From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johan Hovold Date: Fri, 20 Apr 2012 16:45:53 +0000 Subject: Re: [PATCH 3/4] leds: add LM3533 LED driver Message-Id: <20120420164553.GA12376@localhost> List-Id: References: <1334935826-12527-1-git-send-email-jhovold@gmail.com> <1334935826-12527-4-git-send-email-jhovold@gmail.com> <201204201610.15758.arnd@arndb.de> In-Reply-To: <201204201610.15758.arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Arnd Bergmann Cc: Richard Purdie , Samuel Ortiz , Greg Kroah-Hartman , Florian Tobias Schandinat , Andrew Morton , linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org On Fri, Apr 20, 2012 at 04:10:15PM +0000, Arnd Bergmann wrote: > On Friday 20 April 2012, Johan Hovold wrote: > > Add sub-driver for the LEDs in National Semiconductor / TI LM3533 > > lighting power chips. > > > > The chip provides 256 brightness levels, hardware accelerated blinking > > as well as ambient-light-sensor and pwm input control. > > > > Signed-off-by: Johan Hovold > > I notice that there is already driver for lm3530, which sounds related. > Is there an opportunity to share code between these, or are they completely > different devices? Unfortunately not. They are really very different devices despite similar naming and terminology. > > + > > +#define show_ctrlbank_attr(_name) \ > > +static ssize_t show_##_name(struct device *dev, \ > > + struct device_attribute *attr, \ > > + char *buf) \ > > +{ \ > > + struct led_classdev *led_cdev = dev_get_drvdata(dev); \ > > + struct lm3533_led *led = to_lm3533_led(led_cdev); \ > > + u8 val; \ > > + int ret; \ > > + \ > > + ret = lm3533_ctrlbank_get_##_name(&led->cb, &val); \ > > + if (ret) \ > > + return ret; \ > > + \ > > + return scnprintf(buf, PAGE_SIZE, "%d\n", val); \ > > +} > > IMHO this macro adds more in terms of complexity than it saves in terms > of lines of code, and it would be better to open-code the two instances. > If you need more than two or three instances, I would recommend creating > keying the number off of the attribute pointer, either by comparing the > pointer or by adding a data structure derived from device_attribute and > using container_of to get at the other data. Agreed. I'll simply open-code them for now, and do the same with the equivalent instances in the backlight driver. Thanks, Johan