Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751396AbaLQSq5 (ORCPT ); Wed, 17 Dec 2014 13:46:57 -0500 Received: from mail-gw3-out.broadcom.com ([216.31.210.64]:61788 "EHLO mail-gw3-out.broadcom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751033AbaLQSqz (ORCPT ); Wed, 17 Dec 2014 13:46:55 -0500 X-IronPort-AV: E=Sophos;i="5.07,595,1413270000"; d="scan'208";a="53162998" From: Jonathan Richardson To: Tim Kryger CC: Scott Branden , Arun Ramamurthy , Thierry Reding , Ray Jui , , , , "Jonathan Richardson" Subject: [PATCH v3 2/2] pwm: kona: Remove setting default smooth type and polarity for all channels Date: Wed, 17 Dec 2014 10:46:22 -0800 Message-ID: <1418841982-29793-2-git-send-email-jonathar@broadcom.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1418841982-29793-1-git-send-email-jonathar@broadcom.com> References: <1418841982-29793-1-git-send-email-jonathar@broadcom.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Setting the default polarity in probe to normal for all channels caused the speaker pwm channel to click. The polarity does need to be set to normal because the hw default is inversed whereas the pwm framework defaults to normal. If a channel is enabled without setting the polarity then the signal would be inversed while linux reports normal. A check is now done prior to enabling the channel to ensure that the hw polarity matches the desired polarity and is changed if there is a discrepency. This prevents unnecessary settings being applied to unused channels but still ensures the correct polarity to be set. Reviewed-by: Scott Branden Tested-by: Scott Branden Signed-off-by: Jonathan Richardson --- drivers/pwm/pwm-bcm-kona.c | 38 ++++++++++++++++++++++++++++++++++---- 1 file changed, 34 insertions(+), 4 deletions(-) diff --git a/drivers/pwm/pwm-bcm-kona.c b/drivers/pwm/pwm-bcm-kona.c index a831bb2..101137d 100644 --- a/drivers/pwm/pwm-bcm-kona.c +++ b/drivers/pwm/pwm-bcm-kona.c @@ -95,6 +95,32 @@ static void kona_pwmc_apply_settings(struct kona_pwmc *kp, unsigned int chan) ndelay(400); } +static void kona_pwmc_check_set_polarity(struct pwm_chip *chip, + struct pwm_device *pwm) +{ + struct kona_pwmc *kp = to_kona_pwmc(chip); + unsigned int chan = pwm->hwpwm; + enum pwm_polarity polarity = pwm->polarity; + unsigned int hw_pol; + unsigned int value = 0; + + value = hw_pol = readl(kp->base + PWM_CONTROL_OFFSET); + hw_pol = (hw_pol >> PWM_CONTROL_POLARITY_SHIFT(chan)) & 0x1; + + /* + * If current polarity not the same as h/w then set polarity so that + * they match. + */ + if (!hw_pol != polarity) { + if (polarity == PWM_POLARITY_NORMAL) + value |= 1 << PWM_CONTROL_POLARITY_SHIFT(chan); + else + value &= ~(1 << PWM_CONTROL_POLARITY_SHIFT(chan)); + + writel(value, kp->base + PWM_CONTROL_OFFSET); + } +} + static int kona_pwmc_config(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns) { @@ -162,6 +188,13 @@ static int kona_pwmc_config(struct pwm_chip *chip, struct pwm_device *pwm, dev_dbg(chip->dev, "pwm[%d]: period=%lu, duty_high=%lu, prescale=%lu\n", chan, pc, dc, prescale); + /* + * Ensure polarity is set properly. The default value for h/w and the + * PWM framework are different. If a channel is enabled without setting + * the polarity, the default value would be inconsistent to the signal. + */ + kona_pwmc_check_set_polarity(chip, pwm); + value = readl(kp->base + PWM_CONTROL_OFFSET); /* @@ -310,11 +343,8 @@ static int kona_pwmc_probe(struct platform_device *pdev) } /* Set smooth mode, push/pull, and normal polarity for all channels */ - for (chan = 0; chan < kp->chip.npwm; chan++) { - value |= (1 << PWM_CONTROL_SMOOTH_SHIFT(chan)); + for (chan = 0; chan < kp->chip.npwm; chan++) value |= (1 << PWM_CONTROL_TYPE_SHIFT(chan)); - value |= (1 << PWM_CONTROL_POLARITY_SHIFT(chan)); - } writel(value, kp->base + PWM_CONTROL_OFFSET); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/