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![Uwe Kleine-König](/assets/img/avatar_default.png)
A consumer is expected to disable a PWM before calling pwm_put(). And if they didn't there is hopefully a good reason (or the consumer needs fixing). Also if disabling an enabled PWM was the right thing to do, this should better be done in the framework instead of in each low level driver. So drop the hardware modification from the .remove() callback. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Vladimir Zapolskiy <vz@mleia.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
162 lines
4 KiB
C
162 lines
4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright 2012 Alexandre Pereira da Silva <aletes.xgr@gmail.com>
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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/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_address.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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struct lpc32xx_pwm_chip {
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struct pwm_chip chip;
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struct clk *clk;
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void __iomem *base;
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};
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#define PWM_ENABLE BIT(31)
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#define PWM_PIN_LEVEL BIT(30)
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#define to_lpc32xx_pwm_chip(_chip) \
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container_of(_chip, struct lpc32xx_pwm_chip, chip)
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static int lpc32xx_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 lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
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unsigned long long c;
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int period_cycles, duty_cycles;
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u32 val;
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c = clk_get_rate(lpc32xx->clk);
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/* The highest acceptable divisor is 256, which is represented by 0 */
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period_cycles = div64_u64(c * period_ns,
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(unsigned long long)NSEC_PER_SEC * 256);
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if (!period_cycles || period_cycles > 256)
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return -ERANGE;
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if (period_cycles == 256)
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period_cycles = 0;
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/* Compute 256 x #duty/period value and care for corner cases */
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duty_cycles = div64_u64((unsigned long long)(period_ns - duty_ns) * 256,
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period_ns);
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if (!duty_cycles)
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duty_cycles = 1;
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if (duty_cycles > 255)
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duty_cycles = 255;
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val = readl(lpc32xx->base + (pwm->hwpwm << 2));
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val &= ~0xFFFF;
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val |= (period_cycles << 8) | duty_cycles;
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writel(val, lpc32xx->base + (pwm->hwpwm << 2));
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return 0;
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}
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static int lpc32xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
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u32 val;
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int ret;
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ret = clk_prepare_enable(lpc32xx->clk);
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if (ret)
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return ret;
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val = readl(lpc32xx->base + (pwm->hwpwm << 2));
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val |= PWM_ENABLE;
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writel(val, lpc32xx->base + (pwm->hwpwm << 2));
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return 0;
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}
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static void lpc32xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
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u32 val;
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val = readl(lpc32xx->base + (pwm->hwpwm << 2));
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val &= ~PWM_ENABLE;
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writel(val, lpc32xx->base + (pwm->hwpwm << 2));
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clk_disable_unprepare(lpc32xx->clk);
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}
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static const struct pwm_ops lpc32xx_pwm_ops = {
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.config = lpc32xx_pwm_config,
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.enable = lpc32xx_pwm_enable,
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.disable = lpc32xx_pwm_disable,
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.owner = THIS_MODULE,
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};
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static int lpc32xx_pwm_probe(struct platform_device *pdev)
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{
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struct lpc32xx_pwm_chip *lpc32xx;
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int ret;
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u32 val;
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lpc32xx = devm_kzalloc(&pdev->dev, sizeof(*lpc32xx), GFP_KERNEL);
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if (!lpc32xx)
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return -ENOMEM;
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lpc32xx->base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(lpc32xx->base))
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return PTR_ERR(lpc32xx->base);
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lpc32xx->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(lpc32xx->clk))
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return PTR_ERR(lpc32xx->clk);
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lpc32xx->chip.dev = &pdev->dev;
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lpc32xx->chip.ops = &lpc32xx_pwm_ops;
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lpc32xx->chip.npwm = 1;
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ret = pwmchip_add(&lpc32xx->chip);
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if (ret < 0) {
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dev_err(&pdev->dev, "failed to add PWM chip, error %d\n", ret);
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return ret;
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}
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/* When PWM is disable, configure the output to the default value */
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val = readl(lpc32xx->base + (lpc32xx->chip.pwms[0].hwpwm << 2));
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val &= ~PWM_PIN_LEVEL;
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writel(val, lpc32xx->base + (lpc32xx->chip.pwms[0].hwpwm << 2));
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platform_set_drvdata(pdev, lpc32xx);
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return 0;
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}
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static int lpc32xx_pwm_remove(struct platform_device *pdev)
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{
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struct lpc32xx_pwm_chip *lpc32xx = platform_get_drvdata(pdev);
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return pwmchip_remove(&lpc32xx->chip);
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}
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static const struct of_device_id lpc32xx_pwm_dt_ids[] = {
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{ .compatible = "nxp,lpc3220-pwm", },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, lpc32xx_pwm_dt_ids);
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static struct platform_driver lpc32xx_pwm_driver = {
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.driver = {
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.name = "lpc32xx-pwm",
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.of_match_table = lpc32xx_pwm_dt_ids,
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},
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.probe = lpc32xx_pwm_probe,
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.remove = lpc32xx_pwm_remove,
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};
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module_platform_driver(lpc32xx_pwm_driver);
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MODULE_ALIAS("platform:lpc32xx-pwm");
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MODULE_AUTHOR("Alexandre Pereira da Silva <aletes.xgr@gmail.com>");
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MODULE_DESCRIPTION("LPC32XX PWM Driver");
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MODULE_LICENSE("GPL v2");
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