On Mon, Sep 11, 2023 at 3:32 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > > Hi, > > On 9/11/23 15:18, Bartosz Golaszewski wrote: > > On Mon, Sep 11, 2023 at 3:08 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > >> > >> Hi, > >> > >> On 9/11/23 14:50, Bartosz Golaszewski wrote: > >>> On Sat, Sep 9, 2023 at 4:18 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > >>>> > >>>> Refactor x86_android_tablet_get_gpiod() to no longer use > >>>> gpiolib private functions like gpiochip_find(). > >>>> > >>>> As a bonus this allows specifying that the GPIO is active-low, > >>>> like the /CE (charge enable) pin on the bq25892 charger on > >>>> the Lenovo Yoga Tablet 3. > >>>> > >>>> Reported-by: Bartosz Golaszewski <brgl@xxxxxxxx> > >>>> Closes: https://lore.kernel.org/platform-driver-x86/20230905185309.131295-12-brgl@xxxxxxxx/ > >>>> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> > >>>> --- > >>>> .../platform/x86/x86-android-tablets/asus.c | 1 + > >>>> .../platform/x86/x86-android-tablets/core.c | 51 +++++++++++-------- > >>>> .../platform/x86/x86-android-tablets/lenovo.c | 28 +++++----- > >>>> .../platform/x86/x86-android-tablets/other.c | 6 +++ > >>>> .../x86-android-tablets/x86-android-tablets.h | 6 ++- > >>>> 5 files changed, 55 insertions(+), 37 deletions(-) > >>>> > >>>> diff --git a/drivers/platform/x86/x86-android-tablets/asus.c b/drivers/platform/x86/x86-android-tablets/asus.c > >>>> index f9c4083be86d..227afbb51078 100644 > >>>> --- a/drivers/platform/x86/x86-android-tablets/asus.c > >>>> +++ b/drivers/platform/x86/x86-android-tablets/asus.c > >>>> @@ -303,6 +303,7 @@ static const struct x86_i2c_client_info asus_tf103c_i2c_clients[] __initconst = > >>>> .index = 28, > >>>> .trigger = ACPI_EDGE_SENSITIVE, > >>>> .polarity = ACPI_ACTIVE_LOW, > >>>> + .con_id = "atmel_mxt_ts_irq", > >>>> }, > >>>> }, > >>>> }; > >>>> diff --git a/drivers/platform/x86/x86-android-tablets/core.c b/drivers/platform/x86/x86-android-tablets/core.c > >>>> index 3d3101b2848f..673f3a14941b 100644 > >>>> --- a/drivers/platform/x86/x86-android-tablets/core.c > >>>> +++ b/drivers/platform/x86/x86-android-tablets/core.c > >>>> @@ -12,7 +12,7 @@ > >>>> > >>>> #include <linux/acpi.h> > >>>> #include <linux/dmi.h> > >>>> -#include <linux/gpio/driver.h> > >>>> +#include <linux/gpio/consumer.h> > >>>> #include <linux/gpio/machine.h> > >>>> #include <linux/irq.h> > >>>> #include <linux/module.h> > >>>> @@ -21,35 +21,39 @@ > >>>> #include <linux/string.h> > >>>> > >>>> #include "x86-android-tablets.h" > >>>> -/* For gpiochip_get_desc() which is EXPORT_SYMBOL_GPL() */ > >>>> -#include "../../../gpio/gpiolib.h" > >>>> -#include "../../../gpio/gpiolib-acpi.h" > >>>> > >>>> static struct platform_device *x86_android_tablet_device; > >>>> > >>>> -static int gpiochip_find_match_label(struct gpio_chip *gc, void *data) > >>>> -{ > >>>> - return gc->label && !strcmp(gc->label, data); > >>>> -} > >>>> - > >>>> -int x86_android_tablet_get_gpiod(const char *label, int pin, struct gpio_desc **desc) > >>>> +int x86_android_tablet_get_gpiod(const char *chip, int pin, const char *con_id, > >>>> + bool active_low, enum gpiod_flags dflags, > >>>> + struct gpio_desc **desc) > >>>> { > >>>> + struct gpiod_lookup_table *lookup; > >>>> struct gpio_desc *gpiod; > >>>> - struct gpio_chip *chip; > >>>> > >>>> - chip = gpiochip_find((void *)label, gpiochip_find_match_label); > >>>> - if (!chip) { > >>>> - pr_err("error cannot find GPIO chip %s\n", label); > >>>> - return -ENODEV; > >>>> - } > >>>> + lookup = kzalloc(struct_size(lookup, table, 2), GFP_KERNEL); > >>>> + if (!lookup) > >>>> + return -ENOMEM; > >>>> + > >>>> + lookup->dev_id = KBUILD_MODNAME; > >>>> + lookup->table[0].key = chip; > >>>> + lookup->table[0].chip_hwnum = pin; > >>>> + lookup->table[0].con_id = con_id; > >>>> + lookup->table[0].flags = active_low ? GPIO_ACTIVE_LOW : GPIO_ACTIVE_HIGH; > >>>> + > >>>> + gpiod_add_lookup_table(lookup); > >>>> + gpiod = devm_gpiod_get(&x86_android_tablet_device->dev, con_id, dflags); > >>>> + gpiod_remove_lookup_table(lookup); > >>>> + kfree(lookup); > >>>> > >>> > >>> Any reason for not creating static lookup tables for GPIOs here? > >> > >> Not sure what you mean with static? > >> > >> I guess you mean using global or stack memory instead of kmalloc() ? > >> > >> gcc did not like me putting a struct with a variable length array > >> at the end on the stack, so I went with a kzalloc using the > >> struct_size() helper for structs with variable length arrays instead. > >> > >> Note this only runs once at boot, so the small extra cost of > >> the malloc + free is not really a big deal here. > >> > >> I did not try making it global data as that would make the function > >> non re-entrant. Not that it is used in a re-entrant way anywhere, > >> but generally I try to avoid creating code which is not re-entrant. > >> > > > > I meant static-per-compilation-unit. > > I see. > > > It doesn't have to be a variable > > length array either. Typically GPIO lookups are static arrays that are > > added once and never removed. > > Right. > > > The SPI example I posted elsewhere is > > different as it addresses a device quirk and cannot be generalized > > like this. How many GPIOs would you need to describe for this > > use-case? If it's just a few, then I'd go with static lookup tables. > > If it's way more than disregard this comment. > > ATM x86_android_tablet_get_gpiod() gets called for 24 GPIOs, > so more the just a few. For different devices? As in: dev_id would differ? If not then I'd go with a static table, you can use GPIO_LOOKUP() macro and have one line per GPIO. If there are more devices, then I agree - let's keep dynamic allocation. Just please: add a comment why you're doing it this way so that people don't just copy and paste it elsewhere. Bart. > > Regards, > > Hans > >
