[PATCH 3/3] pwm: Add a i.MX23/28 pwm driver
Sascha Hauer
s.hauer at pengutronix.de
Thu Jun 30 06:41:57 EDT 2011
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
drivers/pwm/Kconfig | 6 +-
drivers/pwm/Makefile | 1 +
drivers/pwm/mxs-pwm.c | 312 +++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 318 insertions(+), 1 deletions(-)
create mode 100644 drivers/pwm/mxs-pwm.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 93c1052..5694574 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -2,11 +2,15 @@ menuconfig PWM
bool "PWM Support"
help
This enables PWM support through the generic PWM framework.
- You only need to enable this, if you also want to enable
+ You only need to enable this if you also want to enable
one or more of the PWM drivers below.
If unsure, say N.
if PWM
+config PWM_MXS
+ tristate "MXS pwm support"
+ depends on ARCH_MXS
+
endif
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 3469c3d..2cadd50 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -1 +1,2 @@
obj-$(CONFIG_PWM) += core.o
+obj-$(CONFIG_PWM_MXS) += mxs-pwm.o
diff --git a/drivers/pwm/mxs-pwm.c b/drivers/pwm/mxs-pwm.c
new file mode 100644
index 0000000..150ab32
--- /dev/null
+++ b/drivers/pwm/mxs-pwm.c
@@ -0,0 +1,312 @@
+/*
+ * Copyright (C) 2011 Pengutronix
+ * Sascha Hauer <s.hauer at pengutronix.de>
+ *
+ * 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 at 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/delay.h>
+#include <linux/io.h>
+#include <linux/pwm.h>
+#include <mach/hardware.h>
+#include <asm/div64.h>
+
+enum mxs_pwm_devtype {
+ MXS_PWM_CORE,
+ MXS_PWM,
+};
+
+struct mxs_pwm_device {
+ struct device *dev;
+
+ struct clk *clk;
+
+ int enabled;
+ void __iomem *mmio_base;
+ void __iomem *enable_base;
+
+ unsigned int pwm_id;
+
+ u32 val_active;
+ u32 val_period;
+ int period_us;
+ struct pwm_chip chip;
+};
+
+/* common register space */
+#define REG_PWM_CTRL 0x0
+#define REG_PWM_CTRL_SET 0x4
+#define REG_PWM_CTRL_CLEAR 0x8
+#define PWM_SFTRST (1 << 31)
+#define PWM_CLKGATE (1 << 30)
+#define PWM_ENABLE(p) (1 << (p))
+
+/* per pwm register space */
+#define REG_ACTIVE 0x0
+#define REG_PERIOD 0x10
+
+#define PERIOD_PERIOD(p) ((p) & 0xffff)
+#define PERIOD_ACTIVE_HIGH (3 << 16)
+#define PERIOD_INACTIVE_LOW (2 << 18)
+#define PERIOD_CDIV(div) (((div) & 0x7) << 20)
+
+static void pwm_update(struct mxs_pwm_device *pwm)
+{
+ writel(pwm->val_active, pwm->mmio_base + REG_ACTIVE);
+ writel(pwm->val_period, pwm->mmio_base + REG_PERIOD);
+}
+
+#define to_mxs_pwm_device(chip) container_of(chip, struct mxs_pwm_device, chip)
+
+static int mxs_pwm_config(struct pwm_chip *chip, int duty_ns, int period_ns)
+{
+ struct mxs_pwm_device *pwm = to_mxs_pwm_device(chip);
+ int div = 0;
+ unsigned long rate;
+ unsigned long long c;
+ unsigned long period_cycles, duty_cycles;
+
+ rate = clk_get_rate(pwm->clk);
+
+ dev_dbg(pwm->dev, "config: duty_ns: %d, period_ns: %d (clkrate %ld)\n",
+ duty_ns, period_ns, rate);
+
+ while (1) {
+ c = rate / (1 << div);
+ c = c * period_ns;
+ do_div(c, 1000000000);
+ if (c < 0x10000)
+ break;
+ div++;
+
+ if (div > 8)
+ return -EINVAL;
+ }
+
+ period_cycles = c;
+ duty_cycles = period_cycles * duty_ns / period_ns;
+
+ dev_dbg(pwm->dev, "config period_cycles: %ld duty_cycles: %ld\n",
+ period_cycles, duty_cycles);
+
+ pwm->val_active = period_cycles << 16 | duty_cycles;
+ pwm->val_period = PERIOD_PERIOD(period_cycles) | PERIOD_ACTIVE_HIGH |
+ PERIOD_INACTIVE_LOW | PERIOD_CDIV(div);
+ pwm->period_us = period_ns / 1000;
+
+ pwm_update(pwm);
+
+ return 0;
+}
+
+static void __pwm_enable(struct mxs_pwm_device *pwm, int enable)
+{
+ void __iomem *reg;
+
+ if (enable)
+ reg = pwm->enable_base + REG_PWM_CTRL_SET;
+ else
+ reg = pwm->enable_base + REG_PWM_CTRL_CLEAR;
+
+ writel(PWM_ENABLE(pwm->chip.pwm_id), reg);
+}
+
+static int mxs_pwm_enable(struct pwm_chip *chip)
+{
+ struct mxs_pwm_device *pwm = to_mxs_pwm_device(chip);
+ int ret = 0;
+
+ dev_dbg(pwm->dev, "enable\n");
+
+ if (!pwm->enabled) {
+ ret = clk_enable(pwm->clk);
+ if (!ret) {
+ pwm->enabled = 1;
+ __pwm_enable(pwm, 1);
+ pwm_update(pwm);
+ }
+ }
+ return ret;
+}
+
+static void mxs_pwm_disable(struct pwm_chip *chip)
+{
+ struct mxs_pwm_device *pwm = to_mxs_pwm_device(chip);
+
+ dev_dbg(pwm->dev, "disable\n");
+
+ if (pwm->enabled) {
+ /*
+ * We need a little delay here, it takes one period for
+ * the last pwm_config call to take effect. If we disable
+ * the pwm too early it just freezes the current output
+ * state.
+ */
+ usleep_range(pwm->period_us, pwm->period_us * 2);
+ __pwm_enable(pwm, 0);
+ clk_disable(pwm->clk);
+ pwm->enabled = 0;
+ }
+}
+
+static struct pwm_ops mxs_pwm_ops = {
+ .enable = mxs_pwm_enable,
+ .disable = mxs_pwm_disable,
+ .config = mxs_pwm_config,
+ .owner = THIS_MODULE,
+};
+
+static int mxs_pwm_core_probe(struct platform_device *pdev,
+ struct mxs_pwm_device *pwm)
+{
+ struct resource *r;
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!r)
+ return -ENODEV;
+
+ r = devm_request_mem_region(&pdev->dev, r->start, 0xf, pdev->name);
+ if (!r)
+ return -EBUSY;
+
+ pwm->mmio_base = devm_ioremap(&pdev->dev, r->start, resource_size(r));
+ if (!pwm->mmio_base) {
+ dev_err(&pdev->dev, "failed to ioremap() registers\n");
+ return -ENOMEM;
+ }
+
+ writel(PWM_SFTRST | PWM_CLKGATE, pwm->mmio_base + REG_PWM_CTRL_CLEAR);
+
+ return 0;
+}
+
+static int mxs_pwm_device_probe(struct platform_device *pdev,
+ struct mxs_pwm_device *pwm)
+{
+ struct mxs_pwm_device *parent_pwm;
+ struct resource *r;
+ int ret;
+
+ pwm->chip.ops = &mxs_pwm_ops;
+ pwm->chip.pwm_id = pdev->id;
+
+ parent_pwm = dev_get_drvdata(pdev->dev.parent);
+ if (!parent_pwm) {
+ dev_err(&pdev->dev, "no parent driver data\n");
+ return -EINVAL;
+ }
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!r)
+ return -ENODEV;
+
+ r = devm_request_mem_region(&pdev->dev, r->start, resource_size(r),
+ pdev->name);
+ if (!r)
+ return -EBUSY;
+
+ pwm->enable_base = parent_pwm->mmio_base;
+ pwm->mmio_base = devm_ioremap(&pdev->dev, r->start, resource_size(r));
+
+ pwm->clk = clk_get(&pdev->dev, NULL);
+ if (IS_ERR(pwm->clk))
+ return PTR_ERR(pwm->clk);
+
+ ret = pwmchip_add(&pwm->chip);
+ if (ret) {
+ clk_put(pwm->clk);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int __devinit mxs_pwm_probe(struct platform_device *pdev)
+{
+ struct mxs_pwm_device *pwm;
+
+ pwm = devm_kzalloc(&pdev->dev, sizeof(struct mxs_pwm_device), GFP_KERNEL);
+ if (!pwm) {
+ dev_err(&pdev->dev, "failed to allocate memory\n");
+ return -ENOMEM;
+ }
+
+ pwm->dev = &pdev->dev;
+
+ platform_set_drvdata(pdev, pwm);
+
+ if (pdev->id_entry->driver_data == MXS_PWM_CORE)
+ return mxs_pwm_core_probe(pdev, pwm);
+ else
+ return mxs_pwm_device_probe(pdev, pwm);
+
+ return 0;
+}
+
+static int __devexit mxs_pwm_remove(struct platform_device *pdev)
+{
+ struct mxs_pwm_device *pwm = platform_get_drvdata(pdev);
+ int ret;
+
+ switch (pdev->id_entry->driver_data) {
+ case MXS_PWM_CORE:
+ writel(PWM_CLKGATE, pwm->mmio_base + REG_PWM_CTRL_SET);
+ return 0;
+ case MXS_PWM:
+ ret = pwmchip_remove(&pwm->chip);
+ if (ret)
+ return ret;
+
+ clk_put(pwm->clk);
+ }
+
+ return 0;
+}
+
+static struct platform_device_id mxs_pwm_devtype[] = {
+ {
+ .name = "mxs-pwm-core",
+ .driver_data = MXS_PWM_CORE,
+ }, {
+ .name = "mxs-pwm",
+ .driver_data = MXS_PWM,
+ }, {
+ /* sentinel */
+ }
+};
+
+static struct platform_driver mxs_pwm_driver = {
+ .driver = {
+ .name = "mxs-pwm",
+ },
+ .id_table = mxs_pwm_devtype,
+ .probe = mxs_pwm_probe,
+ .remove = __devexit_p(mxs_pwm_remove),
+};
+
+static int __init mxs_pwm_init(void)
+{
+ return platform_driver_register(&mxs_pwm_driver);
+}
+arch_initcall(mxs_pwm_init);
+
+static void __exit mxs_pwm_exit(void)
+{
+ platform_driver_unregister(&mxs_pwm_driver);
+}
+module_exit(mxs_pwm_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Sascha Hauer <s.hauer at pengutronix.de>");
--
1.7.5.3
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