert reset GPIO: %d\n", ret);
}
or even drop the warnings altogether.
> +
> + gpiod_set_value(priv->reset, true);
> +}
> +
> +void rtl83xx_reset_deassert(struct realtek_priv *priv)
> +{
> + int ret;
> +
> + ret = reset_control_deassert(priv->reset_ctl);
> + if (!ret)
> + return;
> +
> + dev_warn(priv->dev,
> + "Failed to deassert the switch reset control: %pe\n",
> + ERR_PTR(ret));
> +
> + gpiod_set_value(priv->reset, false);
> +}
Same comments apply to this function. Just deassert both.
> +
> MODULE_AUTHOR("Luiz Angelo Daros de Luca <luizluca@gmail.com>");
> MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
> MODULE_DESCRIPTION("Realtek DSA switches common module");
> diff --git a/drivers/net/dsa/realtek/rtl83xx.h b/drivers/net/dsa/realtek/rtl83xx.h
> index 0ddff33df6b0..c8a0ff8fd75e 100644
> --- a/drivers/net/dsa/realtek/rtl83xx.h
> +++ b/drivers/net/dsa/realtek/rtl83xx.h
> @@ -18,5 +18,7 @@ int rtl83xx_register_switch(struct realtek_priv *priv);
> void rtl83xx_unregister_switch(struct realtek_priv *priv);
> void rtl83xx_shutdown(struct realtek_priv *priv);
> void rtl83xx_remove(struct realtek_priv *priv);
> +void rtl83xx_reset_assert(struct realtek_priv *priv);
> +void rtl83xx_reset_deassert(struct realtek_priv *priv);
>
> #endif /* _RTL83XX_H */
>
> --
> 2.43.0
>
Hi Alvin,
> On Mon, Feb 19, 2024 at 08:44:42PM -0300, Luiz Angelo Daros de Luca wrote:
> > +void rtl83xx_reset_assert(struct realtek_priv *priv)
> > +{
> > + int ret;
> > +
> > + ret = reset_control_assert(priv->reset_ctl);
> > + if (!ret)
> > + return;
>
> If priv->reset_ctl is NULL - i.e. if no DT property is specified - then
> this will always return early and the GPIO will not be asserted.
I made a mistake. I should be
if (ret) {
dev_warn...
}
not returning on error (as you suggested below).
I was sure I was doing just that... I was surprised to see it as it
is. I'll recheck my branch with all the integrated changes. It passed
my tests as when reset is missed, it normally does not matter. Thanks
for the catch.
>
> > +
> > + dev_warn(priv->dev,
> > + "Failed to assert the switch reset control: %pe\n",
> > + ERR_PTR(ret));
>
> You only log an error if the reset controller assert fails, but not if
> the GPIO assert fails. Why the unequal treatment?
Because it does not return a value. There is no way to tell if it failed.
>
> I suggest keeping it simple:
>
> void rtl83xx_reset_assert(struct realtek_priv *priv)
> {
> int ret;
>
> ret = reset_control_assert(priv->reset_ctl);
> if (ret)
> dev_warn(priv->dev, "failed to assert reset control: %d\n", ret);
>
> ret = gpiod_set_value(priv->reset, false);
> if (ret)
> dev_warn(priv->dev, "failed to assert reset GPIO: %d\n", ret);
> }
>
> or even drop the warnings altogether.
>
> > +
> > + gpiod_set_value(priv->reset, true);
> > +}
> > +
> > +void rtl83xx_reset_deassert(struct realtek_priv *priv)
> > +{
> > + int ret;
> > +
> > + ret = reset_control_deassert(priv->reset_ctl);
> > + if (!ret)
> > + return;
> > +
> > + dev_warn(priv->dev,
> > + "Failed to deassert the switch reset control: %pe\n",
> > + ERR_PTR(ret));
> > +
> > + gpiod_set_value(priv->reset, false);
> > +}
>
> Same comments apply to this function. Just deassert both.
>
> > +
> > MODULE_AUTHOR("Luiz Angelo Daros de Luca <luizluca@gmail.com>");
> > MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
> > MODULE_DESCRIPTION("Realtek DSA switches common module");
> > diff --git a/drivers/net/dsa/realtek/rtl83xx.h b/drivers/net/dsa/realtek/rtl83xx.h
> > index 0ddff33df6b0..c8a0ff8fd75e 100644
> > --- a/drivers/net/dsa/realtek/rtl83xx.h
> > +++ b/drivers/net/dsa/realtek/rtl83xx.h
> > @@ -18,5 +18,7 @@ int rtl83xx_register_switch(struct realtek_priv *priv);
> > void rtl83xx_unregister_switch(struct realtek_priv *priv);
> > void rtl83xx_shutdown(struct realtek_priv *priv);
> > void rtl83xx_remove(struct realtek_priv *priv);
> > +void rtl83xx_reset_assert(struct realtek_priv *priv);
> > +void rtl83xx_reset_deassert(struct realtek_priv *priv);
> >
> > #endif /* _RTL83XX_H */
> >
> > --
> > 2.43.0
> >
Regards,
Luiz
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