In some SoCs (observed on the STM32MP15) the M_CAN IP core keeps the
CAN state and CAN error counters over an internal reset cycle. The
STM32MP15 SoC provides an external reset, which is shared between both
M_CAN cores.
Add support for an optional external reset. Take care of shared
resets, de-assert reset during the probe phase in
m_can_class_register() and while the interface is up, assert the reset
otherwise.
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
drivers/net/can/m_can/m_can.c | 26 +++++++++++++++++++++++---
drivers/net/can/m_can/m_can.h | 1 +
2 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index c24ea0e5599f..0a6d4b523c33 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -23,6 +23,7 @@
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
+#include <linux/reset.h>
#include "m_can.h"
@@ -1833,6 +1834,7 @@ static int m_can_close(struct net_device *dev)
close_candev(dev);
+ reset_control_assert(cdev->rsts);
m_can_clk_stop(cdev);
phy_power_off(cdev->transceiver);
@@ -2075,11 +2077,15 @@ static int m_can_open(struct net_device *dev)
if (err)
goto out_phy_power_off;
+ err = reset_control_deassert(cdev->rsts);
+ if (err)
+ goto exit_disable_clks;
+
/* open the can device */
err = open_candev(dev);
if (err) {
netdev_err(dev, "failed to open can device\n");
- goto exit_disable_clks;
+ goto out_reset_control_assert;
}
if (cdev->is_peripheral)
@@ -2135,6 +2141,8 @@ static int m_can_open(struct net_device *dev)
else
napi_disable(&cdev->napi);
close_candev(dev);
+out_reset_control_assert:
+ reset_control_assert(cdev->rsts);
exit_disable_clks:
m_can_clk_stop(cdev);
out_phy_power_off:
@@ -2425,15 +2433,23 @@ int m_can_class_register(struct m_can_classdev *cdev)
}
}
+ cdev->rsts = devm_reset_control_get_optional_shared(cdev->dev, NULL);
+ if (IS_ERR(cdev->rsts))
+ return PTR_ERR(cdev->rsts);
+
ret = m_can_clk_start(cdev);
if (ret)
return ret;
+ ret = reset_control_deassert(cdev->rsts);
+ if (ret)
+ goto clk_disable;
+
if (cdev->is_peripheral) {
ret = can_rx_offload_add_manual(cdev->net, &cdev->offload,
NAPI_POLL_WEIGHT);
if (ret)
- goto clk_disable;
+ goto out_reset_control_assert;
}
if (!cdev->net->irq) {
@@ -2462,8 +2478,10 @@ int m_can_class_register(struct m_can_classdev *cdev)
KBUILD_MODNAME, cdev->net->irq, cdev->version);
/* Probe finished
- * Stop clocks. They will be reactivated once the M_CAN device is opened
+ * Assert rest and stop clocks.
+ * They will be reactivated once the M_CAN device is opened
*/
+ reset_control_assert(cdev->rsts);
m_can_clk_stop(cdev);
return 0;
@@ -2471,6 +2489,8 @@ int m_can_class_register(struct m_can_classdev *cdev)
rx_offload_del:
if (cdev->is_peripheral)
can_rx_offload_del(&cdev->offload);
+out_reset_control_assert:
+ reset_control_assert(cdev->rsts);
clk_disable:
m_can_clk_stop(cdev);
diff --git a/drivers/net/can/m_can/m_can.h b/drivers/net/can/m_can/m_can.h
index bd4746c63af3..5e901d5bf6ff 100644
--- a/drivers/net/can/m_can/m_can.h
+++ b/drivers/net/can/m_can/m_can.h
@@ -86,6 +86,7 @@ struct m_can_classdev {
struct device *dev;
struct clk *hclk;
struct clk *cclk;
+ struct reset_control *rsts;
struct workqueue_struct *tx_wq;
struct phy *transceiver;
--
2.50.1On Di, 2025-08-12 at 19:36 +0200, Marc Kleine-Budde wrote: > In some SoCs (observed on the STM32MP15) the M_CAN IP core keeps the > CAN state and CAN error counters over an internal reset cycle. The > STM32MP15 SoC provides an external reset, which is shared between both > M_CAN cores. > > Add support for an optional external reset. Take care of shared > resets, de-assert reset during the probe phase in > m_can_class_register() and while the interface is up, assert the reset > otherwise. > > Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> > --- > drivers/net/can/m_can/m_can.c | 26 +++++++++++++++++++++++--- > drivers/net/can/m_can/m_can.h | 1 + > 2 files changed, 24 insertions(+), 3 deletions(-) > > diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c > index c24ea0e5599f..0a6d4b523c33 100644 > --- a/drivers/net/can/m_can/m_can.c > +++ b/drivers/net/can/m_can/m_can.c > @@ -23,6 +23,7 @@ > #include <linux/pinctrl/consumer.h> > #include <linux/platform_device.h> > #include <linux/pm_runtime.h> > +#include <linux/reset.h> > > #include "m_can.h" > > @@ -1833,6 +1834,7 @@ static int m_can_close(struct net_device *dev) > > close_candev(dev); > > + reset_control_assert(cdev->rsts); Nitpick, "rsts" as in plural? [...] > @@ -2462,8 +2478,10 @@ int m_can_class_register(struct m_can_classdev *cdev) > KBUILD_MODNAME, cdev->net->irq, cdev->version); > > /* Probe finished > - * Stop clocks. They will be reactivated once the M_CAN device is opened > + * Assert rest and stop clocks. Typo, s/rest/reset/. Otherwise, Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> regards Philipp
On 13.08.2025 10:17:52, Philipp Zabel wrote: > On Di, 2025-08-12 at 19:36 +0200, Marc Kleine-Budde wrote: > > In some SoCs (observed on the STM32MP15) the M_CAN IP core keeps the > > CAN state and CAN error counters over an internal reset cycle. The > > STM32MP15 SoC provides an external reset, which is shared between both > > M_CAN cores. > > > > Add support for an optional external reset. Take care of shared > > resets, de-assert reset during the probe phase in > > m_can_class_register() and while the interface is up, assert the reset > > otherwise. > > > > Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> > > --- > > drivers/net/can/m_can/m_can.c | 26 +++++++++++++++++++++++--- > > drivers/net/can/m_can/m_can.h | 1 + > > 2 files changed, 24 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c > > index c24ea0e5599f..0a6d4b523c33 100644 > > --- a/drivers/net/can/m_can/m_can.c > > +++ b/drivers/net/can/m_can/m_can.c > > @@ -23,6 +23,7 @@ > > #include <linux/pinctrl/consumer.h> > > #include <linux/platform_device.h> > > #include <linux/pm_runtime.h> > > +#include <linux/reset.h> > > > > #include "m_can.h" > > > > @@ -1833,6 +1834,7 @@ static int m_can_close(struct net_device *dev) > > > > close_candev(dev); > > > > + reset_control_assert(cdev->rsts); > > Nitpick, "rsts" as in plural? fixed. > > [...] > > @@ -2462,8 +2478,10 @@ int m_can_class_register(struct m_can_classdev *cdev) > > KBUILD_MODNAME, cdev->net->irq, cdev->version); > > > > /* Probe finished > > - * Stop clocks. They will be reactivated once the M_CAN device is opened > > + * Assert rest and stop clocks. > > Typo, s/rest/reset/. fixed. > > Otherwise, > > > Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> Thanks, hmmm, why doesn't b4 pick that up? Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung Nürnberg | Phone: +49-5121-206917-129 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-9 |
On 13.08.2025 10:34:12, Marc Kleine-Budde wrote: > > Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> > > Thanks, hmmm, why doesn't b4 pick that up? Ahh, that's intentional. b4 will only apply the trailer if the patch is unchanged to the posted one. Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung Nürnberg | Phone: +49-5121-206917-129 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-9 |
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