| Message ID | 1512170904-4749-3-git-send-email-timur@codeaurora.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | Andy Gross |
| Headers | show |
On Fri, 2017-12-01 at 17:28 -0600, Timur Tabi wrote: > Add support for specifying that some GPIOs within a range are > unavailable. > Some systems have a sparse list of GPIOs, where a range of GPIOs is > specified (usually 0 to n-1), but some subset within that range is > absent or unavailable for whatever reason. > > To support this, allow drivers to specify a bitmask of GPIOs that > are present or absent. Gpiolib will then block access to those that > are absent. > - status = gpiochip_irqchip_init_valid_mask(chip); > + status = gpiochip_init_valid_mask(chip); > if (status) > goto err_remove_from_list; > > + status = gpiochip_irqchip_init_valid_mask(chip); > + if (status) > + goto err_remove_valid_mask; Yes, this way it looks good! > +static bool gpiochip_available(const struct gpio_chip *gpiochip, > + unsigned int offset) > +{ > + pr_info("%s:%u offset=%u\n", __func__, __LINE__, offset); Debug leftover? > + > + /* No mask means all valid */ > + if (likely(!gpiochip->valid_mask)) > + return true; > + > + return test_bit(offset, gpiochip->valid_mask); Not sure which one is better return test_bit(); or return !!test_bit();
On 12/12/2017 03:58 AM, Andy Shevchenko wrote: > On Fri, 2017-12-01 at 17:28 -0600, Timur Tabi wrote: >> Add support for specifying that some GPIOs within a range are >> unavailable. >> Some systems have a sparse list of GPIOs, where a range of GPIOs is >> specified (usually 0 to n-1), but some subset within that range is >> absent or unavailable for whatever reason. >> >> To support this, allow drivers to specify a bitmask of GPIOs that >> are present or absent. Gpiolib will then block access to those that >> are absent. > >> - status = gpiochip_irqchip_init_valid_mask(chip); >> + status = gpiochip_init_valid_mask(chip); >> if (status) >> goto err_remove_from_list; >> >> + status = gpiochip_irqchip_init_valid_mask(chip); >> + if (status) >> + goto err_remove_valid_mask; > > Yes, this way it looks good! I've discovered that I can remove all this code. I don't need a valid mask, all I need to do is block the request properly. >> +static bool gpiochip_available(const struct gpio_chip *gpiochip, >> + unsigned int offset) >> +{ > >> + pr_info("%s:%u offset=%u\n", __func__, __LINE__, offset); > > Debug leftover? Fixed, thanks. > >> + >> + /* No mask means all valid */ >> + if (likely(!gpiochip->valid_mask)) >> + return true; >> + >> + return test_bit(offset, gpiochip->valid_mask); > > Not sure which one is better > return test_bit(); > or > return !!test_bit(); I've removed this function also.
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 168dd831551d..2c71e8db95a3 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -191,6 +191,28 @@ static int gpiochip_find_base(int ngpio) } } +static int gpiochip_init_valid_mask(struct gpio_chip *chip) +{ + if (!chip->need_valid_mask) + return 0; + + chip->valid_mask = kmalloc_array(BITS_TO_LONGS(chip->ngpio), + sizeof(long), GFP_KERNEL); + if (!chip->valid_mask) + return -ENOMEM; + + /* Assume by default all GPIOs are valid */ + bitmap_fill(chip->valid_mask, chip->ngpio); + + return 0; +} + +static void gpiochip_remove_valid_mask(struct gpio_chip *chip) +{ + kfree(chip->valid_mask); + chip->valid_mask = NULL; +} + /** * gpiod_get_direction - return the current direction of a GPIO * @desc: GPIO to get the direction of @@ -1225,10 +1247,14 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data, if (status) goto err_remove_from_list; - status = gpiochip_irqchip_init_valid_mask(chip); + status = gpiochip_init_valid_mask(chip); if (status) goto err_remove_from_list; + status = gpiochip_irqchip_init_valid_mask(chip); + if (status) + goto err_remove_valid_mask; + status = gpiochip_add_irqchip(chip, key); if (status) goto err_remove_chip; @@ -1259,6 +1285,8 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data, gpiochip_free_hogs(chip); of_gpiochip_remove(chip); gpiochip_irqchip_free_valid_mask(chip); +err_remove_valid_mask: + gpiochip_remove_valid_mask(chip); err_remove_from_list: spin_lock_irqsave(&gpio_lock, flags); list_del(&gdev->list); @@ -1311,6 +1339,7 @@ void gpiochip_remove(struct gpio_chip *chip) /* Numb the device, cancelling all outstanding operations */ gdev->chip = NULL; gpiochip_irqchip_remove(chip); + gpiochip_remove_valid_mask(chip); acpi_gpiochip_remove(chip); gpiochip_remove_pin_ranges(chip); of_gpiochip_remove(chip); @@ -1500,6 +1529,18 @@ static bool gpiochip_irqchip_irq_valid(const struct gpio_chip *gpiochip, return test_bit(offset, gpiochip->irq.valid_mask); } +static bool gpiochip_available(const struct gpio_chip *gpiochip, + unsigned int offset) +{ + pr_info("%s:%u offset=%u\n", __func__, __LINE__, offset); + + /* No mask means all valid */ + if (likely(!gpiochip->valid_mask)) + return true; + + return test_bit(offset, gpiochip->valid_mask); +} + /** * gpiochip_set_cascaded_irqchip() - connects a cascaded irqchip to a gpiochip * @gpiochip: the gpiochip to set the irqchip chain to @@ -3597,6 +3638,10 @@ struct gpio_desc *__must_check gpiod_get_index(struct device *dev, return desc; } + /* Check if the GPIO line itself is valid */ + if (!gpiochip_available(desc->gdev->chip, idx)) + return ERR_PTR(-EACCES); + status = gpiod_request(desc, con_id); if (status < 0) return ERR_PTR(status); diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index 55e672592fa9..b68450caf554 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -316,6 +316,9 @@ struct gpio_chip { int (*of_xlate)(struct gpio_chip *gc, const struct of_phandle_args *gpiospec, u32 *flags); #endif + + bool need_valid_mask; + unsigned long *valid_mask; }; extern const char *gpiochip_is_requested(struct gpio_chip *chip,
Add support for specifying that some GPIOs within a range are unavailable. Some systems have a sparse list of GPIOs, where a range of GPIOs is specified (usually 0 to n-1), but some subset within that range is absent or unavailable for whatever reason. To support this, allow drivers to specify a bitmask of GPIOs that are present or absent. Gpiolib will then block access to those that are absent. Signed-off-by: Timur Tabi <timur@codeaurora.org> --- drivers/gpio/gpiolib.c | 47 ++++++++++++++++++++++++++++++++++++++++++++- include/linux/gpio/driver.h | 3 +++ 2 files changed, 49 insertions(+), 1 deletion(-)