| Message ID | 20230125105416.17406-1-hdegoede@redhat.com |
|---|---|
| Headers | show |
| Series | Input: touchscreen - settings module-param support | expand |
Hi Hans, On Wed, Jan 25, 2023 at 11:54:14AM +0100, Hans de Goede wrote: > On x86/ACPI platforms touchscreens mostly just work without needing any > device/model specific configuration. But in some cases (mostly with Silead > and Goodix touchscreens) it is still necessary to manually specify various > touchscreen-properties on a per model basis. > > This is handled by drivers/platform/x86/touchscreen_dmi.c which contains > a large list of per-model touchscreen properties which it attaches to the > (i2c)device before the touchscreen driver's probe() method gets called. > This means that ATM changing these settings requires recompiling the > kernel. This makes figuring out what settings/properties a specific > touchscreen needs very hard for normal users to do. > > Add a new, optional, settings_override string argument to > touchscreen_parse_properties(), which takes a list of ; separated > property-name=value pairs, e.g. : > "touchscreen-size-x=1665;touchscreen-size-y=1140;touchscreen-swapped-x-y". > > This new argument can be used by drivers to implement a module option which > allows users to easily specify alternative settings for testing. > > The 2 new touchscreen_property_read_u32() and > touchscreen_property_read_bool() helpers are also exported so that > drivers can use these to add settings-override support to the code > for driver-specific properties. > > Reviewed-by: Bastien Nocera <hadess@hadess.net> > Signed-off-by: Hans de Goede <hdegoede@redhat.com> > --- Thank you for resurrecting this series. Perhaps I can give my own $.02 as a fellow customer of input. I can appreciate the hesitancy that was expressed in the past, as this is not a generic solution and is specific to touch devices. However, I also agree with your point that extending dts overrides to all properties opens a can of worms which should not necessarily gate this benign series (i.e., "good is not the enemy of great"). Personally I am highly in favor of this series because I myself have had to support this very situation where a panel arrives 180 degrees from the expected orientation, and fellow teammates who are not in a position to quickly spin a build need a means to quickly unblock themselves through a serial console or other means. The code itself also LGTM and I verified there were no regressions on one of my own drivers that expects these properties to come from dts, and so: Reviewed-by: Jeff LaBundy <jeff@labundy.com> > Changes in v2: > - Instead of patching all drivers rename touchscreen_parse_properties() > to touchscreen_parse_properties_with_override() and add > a static inline wrapper which passes NULL. > --- > drivers/input/touchscreen.c | 103 ++++++++++++++++++++++++++---- > include/linux/input/touchscreen.h | 19 +++++- > 2 files changed, 109 insertions(+), 13 deletions(-) > > diff --git a/drivers/input/touchscreen.c b/drivers/input/touchscreen.c > index 4620e20d0190..3b9505d5468d 100644 > --- a/drivers/input/touchscreen.c > +++ b/drivers/input/touchscreen.c > @@ -12,15 +12,80 @@ > #include <linux/input/touchscreen.h> > #include <linux/module.h> > > +static int touchscreen_get_prop_from_settings_string(const char *settings, > + const char *propname, > + bool is_boolean, > + u32 *val_ret) > +{ > + char *begin, *end; > + u32 val; > + > + if (!settings) > + return -ENOENT; > + > + begin = strstr(settings, propname); > + if (!begin) > + return -ENOENT; > + > + /* begin must be either the begin of settings, or be preceded by a ';' */ > + if (begin != settings && begin[-1] != ';') > + return -EINVAL; > + > + end = begin + strlen(propname); > + if (*end != '=') { > + if (is_boolean && (*end == '\0' || *end == ';')) { > + *val_ret = true; > + return 0; > + } > + return -EINVAL; > + } > + > + val = simple_strtoul(end + 1, &end, 0); > + if (*end != '\0' && *end != ';') > + return -EINVAL; > + > + *val_ret = val; > + return 0; > +} > + > +int touchscreen_property_read_u32(struct device *dev, const char *propname, > + const char *settings, u32 *val) > +{ > + int error; > + > + error = device_property_read_u32(dev, propname, val); > + > + if (touchscreen_get_prop_from_settings_string(settings, propname, > + false, val) == 0) > + error = 0; > + > + return error; > +} > +EXPORT_SYMBOL(touchscreen_property_read_u32); > + > +bool touchscreen_property_read_bool(struct device *dev, const char *propname, > + const char *settings) > +{ > + u32 val; > + > + val = device_property_read_bool(dev, propname); > + > + touchscreen_get_prop_from_settings_string(settings, propname, true, &val); > + > + return val; > +} > +EXPORT_SYMBOL(touchscreen_property_read_bool); > + > static bool touchscreen_get_prop_u32(struct device *dev, > const char *property, > + const char *settings, > unsigned int default_value, > unsigned int *value) > { > u32 val; > int error; > > - error = device_property_read_u32(dev, property, &val); > + error = touchscreen_property_read_u32(dev, property, settings, &val); > if (error) { > *value = default_value; > return false; > @@ -50,20 +115,28 @@ static void touchscreen_set_params(struct input_dev *dev, > } > > /** > - * touchscreen_parse_properties - parse common touchscreen properties > + * touchscreen_parse_properties_with_settings - parse common touchscreen properties > * @input: input device that should be parsed > * @multitouch: specifies whether parsed properties should be applied to > * single-touch or multi-touch axes > * @prop: pointer to a struct touchscreen_properties into which to store > * axis swap and invert info for use with touchscreen_report_x_y(); > * or %NULL > + * @settings: string with ; separated name=value pairs overriding > + * the device-properties or %NULL. > * > * This function parses common properties for touchscreens and sets up the > * input device accordingly. The function keeps previously set up default > * values if no value is specified. > + * > + * Callers can optional specify a settings string overriding the > + * device-properties, this can be used to implement a module option which > + * allows users to easily specify alternative settings for testing. > */ > -void touchscreen_parse_properties(struct input_dev *input, bool multitouch, > - struct touchscreen_properties *prop) > +void touchscreen_parse_properties_with_settings(struct input_dev *input, > + bool multitouch, > + struct touchscreen_properties *prop, > + const char *settings) > { > struct device *dev = input->dev.parent; > struct input_absinfo *absinfo; > @@ -79,26 +152,32 @@ void touchscreen_parse_properties(struct input_dev *input, bool multitouch, > axis_y = multitouch ? ABS_MT_POSITION_Y : ABS_Y; > > data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-x", > + settings, > input_abs_get_min(input, axis_x), > &minimum); > data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-x", > + settings, > input_abs_get_max(input, > axis_x) + 1, > &maximum); > data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-x", > + settings, > input_abs_get_fuzz(input, axis_x), > &fuzz); > if (data_present) > touchscreen_set_params(input, axis_x, minimum, maximum - 1, fuzz); > > data_present = touchscreen_get_prop_u32(dev, "touchscreen-min-y", > + settings, > input_abs_get_min(input, axis_y), > &minimum); > data_present |= touchscreen_get_prop_u32(dev, "touchscreen-size-y", > + settings, > input_abs_get_max(input, > axis_y) + 1, > &maximum); > data_present |= touchscreen_get_prop_u32(dev, "touchscreen-fuzz-y", > + settings, > input_abs_get_fuzz(input, axis_y), > &fuzz); > if (data_present) > @@ -107,10 +186,12 @@ void touchscreen_parse_properties(struct input_dev *input, bool multitouch, > axis = multitouch ? ABS_MT_PRESSURE : ABS_PRESSURE; > data_present = touchscreen_get_prop_u32(dev, > "touchscreen-max-pressure", > + settings, > input_abs_get_max(input, axis), > &maximum); > data_present |= touchscreen_get_prop_u32(dev, > "touchscreen-fuzz-pressure", > + settings, > input_abs_get_fuzz(input, axis), > &fuzz); > if (data_present) > @@ -122,28 +203,28 @@ void touchscreen_parse_properties(struct input_dev *input, bool multitouch, > prop->max_x = input_abs_get_max(input, axis_x); > prop->max_y = input_abs_get_max(input, axis_y); > > - prop->invert_x = > - device_property_read_bool(dev, "touchscreen-inverted-x"); > + prop->invert_x = touchscreen_property_read_bool(dev, "touchscreen-inverted-x", > + settings); > if (prop->invert_x) { > absinfo = &input->absinfo[axis_x]; > absinfo->maximum -= absinfo->minimum; > absinfo->minimum = 0; > } > > - prop->invert_y = > - device_property_read_bool(dev, "touchscreen-inverted-y"); > + prop->invert_y = touchscreen_property_read_bool(dev, "touchscreen-inverted-y", > + settings); > if (prop->invert_y) { > absinfo = &input->absinfo[axis_y]; > absinfo->maximum -= absinfo->minimum; > absinfo->minimum = 0; > } > > - prop->swap_x_y = > - device_property_read_bool(dev, "touchscreen-swapped-x-y"); > + prop->swap_x_y = touchscreen_property_read_bool(dev, "touchscreen-swapped-x-y", > + settings); > if (prop->swap_x_y) > swap(input->absinfo[axis_x], input->absinfo[axis_y]); > } > -EXPORT_SYMBOL(touchscreen_parse_properties); > +EXPORT_SYMBOL(touchscreen_parse_properties_with_settings); > > static void > touchscreen_apply_prop_to_x_y(const struct touchscreen_properties *prop, > diff --git a/include/linux/input/touchscreen.h b/include/linux/input/touchscreen.h > index fe66e2b58f62..0023c6e368ba 100644 > --- a/include/linux/input/touchscreen.h > +++ b/include/linux/input/touchscreen.h > @@ -17,8 +17,23 @@ struct touchscreen_properties { > bool swap_x_y; > }; > > -void touchscreen_parse_properties(struct input_dev *input, bool multitouch, > - struct touchscreen_properties *prop); > +void touchscreen_parse_properties_with_settings(struct input_dev *input, > + bool multitouch, > + struct touchscreen_properties *prop, > + const char *settings); > + > +static inline void touchscreen_parse_properties(struct input_dev *input, > + bool multitouch, > + struct touchscreen_properties *prop) > +{ > + touchscreen_parse_properties_with_settings(input, multitouch, prop, NULL); > +} > + > +int touchscreen_property_read_u32(struct device *dev, const char *propname, > + const char *settings, u32 *val); > + > +bool touchscreen_property_read_bool(struct device *dev, const char *propname, > + const char *settings); > > void touchscreen_set_mt_pos(struct input_mt_pos *pos, > const struct touchscreen_properties *prop, > -- > 2.39.0 > Kind regards, Jeff LaBundy
On Wed, Jan 25, 2023 at 11:54:16AM +0100, Hans de Goede wrote: > Add a settings module-parameter which can be allowed to specify/override > various device-properties. > > Usuually Goodix touchscreens on x86 devices (where there is no devicetree > to specify the properties) just work. But in some cases the touchscreen is > mounted 90 or 180 degrees rotated vs the display, requiring setting the > touchscreen-x/y-inverted or touchscreen-swapped-x-y properties. > > Being able to specify the necessary properties through a module parameter, > allows users of new device-models to help us with bringing up support for > new devices without them needing to do a local kernel-build just to modify > these settings. > > Reviewed-by: Bastien Nocera <hadess@hadess.net> > Signed-off-by: Hans de Goede <hdegoede@redhat.com> Reviewed-by: Jeff LaBundy <jeff@labundy.com> > --- > drivers/input/touchscreen/goodix.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c > index 620f5ec0962f..a105dee04156 100644 > --- a/drivers/input/touchscreen/goodix.c > +++ b/drivers/input/touchscreen/goodix.c > @@ -53,6 +53,10 @@ > #define ACPI_GPIO_SUPPORT > #endif > > +static char *settings; > +module_param(settings, charp, 0444); > +MODULE_PARM_DESC(settings, "Override touchscreen settings using a ; separated key=value list, e.g. \"touchscreen-fuzz-x=5;touchscreen-fuzz-y=5;touchscreen-swapped-x-y\""); > + > struct goodix_chip_id { > const char *id; > const struct goodix_chip_data *data; > @@ -1197,7 +1201,8 @@ static int goodix_configure_dev(struct goodix_ts_data *ts) > goodix_read_config(ts); > > /* Try overriding touchscreen parameters via device properties */ > - touchscreen_parse_properties(ts->input_dev, true, &ts->prop); > + touchscreen_parse_properties_with_settings(ts->input_dev, true, > + &ts->prop, settings); > > if (!ts->prop.max_x || !ts->prop.max_y || !ts->max_touch_num) { > if (!ts->reset_controller_at_probe && > -- > 2.39.0 >
Hi Dmitry, et al, This is a resend, because the discussion surrounding this patch-set seems to have dried up without really coming to any conclusion (summary of previous discussion below). Original cover-letter (edited for already merged bugfix): """ This series adds support for overriding various silead and goodix touchscreen related device-properties from the kernel cmdline. This is a reposting of an earlier version which had the following cover letter: On x86/ACPI platforms touchscreens mostly just work without needing any device/model specific configuration. But in some cases (mostly with Silead and Goodix touchscreens) it is still necessary to manually specify various touchscreen-properties on a per model basis. This is handled by drivers/platform/x86/touchscreen_dmi.c which contains a large list of per-model touchscreen properties which it attaches to the (i2c)device before the touchscreen driver's probe() method gets called. This means that ATM changing these settings requires recompiling the kernel. This makes figuring out what settings/properties a specific touchscreen needs very hard for normal users to do. This new settings parameter support is especially useful for helping users to get their Silead touchscreens to work. These need to have all of their settings (min-x, width, min-y, height, swapping, inverting) hardcoded in touchscreen_dmi.c. The settings mod-param allows users to find the right setting without them needing to be capable of building their own kernel (and without a lot of rebooting) after which they can ask someone with some kernel-dev experience to turn this into a touchscreen_dmi.c patch for them (and yes the way this hw works sucks, but we cannot change that). An example of a user who was stuck getting their touchscreen to work and who was helped by providing a kernel with the settings mod-param added: https://github.com/onitake/gsl-firmware/discussions/193 """ Dmitry, you replied to the first patch of this series with: """ I totally understand the motivation for this, but I do not think that having special handling for only touchscreen properties is the right thing to do. I would very much prefer is we had a more generic approach of adding/overriding properties (via an swnode?). """ To which I wrote the following long reply: """ I understand where you are coming from, but I suspect the devicetree folks are going to not like any generic solution for 2 reasons: 1. Allowing overriding devicetree properties like regulator voltage is a bad idea, granted users can already do this with a custom DTB, but that is a higher threshold to pass for a user then just adding something on the kernel cmdline 2. Devicetree supports devicetree-overlays and I expect the devicetree folks to steer people who want to override random devicetree properties in that direction (or in the direction of using a custom DTB) So the ACPI/x86 case really is somewhat special here and especially the silead touchscreens are special here. Normally all the settings we are talking here come from ACPI tables (or can directly be read from the touchscreen controller) and then messing with these settings would be a case of using an initrd with a custom ACPI DSDT, just like how on devicetree I think we would expect people to use a custom DTB and or a devicetree overlay. but because of this info lacking from the ACPI tables we have it hardcoded per 2-in-1/tablet model in: drivers/platform/x86/touchscreen_dmi.c The downside of this hardcoding is that testing new settings requires building a custom kernel, which is both not helpful for having a quick change settings -> test -> adjust settings cycle when trying to find the right settings for a new model as well as quite a steep hill to climb for novice users who want to get things to work on a new model. So I do believe that because of this the touchscreen properties or special in this case and a somewhat custom solution to allow setting just the touchscreen properties from the cmdline thus is justified. Also: 1. Having a mechanism specific to touchscreen properties is simpler (more KISS) then having to come up with some more complicated generic property override mechanism. 2. A touchscreen property specific mechanism is much less susceptible to being misused. Setting the touchscreen properties wrong cannot really result in any harm. OTOH setting the max / end-of charging voltage of a lipo cell to 4.6 volt (this is a real world example) is very much harmful. The lipo-cell max charge voltage is something which we in the sysfs interface deliberately disallow to be set any higher then the boot-time value (lower is allowed). Adding a generic cmdline mechanism for setting properties would allow overriding this. """ And then the discussion stopped. Regards, Hans Hans de Goede (3): Input: touchscreen - Extend touchscreen_parse_properties() to allow overriding settings with a module option Input: silead - Add a settings module-parameter Input: goodix - Add a settings module-parameter drivers/input/touchscreen.c | 103 ++++++++++++++++++++++++++--- drivers/input/touchscreen/goodix.c | 7 +- drivers/input/touchscreen/silead.c | 26 +++++--- include/linux/input/touchscreen.h | 19 +++++- 4 files changed, 131 insertions(+), 24 deletions(-)