163 lines
3.2 KiB
C
163 lines
3.2 KiB
C
/*
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* Blackfin Pulse Width Modulation (PWM) core
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*
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* Copyright (c) 2011 Analog Devices Inc.
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*
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* Licensed under the GPL-2 or later.
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*/
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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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#include <linux/slab.h>
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#include <asm/gptimers.h>
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#include <asm/portmux.h>
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struct bfin_pwm_chip {
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struct pwm_chip chip;
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};
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struct bfin_pwm {
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unsigned short pin;
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};
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static const unsigned short pwm_to_gptimer_per[] = {
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P_TMR0, P_TMR1, P_TMR2, P_TMR3, P_TMR4, P_TMR5,
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P_TMR6, P_TMR7, P_TMR8, P_TMR9, P_TMR10, P_TMR11,
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};
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static int bfin_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct bfin_pwm *priv;
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int ret;
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if (pwm->hwpwm >= ARRAY_SIZE(pwm_to_gptimer_per))
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return -EINVAL;
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priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->pin = pwm_to_gptimer_per[pwm->hwpwm];
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ret = peripheral_request(priv->pin, NULL);
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if (ret) {
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kfree(priv);
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return ret;
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}
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pwm_set_chip_data(pwm, priv);
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return 0;
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}
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static void bfin_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct bfin_pwm *priv = pwm_get_chip_data(pwm);
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if (priv) {
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peripheral_free(priv->pin);
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kfree(priv);
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}
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}
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static int bfin_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 bfin_pwm *priv = pwm_get_chip_data(pwm);
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unsigned long period, duty;
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unsigned long long val;
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if (duty_ns < 0 || duty_ns > period_ns)
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return -EINVAL;
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val = (unsigned long long)get_sclk() * period_ns;
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do_div(val, NSEC_PER_SEC);
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period = val;
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val = (unsigned long long)period * duty_ns;
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do_div(val, period_ns);
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duty = period - val;
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if (duty >= period)
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duty = period - 1;
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set_gptimer_config(priv->pin, TIMER_MODE_PWM | TIMER_PERIOD_CNT);
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set_gptimer_pwidth(priv->pin, duty);
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set_gptimer_period(priv->pin, period);
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return 0;
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}
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static int bfin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct bfin_pwm *priv = pwm_get_chip_data(pwm);
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enable_gptimer(priv->pin);
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return 0;
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}
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static void bfin_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct bfin_pwm *priv = pwm_get_chip_data(pwm);
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disable_gptimer(priv->pin);
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}
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static struct pwm_ops bfin_pwm_ops = {
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.request = bfin_pwm_request,
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.free = bfin_pwm_free,
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.config = bfin_pwm_config,
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.enable = bfin_pwm_enable,
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.disable = bfin_pwm_disable,
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.owner = THIS_MODULE,
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};
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static int bfin_pwm_probe(struct platform_device *pdev)
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{
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struct bfin_pwm_chip *pwm;
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int ret;
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pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
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if (!pwm) {
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dev_err(&pdev->dev, "failed to allocate memory\n");
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return -ENOMEM;
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}
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platform_set_drvdata(pdev, pwm);
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pwm->chip.dev = &pdev->dev;
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pwm->chip.ops = &bfin_pwm_ops;
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pwm->chip.base = -1;
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pwm->chip.npwm = 12;
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ret = pwmchip_add(&pwm->chip);
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if (ret < 0) {
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dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
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return ret;
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}
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return 0;
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}
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static int __devexit bfin_pwm_remove(struct platform_device *pdev)
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{
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struct bfin_pwm_chip *pwm = platform_get_drvdata(pdev);
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return pwmchip_remove(&pwm->chip);
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}
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static struct platform_driver bfin_pwm_driver = {
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.driver = {
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.name = "bfin-pwm",
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},
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.probe = bfin_pwm_probe,
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.remove = __devexit_p(bfin_pwm_remove),
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};
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module_platform_driver(bfin_pwm_driver);
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MODULE_LICENSE("GPL");
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