Hi Khouloud, 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()? Once that's implemented, I assume it will be auto-released on registration failure by the call to put_device()? > + if (IS_ERR(nvmem->wp_gpio)) > + return PTR_ERR(nvmem->wp_gpio); > + > > kref_init(&nvmem->refcnt); > INIT_LIST_HEAD(&nvmem->cells); 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
