From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Date: Fri, 20 Apr 2012 16:10:15 +0000 Subject: Re: [PATCH 3/4] leds: add LM3533 LED driver Message-Id: <201204201610.15758.arnd@arndb.de> List-Id: References: <1334935826-12527-1-git-send-email-jhovold@gmail.com> <1334935826-12527-4-git-send-email-jhovold@gmail.com> In-Reply-To: <1334935826-12527-4-git-send-email-jhovold@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Johan Hovold Cc: Richard Purdie , Samuel Ortiz , Greg Kroah-Hartman , Florian Tobias Schandinat , Andrew Morton , linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org 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? > + > +#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. Arnd