Messages in this thread | | | Subject | RE: [spi-devel-general] [PATCH] drivers/misc: add driver for TexasInstruments DAC7512 | Date | Mon, 12 Oct 2009 12:31:46 -0400 | From | "H Hartley Sweeten" <> |
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On Wednesday, October 07, 2009 1:01 PM, Daniel Mack wrote: > This is actually too trivial to publish, but to export the function of > that chip to the userspace, a module like this is needed. > > Signed-off-by: Daniel Mack <daniel@caiaq.de> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: David Brownell <dbrownell@users.sourceforge.net> > Cc: spi-devel-general@lists.sourceforge.net > ---
[snip]
> +static ssize_t dac7512_store_val(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + struct spi_device *spi = to_spi_device(dev); > + unsigned char tmp[2]; > + unsigned long val; > + > + if (strict_strtoul(buf, 10, &val) < 0) > + return -EINVAL; > + > + tmp[0] = val >> 8; > + tmp[1] = val & 0xff; > + spi_write(spi, tmp, sizeof(tmp)); > + return count; > +} > + > +static DEVICE_ATTR(value, S_IWUSR | S_IRUGO, > + NULL, dac7512_store_val);
You have declared the "value" device attribute with mode S_IWUSR | S_IRUGO but have not provided a show callback.
Regards, Hartley
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