pwm: Add Ingenic JZ4740 support

This commit moves the driver to drivers/pwm and converts it to the new
PWM framework.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 221 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c
new file mode 100644
index 0000000..10250fc
--- /dev/null
+++ b/drivers/pwm/pwm-jz4740.c
@@ -0,0 +1,221 @@
+/*
+ *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
+ *  JZ4740 platform PWM support
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under  the terms of the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+
+#include <asm/mach-jz4740/gpio.h>
+#include <asm/mach-jz4740/timer.h>
+
+#define NUM_PWM 8
+
+static const unsigned int jz4740_pwm_gpio_list[NUM_PWM] = {
+	JZ_GPIO_PWM0,
+	JZ_GPIO_PWM1,
+	JZ_GPIO_PWM2,
+	JZ_GPIO_PWM3,
+	JZ_GPIO_PWM4,
+	JZ_GPIO_PWM5,
+	JZ_GPIO_PWM6,
+	JZ_GPIO_PWM7,
+};
+
+struct jz4740_pwm_chip {
+	struct pwm_chip chip;
+	struct clk *clk;
+};
+
+static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip)
+{
+	return container_of(chip, struct jz4740_pwm_chip, chip);
+}
+
+static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	unsigned int gpio = jz4740_pwm_gpio_list[pwm->hwpwm];
+	int ret;
+
+	/*
+	 * Timers 0 and 1 are used for system tasks, so they are unavailable
+	 * for use as PWMs.
+	 */
+	if (pwm->hwpwm < 2)
+		return -EBUSY;
+
+	ret = gpio_request(gpio, pwm->label);
+	if (ret) {
+		dev_err(chip->dev, "Failed to request GPIO#%u for PWM: %d\n",
+			gpio, ret);
+		return ret;
+	}
+
+	jz_gpio_set_function(gpio, JZ_GPIO_FUNC_PWM);
+
+	jz4740_timer_start(pwm->hwpwm);
+
+	return 0;
+}
+
+static void jz4740_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	unsigned int gpio = jz4740_pwm_gpio_list[pwm->hwpwm];
+
+	jz4740_timer_set_ctrl(pwm->hwpwm, 0);
+
+	jz_gpio_set_function(gpio, JZ_GPIO_FUNC_NONE);
+	gpio_free(gpio);
+
+	jz4740_timer_stop(pwm->hwpwm);
+}
+
+static int jz4740_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	uint32_t ctrl = jz4740_timer_get_ctrl(pwm->pwm);
+
+	ctrl |= JZ_TIMER_CTRL_PWM_ENABLE;
+	jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
+	jz4740_timer_enable(pwm->hwpwm);
+
+	return 0;
+}
+
+static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	uint32_t ctrl = jz4740_timer_get_ctrl(pwm->hwpwm);
+
+	ctrl &= ~JZ_TIMER_CTRL_PWM_ENABLE;
+	jz4740_timer_disable(pwm->hwpwm);
+	jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
+}
+
+static int jz4740_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			     int duty_ns, int period_ns)
+{
+	struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip);
+	unsigned long long tmp;
+	unsigned long period, duty;
+	unsigned int prescaler = 0;
+	uint16_t ctrl;
+	bool is_enabled;
+
+	tmp = (unsigned long long)clk_get_rate(jz4740->clk) * period_ns;
+	do_div(tmp, 1000000000);
+	period = tmp;
+
+	while (period > 0xffff && prescaler < 6) {
+		period >>= 2;
+		++prescaler;
+	}
+
+	if (prescaler == 6)
+		return -EINVAL;
+
+	tmp = (unsigned long long)period * duty_ns;
+	do_div(tmp, period_ns);
+	duty = period - tmp;
+
+	if (duty >= period)
+		duty = period - 1;
+
+	is_enabled = jz4740_timer_is_enabled(pwm->hwpwm);
+	if (is_enabled)
+		jz4740_pwm_disable(chip, pwm);
+
+	jz4740_timer_set_count(pwm->hwpwm, 0);
+	jz4740_timer_set_duty(pwm->hwpwm, duty);
+	jz4740_timer_set_period(pwm->hwpwm, period);
+
+	ctrl = JZ_TIMER_CTRL_PRESCALER(prescaler) | JZ_TIMER_CTRL_SRC_EXT |
+		JZ_TIMER_CTRL_PWM_ABBRUPT_SHUTDOWN;
+
+	jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
+
+	if (is_enabled)
+		jz4740_pwm_enable(chip, pwm);
+
+	return 0;
+}
+
+static const struct pwm_ops jz4740_pwm_ops = {
+	.request = jz4740_pwm_request,
+	.free = jz4740_pwm_free,
+	.config = jz4740_pwm_config,
+	.enable = jz4740_pwm_enable,
+	.disable = jz4740_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+static int __devinit jz4740_pwm_probe(struct platform_device *pdev)
+{
+	struct jz4740_pwm_chip *jz4740;
+	int ret;
+
+	jz4740 = devm_kzalloc(&pdev->dev, sizeof(*jz4740), GFP_KERNEL);
+	if (!jz4740)
+		return -ENOMEM;
+
+	jz4740->clk = clk_get(NULL, "ext");
+	if (IS_ERR(jz4740->clk))
+		return PTR_ERR(jz4740->clk);
+
+	jz4740->chip.dev = &pdev->dev;
+	jz4740->chip.ops = &jz4740_pwm_ops;
+	jz4740->chip.npwm = NUM_PWM;
+	jz4740->chip.base = -1;
+
+	ret = pwmchip_add(&jz4740->chip);
+	if (ret < 0) {
+		clk_put(jz4740->clk);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, jz4740);
+
+	return 0;
+}
+
+static int __devexit jz4740_pwm_remove(struct platform_device *pdev)
+{
+	struct jz4740_pwm_chip *jz4740 = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = pwmchip_remove(&jz4740->chip);
+	if (ret < 0)
+		return ret;
+
+	clk_put(jz4740->clk);
+
+	return 0;
+}
+
+static struct platform_driver jz4740_pwm_driver = {
+	.driver = {
+		.name = "jz4740-pwm",
+		.owner = THIS_MODULE,
+	},
+	.probe = jz4740_pwm_probe,
+	.remove = __devexit_p(jz4740_pwm_remove),
+};
+module_platform_driver(jz4740_pwm_driver);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("Ingenic JZ4740 PWM driver");
+MODULE_ALIAS("platform:jz4740-pwm");
+MODULE_LICENSE("GPL");