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- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * Copyright 2012 Alexandre Pereira da Silva <[email protected]>
- */
- #include <linux/clk.h>
- #include <linux/err.h>
- #include <linux/io.h>
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/of.h>
- #include <linux/of_address.h>
- #include <linux/platform_device.h>
- #include <linux/pwm.h>
- #include <linux/slab.h>
- struct lpc32xx_pwm_chip {
- struct pwm_chip chip;
- struct clk *clk;
- void __iomem *base;
- };
- #define PWM_ENABLE BIT(31)
- #define PWM_PIN_LEVEL BIT(30)
- #define to_lpc32xx_pwm_chip(_chip) \
- container_of(_chip, struct lpc32xx_pwm_chip, chip)
- static int lpc32xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
- int duty_ns, int period_ns)
- {
- struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
- unsigned long long c;
- int period_cycles, duty_cycles;
- u32 val;
- c = clk_get_rate(lpc32xx->clk);
- /* The highest acceptable divisor is 256, which is represented by 0 */
- period_cycles = div64_u64(c * period_ns,
- (unsigned long long)NSEC_PER_SEC * 256);
- if (!period_cycles || period_cycles > 256)
- return -ERANGE;
- if (period_cycles == 256)
- period_cycles = 0;
- /* Compute 256 x #duty/period value and care for corner cases */
- duty_cycles = div64_u64((unsigned long long)(period_ns - duty_ns) * 256,
- period_ns);
- if (!duty_cycles)
- duty_cycles = 1;
- if (duty_cycles > 255)
- duty_cycles = 255;
- val = readl(lpc32xx->base);
- val &= ~0xFFFF;
- val |= (period_cycles << 8) | duty_cycles;
- writel(val, lpc32xx->base);
- return 0;
- }
- static int lpc32xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
- {
- struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
- u32 val;
- int ret;
- ret = clk_prepare_enable(lpc32xx->clk);
- if (ret)
- return ret;
- val = readl(lpc32xx->base);
- val |= PWM_ENABLE;
- writel(val, lpc32xx->base);
- return 0;
- }
- static void lpc32xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
- {
- struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
- u32 val;
- val = readl(lpc32xx->base);
- val &= ~PWM_ENABLE;
- writel(val, lpc32xx->base);
- clk_disable_unprepare(lpc32xx->clk);
- }
- static int lpc32xx_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
- const struct pwm_state *state)
- {
- int err;
- if (state->polarity != PWM_POLARITY_NORMAL)
- return -EINVAL;
- if (!state->enabled) {
- if (pwm->state.enabled)
- lpc32xx_pwm_disable(chip, pwm);
- return 0;
- }
- err = lpc32xx_pwm_config(pwm->chip, pwm, state->duty_cycle, state->period);
- if (err)
- return err;
- if (!pwm->state.enabled)
- err = lpc32xx_pwm_enable(chip, pwm);
- return err;
- }
- static const struct pwm_ops lpc32xx_pwm_ops = {
- .apply = lpc32xx_pwm_apply,
- .owner = THIS_MODULE,
- };
- static int lpc32xx_pwm_probe(struct platform_device *pdev)
- {
- struct lpc32xx_pwm_chip *lpc32xx;
- int ret;
- u32 val;
- lpc32xx = devm_kzalloc(&pdev->dev, sizeof(*lpc32xx), GFP_KERNEL);
- if (!lpc32xx)
- return -ENOMEM;
- lpc32xx->base = devm_platform_ioremap_resource(pdev, 0);
- if (IS_ERR(lpc32xx->base))
- return PTR_ERR(lpc32xx->base);
- lpc32xx->clk = devm_clk_get(&pdev->dev, NULL);
- if (IS_ERR(lpc32xx->clk))
- return PTR_ERR(lpc32xx->clk);
- lpc32xx->chip.dev = &pdev->dev;
- lpc32xx->chip.ops = &lpc32xx_pwm_ops;
- lpc32xx->chip.npwm = 1;
- /* If PWM is disabled, configure the output to the default value */
- val = readl(lpc32xx->base);
- val &= ~PWM_PIN_LEVEL;
- writel(val, lpc32xx->base);
- ret = devm_pwmchip_add(&pdev->dev, &lpc32xx->chip);
- if (ret < 0) {
- dev_err(&pdev->dev, "failed to add PWM chip, error %d\n", ret);
- return ret;
- }
- return 0;
- }
- static const struct of_device_id lpc32xx_pwm_dt_ids[] = {
- { .compatible = "nxp,lpc3220-pwm", },
- { /* sentinel */ }
- };
- MODULE_DEVICE_TABLE(of, lpc32xx_pwm_dt_ids);
- static struct platform_driver lpc32xx_pwm_driver = {
- .driver = {
- .name = "lpc32xx-pwm",
- .of_match_table = lpc32xx_pwm_dt_ids,
- },
- .probe = lpc32xx_pwm_probe,
- };
- module_platform_driver(lpc32xx_pwm_driver);
- MODULE_ALIAS("platform:lpc32xx-pwm");
- MODULE_AUTHOR("Alexandre Pereira da Silva <[email protected]>");
- MODULE_DESCRIPTION("LPC32XX PWM Driver");
- MODULE_LICENSE("GPL v2");
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