[ARM] MXC: add pwm driver for i.MX SoCs

This driver has been tested on MX27/MX31. It should work on MX1/MX1
aswell, but the actual setting of the PWM is missing so far.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

3 files changed, 307 insertions, 0 deletions

diff --git a/arch/arm/plat-mxc/Kconfig b/arch/arm/plat-mxc/Kconfig
index 10f65bf27b27..71c3c848b0e2 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 db74a929179d..f204192f9b94 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 000000000000..9bffbc507cc2
--- /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>");
+