Message ID | 20100125181103.GB13805@oksana.dev.rtsoft.ru (mailing list archive) |
---|---|
State | Superseded |
Delegated to: | Grant Likely |
Headers | show |
On Monday 25 January 2010, Anton Vorontsov wrote: > With this patch there are two ways to register OF GPIO controllers: > > 1. Allocating the of_gpio_chip structure and passing the > &of_gc->gc pointer to the gpiochip_add. (Can use container_of > to convert the gpio_chip to the of_gpio_chip.) > > 2. Allocating and registering the gpio_chip structure separately > from the of_gpio_chip. (Since two allocations are separate, > container_of won't work.) > > As time goes by we'll kill the first option. Why have two options, instead of just the first/simpler one??
On Mon, Jan 25, 2010 at 10:36:15PM -0800, David Brownell wrote: > On Monday 25 January 2010, Anton Vorontsov wrote: > > With this patch there are two ways to register OF GPIO controllers: > > > > 1. Allocating the of_gpio_chip structure and passing the > > &of_gc->gc pointer to the gpiochip_add. (Can use container_of > > to convert the gpio_chip to the of_gpio_chip.) > > > > 2. Allocating and registering the gpio_chip structure separately > > from the of_gpio_chip. (Since two allocations are separate, > > container_of won't work.) > > > > As time goes by we'll kill the first option. > > Why have two options, instead of just the first/simpler one?? Because I2C/SPI drivers allocate (and register) gpio_chip structures by themselves, so the first option is a no-go. You can see the first option in use in arch/powerpc/sysdev/qe_lib/gpio.c: struct qe_gpio_chip { struct of_mm_gpio_chip mm_gc; .... }; Now include/linux/of_gpio.h: struct of_mm_gpio_chip { struct of_gpio_chip of_gc; ... }; struct of_gpio_chip { struct gpio_chip gc; <- here, I'm going to get rid of it ... }; I2C/SPI drivers allocate gpio_chip structure already, so we don't need to store 'struct gpio_chip gc', instead we need to store just a pointer, and then attach the already allocated gpio_chip to the of_gpio_chip stuff. Having two ways to store gpio_chip isn't good, that's why I stated that the first option will have to go, i.e. I'm going to convert arch/powerpc/sysdev/qe_lib/gpio.c and few other of_mm gpio chips to the new registration scheme soon. Thanks,
On Tuesday 26 January 2010, Anton Vorontsov wrote: > > > Why have two options, instead of just the first/simpler one?? > > Because I2C/SPI drivers allocate (and register) gpio_chip structures > by themselves, so the first option is a no-go. You should be mentioning such issues in the patch comments.
diff --git a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c index 82a9bcb..73c7e6b 100644 --- a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c +++ b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c @@ -93,6 +93,7 @@ static int mcu_gpiochip_add(struct mcu *mcu) gc->base = -1; gc->set = mcu_gpio_set; gc->direction_output = mcu_gpio_dir_out; + of_gc->chip = gc; of_gc->gpio_cells = 2; of_gc->xlate = of_gpio_simple_xlate; diff --git a/drivers/of/gpio.c b/drivers/of/gpio.c index 6eea601..12c4af0 100644 --- a/drivers/of/gpio.c +++ b/drivers/of/gpio.c @@ -70,7 +70,7 @@ int of_get_gpio_flags(struct device_node *np, int index, if (ret < 0) goto err1; - ret += of_gc->gc.base; + ret += of_gc->chip->base; err1: of_node_put(gc); err0: @@ -140,7 +140,7 @@ int of_gpio_simple_xlate(struct of_gpio_chip *of_gc, struct device_node *np, return -EINVAL; } - if (*gpio > of_gc->gc.ngpio) + if (*gpio > of_gc->chip->ngpio) return -EINVAL; if (flags) @@ -178,6 +178,25 @@ int of_mm_gpiochip_add(struct device_node *np, struct of_gpio_chip *of_gc = &mm_gc->of_gc; struct gpio_chip *gc = &of_gc->gc; + /* + * Currently there are two ways to register OF GPIO controllers: + * + * 1. Allocating the of_gpio_chip structure and passing the + * &of_gc->gc pointer to the gpiochip_add. (Can use container_of + * to convert the gpio_chip to the of_gpio_chip.) + * + * 2. Allocating and registering the gpio_chip structure separately + * from the of_gpio_chip. (Since two allocations are separate, + * container_of won't work.) + * + * As time goes by we'll kill the first option. For now just check + * if it's the new-style registration or the old-style. + */ + if (!of_gc->chip) + of_gc->chip = gc; + else + gc = of_gc->chip; + gc->label = kstrdup(np->full_name, GFP_KERNEL); if (!gc->label) goto err0; diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h index fc2472c..c74cb37 100644 --- a/include/linux/of_gpio.h +++ b/include/linux/of_gpio.h @@ -36,7 +36,8 @@ enum of_gpio_flags { * Generic OF GPIO chip */ struct of_gpio_chip { - struct gpio_chip gc; + struct gpio_chip gc; /* legacy, don't use for a new code */ + struct gpio_chip *chip; int gpio_cells; int (*xlate)(struct of_gpio_chip *of_gc, struct device_node *np, const void *gpio_spec, enum of_gpio_flags *flags);
With this patch there are two ways to register OF GPIO controllers: 1. Allocating the of_gpio_chip structure and passing the &of_gc->gc pointer to the gpiochip_add. (Can use container_of to convert the gpio_chip to the of_gpio_chip.) 2. Allocating and registering the gpio_chip structure separately from the of_gpio_chip. (Since two allocations are separate, container_of won't work.) As time goes by we'll kill the first option. Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com> --- arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c | 1 + drivers/of/gpio.c | 23 +++++++++++++++++++++-- include/linux/of_gpio.h | 3 ++- 3 files changed, 24 insertions(+), 3 deletions(-)