| /* |
| * linux/arch/arm/mach-pxa/pwm.c |
| * |
| * simple driver for PWM (Pulse Width Modulator) controller |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * 2008-02-13 initial version |
| * eric miao <eric.miao@marvell.com> |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/kernel.h> |
| #include <linux/platform_device.h> |
| #include <linux/err.h> |
| #include <linux/clk.h> |
| #include <linux/io.h> |
| #include <linux/pwm.h> |
| |
| #include <asm/div64.h> |
| #include <asm/arch/pxa-regs.h> |
| |
| /* PWM registers and bits definitions */ |
| #define PWMCR (0x00) |
| #define PWMDCR (0x04) |
| #define PWMPCR (0x08) |
| |
| #define PWMCR_SD (1 << 6) |
| #define PWMDCR_FD (1 << 10) |
| |
| struct pwm_device { |
| struct list_head node; |
| struct platform_device *pdev; |
| |
| const char *label; |
| struct clk *clk; |
| void __iomem *mmio_base; |
| |
| unsigned int use_count; |
| unsigned int pwm_id; |
| }; |
| |
| /* |
| * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE |
| * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE |
| */ |
| int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) |
| { |
| unsigned long long c; |
| unsigned long period_cycles, prescale, pv, dc; |
| |
| if (pwm == NULL || period_ns == 0 || duty_ns > period_ns) |
| return -EINVAL; |
| |
| c = clk_get_rate(pwm->clk); |
| c = c * period_ns; |
| do_div(c, 1000000000); |
| period_cycles = c; |
| |
| if (period_cycles < 0) |
| period_cycles = 1; |
| prescale = (period_cycles - 1) / 1024; |
| pv = period_cycles / (prescale + 1) - 1; |
| |
| if (prescale > 63) |
| return -EINVAL; |
| |
| if (duty_ns == period_ns) |
| dc = PWMDCR_FD; |
| else |
| dc = (pv + 1) * duty_ns / period_ns; |
| |
| /* NOTE: the clock to PWM has to be enabled first |
| * before writing to the registers |
| */ |
| clk_enable(pwm->clk); |
| __raw_writel(prescale, pwm->mmio_base + PWMCR); |
| __raw_writel(dc, pwm->mmio_base + PWMDCR); |
| __raw_writel(pv, pwm->mmio_base + PWMPCR); |
| clk_disable(pwm->clk); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(pwm_config); |
| |
| int pwm_enable(struct pwm_device *pwm) |
| { |
| return clk_enable(pwm->clk); |
| } |
| EXPORT_SYMBOL(pwm_enable); |
| |
| void pwm_disable(struct pwm_device *pwm) |
| { |
| clk_disable(pwm->clk); |
| } |
| EXPORT_SYMBOL(pwm_disable); |
| |
| static DEFINE_MUTEX(pwm_lock); |
| static LIST_HEAD(pwm_list); |
| |
| struct pwm_device *pwm_request(int pwm_id, const char *label) |
| { |
| struct pwm_device *pwm; |
| int found = 0; |
| |
| mutex_lock(&pwm_lock); |
| |
| list_for_each_entry(pwm, &pwm_list, node) { |
| if (pwm->pwm_id == pwm_id && pwm->use_count == 0) { |
| pwm->use_count++; |
| pwm->label = label; |
| found = 1; |
| break; |
| } |
| } |
| |
| mutex_unlock(&pwm_lock); |
| |
| return (found) ? pwm : NULL; |
| } |
| EXPORT_SYMBOL(pwm_request); |
| |
| void pwm_free(struct pwm_device *pwm) |
| { |
| mutex_lock(&pwm_lock); |
| |
| if (pwm->use_count) { |
| pwm->use_count--; |
| pwm->label = NULL; |
| } else |
| pr_warning("PWM device already freed\n"); |
| |
| mutex_unlock(&pwm_lock); |
| } |
| EXPORT_SYMBOL(pwm_free); |
| |
| static inline void __add_pwm(struct pwm_device *pwm) |
| { |
| mutex_lock(&pwm_lock); |
| list_add_tail(&pwm->node, &pwm_list); |
| mutex_unlock(&pwm_lock); |
| } |
| |
| static struct pwm_device *pwm_probe(struct platform_device *pdev, |
| unsigned int pwm_id, struct pwm_device *parent_pwm) |
| { |
| struct pwm_device *pwm; |
| struct resource *r; |
| int ret = 0; |
| |
| pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); |
| if (pwm == NULL) { |
| dev_err(&pdev->dev, "failed to allocate memory\n"); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| pwm->clk = clk_get(&pdev->dev, "PWMCLK"); |
| if (IS_ERR(pwm->clk)) { |
| ret = PTR_ERR(pwm->clk); |
| goto err_free; |
| } |
| |
| pwm->use_count = 0; |
| pwm->pwm_id = pwm_id; |
| pwm->pdev = pdev; |
| |
| if (parent_pwm != NULL) { |
| /* registers for the second PWM has offset of 0x10 */ |
| pwm->mmio_base = parent_pwm->mmio_base + 0x10; |
| __add_pwm(pwm); |
| return pwm; |
| } |
| |
| r = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| if (r == NULL) { |
| dev_err(&pdev->dev, "no memory resource defined\n"); |
| ret = -ENODEV; |
| goto err_free_clk; |
| } |
| |
| r = request_mem_region(r->start, r->end - r->start + 1, pdev->name); |
| if (r == NULL) { |
| dev_err(&pdev->dev, "failed to request memory resource\n"); |
| ret = -EBUSY; |
| goto err_free_clk; |
| } |
| |
| pwm->mmio_base = ioremap(r->start, r->end - r->start + 1); |
| if (pwm->mmio_base == NULL) { |
| dev_err(&pdev->dev, "failed to ioremap() registers\n"); |
| ret = -ENODEV; |
| goto err_free_mem; |
| } |
| |
| __add_pwm(pwm); |
| platform_set_drvdata(pdev, pwm); |
| return pwm; |
| |
| err_free_mem: |
| release_mem_region(r->start, r->end - r->start + 1); |
| err_free_clk: |
| clk_put(pwm->clk); |
| err_free: |
| kfree(pwm); |
| return ERR_PTR(ret); |
| } |
| |
| static int __devinit pxa25x_pwm_probe(struct platform_device *pdev) |
| { |
| struct pwm_device *pwm = pwm_probe(pdev, pdev->id, NULL); |
| |
| if (IS_ERR(pwm)) |
| return PTR_ERR(pwm); |
| |
| return 0; |
| } |
| |
| static int __devinit pxa27x_pwm_probe(struct platform_device *pdev) |
| { |
| struct pwm_device *pwm; |
| |
| pwm = pwm_probe(pdev, pdev->id, NULL); |
| if (IS_ERR(pwm)) |
| return PTR_ERR(pwm); |
| |
| pwm = pwm_probe(pdev, pdev->id + 2, pwm); |
| if (IS_ERR(pwm)) |
| return PTR_ERR(pwm); |
| |
| return 0; |
| } |
| |
| static int __devexit pwm_remove(struct platform_device *pdev) |
| { |
| struct pwm_device *pwm; |
| struct resource *r; |
| |
| pwm = platform_get_drvdata(pdev); |
| if (pwm == NULL) |
| return -ENODEV; |
| |
| mutex_lock(&pwm_lock); |
| list_del(&pwm->node); |
| mutex_unlock(&pwm_lock); |
| |
| iounmap(pwm->mmio_base); |
| |
| r = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| release_mem_region(r->start, r->end - r->start + 1); |
| |
| clk_put(pwm->clk); |
| kfree(pwm); |
| return 0; |
| } |
| |
| static struct platform_driver pxa25x_pwm_driver = { |
| .driver = { |
| .name = "pxa25x-pwm", |
| }, |
| .probe = pxa25x_pwm_probe, |
| .remove = __devexit_p(pwm_remove), |
| }; |
| |
| static struct platform_driver pxa27x_pwm_driver = { |
| .driver = { |
| .name = "pxa27x-pwm", |
| }, |
| .probe = pxa27x_pwm_probe, |
| .remove = __devexit_p(pwm_remove), |
| }; |
| |
| static int __init pwm_init(void) |
| { |
| int ret = 0; |
| |
| ret = platform_driver_register(&pxa25x_pwm_driver); |
| if (ret) { |
| printk(KERN_ERR "failed to register pxa25x_pwm_driver\n"); |
| return ret; |
| } |
| |
| ret = platform_driver_register(&pxa27x_pwm_driver); |
| if (ret) { |
| printk(KERN_ERR "failed to register pxa27x_pwm_driver\n"); |
| return ret; |
| } |
| |
| return ret; |
| } |
| arch_initcall(pwm_init); |
| |
| static void __exit pwm_exit(void) |
| { |
| platform_driver_unregister(&pxa25x_pwm_driver); |
| platform_driver_unregister(&pxa27x_pwm_driver); |
| } |
| module_exit(pwm_exit); |
| |
| MODULE_LICENSE("GPL v2"); |