Re: [PATCH v8 2/3] mfd: add Gateworks System Controller core driver
On Wed, 29 Apr 2020, Tim Harvey wrote:
> On Tue, Apr 28, 2020 at 11:33 PM Lee Jones wrote:
> >
> > On Tue, 28 Apr 2020, Tim Harvey wrote:
> >
> > > On Tue, Apr 28, 2020 at 2:44 AM Lee Jones wrote:
> > > >
> > >
> > > > > +
> > > > > +static int gsc_probe(struct i2c_client *client)
> > > > > +{
> > > > > + struct device *dev = >dev;
> > > > > + struct gsc_dev *gsc;
> > > > > + int ret;
> > > > > + unsigned int reg;
> > > > > +
> > > > > + gsc = devm_kzalloc(dev, sizeof(*gsc), GFP_KERNEL);
> > > > > + if (!gsc)
> > > > > + return -ENOMEM;
> > > > > +
> > > > > + gsc->dev = >dev;
> > > > > + gsc->i2c = client;
> > > > > + i2c_set_clientdata(client, gsc);
> > > > > +
> > > > > + gsc->bus.reg_write = gsc_regmap_regwrite;
> > > > > + gsc->bus.reg_read = gsc_regmap_regread;
> > > >
> > > > Why do you need to store these in ddata?
> > >
> > > Lee,
> > >
> > > Thanks for the review!
> > >
> > > I need the remap_bus* for devm_regmap_init() in the hwmon sub-module
> > > driver:
> > >
> > > hwmon->regmap = devm_regmap_init(dev, >bus, gsc->i2c_hwmon,
> > > _hwmon_regmap_config);
> > >
> > > Is there something easier I'm missing?
> >
> > This is an odd setup. I haven't seen one driver registering another
> > driver's Regmap call-backs before, related or otherwise. Normally the
> > Regmap is setup (initialised) in the parent driver and child drivers
> > just make use of it. Here it looks like you are registering 2
> > separate Regmaps, but using the same call-backs for both, which seems
> > wrong to me.
> >
>
> Lee,
>
> It is perhaps an odd setup. The hwmon sub-device is at a different i2c
> slave address than the other sub-devices. The same callbacks are used
> for reg read/write to take advantage of the retries due to the errata
> resulting in occasional NAK'd register reads.
Then I suggest putting them somewhere shared or exporting them.
Passing pointers to the via ddata sounds a bit batty.
--
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
Re: [PATCH v8 2/3] mfd: add Gateworks System Controller core driver
On Tue, Apr 28, 2020 at 11:33 PM Lee Jones wrote:
>
> On Tue, 28 Apr 2020, Tim Harvey wrote:
>
> > On Tue, Apr 28, 2020 at 2:44 AM Lee Jones wrote:
> > >
> >
> > > > +
> > > > +static int gsc_probe(struct i2c_client *client)
> > > > +{
> > > > + struct device *dev = >dev;
> > > > + struct gsc_dev *gsc;
> > > > + int ret;
> > > > + unsigned int reg;
> > > > +
> > > > + gsc = devm_kzalloc(dev, sizeof(*gsc), GFP_KERNEL);
> > > > + if (!gsc)
> > > > + return -ENOMEM;
> > > > +
> > > > + gsc->dev = >dev;
> > > > + gsc->i2c = client;
> > > > + i2c_set_clientdata(client, gsc);
> > > > +
> > > > + gsc->bus.reg_write = gsc_regmap_regwrite;
> > > > + gsc->bus.reg_read = gsc_regmap_regread;
> > >
> > > Why do you need to store these in ddata?
> >
> > Lee,
> >
> > Thanks for the review!
> >
> > I need the remap_bus* for devm_regmap_init() in the hwmon sub-module driver:
> >
> > hwmon->regmap = devm_regmap_init(dev, >bus, gsc->i2c_hwmon,
> > _hwmon_regmap_config);
> >
> > Is there something easier I'm missing?
>
> This is an odd setup. I haven't seen one driver registering another
> driver's Regmap call-backs before, related or otherwise. Normally the
> Regmap is setup (initialised) in the parent driver and child drivers
> just make use of it. Here it looks like you are registering 2
> separate Regmaps, but using the same call-backs for both, which seems
> wrong to me.
>
Lee,
It is perhaps an odd setup. The hwmon sub-device is at a different i2c
slave address than the other sub-devices. The same callbacks are used
for reg read/write to take advantage of the retries due to the errata
resulting in occasional NAK'd register reads.
Tim
Re: [PATCH v8 2/3] mfd: add Gateworks System Controller core driver
On Tue, 28 Apr 2020, Tim Harvey wrote:
> On Tue, Apr 28, 2020 at 2:44 AM Lee Jones wrote:
> >
>
> > > +
> > > +static int gsc_probe(struct i2c_client *client)
> > > +{
> > > + struct device *dev = >dev;
> > > + struct gsc_dev *gsc;
> > > + int ret;
> > > + unsigned int reg;
> > > +
> > > + gsc = devm_kzalloc(dev, sizeof(*gsc), GFP_KERNEL);
> > > + if (!gsc)
> > > + return -ENOMEM;
> > > +
> > > + gsc->dev = >dev;
> > > + gsc->i2c = client;
> > > + i2c_set_clientdata(client, gsc);
> > > +
> > > + gsc->bus.reg_write = gsc_regmap_regwrite;
> > > + gsc->bus.reg_read = gsc_regmap_regread;
> >
> > Why do you need to store these in ddata?
>
> Lee,
>
> Thanks for the review!
>
> I need the remap_bus* for devm_regmap_init() in the hwmon sub-module driver:
>
> hwmon->regmap = devm_regmap_init(dev, >bus, gsc->i2c_hwmon,
> _hwmon_regmap_config);
>
> Is there something easier I'm missing?
This is an odd setup. I haven't seen one driver registering another
driver's Regmap call-backs before, related or otherwise. Normally the
Regmap is setup (initialised) in the parent driver and child drivers
just make use of it. Here it looks like you are registering 2
separate Regmaps, but using the same call-backs for both, which seems
wrong to me.
--
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
Re: [PATCH v8 2/3] mfd: add Gateworks System Controller core driver
On Tue, Apr 28, 2020 at 2:44 AM Lee Jones wrote:
>
> > +
> > +static int gsc_probe(struct i2c_client *client)
> > +{
> > + struct device *dev = >dev;
> > + struct gsc_dev *gsc;
> > + int ret;
> > + unsigned int reg;
> > +
> > + gsc = devm_kzalloc(dev, sizeof(*gsc), GFP_KERNEL);
> > + if (!gsc)
> > + return -ENOMEM;
> > +
> > + gsc->dev = >dev;
> > + gsc->i2c = client;
> > + i2c_set_clientdata(client, gsc);
> > +
> > + gsc->bus.reg_write = gsc_regmap_regwrite;
> > + gsc->bus.reg_read = gsc_regmap_regread;
>
> Why do you need to store these in ddata?
Lee,
Thanks for the review!
I need the remap_bus* for devm_regmap_init() in the hwmon sub-module driver:
hwmon->regmap = devm_regmap_init(dev, >bus, gsc->i2c_hwmon,
_hwmon_regmap_config);
Is there something easier I'm missing?
Thanks,
Tim
Re: [PATCH v8 2/3] mfd: add Gateworks System Controller core driver
On Fri, 27 Mar 2020, Tim Harvey wrote: > The Gateworks System Controller (GSC) is an I2C slave controller > implemented with an MSP430 micro-controller whose firmware embeds the > following features: > - I/O expander (16 GPIO's) using PCA955x protocol > - Real Time Clock using DS1672 protocol > - User EEPROM using AT24 protocol > - HWMON using custom protocol > - Interrupt controller with tamper detect, user pushbotton > - Watchdog controller capable of full board power-cycle > - Power Control capable of full board power-cycle > > see http://trac.gateworks.com/wiki/gsc for more details > > Cc: Randy Dunlap > Signed-off-by: Tim Harvey > --- > v8: > - whitespace fixes > - describe sub-devices in Kconfig > - add error print for invalid command > - update copyright > - use devm_of_platform_populate > - use probe_new > - move hwmon's regmap init to hwmon > > v7: > - remove irq from private data struct > > v6: > - remove duplicate signature and fix commit log > > v5: > - simplify powerdown function > > v4: > - remove hwmon max reg check/define > - fix powerdown function > > v3: > - rename gsc->gateworks-gsc > - remove uncecessary include for linux/mfd/core.h > - upercase I2C in comments > - remove i2c debug > - remove uncecessary comments > - don't use KBUILD_MODNAME for name > - remove unnecessary v1/v2/v3 tracking > - unregister hwmon i2c adapter on remove > > v2: > - change license comment block style > - remove COMPILE_TEST (Randy) > - fixed whitespace issues > - replaced a printk with dev_err > --- > MAINTAINERS | 8 ++ > drivers/mfd/Kconfig | 10 ++ > drivers/mfd/Makefile| 1 + > drivers/mfd/gateworks-gsc.c | 288 > > include/linux/mfd/gsc.h | 73 +++ > 5 files changed, 380 insertions(+) > create mode 100644 drivers/mfd/gateworks-gsc.c > create mode 100644 include/linux/mfd/gsc.h > > diff --git a/MAINTAINERS b/MAINTAINERS > index 56765f5..bb79b60 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -6839,6 +6839,14 @@ F: tools/testing/selftests/futex/ > F: tools/perf/bench/futex* > F: Documentation/*futex* > > +GATEWORKS SYSTEM CONTROLLER (GSC) DRIVER > +M: Tim Harvey > +M: Robert Jones > +S: Maintained > +F: Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml > +F: drivers/mfd/gateworks-gsc.c > +F: include/linux/mfd/gsc.h > + > GCC PLUGINS > M: Kees Cook > R: Emese Revfy > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig > index 4209008..d84725a 100644 > --- a/drivers/mfd/Kconfig > +++ b/drivers/mfd/Kconfig > @@ -407,6 +407,16 @@ config MFD_EXYNOS_LPASS > Select this option to enable support for Samsung Exynos Low Power > Audio Subsystem. > > +config MFD_GATEWORKS_GSC > + tristate "Gateworks System Controller" > + depends on (I2C && OF) > + select MFD_CORE > + select REGMAP_I2C > + select REGMAP_IRQ > + help > + Enable support for the Gateworks System Controller found > + on Gateworks Single Board Computers. Please expand on the help section some more. What is the purpose of the device? What sub-devices make up the GSC? What does this device driver offer/provide? > config MFD_MC13XXX > tristate > depends on (SPI_MASTER || I2C) > diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile > index aed99f0..c82b442 100644 > --- a/drivers/mfd/Makefile > +++ b/drivers/mfd/Makefile > @@ -15,6 +15,7 @@ obj-$(CONFIG_MFD_BCM590XX) += bcm590xx.o > obj-$(CONFIG_MFD_BD9571MWV) += bd9571mwv.o > obj-$(CONFIG_MFD_CROS_EC_DEV)+= cros_ec_dev.o > obj-$(CONFIG_MFD_EXYNOS_LPASS) += exynos-lpass.o > +obj-$(CONFIG_MFD_GATEWORKS_GSC) += gateworks-gsc.o > > obj-$(CONFIG_HTC_PASIC3) += htc-pasic3.o > obj-$(CONFIG_HTC_I2CPLD) += htc-i2cpld.o > diff --git a/drivers/mfd/gateworks-gsc.c b/drivers/mfd/gateworks-gsc.c > new file mode 100644 > index ..020e1e1 > --- /dev/null > +++ b/drivers/mfd/gateworks-gsc.c > @@ -0,0 +1,288 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * The Gateworks System Controller (GSC) is a multi-function > + * device designed for use in Gateworks Single Board Computers. > + * The control interface is I2C, with an interrupt. The device supports > + * system functions such as pushbutton monitoring, multiple ADC's for > + * voltage and temperature, fan controller, and watchdog monitor. Looks like good information for the help. > + * Copyright (C) 2020 Gateworks Corporation > + */ Nit: '\n' here. > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +/* > + * The GSC suffers from an errata where occasionally during > + * ADC cycles the chip can NAK I2C transactions. To ensure we have reliable > + * register access we place retries around register access. > + */ > +#define I2C_RETRIES 3 > + > +static int gsc_regmap_regwrite(void *context, unsigned int
