Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752048AbaKYTlc (ORCPT ); Tue, 25 Nov 2014 14:41:32 -0500 Received: from mail-gw1-out.broadcom.com ([216.31.210.62]:17061 "EHLO mail-gw1-out.broadcom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751961AbaKYTl2 (ORCPT ); Tue, 25 Nov 2014 14:41:28 -0500 X-IronPort-AV: E=Sophos;i="5.07,457,1413270000"; d="scan'208";a="51807624" From: Scott Branden To: Scott Branden , Thierry Reding CC: Ray Jui , Arun Ramamurthy , Tim Kryger , , , Subject: [PATCH v2 3/4] pwm: kona: Fix enable, disable and config procedures Date: Tue, 25 Nov 2014 11:40:40 -0800 Message-ID: <1416944441-12066-4-git-send-email-sbranden@broadcom.com> X-Mailer: git-send-email 2.1.3 In-Reply-To: <1416944441-12066-1-git-send-email-sbranden@broadcom.com> References: <1416944441-12066-1-git-send-email-sbranden@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 From: Arun Ramamurthy - Added helper functions to set and clear smooth and trigger bits - Added 400ns delays when clearing and setting trigger bit as requied by spec - Added helper function to write prescale and other settings - Updated config procedure to match spec - Added code to handle pwn config when channel is disabled - Updated disable procedure to match spec Signed-off-by: Arun Ramamurthy Reviewed-by: Ray Jui Signed-off-by: Scott Branden --- drivers/pwm/pwm-bcm-kona.c | 100 +++++++++++++++++++++++++++++++++++---------- 1 file changed, 78 insertions(+), 22 deletions(-) diff --git a/drivers/pwm/pwm-bcm-kona.c b/drivers/pwm/pwm-bcm-kona.c index fa0b5bf..06fa983 100644 --- a/drivers/pwm/pwm-bcm-kona.c +++ b/drivers/pwm/pwm-bcm-kona.c @@ -65,6 +65,10 @@ #define DUTY_CYCLE_HIGH_MIN (0x00000000) #define DUTY_CYCLE_HIGH_MAX (0x00ffffff) +/* The delay required after clearing or setting + PWMOUT_ENABLE*/ +#define PWMOUT_ENABLE_HOLD_DELAY 400 + struct kona_pwmc { struct pwm_chip chip; void __iomem *base; @@ -76,28 +80,70 @@ static inline struct kona_pwmc *to_kona_pwmc(struct pwm_chip *_chip) return container_of(_chip, struct kona_pwmc, chip); } -static void kona_pwmc_apply_settings(struct kona_pwmc *kp, unsigned int chan) +static inline void kona_pwmc_set_trigger(struct kona_pwmc *kp, + unsigned int chan) { unsigned int value = readl(kp->base + PWM_CONTROL_OFFSET); - /* Clear trigger bit but set smooth bit to maintain old output */ - value |= 1 << PWM_CONTROL_SMOOTH_SHIFT(chan); + /* set trigger bit to enable channel */ + value |= 1 << PWM_CONTROL_TRIGGER_SHIFT(chan); + writel(value, kp->base + PWM_CONTROL_OFFSET); + ndelay(PWMOUT_ENABLE_HOLD_DELAY); +} +static inline void kona_pwmc_clear_trigger(struct kona_pwmc *kp, + unsigned int chan) +{ + unsigned int value = readl(kp->base + PWM_CONTROL_OFFSET); + + /* Clear trigger bit */ value &= ~(1 << PWM_CONTROL_TRIGGER_SHIFT(chan)); writel(value, kp->base + PWM_CONTROL_OFFSET); + ndelay(PWMOUT_ENABLE_HOLD_DELAY); +} - /* Set trigger bit and clear smooth bit to apply new settings */ +static inline void kona_pwmc_clear_smooth(struct kona_pwmc *kp, + unsigned int chan) +{ + unsigned int value = readl(kp->base + PWM_CONTROL_OFFSET); + + /* Clear smooth bit */ value &= ~(1 << PWM_CONTROL_SMOOTH_SHIFT(chan)); - value |= 1 << PWM_CONTROL_TRIGGER_SHIFT(chan); writel(value, kp->base + PWM_CONTROL_OFFSET); } +static inline void kona_pwmc_set_smooth(struct kona_pwmc *kp, unsigned int chan) +{ + unsigned int value = readl(kp->base + PWM_CONTROL_OFFSET); + + /* set smooth bit to maintain old output */ + value |= 1 << PWM_CONTROL_SMOOTH_SHIFT(chan); + writel(value, kp->base + PWM_CONTROL_OFFSET); +} + +static void kona_pwmc_write_settings(struct kona_pwmc *kp, unsigned int chan, + unsigned long prescale, unsigned long pc, + unsigned long dc) +{ + unsigned int value; + + value = readl(kp->base + PRESCALE_OFFSET); + value &= ~PRESCALE_MASK(chan); + value |= prescale << PRESCALE_SHIFT(chan); + writel(value, kp->base + PRESCALE_OFFSET); + + writel(pc, kp->base + PERIOD_COUNT_OFFSET(chan)); + + writel(dc, kp->base + DUTY_CYCLE_HIGH_OFFSET(chan)); + +} + static int kona_pwmc_config(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns) { struct kona_pwmc *kp = to_kona_pwmc(chip); u64 val, div, rate; unsigned long prescale = PRESCALE_MIN, pc, dc; - unsigned int value, chan = pwm->hwpwm; + unsigned int ret, chan = pwm->hwpwm; /* * Find period count, duty count and prescale to suit duty_ns and @@ -133,19 +179,30 @@ static int kona_pwmc_config(struct pwm_chip *chip, struct pwm_device *pwm, return -EINVAL; } - /* If the PWM channel is enabled, write the settings to the HW */ - if (test_bit(PWMF_ENABLED, &pwm->flags)) { - value = readl(kp->base + PRESCALE_OFFSET); - value &= ~PRESCALE_MASK(chan); - value |= prescale << PRESCALE_SHIFT(chan); - writel(value, kp->base + PRESCALE_OFFSET); - writel(pc, kp->base + PERIOD_COUNT_OFFSET(chan)); + /* If the PWM channel is not enabled, enable the clock */ + if (!test_bit(PWMF_ENABLED, &pwm->flags)) { + ret = clk_prepare_enable(kp->clk); + if (ret < 0) { + dev_err(chip->dev, "failed to enable clock: %d\n", ret); + return ret; + } + } - writel(dc, kp->base + DUTY_CYCLE_HIGH_OFFSET(chan)); + /* Set smooth bit to maintain old output */ + kona_pwmc_set_smooth(kp, chan); + kona_pwmc_clear_trigger(kp, chan); + + /* apply new settings */ + kona_pwmc_write_settings(kp, chan, prescale, pc, dc); + + /*If the PWM is enabled, enable the channel with the new settings + and if not disable the clock*/ + if (test_bit(PWMF_ENABLED, &pwm->flags)) + kona_pwmc_set_trigger(kp, chan); + else + clk_disable_unprepare(kp->clk); - kona_pwmc_apply_settings(kp, chan); - } return 0; } @@ -188,7 +245,6 @@ static int kona_pwmc_enable(struct pwm_chip *chip, struct pwm_device *pwm) dev_err(chip->dev, "failed to enable clock: %d\n", ret); return ret; } - ret = kona_pwmc_config(chip, pwm, pwm->duty_cycle, pwm->period); if (ret < 0) { clk_disable_unprepare(kp->clk); @@ -203,12 +259,12 @@ static void kona_pwmc_disable(struct pwm_chip *chip, struct pwm_device *pwm) struct kona_pwmc *kp = to_kona_pwmc(chip); unsigned int chan = pwm->hwpwm; + kona_pwmc_clear_smooth(kp, chan); + kona_pwmc_clear_trigger(kp, chan); /* Simulate a disable by configuring for zero duty */ - writel(0, kp->base + DUTY_CYCLE_HIGH_OFFSET(chan)); - kona_pwmc_apply_settings(kp, chan); - - /* Wait for waveform to settle before gating off the clock */ - ndelay(400); + kona_pwmc_write_settings(kp, chan, 0, 0, 0); + kona_pwmc_set_polarity(chip, pwm, PWM_POLARITY_NORMAL); + kona_pwmc_set_trigger(kp, chan); clk_disable_unprepare(kp->clk); } -- 2.1.3 -- 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/