Hi Bartosz, On Mon, Feb 17, 2020 at 3:34 PM Bartosz Golaszewski <brgl@xxxxxxxx> wrote: > czw., 30 sty 2020 o 09:06 Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> napisał(a): > > On Tue, Jan 7, 2020 at 10:30 AM Khouloud Touil <ktouil@xxxxxxxxxxxx> wrote: > > > The write-protect pin handling looks like a standard property that > > > could benefit other users if available in the core nvmem framework. > > > > > > Instead of modifying all the memory drivers to check this pin, make > > > the NVMEM subsystem check if the write-protect GPIO being passed > > > through the nvmem_config or defined in the device tree and pull it > > > low whenever writing to the memory. > > > > > > There was a suggestion for introducing the gpiodesc from pdata, but > > > as pdata is already removed it could be replaced by adding it to > > > nvmem_config. > > > > > > Reference: https://lists.96boards.org/pipermail/dev/2018-August/001056.html > > > > > > Signed-off-by: Khouloud Touil <ktouil@xxxxxxxxxxxx> > > > Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx> > > > Acked-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx> > > > > Thanks for your patch! > > > > > --- a/drivers/nvmem/core.c > > > +++ b/drivers/nvmem/core.c > > > @@ -15,6 +15,7 @@ > > > #include <linux/module.h> > > > #include <linux/nvmem-consumer.h> > > > #include <linux/nvmem-provider.h> > > > +#include <linux/gpio/consumer.h> > > > #include <linux/of.h> > > > #include <linux/slab.h> > > > #include "nvmem.h" > > > @@ -54,8 +55,14 @@ static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset, > > > static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset, > > > void *val, size_t bytes) > > > { > > > - if (nvmem->reg_write) > > > - return nvmem->reg_write(nvmem->priv, offset, val, bytes); > > > + int ret; > > > + > > > + if (nvmem->reg_write) { > > > + gpiod_set_value_cansleep(nvmem->wp_gpio, 0); > > > + ret = nvmem->reg_write(nvmem->priv, offset, val, bytes); > > > + gpiod_set_value_cansleep(nvmem->wp_gpio, 1); > > > + return ret; > > > + } > > > > > > return -EINVAL; > > > } > > > @@ -338,6 +345,14 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) > > > kfree(nvmem); > > > return ERR_PTR(rval); > > > } > > > + if (config->wp_gpio) > > > + nvmem->wp_gpio = config->wp_gpio; > > > + else > > > + nvmem->wp_gpio = gpiod_get_optional(config->dev, "wp", > > > + GPIOD_OUT_HIGH); > > > > Shouldn't this GPIO be released in nvmem_release(), by calling gpiod_put()? > > > > Hi Geert, > > Khouloud already sent out a patch but I think it still doesn't fix all > the problems. > > While we should call gpiod_put() for the descs we request - we must > not do it for the desc we get over the config structure. Unless... we That's true. > make descs reference counted with kref and add gpiod_ref() helper. > That way we could increase the reference counter in the upper branch > of the if and not do it in the lower. Calling gpiod_put() would > internally call kref_put(). Does it make sense? I think that a > function that's called gpiod_put() but doesn't really use reference > counting is misleading anyway. Yep. > > Once that's implemented, I assume it will be auto-released on registration > > failure by the call to put_device()? > > No, I think this is another leak - why would put_device() lead to > freeing any resources? Am I missing something? Sorry, I don't remember why I wrote that part... Anyway, requested GPIOs should be released on failure, and on unregistration. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
