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. It doesn't have to be a variable length array either. Typically GPIO lookups are static arrays that are added once and never removed. 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. Bart > Regards, > > Hans > > > > > >> - gpiod = gpiochip_get_desc(chip, pin); > >> if (IS_ERR(gpiod)) { > >> - pr_err("error %ld getting GPIO %s %d\n", PTR_ERR(gpiod), label, pin); > >> + pr_err("error %ld getting GPIO %s %d\n", PTR_ERR(gpiod), chip, pin); > >> return PTR_ERR(gpiod); > >> } > >> > > >
