From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Gatliff Subject: Re: [PWM PATCH 1/7] API to consolidate PWM devices behind a common user and kernel interface Date: Wed, 10 Feb 2010 07:55:04 -0600 Message-ID: <4B72BAB8.4090008@billgatliff.com> References: Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: H Hartley Sweeten Cc: linux-embedded@vger.kernel.org, linux-kernel@vger.kernel.org H Hartley Sweeten wrote: >> +int pwm_set_polarity(struct pwm_channel *p, >> + int active_high) >> +{ >> + struct pwm_channel_config c = { >> + .config_mask = PWM_CONFIG_POLARITY, >> + .polarity = active_high, >> + }; >> + return pwm_config(p, &c); >> +} >> +EXPORT_SYMBOL(pwm_set_polarity); >> > > Has the 'polarity' logic been verified? > > pwm_set_polarity takes an active high flag that is passed to pwm_config. > A write to the sysfs 'polarity' file passes the value directly to pwm_config. > A read from the sysfs 'polarity' file returns struct pwm_channel ->active_low. > > Seems like a mis-match in logic. > It was. And on top of that, none of the drivers were reflecting their polarity in their pwm_channel structures. I renamed the channel structure variable to active_high for consistency, and updated each of the drivers to set that value consistent with their actual polarities. Very good catch. b.g. -- Bill Gatliff Embedded systems training and consulting http://billgatliff.com bgat@billgatliff.com