1 files changed, 230 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
new file mode 100644
index 000000000000..2a0b35333972
--- /dev/null
+++ b/drivers/pwm/pwm-imx.c
@@ -0,0 +1,230 @@
+/*
+ * 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/slab.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/pwm.h>
+#include <mach/hardware.h>
+
+
+/* i.MX1 and i.MX21 share the same PWM function block: */
+
+#define MX1_PWMC    0x00   /* PWM Control Register */
+#define MX1_PWMS    0x04   /* PWM Sample Register */
+#define MX1_PWMP    0x08   /* PWM Period Register */
+
+
+/* i.MX27, i.MX31, i.MX35 share the same PWM function block: */
+
+#define MX3_PWMCR                 0x00    /* PWM Control Register */
+#define MX3_PWMSAR                0x0C    /* PWM Sample Register */
+#define MX3_PWMPR                 0x10    /* PWM Period Register */
+#define MX3_PWMCR_PRESCALER(x)    (((x - 1) & 0xFFF) << 4)
+#define MX3_PWMCR_DOZEEN                (1 << 24)
+#define MX3_PWMCR_WAITEN                (1 << 23)
+#define MX3_PWMCR_DBGEN                 (1 << 22)
+#define MX3_PWMCR_CLKSRC_IPG_HIGH (2 << 16)
+#define MX3_PWMCR_CLKSRC_IPG      (1 << 16)
+#define MX3_PWMCR_EN              (1 << 0)
+
+struct imx_chip {
+        struct clk      *clk;
+
+        int             clk_enabled;
+        void __iomem    *mmio_base;
+
+        struct pwm_chip chip;
+};
+
+#define to_imx_chip(chip)       container_of(chip, struct imx_chip, chip)
+
+static int imx_pwm_config(struct pwm_chip *chip,
+                struct pwm_device *pwm, int duty_ns, int period_ns)
+{
+        struct imx_chip *imx = to_imx_chip(chip);
+
+        if (!(cpu_is_mx1() || cpu_is_mx21())) {
+                unsigned long long c;
+                unsigned long period_cycles, duty_cycles, prescale;
+                u32 cr;
+
+                c = clk_get_rate(imx->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;
+
+                /*
+                 * according to imx pwm RM, the real period value should be
+                 * PERIOD value in PWMPR plus 2.
+                 */
+                if (period_cycles > 2)
+                        period_cycles -= 2;
+                else
+                        period_cycles = 0;
+
+                writel(duty_cycles, imx->mmio_base + MX3_PWMSAR);
+                writel(period_cycles, imx->mmio_base + MX3_PWMPR);
+
+                cr = MX3_PWMCR_PRESCALER(prescale) |
+                        MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN |
+                        MX3_PWMCR_DBGEN | MX3_PWMCR_EN;
+
+                if (cpu_is_mx25())
+                        cr |= MX3_PWMCR_CLKSRC_IPG;
+                else
+                        cr |= MX3_PWMCR_CLKSRC_IPG_HIGH;
+
+                writel(cr, imx->mmio_base + MX3_PWMCR);
+        } else if (cpu_is_mx1() || cpu_is_mx21()) {
+                /* The PWM subsystem allows for exact frequencies. However,
+                 * I cannot connect a scope on my device to the PWM line and
+                 * thus cannot provide the program the PWM controller
+                 * exactly. Instead, I'm relying on the fact that the
+                 * Bootloader (u-boot or WinCE+haret) has programmed the PWM
+                 * function group already. So I'll just modify the PWM sample
+                 * register to follow the ratio of duty_ns vs. period_ns
+                 * accordingly.
+                 *
+                 * This is good enough for programming the brightness of
+                 * the LCD backlight.
+                 *
+                 * The real implementation would divide PERCLK[0] first by
+                 * both the prescaler (/1 .. /128) and then by CLKSEL
+                 * (/2 .. /16).
+                 */
+                u32 max = readl(imx->mmio_base + MX1_PWMP);
+                u32 p = max * duty_ns / period_ns;
+                writel(max - p, imx->mmio_base + MX1_PWMS);
+        } else {
+                BUG();
+        }
+
+        return 0;
+}
+
+static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+        struct imx_chip *imx = to_imx_chip(chip);
+        int rc = 0;
+
+        if (!imx->clk_enabled) {
+                rc = clk_prepare_enable(imx->clk);
+                if (!rc)
+                        imx->clk_enabled = 1;
+        }
+        return rc;
+}
+
+static void imx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+        struct imx_chip *imx = to_imx_chip(chip);
+
+        writel(0, imx->mmio_base + MX3_PWMCR);
+
+        if (imx->clk_enabled) {
+                clk_disable_unprepare(imx->clk);
+                imx->clk_enabled = 0;
+        }
+}
+
+static struct pwm_ops imx_pwm_ops = {
+        .enable = imx_pwm_enable,
+        .disable = imx_pwm_disable,
+        .config = imx_pwm_config,
+        .owner = THIS_MODULE,
+};
+
+static int __devinit imx_pwm_probe(struct platform_device *pdev)
+{
+        struct imx_chip *imx;
+        struct resource *r;
+        int ret = 0;
+
+        imx = devm_kzalloc(&pdev->dev, sizeof(*imx), GFP_KERNEL);
+        if (imx == NULL) {
+                dev_err(&pdev->dev, "failed to allocate memory\n");
+                return -ENOMEM;
+        }
+
+        imx->clk = devm_clk_get(&pdev->dev, "pwm");
+
+        if (IS_ERR(imx->clk))
+                return PTR_ERR(imx->clk);
+
+        imx->chip.ops = &imx_pwm_ops;
+        imx->chip.dev = &pdev->dev;
+        imx->chip.base = -1;
+        imx->chip.npwm = 1;
+
+        imx->clk_enabled = 0;
+
+        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (r == NULL) {
+                dev_err(&pdev->dev, "no memory resource defined\n");
+                return -ENODEV;
+        }
+
+        imx->mmio_base = devm_request_and_ioremap(&pdev->dev, r);
+        if (imx->mmio_base == NULL)
+                return -EADDRNOTAVAIL;
+
+        ret = pwmchip_add(&imx->chip);
+        if (ret < 0)
+                return ret;
+
+        platform_set_drvdata(pdev, imx);
+        return 0;
+}
+
+static int __devexit imx_pwm_remove(struct platform_device *pdev)
+{
+        struct imx_chip *imx;
+
+        imx = platform_get_drvdata(pdev);
+        if (imx == NULL)
+                return -ENODEV;
+
+        return pwmchip_remove(&imx->chip);
+}
+
+static struct platform_driver imx_pwm_driver = {
+        .driver         = {
+                .name   = "mxc_pwm",
+        },
+        .probe          = imx_pwm_probe,
+        .remove         = __devexit_p(imx_pwm_remove),
+};
+
+static int __init imx_pwm_init(void)
+{
+        return platform_driver_register(&imx_pwm_driver);
+}
+arch_initcall(imx_pwm_init);
+
+static void __exit imx_pwm_exit(void)
+{
+        platform_driver_unregister(&imx_pwm_driver);
+}
+module_exit(imx_pwm_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");