From patchwork Wed Oct 8 16:43:15 2008 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bill Gatliff X-Patchwork-Id: 3330 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [127.0.0.1]) by ozlabs.org (Postfix) with ESMTP id BB1A9DE923 for ; Thu, 9 Oct 2008 04:18:12 +1100 (EST) X-Original-To: linuxppc-dev@ozlabs.org Delivered-To: linuxppc-dev@ozlabs.org Received: from venus.billgatliff.com (venus.billgatliff.com [209.251.101.201]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 6E7EBDDF3A for ; Thu, 9 Oct 2008 04:17:17 +1100 (EST) Received: from mercury.billgatliff.com (adsl-75-17-76-65.dsl.peoril.sbcglobal.net [75.17.76.65]) by venus.billgatliff.com (Postfix) with ESMTP id 8F97EDC130; Wed, 8 Oct 2008 11:43:16 -0500 (CDT) Received: by mercury.billgatliff.com (Postfix, from userid 1000) id 79A7A149A356; Wed, 8 Oct 2008 11:43:17 -0500 (CDT) From: Bill Gatliff To: linuxppc-dev@ozlabs.org Subject: [RFC 4/6] [PWM] Driver for Atmel PWMC peripheral Date: Wed, 8 Oct 2008 11:43:15 -0500 Message-Id: <5640f37b779f953c83e79c16b2a0466c0f5da702.1223482372.git.bgat@billgatliff.com> X-Mailer: git-send-email 1.5.6.5 In-Reply-To: <7b16004ca5f8030184c2de96cbcee38657d56252.1223482372.git.bgat@billgatliff.com> References: <4b5c3aa2b1bc2b7efad834da49c2dec8c0a8726b.1223482372.git.bgat@billgatliff.com> <88de40673cc33e014928c2ee3a86bdac566021c8.1223482372.git.bgat@billgatliff.com> <7b16004ca5f8030184c2de96cbcee38657d56252.1223482372.git.bgat@billgatliff.com> In-Reply-To: References: Cc: Bill Gatliff X-BeenThere: linuxppc-dev@ozlabs.org X-Mailman-Version: 2.1.11 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@ozlabs.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@ozlabs.org Signed-off-by: Bill Gatliff --- drivers/pwm/atmel-pwm.c | 631 +++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 631 insertions(+), 0 deletions(-) create mode 100644 drivers/pwm/atmel-pwm.c diff --git a/drivers/pwm/atmel-pwm.c b/drivers/pwm/atmel-pwm.c new file mode 100644 index 0000000..b65e84f --- /dev/null +++ b/drivers/pwm/atmel-pwm.c @@ -0,0 +1,631 @@ +/* + * drivers/pwm/atmel-pwm.c + * + * Copyright (C) 2008 Bill Gatliff + * Copyright (C) 2007 David Brownell + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include +#include +#include +#include +#include +#include +#include +#include + + +enum { + /* registers common to the PWMC peripheral */ + PWMC_MR = 0, + PWMC_ENA = 4, + PWMC_DIS = 8, + PWMC_SR = 0xc, + PWMC_IER = 0x10, + PWMC_IDR = 0x14, + PWMC_IMR = 0x18, + PWMC_ISR = 0x1c, + + /* registers per each PWMC channel */ + PWMC_CMR = 0, + PWMC_CDTY = 4, + PWMC_CPRD = 8, + PWMC_CCNT = 0xc, + PWMC_CUPD = 0x10, + + /* how to find each channel */ + PWMC_CHAN_BASE = 0x200, + PWMC_CHAN_STRIDE = 0x20, + + /* CMR bits of interest */ + PWMC_CMR_CPD = 10, + PWMC_CMR_CPOL = 9, + PWMC_CMR_CALG = 8, + PWMC_CMR_CPRE_MASK = 0xf, +}; + +struct atmel_pwm { + struct pwm_device pwm; + spinlock_t lock; + void __iomem *iobase; + struct clk *clk; + u32 *sync_mask; + int irq; + u32 ccnt_mask; +}; + + +static inline void +pwmc_writel(const struct atmel_pwm *p, + unsigned offset, u32 val) +{ + __raw_writel(val, p->iobase + offset); +} + + +static inline u32 +pwmc_readl(const struct atmel_pwm *p, + unsigned offset) +{ + return __raw_readl(p->iobase + offset); +} + + +static inline void +pwmc_chan_writel(const struct pwm_channel *p, + u32 offset, u32 val) +{ + const struct atmel_pwm *ap + = container_of(p->pwm, struct atmel_pwm, pwm); + + if (PWMC_CMR == offset) + val &= ((1 << PWMC_CMR_CPD) + | (1 << PWMC_CMR_CPOL) + | (1 << PWMC_CMR_CALG) + | (PWMC_CMR_CPRE_MASK)); + else + val &= ap->ccnt_mask; + + pwmc_writel(ap, offset + PWMC_CHAN_BASE + + (p->chan * PWMC_CHAN_STRIDE), val); +} + + +static inline u32 +pwmc_chan_readl(const struct pwm_channel *p, + u32 offset) +{ + const struct atmel_pwm *ap + = container_of(p->pwm, struct atmel_pwm, pwm); + + return pwmc_readl(ap, offset + PWMC_CHAN_BASE + + (p->chan * PWMC_CHAN_STRIDE)); +} + + +static inline int +__atmel_pwm_is_on(struct pwm_channel *p) +{ + struct atmel_pwm *ap = container_of(p->pwm, struct atmel_pwm, pwm); + return (pwmc_readl(ap, PWMC_SR) & (1 << p->chan)) ? 1 : 0; +} + + +static inline void +__atmel_pwm_unsynchronize(struct pwm_channel *p, + struct pwm_channel *to_p) +{ + const struct atmel_pwm *ap + = container_of(p->pwm, struct atmel_pwm, pwm); + int wchan; + + if (to_p) { + ap->sync_mask[p->chan] &= ~(1 << to_p->chan); + ap->sync_mask[to_p->chan] &= ~(1 << p->chan); + goto done; + } + + ap->sync_mask[p->chan] = 0; + for (wchan = 0; wchan < ap->pwm.nchan; wchan++) + ap->sync_mask[wchan] &= ~(1 << p->chan); +done: + pr_debug("%s:%d sync_mask %x\n", + p->pwm->bus_id, p->chan, ap->sync_mask[p->chan]); +} + + +static inline void +__atmel_pwm_synchronize(struct pwm_channel *p, + struct pwm_channel *to_p) +{ + const struct atmel_pwm *ap + = container_of(p->pwm, struct atmel_pwm, pwm); + + if (!to_p) + return; + + ap->sync_mask[p->chan] |= (1 << to_p->chan); + ap->sync_mask[to_p->chan] |= (1 << p->chan); + + pr_debug("%s:%d sync_mask %x\n", + p->pwm->bus_id, p->chan, ap->sync_mask[p->chan]); +} + + +static inline void +__atmel_pwm_stop(struct pwm_channel *p) +{ + struct atmel_pwm *ap = container_of(p->pwm, struct atmel_pwm, pwm); + u32 chid = 1 << p->chan; + + pwmc_writel(ap, PWMC_DIS, ap->sync_mask[p->chan] | chid); +} + + +static inline void +__atmel_pwm_start(struct pwm_channel *p) +{ + struct atmel_pwm *ap = container_of(p->pwm, struct atmel_pwm, pwm); + u32 chid = 1 << p->chan; + + pwmc_writel(ap, PWMC_ENA, ap->sync_mask[p->chan] | chid); +} + + +static int +atmel_pwm_synchronize(struct pwm_channel *p, + struct pwm_channel *to_p) +{ + unsigned long flags; + spin_lock_irqsave(&p->lock, flags); + __atmel_pwm_synchronize(p, to_p); + spin_unlock_irqrestore(&p->lock, flags); + return 0; +} + + +static int +atmel_pwm_unsynchronize(struct pwm_channel *p, + struct pwm_channel *from_p) +{ + unsigned long flags; + spin_lock_irqsave(&p->lock, flags); + __atmel_pwm_unsynchronize(p, from_p); + spin_unlock_irqrestore(&p->lock, flags); + return 0; +} + + +static inline int +__atmel_pwm_config_polarity(struct pwm_channel *p, + struct pwm_channel_config *c) +{ + u32 cmr = pwmc_chan_readl(p, PWMC_CMR); + + if (c->polarity) + cmr &= ~BIT(PWMC_CMR_CPOL); + else + cmr |= BIT(PWMC_CMR_CPOL); + pwmc_chan_writel(p, PWMC_CMR, cmr); + + pr_debug("%s:%d polarity %d\n", p->pwm->bus_id, + p->chan, c->polarity); + return 0; +} + + +static inline int +__atmel_pwm_config_duty_ticks(struct pwm_channel *p, + struct pwm_channel_config *c) +{ + u32 cmr, cprd, cpre, cdty; + + cmr = pwmc_chan_readl(p, PWMC_CMR); + cprd = pwmc_chan_readl(p, PWMC_CPRD); + + cpre = cmr & PWMC_CMR_CPRE_MASK; + cmr &= ~BIT(PWMC_CMR_CPD); + + cdty = cprd - (c->duty_ticks >> cpre); + + p->duty_ticks = c->duty_ticks; + + if (__atmel_pwm_is_on(p)) { + pwmc_chan_writel(p, PWMC_CMR, cmr); + pwmc_chan_writel(p, PWMC_CUPD, cdty); + } else + pwmc_chan_writel(p, PWMC_CDTY, cdty); + + pr_debug("%s:%d duty_ticks = %lu cprd = %x" + " cdty = %x cpre = %x\n", + p->pwm->bus_id, p->chan, p->duty_ticks, + cprd, cdty, cpre); + + return 0; +} + + +static inline int +__atmel_pwm_config_period_ticks(struct pwm_channel *p, + struct pwm_channel_config *c) +{ + u32 cmr, cprd, cpre; + + cpre = fls(c->period_ticks); + if (cpre < 16) + cpre = 0; + else { + cpre -= 15; + if (cpre > 10) + return -EINVAL; + } + + cmr = pwmc_chan_readl(p, PWMC_CMR); + cmr &= ~PWMC_CMR_CPRE_MASK; + cmr |= cpre; + + cprd = c->period_ticks >> cpre; + + pwmc_chan_writel(p, PWMC_CMR, cmr); + pwmc_chan_writel(p, PWMC_CPRD, cprd); + p->period_ticks = c->period_ticks; + + pr_debug("%s:%d period_ticks = %lu cprd = %x cpre = %x\n", + p->pwm->bus_id, p->chan, p->period_ticks, cprd, cpre); + + return 0; +} + + + +static int +atmel_pwm_config_nosleep(struct pwm_channel *p, + struct pwm_channel_config *c) +{ + int ret = 0; + unsigned long flags; + + spin_lock_irqsave(&p->lock, flags); + + switch (c->config_mask) { + + case PWM_CONFIG_DUTY_TICKS: + __atmel_pwm_config_duty_ticks(p, c); + break; + + case PWM_CONFIG_STOP: + __atmel_pwm_stop(p); + pr_debug("%s:%d stop\n", p->pwm->bus_id, p->chan); + break; + + case PWM_CONFIG_START: + __atmel_pwm_start(p); + pr_debug("%s:%d start\n", p->pwm->bus_id, p->chan); + break; + + case PWM_CONFIG_POLARITY: + __atmel_pwm_config_polarity(p, c); + break; + + default: + ret = -EINVAL; + break; + } + + spin_unlock_irqrestore(&p->lock, flags); + return ret; +} + + +static int +atmel_pwm_stop_sync(struct pwm_channel *p) +{ + struct atmel_pwm *ap = container_of(p->pwm, struct atmel_pwm, pwm); + int ret; + int was_on = __atmel_pwm_is_on(p); + + if (was_on) { + do { + init_completion(&p->complete); + set_bit(FLAG_STOP, &p->flags); + pwmc_writel(ap, PWMC_IER, 1 << p->chan); + + pr_debug("%s:%d waiting on stop_sync completion...\n", + p->pwm->bus_id, p->chan); + + ret = wait_for_completion_interruptible(&p->complete); + + pr_debug("%s:%d stop_sync complete (%d)\n", + p->pwm->bus_id, p->chan, ret); + + if (ret) + return ret; + } while (p->flags & BIT(FLAG_STOP)); + } + + pr_debug("%s:%d stop_sync returning %d\n", + p->pwm->bus_id, p->chan, was_on); + + return was_on; +} + + +static int +atmel_pwm_config(struct pwm_channel *p, + struct pwm_channel_config *c) +{ + int was_on = 0; + + might_sleep(); + + if (p->pwm->config_nosleep) { + if (!p->pwm->config_nosleep(p, c)) + return 0; + } + + pr_debug("%s:%d config_mask %x\n", + p->pwm->bus_id, p->chan, c->config_mask); + + was_on = atmel_pwm_stop_sync(p); + if (was_on < 0) + return was_on; + + if (c->config_mask & PWM_CONFIG_PERIOD_TICKS) { + __atmel_pwm_config_period_ticks(p, c); + if (!(c->config_mask & PWM_CONFIG_DUTY_TICKS)) { + struct pwm_channel_config d = { + .config_mask = PWM_CONFIG_DUTY_TICKS, + .duty_ticks = p->duty_ticks, + }; + __atmel_pwm_config_duty_ticks(p, &d); + } + } + + if (c->config_mask & PWM_CONFIG_DUTY_TICKS) + __atmel_pwm_config_duty_ticks(p, c); + + if (c->config_mask & PWM_CONFIG_POLARITY) + __atmel_pwm_config_polarity(p, c); + + if ((c->config_mask & PWM_CONFIG_START) + || (was_on && !(c->config_mask & PWM_CONFIG_STOP))) + __atmel_pwm_start(p); + + return 0; +} + + +static void +__atmel_pwm_set_callback(struct pwm_channel *p, + pwm_callback_t callback) +{ + struct atmel_pwm *ap = container_of(p->pwm, struct atmel_pwm, pwm); + + p->callback = callback; + pwmc_writel(ap, p->callback ? PWMC_IER : PWMC_IDR, 1 << p->chan); + pr_debug("%s:%d set_callback %p\n", p->pwm->bus_id, p->chan, callback); +} + + +static int +atmel_pwm_set_callback(struct pwm_channel *p, + pwm_callback_t callback) +{ + struct atmel_pwm *ap = container_of(p->pwm, struct atmel_pwm, pwm); + unsigned long flags; + + spin_lock_irqsave(&ap->lock, flags); + __atmel_pwm_set_callback(p, callback); + spin_unlock_irqrestore(&ap->lock, flags); + + return 0; +} + + +static int +atmel_pwm_request(struct pwm_channel *p) +{ + struct atmel_pwm *ap = container_of(p->pwm, struct atmel_pwm, pwm); + unsigned long flags; + + spin_lock_irqsave(&p->lock, flags); + clk_enable(ap->clk); + p->tick_hz = clk_get_rate(ap->clk); + __atmel_pwm_unsynchronize(p, NULL); + __atmel_pwm_stop(p); + spin_unlock_irqrestore(&p->lock, flags); + + return 0; +} + + +static void +atmel_pwm_free(struct pwm_channel *p) +{ + struct atmel_pwm *ap = container_of(p->pwm, struct atmel_pwm, pwm); + clk_disable(ap->clk); +} + + +static irqreturn_t +atmel_pwmc_irq(int irq, void *data) +{ + struct atmel_pwm *ap = data; + struct pwm_channel *p; + u32 isr; + int chid; + unsigned long flags; + + spin_lock_irqsave(&ap->lock, flags); + + isr = pwmc_readl(ap, PWMC_ISR); + for (chid = 0; isr; chid++, isr >>= 1) { + p = &ap->pwm.channels[chid]; + if (isr & 1) { + if (p->callback) + p->callback(p); + if (p->flags & BIT(FLAG_STOP)) { + __atmel_pwm_stop(p); + clear_bit(FLAG_STOP, &p->flags); + } + complete_all(&p->complete); + } + } + + spin_unlock_irqrestore(&ap->lock, flags); + + return IRQ_HANDLED; +} + + +static int __init +atmel_pwmc_probe(struct platform_device *pdev) +{ + struct atmel_pwm *ap; + struct resource *r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + int ret = 0; + + ap = kzalloc(sizeof(*ap), GFP_KERNEL); + if (!ap) { + ret = -ENOMEM; + goto err_atmel_pwm_alloc; + } + + spin_lock_init(&ap->lock); + platform_set_drvdata(pdev, ap); + + ap->pwm.bus_id = pdev->dev.bus_id; + + ap->pwm.nchan = 4; /* TODO: true only for SAM9263 and AP7000 */ + ap->ccnt_mask = 0xffffUL; /* TODO: true only for SAM9263 */ + + ap->sync_mask = kzalloc(ap->pwm.nchan * sizeof(u32), GFP_KERNEL); + if (!ap->sync_mask) { + ret = -ENOMEM; + goto err_alloc_sync_masks; + } + + ap->pwm.owner = THIS_MODULE; + ap->pwm.request = atmel_pwm_request; + ap->pwm.free = atmel_pwm_free; + ap->pwm.config_nosleep = atmel_pwm_config_nosleep; + ap->pwm.config = atmel_pwm_config; + ap->pwm.synchronize = atmel_pwm_synchronize; + ap->pwm.unsynchronize = atmel_pwm_unsynchronize; + ap->pwm.set_callback = atmel_pwm_set_callback; + + ap->clk = clk_get(&pdev->dev, "pwmc_clk"); + if (!ap->clk) { + ret = -ENODEV; + goto err_clk_get; + } + + ap->iobase = ioremap_nocache(r->start, r->end - r->start + 1); + if (!ap->iobase) { + ret = -ENODEV; + goto err_ioremap; + } + + clk_enable(ap->clk); + pwmc_writel(ap, PWMC_DIS, -1); + pwmc_writel(ap, PWMC_IDR, -1); + clk_disable(ap->clk); + + ap->irq = platform_get_irq(pdev, 0); + if (ap->irq != -ENXIO) { + ret = request_irq(ap->irq, atmel_pwmc_irq, 0, + ap->pwm.bus_id, ap); + if (ret) + goto err_request_irq; + } + + ret = pwm_register(&ap->pwm); + if (ret) + goto err_pwm_register; + + return 0; + +err_pwm_register: + if (ap->irq != -ENXIO) + free_irq(ap->irq, ap); +err_request_irq: + iounmap(ap->iobase); +err_ioremap: + clk_put(ap->clk); +err_clk_get: + platform_set_drvdata(pdev, NULL); +err_alloc_sync_masks: + kfree(ap); +err_atmel_pwm_alloc: + return ret; +} + + +static int __devexit +atmel_pwmc_remove(struct platform_device *pdev) +{ + struct atmel_pwm *ap = platform_get_drvdata(pdev); + int ret; + + /* TODO: what can we do if this fails? */ + ret = pwm_unregister(&ap->pwm); + + clk_enable(ap->clk); + pwmc_writel(ap, PWMC_IDR, -1); + pwmc_writel(ap, PWMC_DIS, -1); + clk_disable(ap->clk); + + if (ap->irq != -ENXIO) + free_irq(ap->irq, ap); + + clk_put(ap->clk); + iounmap(ap->iobase); + + kfree(ap); + + return 0; +} + + +static struct platform_driver atmel_pwm_driver = { + .driver = { + .name = "atmel_pwmc", + .owner = THIS_MODULE, + }, + .probe = atmel_pwmc_probe, + .remove = __devexit_p(atmel_pwmc_remove), +}; + + +static int __init atmel_pwm_init(void) +{ + return platform_driver_register(&atmel_pwm_driver); +} +module_init(atmel_pwm_init); + + +static void atmel_pwm_exit(void) +{ + platform_driver_unregister(&atmel_pwm_driver); +} +module_exit(atmel_pwm_exit); + + +MODULE_AUTHOR("Bill Gatliff "); +MODULE_DESCRIPTION("Driver for Atmel PWMC peripheral"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:atmel_pwmc");