| Message ID | 20221128105158.1536551-1-carsten.haitzler@foss.arm.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v2] i2c: cadence: Fix regression with bus recovery | expand |
[AMD Official Use Only - General] > -----Original Message----- > From: carsten.haitzler@foss.arm.com <carsten.haitzler@foss.arm.com> > Sent: Monday, November 28, 2022 4:22 PM > To: michal.simek@xilinx.com; shubhrajyoti.datta@xilinx.com; linux-arm- > kernel@lists.infradead.org; linux-i2c@vger.kernel.org; linux- > kernel@vger.kernel.org > Subject: [PATCH v2] i2c: cadence: Fix regression with bus recovery > > CAUTION: This message has originated from an External Source. Please use > proper judgment and caution when opening attachments, clicking links, or > responding to this email. > > > From: Carsten Haitzler <carsten.haitzler@arm.com> > > Commit "i2c: cadence: Add standard bus recovery support" breaks for i2c > devices that have no pinctrl defined. There is no requirement for this to exist > in the DT. This has worked perfectly well without this before in at least 1 real > usage case on hardware (Mali Komeda DPU, Cadence i2c to talk to a tda99xx > phy). Adding the requirement to have pinctrl set up in the device tree (or > otherwise be found) is a regression where the whole i2c device is lost > entirely (in this case dropping entire devices which then leads to the drm > display stack unable to find the phy for display output, thus having no drm > display device and so on down the chain). > > This converts the above commit to an enhancement if pinctrl can be found > for the i2c device, providing a timeout on read with recovery, but if not, do > what used to be done rather than a fatal loss of a device. > > This restores the mentioned display devices to their working state again. > > Fixes: 58b924241d0a ("i2c: cadence: Add standard bus recovery support") > Signed-off-by: Carsten Haitzler <carsten.haitzler@arm.com> Reviewed-by: Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>
+Wolfram, On 11/28/22 11:51, carsten.haitzler@foss.arm.com wrote: > CAUTION: This message has originated from an External Source. Please use proper judgment and caution when opening attachments, clicking links, or responding to this email. > > > From: Carsten Haitzler <carsten.haitzler@arm.com> > > Commit "i2c: cadence: Add standard bus recovery support" breaks for i2c > devices that have no pinctrl defined. There is no requirement for this > to exist in the DT. This has worked perfectly well without this before in > at least 1 real usage case on hardware (Mali Komeda DPU, Cadence i2c to > talk to a tda99xx phy). Adding the requirement to have pinctrl set up in > the device tree (or otherwise be found) is a regression where the whole > i2c device is lost entirely (in this case dropping entire devices which > then leads to the drm display stack unable to find the phy for display > output, thus having no drm display device and so on down the chain). > > This converts the above commit to an enhancement if pinctrl can be found > for the i2c device, providing a timeout on read with recovery, but if not, > do what used to be done rather than a fatal loss of a device. > > This restores the mentioned display devices to their working state again. > > Fixes: 58b924241d0a ("i2c: cadence: Add standard bus recovery support") > Signed-off-by: Carsten Haitzler <carsten.haitzler@arm.com> > --- > Note: This issue was discovered during the porting of the linux kernel > on Morello [1]. > > [1] https://git.morello-project.org/morello/kernel/linux > --- > drivers/i2c/busses/i2c-cadence.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c > index fe0cd205502d..09acd2d399d5 100644 > --- a/drivers/i2c/busses/i2c-cadence.c > +++ b/drivers/i2c/busses/i2c-cadence.c > @@ -852,7 +852,8 @@ static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > CDNS_I2C_POLL_US, CDNS_I2C_TIMEOUT_US); > if (ret) { > ret = -EAGAIN; > - i2c_recover_bus(adap); > + if (id->adap.bus_recovery_info) > + i2c_recover_bus(adap); > goto out; > } > > @@ -1263,9 +1264,13 @@ static int cdns_i2c_probe(struct platform_device *pdev) > > id->rinfo.pinctrl = devm_pinctrl_get(&pdev->dev); > if (IS_ERR(id->rinfo.pinctrl)) { > + int err = PTR_ERR(id->rinfo.pinctrl); > + > dev_info(&pdev->dev, "can't get pinctrl, bus recovery not supported\n"); > - return PTR_ERR(id->rinfo.pinctrl); > - } > + if (err != -ENODEV) > + return err; > + } else > + id->adap.bus_recovery_info = &id->rinfo; > > id->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &r_mem); > if (IS_ERR(id->membase)) > @@ -1283,7 +1288,6 @@ static int cdns_i2c_probe(struct platform_device *pdev) > id->adap.retries = 3; /* Default retry value. */ > id->adap.algo_data = id; > id->adap.dev.parent = &pdev->dev; > - id->adap.bus_recovery_info = &id->rinfo; > init_completion(&id->xfer_done); > snprintf(id->adap.name, sizeof(id->adap.name), > "Cadence I2C at %08lx", (unsigned long)r_mem->start); > -- > 2.32.0 > Acked-by: Michal Simek <michal.simek@amd.com> Wolfram: up2you if you want to take it for 6.1. If it is too late I think it should be labeled as stable material for 6.1. Thanks, Michal
On Mon, Nov 28, 2022 at 10:51:58AM +0000, carsten.haitzler@foss.arm.com wrote: > From: Carsten Haitzler <carsten.haitzler@arm.com> > > Commit "i2c: cadence: Add standard bus recovery support" breaks for i2c > devices that have no pinctrl defined. There is no requirement for this > to exist in the DT. This has worked perfectly well without this before in > at least 1 real usage case on hardware (Mali Komeda DPU, Cadence i2c to > talk to a tda99xx phy). Adding the requirement to have pinctrl set up in > the device tree (or otherwise be found) is a regression where the whole > i2c device is lost entirely (in this case dropping entire devices which > then leads to the drm display stack unable to find the phy for display > output, thus having no drm display device and so on down the chain). > > This converts the above commit to an enhancement if pinctrl can be found > for the i2c device, providing a timeout on read with recovery, but if not, > do what used to be done rather than a fatal loss of a device. > > This restores the mentioned display devices to their working state again. > > Fixes: 58b924241d0a ("i2c: cadence: Add standard bus recovery support") > Signed-off-by: Carsten Haitzler <carsten.haitzler@arm.com> Fixed this checkpatch check: CHECK: Unbalanced braces around else statement #55: FILE: drivers/i2c/busses/i2c-cadence.c:1272: + } else and applied to for-current, thanks!
diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c index fe0cd205502d..09acd2d399d5 100644 --- a/drivers/i2c/busses/i2c-cadence.c +++ b/drivers/i2c/busses/i2c-cadence.c @@ -852,7 +852,8 @@ static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, CDNS_I2C_POLL_US, CDNS_I2C_TIMEOUT_US); if (ret) { ret = -EAGAIN; - i2c_recover_bus(adap); + if (id->adap.bus_recovery_info) + i2c_recover_bus(adap); goto out; } @@ -1263,9 +1264,13 @@ static int cdns_i2c_probe(struct platform_device *pdev) id->rinfo.pinctrl = devm_pinctrl_get(&pdev->dev); if (IS_ERR(id->rinfo.pinctrl)) { + int err = PTR_ERR(id->rinfo.pinctrl); + dev_info(&pdev->dev, "can't get pinctrl, bus recovery not supported\n"); - return PTR_ERR(id->rinfo.pinctrl); - } + if (err != -ENODEV) + return err; + } else + id->adap.bus_recovery_info = &id->rinfo; id->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &r_mem); if (IS_ERR(id->membase)) @@ -1283,7 +1288,6 @@ static int cdns_i2c_probe(struct platform_device *pdev) id->adap.retries = 3; /* Default retry value. */ id->adap.algo_data = id; id->adap.dev.parent = &pdev->dev; - id->adap.bus_recovery_info = &id->rinfo; init_completion(&id->xfer_done); snprintf(id->adap.name, sizeof(id->adap.name), "Cadence I2C at %08lx", (unsigned long)r_mem->start);