/* * Marvell Berlin PWM driver * * Copyright (C) 2015 Marvell Technology Group Ltd. * * Author: Antoine Tenart <antoine.tenart@free-electrons.com> * * This file is licensed under the terms of the GNU General Public * License version 2. This program is licensed "as is" without any * warranty of any kind, whether express or implied. */ #include <linux/clk.h> #include <linux/io.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/platform_device.h> #include <linux/pwm.h> #include <linux/slab.h> #define BERLIN_PWM_EN 0x0 #define BERLIN_PWM_ENABLE BIT(0) #define BERLIN_PWM_CONTROL 0x4 /* * The prescaler claims to support 8 different moduli, configured using the * low three bits of PWM_CONTROL. (Sequentially, they are 1, 4, 8, 16, 64, * 256, 1024, and 4096.) However, the moduli from 4 to 1024 appear to be * implemented by internally shifting TCNT left without adding additional * bits. So, the max TCNT that actually works for a modulus of 4 is 0x3fff; * for 8, 0x1fff; and so on. This means that those moduli are entirely * useless, as we could just do the shift ourselves. The 4096 modulus is * implemented with a real prescaler, so we do use that, but we treat it * as a flag instead of pretending the modulus is actually configurable. */ #define BERLIN_PWM_PRESCALE_4096 0x7 #define BERLIN_PWM_INVERT_POLARITY BIT(3) #define BERLIN_PWM_DUTY 0x8 #define BERLIN_PWM_TCNT 0xc #define BERLIN_PWM_MAX_TCNT 65535 struct berlin_pwm_channel { u32 enable; u32 ctrl; u32 duty; u32 tcnt; }; struct berlin_pwm_chip { struct pwm_chip chip; struct clk *clk; void __iomem *base; }; static inline struct berlin_pwm_chip *to_berlin_pwm_chip(struct pwm_chip *chip) { return container_of(chip, struct berlin_pwm_chip, chip); } static inline u32 berlin_pwm_readl(struct berlin_pwm_chip *chip, unsigned int channel, unsigned long offset) { return readl_relaxed(chip->base + channel * 0x10 + offset); } static inline void berlin_pwm_writel(struct berlin_pwm_chip *chip, unsigned int channel, u32 value, unsigned long offset) { writel_relaxed(value, chip->base + channel * 0x10 + offset); } static int berlin_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) { struct berlin_pwm_channel *channel; channel = kzalloc(sizeof(*channel), GFP_KERNEL); if (!channel) return -ENOMEM; return pwm_set_chip_data(pwm, channel); } static void berlin_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) { struct berlin_pwm_channel *channel = pwm_get_chip_data(pwm); kfree(channel); } static int berlin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm_dev, int duty_ns, int period_ns) { struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip); bool prescale_4096 = false; u32 value, duty, period; u64 cycles; cycles = clk_get_rate(pwm->clk); cycles *= period_ns; do_div(cycles, NSEC_PER_SEC); if (cycles > BERLIN_PWM_MAX_TCNT) { prescale_4096 = true; cycles >>= 12; // Prescaled by 4096 if (cycles > BERLIN_PWM_MAX_TCNT) return -ERANGE; } period = cycles; cycles *= duty_ns; do_div(cycles, period_ns); duty = cycles; value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL); if (prescale_4096) value |= BERLIN_PWM_PRESCALE_4096; else value &= ~BERLIN_PWM_PRESCALE_4096; berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL); berlin_pwm_writel(pwm, pwm_dev->hwpwm, duty, BERLIN_PWM_DUTY); berlin_pwm_writel(pwm, pwm_dev->hwpwm, period, BERLIN_PWM_TCNT); return 0; } static int berlin_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm_dev, enum pwm_polarity polarity) { struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip); u32 value; value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL); if (polarity == PWM_POLARITY_NORMAL) value &= ~BERLIN_PWM_INVERT_POLARITY; else value |= BERLIN_PWM_INVERT_POLARITY; berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL); return 0; } static int berlin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm_dev) { struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip); u32 value; value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN); value |= BERLIN_PWM_ENABLE; berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN); return 0; } static void berlin_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm_dev) { struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip); u32 value; value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN); value &= ~BERLIN_PWM_ENABLE; berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN); } static const struct pwm_ops berlin_pwm_ops = { .request = berlin_pwm_request, .free = berlin_pwm_free, .config = berlin_pwm_config, .set_polarity = berlin_pwm_set_polarity, .enable = berlin_pwm_enable, .disable = berlin_pwm_disable, .owner = THIS_MODULE, }; static const struct of_device_id berlin_pwm_match[] = { { .compatible = "marvell,berlin-pwm" }, { }, }; MODULE_DEVICE_TABLE(of, berlin_pwm_match); static int berlin_pwm_probe(struct platform_device *pdev) { struct berlin_pwm_chip *pwm; struct resource *res; int ret; pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); if (!pwm) return -ENOMEM; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); pwm->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(pwm->base)) return PTR_ERR(pwm->base); pwm->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(pwm->clk)) return PTR_ERR(pwm->clk); ret = clk_prepare_enable(pwm->clk); if (ret) return ret; pwm->chip.dev = &pdev->dev; pwm->chip.ops = &berlin_pwm_ops; pwm->chip.base = -1; pwm->chip.npwm = 4; pwm->chip.of_xlate = of_pwm_xlate_with_flags; pwm->chip.of_pwm_n_cells = 3; ret = pwmchip_add(&pwm->chip); if (ret < 0) { dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret); clk_disable_unprepare(pwm->clk); return ret; } platform_set_drvdata(pdev, pwm); return 0; } static int berlin_pwm_remove(struct platform_device *pdev) { struct berlin_pwm_chip *pwm = platform_get_drvdata(pdev); int ret; ret = pwmchip_remove(&pwm->chip); clk_disable_unprepare(pwm->clk); return ret; } #ifdef CONFIG_PM_SLEEP static int berlin_pwm_suspend(struct device *dev) { struct berlin_pwm_chip *pwm = dev_get_drvdata(dev); unsigned int i; for (i = 0; i < pwm->chip.npwm; i++) { struct berlin_pwm_channel *channel; channel = pwm_get_chip_data(&pwm->chip.pwms[i]); if (!channel) continue; channel->enable = berlin_pwm_readl(pwm, i, BERLIN_PWM_ENABLE); channel->ctrl = berlin_pwm_readl(pwm, i, BERLIN_PWM_CONTROL); channel->duty = berlin_pwm_readl(pwm, i, BERLIN_PWM_DUTY); channel->tcnt = berlin_pwm_readl(pwm, i, BERLIN_PWM_TCNT); } clk_disable_unprepare(pwm->clk); return 0; } static int berlin_pwm_resume(struct device *dev) { struct berlin_pwm_chip *pwm = dev_get_drvdata(dev); unsigned int i; int ret; ret = clk_prepare_enable(pwm->clk); if (ret) return ret; for (i = 0; i < pwm->chip.npwm; i++) { struct berlin_pwm_channel *channel; channel = pwm_get_chip_data(&pwm->chip.pwms[i]); if (!channel) continue; berlin_pwm_writel(pwm, i, channel->ctrl, BERLIN_PWM_CONTROL); berlin_pwm_writel(pwm, i, channel->duty, BERLIN_PWM_DUTY); berlin_pwm_writel(pwm, i, channel->tcnt, BERLIN_PWM_TCNT); berlin_pwm_writel(pwm, i, channel->enable, BERLIN_PWM_ENABLE); } return 0; } #endif static SIMPLE_DEV_PM_OPS(berlin_pwm_pm_ops, berlin_pwm_suspend, berlin_pwm_resume); static struct platform_driver berlin_pwm_driver = { .probe = berlin_pwm_probe, .remove = berlin_pwm_remove, .driver = { .name = "berlin-pwm", .of_match_table = berlin_pwm_match, .pm = &berlin_pwm_pm_ops, }, }; module_platform_driver(berlin_pwm_driver); MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>"); MODULE_DESCRIPTION("Marvell Berlin PWM driver"); MODULE_LICENSE("GPL v2");