| #include <linux/module.h> |
| #include <linux/clk.h> |
| #include <linux/err.h> |
| #include <linux/slab.h> |
| #include <linux/io.h> |
| #include <linux/interrupt.h> |
| #include <linux/platform_device.h> |
| #include <linux/atmel_pwm.h> |
| |
| |
| /* |
| * This is a simple driver for the PWM controller found in various newer |
| * Atmel SOCs, including the AVR32 series and the AT91sam9263. |
| * |
| * Chips with current Linux ports have only 4 PWM channels, out of max 32. |
| * AT32UC3A and AT32UC3B chips have 7 channels (but currently no Linux). |
| * Docs are inconsistent about the width of the channel counter registers; |
| * it's at least 16 bits, but several places say 20 bits. |
| */ |
| #define PWM_NCHAN 4 /* max 32 */ |
| |
| struct pwm { |
| spinlock_t lock; |
| struct platform_device *pdev; |
| u32 mask; |
| int irq; |
| void __iomem *base; |
| struct clk *clk; |
| struct pwm_channel *channel[PWM_NCHAN]; |
| void (*handler[PWM_NCHAN])(struct pwm_channel *); |
| }; |
| |
| |
| /* global PWM controller registers */ |
| #define PWM_MR 0x00 |
| #define PWM_ENA 0x04 |
| #define PWM_DIS 0x08 |
| #define PWM_SR 0x0c |
| #define PWM_IER 0x10 |
| #define PWM_IDR 0x14 |
| #define PWM_IMR 0x18 |
| #define PWM_ISR 0x1c |
| |
| static inline void pwm_writel(const struct pwm *p, unsigned offset, u32 val) |
| { |
| __raw_writel(val, p->base + offset); |
| } |
| |
| static inline u32 pwm_readl(const struct pwm *p, unsigned offset) |
| { |
| return __raw_readl(p->base + offset); |
| } |
| |
| static inline void __iomem *pwmc_regs(const struct pwm *p, int index) |
| { |
| return p->base + 0x200 + index * 0x20; |
| } |
| |
| static struct pwm *pwm; |
| |
| static void pwm_dumpregs(struct pwm_channel *ch, char *tag) |
| { |
| struct device *dev = &pwm->pdev->dev; |
| |
| dev_dbg(dev, "%s: mr %08x, sr %08x, imr %08x\n", |
| tag, |
| pwm_readl(pwm, PWM_MR), |
| pwm_readl(pwm, PWM_SR), |
| pwm_readl(pwm, PWM_IMR)); |
| dev_dbg(dev, |
| "pwm ch%d - mr %08x, dty %u, prd %u, cnt %u\n", |
| ch->index, |
| pwm_channel_readl(ch, PWM_CMR), |
| pwm_channel_readl(ch, PWM_CDTY), |
| pwm_channel_readl(ch, PWM_CPRD), |
| pwm_channel_readl(ch, PWM_CCNT)); |
| } |
| |
| |
| /** |
| * pwm_channel_alloc - allocate an unused PWM channel |
| * @index: identifies the channel |
| * @ch: structure to be initialized |
| * |
| * Drivers allocate PWM channels according to the board's wiring, and |
| * matching board-specific setup code. Returns zero or negative errno. |
| */ |
| int pwm_channel_alloc(int index, struct pwm_channel *ch) |
| { |
| unsigned long flags; |
| int status = 0; |
| |
| if (!pwm) |
| return -EPROBE_DEFER; |
| |
| if (!(pwm->mask & 1 << index)) |
| return -ENODEV; |
| |
| if (index < 0 || index >= PWM_NCHAN || !ch) |
| return -EINVAL; |
| memset(ch, 0, sizeof *ch); |
| |
| spin_lock_irqsave(&pwm->lock, flags); |
| if (pwm->channel[index]) |
| status = -EBUSY; |
| else { |
| clk_enable(pwm->clk); |
| |
| ch->regs = pwmc_regs(pwm, index); |
| ch->index = index; |
| |
| /* REVISIT: ap7000 seems to go 2x as fast as we expect!! */ |
| ch->mck = clk_get_rate(pwm->clk); |
| |
| pwm->channel[index] = ch; |
| pwm->handler[index] = NULL; |
| |
| /* channel and irq are always disabled when we return */ |
| pwm_writel(pwm, PWM_DIS, 1 << index); |
| pwm_writel(pwm, PWM_IDR, 1 << index); |
| } |
| spin_unlock_irqrestore(&pwm->lock, flags); |
| return status; |
| } |
| EXPORT_SYMBOL(pwm_channel_alloc); |
| |
| static int pwmcheck(struct pwm_channel *ch) |
| { |
| int index; |
| |
| if (!pwm) |
| return -ENODEV; |
| if (!ch) |
| return -EINVAL; |
| index = ch->index; |
| if (index < 0 || index >= PWM_NCHAN || pwm->channel[index] != ch) |
| return -EINVAL; |
| |
| return index; |
| } |
| |
| /** |
| * pwm_channel_free - release a previously allocated channel |
| * @ch: the channel being released |
| * |
| * The channel is completely shut down (counter and IRQ disabled), |
| * and made available for re-use. Returns zero, or negative errno. |
| */ |
| int pwm_channel_free(struct pwm_channel *ch) |
| { |
| unsigned long flags; |
| int t; |
| |
| spin_lock_irqsave(&pwm->lock, flags); |
| t = pwmcheck(ch); |
| if (t >= 0) { |
| pwm->channel[t] = NULL; |
| pwm->handler[t] = NULL; |
| |
| /* channel and irq are always disabled when we return */ |
| pwm_writel(pwm, PWM_DIS, 1 << t); |
| pwm_writel(pwm, PWM_IDR, 1 << t); |
| |
| clk_disable(pwm->clk); |
| t = 0; |
| } |
| spin_unlock_irqrestore(&pwm->lock, flags); |
| return t; |
| } |
| EXPORT_SYMBOL(pwm_channel_free); |
| |
| int __pwm_channel_onoff(struct pwm_channel *ch, int enabled) |
| { |
| unsigned long flags; |
| int t; |
| |
| /* OMITTED FUNCTIONALITY: starting several channels in synch */ |
| |
| spin_lock_irqsave(&pwm->lock, flags); |
| t = pwmcheck(ch); |
| if (t >= 0) { |
| pwm_writel(pwm, enabled ? PWM_ENA : PWM_DIS, 1 << t); |
| t = 0; |
| pwm_dumpregs(ch, enabled ? "enable" : "disable"); |
| } |
| spin_unlock_irqrestore(&pwm->lock, flags); |
| |
| return t; |
| } |
| EXPORT_SYMBOL(__pwm_channel_onoff); |
| |
| /** |
| * pwm_clk_alloc - allocate and configure CLKA or CLKB |
| * @prescale: from 0..10, the power of two used to divide MCK |
| * @div: from 1..255, the linear divisor to use |
| * |
| * Returns PWM_CPR_CLKA, PWM_CPR_CLKB, or negative errno. The allocated |
| * clock will run with a period of (2^prescale * div) / MCK, or twice as |
| * long if center aligned PWM output is used. The clock must later be |
| * deconfigured using pwm_clk_free(). |
| */ |
| int pwm_clk_alloc(unsigned prescale, unsigned div) |
| { |
| unsigned long flags; |
| u32 mr; |
| u32 val = (prescale << 8) | div; |
| int ret = -EBUSY; |
| |
| if (prescale >= 10 || div == 0 || div > 255) |
| return -EINVAL; |
| |
| spin_lock_irqsave(&pwm->lock, flags); |
| mr = pwm_readl(pwm, PWM_MR); |
| if ((mr & 0xffff) == 0) { |
| mr |= val; |
| ret = PWM_CPR_CLKA; |
| } else if ((mr & (0xffff << 16)) == 0) { |
| mr |= val << 16; |
| ret = PWM_CPR_CLKB; |
| } |
| if (ret > 0) |
| pwm_writel(pwm, PWM_MR, mr); |
| spin_unlock_irqrestore(&pwm->lock, flags); |
| return ret; |
| } |
| EXPORT_SYMBOL(pwm_clk_alloc); |
| |
| /** |
| * pwm_clk_free - deconfigure and release CLKA or CLKB |
| * |
| * Reverses the effect of pwm_clk_alloc(). |
| */ |
| void pwm_clk_free(unsigned clk) |
| { |
| unsigned long flags; |
| u32 mr; |
| |
| spin_lock_irqsave(&pwm->lock, flags); |
| mr = pwm_readl(pwm, PWM_MR); |
| if (clk == PWM_CPR_CLKA) |
| pwm_writel(pwm, PWM_MR, mr & ~(0xffff << 0)); |
| if (clk == PWM_CPR_CLKB) |
| pwm_writel(pwm, PWM_MR, mr & ~(0xffff << 16)); |
| spin_unlock_irqrestore(&pwm->lock, flags); |
| } |
| EXPORT_SYMBOL(pwm_clk_free); |
| |
| /** |
| * pwm_channel_handler - manage channel's IRQ handler |
| * @ch: the channel |
| * @handler: the handler to use, possibly NULL |
| * |
| * If the handler is non-null, the handler will be called after every |
| * period of this PWM channel. If the handler is null, this channel |
| * won't generate an IRQ. |
| */ |
| int pwm_channel_handler(struct pwm_channel *ch, |
| void (*handler)(struct pwm_channel *ch)) |
| { |
| unsigned long flags; |
| int t; |
| |
| spin_lock_irqsave(&pwm->lock, flags); |
| t = pwmcheck(ch); |
| if (t >= 0) { |
| pwm->handler[t] = handler; |
| pwm_writel(pwm, handler ? PWM_IER : PWM_IDR, 1 << t); |
| t = 0; |
| } |
| spin_unlock_irqrestore(&pwm->lock, flags); |
| |
| return t; |
| } |
| EXPORT_SYMBOL(pwm_channel_handler); |
| |
| static irqreturn_t pwm_irq(int id, void *_pwm) |
| { |
| struct pwm *p = _pwm; |
| irqreturn_t handled = IRQ_NONE; |
| u32 irqstat; |
| int index; |
| |
| spin_lock(&p->lock); |
| |
| /* ack irqs, then handle them */ |
| irqstat = pwm_readl(pwm, PWM_ISR); |
| |
| while (irqstat) { |
| struct pwm_channel *ch; |
| void (*handler)(struct pwm_channel *ch); |
| |
| index = ffs(irqstat) - 1; |
| irqstat &= ~(1 << index); |
| ch = pwm->channel[index]; |
| handler = pwm->handler[index]; |
| if (handler && ch) { |
| spin_unlock(&p->lock); |
| handler(ch); |
| spin_lock(&p->lock); |
| handled = IRQ_HANDLED; |
| } |
| } |
| |
| spin_unlock(&p->lock); |
| return handled; |
| } |
| |
| static int __init pwm_probe(struct platform_device *pdev) |
| { |
| struct resource *r = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| int irq = platform_get_irq(pdev, 0); |
| u32 *mp = pdev->dev.platform_data; |
| struct pwm *p; |
| int status = -EIO; |
| |
| if (pwm) |
| return -EBUSY; |
| if (!r || irq < 0 || !mp || !*mp) |
| return -ENODEV; |
| if (*mp & ~((1<<PWM_NCHAN)-1)) { |
| dev_warn(&pdev->dev, "mask 0x%x ... more than %d channels\n", |
| *mp, PWM_NCHAN); |
| return -EINVAL; |
| } |
| |
| p = kzalloc(sizeof(*p), GFP_KERNEL); |
| if (!p) |
| return -ENOMEM; |
| |
| spin_lock_init(&p->lock); |
| p->pdev = pdev; |
| p->mask = *mp; |
| p->irq = irq; |
| p->base = ioremap(r->start, resource_size(r)); |
| if (!p->base) |
| goto fail; |
| p->clk = clk_get(&pdev->dev, "pwm_clk"); |
| if (IS_ERR(p->clk)) { |
| status = PTR_ERR(p->clk); |
| p->clk = NULL; |
| goto fail; |
| } |
| |
| status = request_irq(irq, pwm_irq, 0, pdev->name, p); |
| if (status < 0) |
| goto fail; |
| |
| pwm = p; |
| platform_set_drvdata(pdev, p); |
| |
| return 0; |
| |
| fail: |
| if (p->clk) |
| clk_put(p->clk); |
| if (p->base) |
| iounmap(p->base); |
| |
| kfree(p); |
| return status; |
| } |
| |
| static int __exit pwm_remove(struct platform_device *pdev) |
| { |
| struct pwm *p = platform_get_drvdata(pdev); |
| |
| if (p != pwm) |
| return -EINVAL; |
| |
| clk_enable(pwm->clk); |
| pwm_writel(pwm, PWM_DIS, (1 << PWM_NCHAN) - 1); |
| pwm_writel(pwm, PWM_IDR, (1 << PWM_NCHAN) - 1); |
| clk_disable(pwm->clk); |
| |
| pwm = NULL; |
| |
| free_irq(p->irq, p); |
| clk_put(p->clk); |
| iounmap(p->base); |
| kfree(p); |
| |
| return 0; |
| } |
| |
| static struct platform_driver atmel_pwm_driver = { |
| .driver = { |
| .name = "atmel_pwm", |
| .owner = THIS_MODULE, |
| }, |
| .remove = __exit_p(pwm_remove), |
| |
| /* NOTE: PWM can keep running in AVR32 "idle" and "frozen" states; |
| * and all AT91sam9263 states, albeit at reduced clock rate if |
| * MCK becomes the slow clock (i.e. what Linux labels STR). |
| */ |
| }; |
| |
| module_platform_driver_probe(atmel_pwm_driver, pwm_probe); |
| |
| MODULE_DESCRIPTION("Driver for AT32/AT91 PWM module"); |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS("platform:atmel_pwm"); |