diff options
Diffstat (limited to 'arch/arm/plat-mxc')
| -rw-r--r-- | arch/arm/plat-mxc/Kconfig | 6 | ||||
| -rw-r--r-- | arch/arm/plat-mxc/Makefile | 1 | ||||
| -rw-r--r-- | arch/arm/plat-mxc/pwm.c | 300 |
3 files changed, 307 insertions, 0 deletions
diff --git a/arch/arm/plat-mxc/Kconfig b/arch/arm/plat-mxc/Kconfig index 10f65bf27b2..71c3c848b0e 100644 --- a/arch/arm/plat-mxc/Kconfig +++ b/arch/arm/plat-mxc/Kconfig @@ -44,4 +44,10 @@ config MXC_IRQ_PRIOR requirements for timing. Say N here, unless you have a specialized requirement. +config MXC_PWM + tristate "Enable PWM driver" + depends on ARCH_MXC + help + Enable support for the i.MX PWM controller(s). + endif diff --git a/arch/arm/plat-mxc/Makefile b/arch/arm/plat-mxc/Makefile index db74a929179..f204192f9b9 100644 --- a/arch/arm/plat-mxc/Makefile +++ b/arch/arm/plat-mxc/Makefile @@ -7,3 +7,4 @@ obj-y := irq.o clock.o gpio.o time.o devices.o obj-$(CONFIG_ARCH_MX1) += iomux-mx1-mx2.o dma-mx1-mx2.o obj-$(CONFIG_ARCH_MX2) += iomux-mx1-mx2.o dma-mx1-mx2.o +obj-$(CONFIG_MXC_PWM) += pwm.o diff --git a/arch/arm/plat-mxc/pwm.c b/arch/arm/plat-mxc/pwm.c new file mode 100644 index 00000000000..9bffbc507cc --- /dev/null +++ b/arch/arm/plat-mxc/pwm.c @@ -0,0 +1,300 @@ +/* + * 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. + * + * Derived from pxa PWM driver by 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> + +#if defined CONFIG_ARCH_MX1 || defined CONFIG_ARCH_MX21 +#define PWM_VER_1 + +#define PWMCR 0x00 /* PWM Control Register */ +#define PWMSR 0x04 /* PWM Sample Register */ +#define PWMPR 0x08 /* PWM Period Register */ +#define PWMCNR 0x0C /* PWM Counter Register */ + +#define PWMCR_HCTR (1 << 18) /* Halfword FIFO Data Swapping */ +#define PWMCR_BCTR (1 << 17) /* Byte FIFO Data Swapping */ +#define PWMCR_SWR (1 << 16) /* Software Reset */ +#define PWMCR_CLKSRC_PERCLK (0 << 15) /* PERCLK Clock Source */ +#define PWMCR_CLKSRC_CLK32 (1 << 15) /* 32KHz Clock Source */ +#define PWMCR_PRESCALER(x) (((x - 1) & 0x7F) << 8) /* PRESCALER */ +#define PWMCR_IRQ (1 << 7) /* Interrupt Request */ +#define PWMCR_IRQEN (1 << 6) /* Interrupt Request Enable */ +#define PWMCR_FIFOAV (1 << 5) /* FIFO Available */ +#define PWMCR_EN (1 << 4) /* Enables/Disables the PWM */ +#define PWMCR_REPEAT(x) (((x) & 0x03) << 2) /* Sample Repeats */ +#define PWMCR_DIV(x) (((x) & 0x03) << 0) /* Clock divider 2/4/8/16 */ + +#define MAX_DIV (128 * 16) +#endif + +#if defined CONFIG_MACH_MX27 || defined CONFIG_ARCH_MX31 +#define PWM_VER_2 + +#define PWMCR 0x00 /* PWM Control Register */ +#define PWMSR 0x04 /* PWM Status Register */ +#define PWMIR 0x08 /* PWM Interrupt Register */ +#define PWMSAR 0x0C /* PWM Sample Register */ +#define PWMPR 0x10 /* PWM Period Register */ +#define PWMCNR 0x14 /* PWM Counter Register */ + +#define PWMCR_EN (1 << 0) /* Enables/Disables the PWM */ +#define PWMCR_REPEAT(x) (((x) & 0x03) << 1) /* Sample Repeats */ +#define PWMCR_SWR (1 << 3) /* Software Reset */ +#define PWMCR_PRESCALER(x) (((x - 1) & 0xFFF) << 4)/* PRESCALER */ +#define PWMCR_CLKSRC(x) (((x) & 0x3) << 16) +#define PWMCR_CLKSRC_OFF (0 << 16) +#define PWMCR_CLKSRC_IPG (1 << 16) +#define PWMCR_CLKSRC_IPG_HIGH (2 << 16) +#define PWMCR_CLKSRC_CLK32 (3 << 16) +#define PWMCR_POUTC +#define PWMCR_HCTR (1 << 20) /* Halfword FIFO Data Swapping */ +#define PWMCR_BCTR (1 << 21) /* Byte FIFO Data Swapping */ +#define PWMCR_DBGEN (1 << 22) /* Debug Mode */ +#define PWMCR_WAITEN (1 << 23) /* Wait Mode */ +#define PWMCR_DOZEN (1 << 24) /* Doze Mode */ +#define PWMCR_STOPEN (1 << 25) /* Stop Mode */ +#define PWMCR_FWM(x) (((x) & 0x3) << 26) /* FIFO Water Mark */ + +#define MAX_DIV 4096 +#endif + +#define PWMS_SAMPLE(x) ((x) & 0xFFFF) /* Contains a two-sample word */ +#define PWMP_PERIOD(x) ((x) & 0xFFFF) /* Represents the PWM's period */ +#define PWMC_COUNTER(x) ((x) & 0xFFFF) /* Represents the current count value */ + +struct pwm_device { + struct list_head node; + struct platform_device *pdev; + + const char *label; + struct clk *clk; + + int clk_enabled; + void __iomem *mmio_base; + + unsigned int use_count; + unsigned int pwm_id; +}; + +int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) +{ + unsigned long long c; + unsigned long period_cycles, duty_cycles, prescale; + + 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; + + prescale = period_cycles / 0x10000 + 1; + + period_cycles /= prescale; + c = (unsigned long long)period_cycles * duty_ns; + do_div(c, period_ns); + duty_cycles = c; + +#ifdef PWM_VER_2 + writel(duty_cycles, pwm->mmio_base + PWMSAR); + writel(period_cycles, pwm->mmio_base + PWMPR); + writel(PWMCR_PRESCALER(prescale - 1) | PWMCR_CLKSRC_IPG_HIGH | PWMCR_EN, + pwm->mmio_base + PWMCR); +#elif defined PWM_VER_1 +#error PWM not yet working on MX1 / MX21 +#endif + + return 0; +} +EXPORT_SYMBOL(pwm_config); + +int pwm_enable(struct pwm_device *pwm) +{ + int rc = 0; + + if (!pwm->clk_enabled) { + rc = clk_enable(pwm->clk); + if (!rc) + pwm->clk_enabled = 1; + } + return rc; +} +EXPORT_SYMBOL(pwm_enable); + +void pwm_disable(struct pwm_device *pwm) +{ + if (pwm->clk_enabled) { + clk_disable(pwm->clk); + pwm->clk_enabled = 0; + } +} +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) { + found = 1; + break; + } + } + + if (found) { + if (pwm->use_count == 0) { + pwm->use_count++; + pwm->label = label; + } else + pwm = ERR_PTR(-EBUSY); + } else + pwm = ERR_PTR(-ENOENT); + + mutex_unlock(&pwm_lock); + return pwm; +} +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 int __devinit mxc_pwm_probe(struct platform_device *pdev) +{ + 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 -ENOMEM; + } + + pwm->clk = clk_get(&pdev->dev, "pwm"); + + if (IS_ERR(pwm->clk)) { + ret = PTR_ERR(pwm->clk); + goto err_free; + } + + pwm->clk_enabled = 0; + + pwm->use_count = 0; + pwm->pwm_id = pdev->id; + pwm->pdev = pdev; + + 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; + } + + mutex_lock(&pwm_lock); + list_add_tail(&pwm->node, &pwm_list); + mutex_unlock(&pwm_lock); + + platform_set_drvdata(pdev, pwm); + return 0; + +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 ret; +} + +static int __devexit mxc_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 mxc_pwm_driver = { + .driver = { + .name = "mxc_pwm", + }, + .probe = mxc_pwm_probe, + .remove = __devexit_p(mxc_pwm_remove), +}; + +static int __init mxc_pwm_init(void) +{ + return platform_driver_register(&mxc_pwm_driver); +} +arch_initcall(mxc_pwm_init); + +static void __exit mxc_pwm_exit(void) +{ + platform_driver_unregister(&mxc_pwm_driver); +} +module_exit(mxc_pwm_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>"); + |