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