c2d476a98f
Make sure the duty-cycle and period passed in are not negative. This should eventually be made implicit by making them unsigned. While at it, the drivers' .config() implementations can have the equivalent checks removed. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de> Cc: Shawn Guo <shawn.guo@linaro.org> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Sachin Kamat <sachin.kamat@linaro.org> Cc: Axel Lin <axel.lin@gmail.com> Cc: Kukjin Kim <kgene.kim@samsung.com> Cc: Jingoo Han <jg1.han@samsung.com> Cc: Jonghwan Choi <jhbird.choi@samsung.com> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: "Philip, Avinash" <avinashphilip@ti.com> Cc: Vaibhav Bedia <vaibhav.bedia@ti.com> Acked-by: Jingoo Han <jg1.han@samsung.com>
159 lines
3.2 KiB
C
159 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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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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