--- /dev/null
+/*
+ * 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 jz4740_pwm_probe(struct platform_device *pdev)
+{
+ struct jz4740_pwm_chip *jz4740;
+
+ jz4740 = devm_kzalloc(&pdev->dev, sizeof(*jz4740), GFP_KERNEL);
+ if (!jz4740)
+ return -ENOMEM;
+
+ jz4740->clk = devm_clk_get(&pdev->dev, "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;
+
+ platform_set_drvdata(pdev, jz4740);
+
+ return pwmchip_add(&jz4740->chip);
+}
+
+static int jz4740_pwm_remove(struct platform_device *pdev)
+{
+ struct jz4740_pwm_chip *jz4740 = platform_get_drvdata(pdev);
+
+ return pwmchip_remove(&jz4740->chip);
+}
+
+static struct platform_driver jz4740_pwm_driver = {
+ .driver = {
+ .name = "jz4740-pwm",
+ },
+ .probe = jz4740_pwm_probe,
+ .remove = 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");
Code Review / kvmfornfv.git / blobdiff