| Message ID | 20191028073912.25743-1-warthog618@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | gpio: add new SET_CONFIG ioctl() to gpio chardev | expand |
pon., 28 paź 2019 o 08:39 Kent Gibson <warthog618@gmail.com> napisał(a): > > Add the GPIOHANDLE_SET_CONFIG_IOCTL to the gpio chardev. > The ioctl allows some of the configuration of a requested handle to be > changed without having to release the line. > The primary use case is the changing of direction for bi-directional > lines. > > Based on initial work by Bartosz Golaszewski <bgolaszewski@baylibre.com> > > Signed-off-by: Kent Gibson <warthog618@gmail.com> > --- > > The patch is against Bart's gpio/for-next branch[1] with v4 of my bias > patch series "gpio: expose line bias flags to userspace" applied. > This is necessary to support setting of the bias flags introduced > there. > > The patch has been successfully tested against gpio-mockup using the > feature/pud_set_config branch of my Go gpiod library[2], as libgpiod has > not yet been updated with the uAPI change. > > drivers/gpio/gpiolib.c | 163 ++++++++++++++++++++++++++------------ > include/uapi/linux/gpio.h | 18 +++++ > 2 files changed, 132 insertions(+), 49 deletions(-) > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > index df27f05f9b8d..62a74e27ad02 100644 > --- a/drivers/gpio/gpiolib.c > +++ b/drivers/gpio/gpiolib.c > @@ -427,23 +427,74 @@ struct linehandle_state { > GPIOHANDLE_REQUEST_OPEN_DRAIN | \ > GPIOHANDLE_REQUEST_OPEN_SOURCE) > > +static int linehandle_validate_flags(u32 flags) > +{ > + /* Return an error if an unknown flag is set */ > + if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) > + return -EINVAL; > + > + /* > + * Do not allow both INPUT & OUTPUT flags to be set as they are > + * contradictory. > + */ > + if ((flags & GPIOHANDLE_REQUEST_INPUT) && > + (flags & GPIOHANDLE_REQUEST_OUTPUT)) > + return -EINVAL; > + > + /* > + * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If > + * the hardware actually supports enabling both at the same time the > + * electrical result would be disastrous. > + */ > + if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) && > + (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) > + return -EINVAL; > + > + /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */ > + if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) && > + ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || > + (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))) > + return -EINVAL; > + > + /* Bias flags only allowed for input or output mode. */ > + if (!((flags & GPIOHANDLE_REQUEST_INPUT) || > + (flags & GPIOHANDLE_REQUEST_OUTPUT)) && > + ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) || > + (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) || > + (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN))) > + return -EINVAL; > + > + /* Only one bias flag can be set. */ > + if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && > + (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | > + GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || > + ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && > + (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) > + return -EINVAL; > + > + return 0; > +} > + This is great but I'd prefer that it be put into a separate patch with its own description that would come before the other changes. > static long linehandle_ioctl(struct file *filep, unsigned int cmd, > unsigned long arg) > { > struct linehandle_state *lh = filep->private_data; > void __user *ip = (void __user *)arg; > struct gpiohandle_data ghd; > + struct gpiohandle_config gcnf; > + struct gpio_desc *desc; > DECLARE_BITMAP(vals, GPIOHANDLES_MAX); > - int i; > + int i, ret; > + u32 lflags; > > if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { > /* NOTE: It's ok to read values of output lines. */ > - int ret = gpiod_get_array_value_complex(false, > - true, > - lh->numdescs, > - lh->descs, > - NULL, > - vals); > + ret = gpiod_get_array_value_complex(false, > + true, > + lh->numdescs, > + lh->descs, > + NULL, > + vals); > if (ret) > return ret; > > @@ -477,6 +528,59 @@ static long linehandle_ioctl(struct file *filep, unsigned int cmd, > lh->descs, > NULL, > vals); > + } else if (cmd == GPIOHANDLE_SET_CONFIG_IOCTL) { > + if (copy_from_user(&gcnf, ip, sizeof(gcnf))) > + return -EFAULT; > + > + lflags = gcnf.flags; > + ret = linehandle_validate_flags(lflags); > + if (ret) > + return ret; > + > + for (i = 0; i < lh->numdescs; i++) { > + desc = lh->descs[i]; > + if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW) > + set_bit(FLAG_ACTIVE_LOW, &desc->flags); > + else > + clear_bit(FLAG_ACTIVE_LOW, &desc->flags); > + if (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) > + set_bit(FLAG_OPEN_DRAIN, &desc->flags); > + else > + clear_bit(FLAG_OPEN_DRAIN, &desc->flags); > + if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE) > + set_bit(FLAG_OPEN_SOURCE, &desc->flags); > + else > + clear_bit(FLAG_OPEN_SOURCE, &desc->flags); > + if (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) > + set_bit(FLAG_PULL_UP, &desc->flags); > + else > + clear_bit(FLAG_PULL_UP, &desc->flags); > + if (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) > + set_bit(FLAG_PULL_DOWN, &desc->flags); > + else > + clear_bit(FLAG_PULL_DOWN, &desc->flags); > + if (lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) > + set_bit(FLAG_BIAS_DISABLE, &desc->flags); > + else > + clear_bit(FLAG_BIAS_DISABLE, &desc->flags); Could you add some new lines between the if elses? I think it'll be more readable. > + > + /* > + * Lines have to be requested explicitly for input > + * or output, else the line will be treated "as is". > + */ > + if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { > + int val = !!gcnf.default_values[i]; > + > + ret = gpiod_direction_output(desc, val); > + if (ret) > + return ret; > + } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { > + ret = gpiod_direction_input(desc); > + if (ret) > + return ret; > + } > + } > + return 0; > } > return -EINVAL; > } > @@ -528,48 +632,9 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip) > > lflags = handlereq.flags; > > - /* Return an error if an unknown flag is set */ > - if (lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) > - return -EINVAL; > - > - /* > - * Do not allow both INPUT & OUTPUT flags to be set as they are > - * contradictory. > - */ > - if ((lflags & GPIOHANDLE_REQUEST_INPUT) && > - (lflags & GPIOHANDLE_REQUEST_OUTPUT)) > - return -EINVAL; > - > - /* > - * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If > - * the hardware actually supports enabling both at the same time the > - * electrical result would be disastrous. > - */ > - if ((lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) && > - (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) > - return -EINVAL; > - > - /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */ > - if (!(lflags & GPIOHANDLE_REQUEST_OUTPUT) && > - ((lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || > - (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))) > - return -EINVAL; > - > - /* Bias flags only allowed for input or output mode. */ > - if (!((lflags & GPIOHANDLE_REQUEST_INPUT) || > - (lflags & GPIOHANDLE_REQUEST_OUTPUT)) && > - ((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) || > - (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) || > - (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN))) > - return -EINVAL; > - > - /* Only one bias flag can be set. */ > - if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && > - (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | > - GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || > - ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && > - (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) > - return -EINVAL; > + ret = linehandle_validate_flags(lflags); > + if (ret) > + return ret; > > lh = kzalloc(sizeof(*lh), GFP_KERNEL); > if (!lh) > diff --git a/include/uapi/linux/gpio.h b/include/uapi/linux/gpio.h > index 7cc21c3b0839..799cf823d493 100644 > --- a/include/uapi/linux/gpio.h > +++ b/include/uapi/linux/gpio.h > @@ -100,6 +100,24 @@ struct gpiohandle_request { > int fd; > }; > > +/** > + * struct gpiohandle_config - Configuration for a GPIO handle request > + * @flags: updated flags for the requested GPIO lines, such as > + * GPIOHANDLE_REQUEST_OUTPUT, GPIOHANDLE_REQUEST_ACTIVE_LOW etc, OR:ed > + * together > + * @default_values: if the GPIOHANDLE_REQUEST_OUTPUT is set in flags, > + * this specifies the default output value, should be 0 (low) or > + * 1 (high), anything else than 0 or 1 will be interpreted as 1 (high) > + * @padding: reserved for future use and should be zero filled > + */ > +struct gpiohandle_config { > + __u32 flags; > + __u8 default_values[GPIOHANDLES_MAX]; > + __u32 padding[4]; /* padding for future use */ > +}; > + > +#define GPIOHANDLE_SET_CONFIG_IOCTL _IOWR(0xB4, 0x0a, struct gpiohandle_config) > + > /** > * struct gpiohandle_data - Information of values on a GPIO handle > * @values: when getting the state of lines this contains the current > -- > 2.23.0 > > [1] git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux.git > [2] https://github.com/warthog618/gpiod.git Bart
On Thu, Oct 31, 2019 at 08:11:00AM +0100, Bartosz Golaszewski wrote: > pon., 28 paź 2019 o 08:39 Kent Gibson <warthog618@gmail.com> napisał(a): > > > > Add the GPIOHANDLE_SET_CONFIG_IOCTL to the gpio chardev. > > The ioctl allows some of the configuration of a requested handle to be > > changed without having to release the line. > > The primary use case is the changing of direction for bi-directional > > lines. > > > > Based on initial work by Bartosz Golaszewski <bgolaszewski@baylibre.com> > > > > Signed-off-by: Kent Gibson <warthog618@gmail.com> > > --- > > > > The patch is against Bart's gpio/for-next branch[1] with v4 of my bias > > patch series "gpio: expose line bias flags to userspace" applied. > > This is necessary to support setting of the bias flags introduced > > there. > > > > The patch has been successfully tested against gpio-mockup using the > > feature/pud_set_config branch of my Go gpiod library[2], as libgpiod has > > not yet been updated with the uAPI change. > > > > drivers/gpio/gpiolib.c | 163 ++++++++++++++++++++++++++------------ > > include/uapi/linux/gpio.h | 18 +++++ > > 2 files changed, 132 insertions(+), 49 deletions(-) > > > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > > index df27f05f9b8d..62a74e27ad02 100644 > > --- a/drivers/gpio/gpiolib.c > > +++ b/drivers/gpio/gpiolib.c > > @@ -427,23 +427,74 @@ struct linehandle_state { > > GPIOHANDLE_REQUEST_OPEN_DRAIN | \ > > GPIOHANDLE_REQUEST_OPEN_SOURCE) > > > > +static int linehandle_validate_flags(u32 flags) > > +{ > > + /* Return an error if an unknown flag is set */ > > + if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) > > + return -EINVAL; > > + > > + /* > > + * Do not allow both INPUT & OUTPUT flags to be set as they are > > + * contradictory. > > + */ > > + if ((flags & GPIOHANDLE_REQUEST_INPUT) && > > + (flags & GPIOHANDLE_REQUEST_OUTPUT)) > > + return -EINVAL; > > + > > + /* > > + * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If > > + * the hardware actually supports enabling both at the same time the > > + * electrical result would be disastrous. > > + */ > > + if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) && > > + (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) > > + return -EINVAL; > > + > > + /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */ > > + if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) && > > + ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || > > + (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))) > > + return -EINVAL; > > + > > + /* Bias flags only allowed for input or output mode. */ > > + if (!((flags & GPIOHANDLE_REQUEST_INPUT) || > > + (flags & GPIOHANDLE_REQUEST_OUTPUT)) && > > + ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) || > > + (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) || > > + (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN))) > > + return -EINVAL; > > + > > + /* Only one bias flag can be set. */ > > + if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && > > + (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | > > + GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || > > + ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && > > + (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) > > + return -EINVAL; > > + > > + return 0; > > +} > > + > > This is great but I'd prefer that it be put into a separate patch with > its own description that would come before the other changes. > Will do. > > static long linehandle_ioctl(struct file *filep, unsigned int cmd, > > unsigned long arg) > > { > > struct linehandle_state *lh = filep->private_data; > > void __user *ip = (void __user *)arg; > > struct gpiohandle_data ghd; > > + struct gpiohandle_config gcnf; > > + struct gpio_desc *desc; > > DECLARE_BITMAP(vals, GPIOHANDLES_MAX); > > - int i; > > + int i, ret; > > + u32 lflags; > > > > if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { > > /* NOTE: It's ok to read values of output lines. */ > > - int ret = gpiod_get_array_value_complex(false, > > - true, > > - lh->numdescs, > > - lh->descs, > > - NULL, > > - vals); > > + ret = gpiod_get_array_value_complex(false, > > + true, > > + lh->numdescs, > > + lh->descs, > > + NULL, > > + vals); > > if (ret) > > return ret; > > > > @@ -477,6 +528,59 @@ static long linehandle_ioctl(struct file *filep, unsigned int cmd, > > lh->descs, > > NULL, > > vals); > > + } else if (cmd == GPIOHANDLE_SET_CONFIG_IOCTL) { > > + if (copy_from_user(&gcnf, ip, sizeof(gcnf))) > > + return -EFAULT; > > + > > + lflags = gcnf.flags; > > + ret = linehandle_validate_flags(lflags); > > + if (ret) > > + return ret; > > + > > + for (i = 0; i < lh->numdescs; i++) { > > + desc = lh->descs[i]; > > + if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW) > > + set_bit(FLAG_ACTIVE_LOW, &desc->flags); > > + else > > + clear_bit(FLAG_ACTIVE_LOW, &desc->flags); > > + if (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) > > + set_bit(FLAG_OPEN_DRAIN, &desc->flags); > > + else > > + clear_bit(FLAG_OPEN_DRAIN, &desc->flags); > > + if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE) > > + set_bit(FLAG_OPEN_SOURCE, &desc->flags); > > + else > > + clear_bit(FLAG_OPEN_SOURCE, &desc->flags); > > + if (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) > > + set_bit(FLAG_PULL_UP, &desc->flags); > > + else > > + clear_bit(FLAG_PULL_UP, &desc->flags); > > + if (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) > > + set_bit(FLAG_PULL_DOWN, &desc->flags); > > + else > > + clear_bit(FLAG_PULL_DOWN, &desc->flags); > > + if (lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) > > + set_bit(FLAG_BIAS_DISABLE, &desc->flags); > > + else > > + clear_bit(FLAG_BIAS_DISABLE, &desc->flags); > > Could you add some new lines between the if elses? I think it'll be > more readable. > Agreed. I would prefer to call a function that atomically sets or clears the flag bit based on the requested state, but there doesn't seem to be one. Cheers, Kent.
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index df27f05f9b8d..62a74e27ad02 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -427,23 +427,74 @@ struct linehandle_state { GPIOHANDLE_REQUEST_OPEN_DRAIN | \ GPIOHANDLE_REQUEST_OPEN_SOURCE) +static int linehandle_validate_flags(u32 flags) +{ + /* Return an error if an unknown flag is set */ + if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) + return -EINVAL; + + /* + * Do not allow both INPUT & OUTPUT flags to be set as they are + * contradictory. + */ + if ((flags & GPIOHANDLE_REQUEST_INPUT) && + (flags & GPIOHANDLE_REQUEST_OUTPUT)) + return -EINVAL; + + /* + * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If + * the hardware actually supports enabling both at the same time the + * electrical result would be disastrous. + */ + if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) && + (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) + return -EINVAL; + + /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */ + if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) && + ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || + (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))) + return -EINVAL; + + /* Bias flags only allowed for input or output mode. */ + if (!((flags & GPIOHANDLE_REQUEST_INPUT) || + (flags & GPIOHANDLE_REQUEST_OUTPUT)) && + ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) || + (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) || + (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN))) + return -EINVAL; + + /* Only one bias flag can be set. */ + if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && + (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | + GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || + ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && + (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) + return -EINVAL; + + return 0; +} + static long linehandle_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) { struct linehandle_state *lh = filep->private_data; void __user *ip = (void __user *)arg; struct gpiohandle_data ghd; + struct gpiohandle_config gcnf; + struct gpio_desc *desc; DECLARE_BITMAP(vals, GPIOHANDLES_MAX); - int i; + int i, ret; + u32 lflags; if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) { /* NOTE: It's ok to read values of output lines. */ - int ret = gpiod_get_array_value_complex(false, - true, - lh->numdescs, - lh->descs, - NULL, - vals); + ret = gpiod_get_array_value_complex(false, + true, + lh->numdescs, + lh->descs, + NULL, + vals); if (ret) return ret; @@ -477,6 +528,59 @@ static long linehandle_ioctl(struct file *filep, unsigned int cmd, lh->descs, NULL, vals); + } else if (cmd == GPIOHANDLE_SET_CONFIG_IOCTL) { + if (copy_from_user(&gcnf, ip, sizeof(gcnf))) + return -EFAULT; + + lflags = gcnf.flags; + ret = linehandle_validate_flags(lflags); + if (ret) + return ret; + + for (i = 0; i < lh->numdescs; i++) { + desc = lh->descs[i]; + if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW) + set_bit(FLAG_ACTIVE_LOW, &desc->flags); + else + clear_bit(FLAG_ACTIVE_LOW, &desc->flags); + if (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) + set_bit(FLAG_OPEN_DRAIN, &desc->flags); + else + clear_bit(FLAG_OPEN_DRAIN, &desc->flags); + if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE) + set_bit(FLAG_OPEN_SOURCE, &desc->flags); + else + clear_bit(FLAG_OPEN_SOURCE, &desc->flags); + if (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) + set_bit(FLAG_PULL_UP, &desc->flags); + else + clear_bit(FLAG_PULL_UP, &desc->flags); + if (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) + set_bit(FLAG_PULL_DOWN, &desc->flags); + else + clear_bit(FLAG_PULL_DOWN, &desc->flags); + if (lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) + set_bit(FLAG_BIAS_DISABLE, &desc->flags); + else + clear_bit(FLAG_BIAS_DISABLE, &desc->flags); + + /* + * Lines have to be requested explicitly for input + * or output, else the line will be treated "as is". + */ + if (lflags & GPIOHANDLE_REQUEST_OUTPUT) { + int val = !!gcnf.default_values[i]; + + ret = gpiod_direction_output(desc, val); + if (ret) + return ret; + } else if (lflags & GPIOHANDLE_REQUEST_INPUT) { + ret = gpiod_direction_input(desc); + if (ret) + return ret; + } + } + return 0; } return -EINVAL; } @@ -528,48 +632,9 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip) lflags = handlereq.flags; - /* Return an error if an unknown flag is set */ - if (lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) - return -EINVAL; - - /* - * Do not allow both INPUT & OUTPUT flags to be set as they are - * contradictory. - */ - if ((lflags & GPIOHANDLE_REQUEST_INPUT) && - (lflags & GPIOHANDLE_REQUEST_OUTPUT)) - return -EINVAL; - - /* - * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If - * the hardware actually supports enabling both at the same time the - * electrical result would be disastrous. - */ - if ((lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) && - (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)) - return -EINVAL; - - /* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */ - if (!(lflags & GPIOHANDLE_REQUEST_OUTPUT) && - ((lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) || - (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))) - return -EINVAL; - - /* Bias flags only allowed for input or output mode. */ - if (!((lflags & GPIOHANDLE_REQUEST_INPUT) || - (lflags & GPIOHANDLE_REQUEST_OUTPUT)) && - ((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) || - (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) || - (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN))) - return -EINVAL; - - /* Only one bias flag can be set. */ - if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) && - (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | - GPIOHANDLE_REQUEST_BIAS_PULL_UP))) || - ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) && - (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP))) - return -EINVAL; + ret = linehandle_validate_flags(lflags); + if (ret) + return ret; lh = kzalloc(sizeof(*lh), GFP_KERNEL); if (!lh) diff --git a/include/uapi/linux/gpio.h b/include/uapi/linux/gpio.h index 7cc21c3b0839..799cf823d493 100644 --- a/include/uapi/linux/gpio.h +++ b/include/uapi/linux/gpio.h @@ -100,6 +100,24 @@ struct gpiohandle_request { int fd; }; +/** + * struct gpiohandle_config - Configuration for a GPIO handle request + * @flags: updated flags for the requested GPIO lines, such as + * GPIOHANDLE_REQUEST_OUTPUT, GPIOHANDLE_REQUEST_ACTIVE_LOW etc, OR:ed + * together + * @default_values: if the GPIOHANDLE_REQUEST_OUTPUT is set in flags, + * this specifies the default output value, should be 0 (low) or + * 1 (high), anything else than 0 or 1 will be interpreted as 1 (high) + * @padding: reserved for future use and should be zero filled + */ +struct gpiohandle_config { + __u32 flags; + __u8 default_values[GPIOHANDLES_MAX]; + __u32 padding[4]; /* padding for future use */ +}; + +#define GPIOHANDLE_SET_CONFIG_IOCTL _IOWR(0xB4, 0x0a, struct gpiohandle_config) + /** * struct gpiohandle_data - Information of values on a GPIO handle * @values: when getting the state of lines this contains the current
Add the GPIOHANDLE_SET_CONFIG_IOCTL to the gpio chardev. The ioctl allows some of the configuration of a requested handle to be changed without having to release the line. The primary use case is the changing of direction for bi-directional lines. Based on initial work by Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Kent Gibson <warthog618@gmail.com> --- The patch is against Bart's gpio/for-next branch[1] with v4 of my bias patch series "gpio: expose line bias flags to userspace" applied. This is necessary to support setting of the bias flags introduced there. The patch has been successfully tested against gpio-mockup using the feature/pud_set_config branch of my Go gpiod library[2], as libgpiod has not yet been updated with the uAPI change. drivers/gpio/gpiolib.c | 163 ++++++++++++++++++++++++++------------ include/uapi/linux/gpio.h | 18 +++++ 2 files changed, 132 insertions(+), 49 deletions(-)