/* * PWM framework driver for Cirrus Logic EP93xx * * Copyright (c) 2009 Matthieu Crapet <mcrapet@gmail.com> * Copyright (c) 2009, 2013 H Hartley Sweeten <hsweeten@visionengravers.com> * * EP9301/02 have only one channel: * platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14) * * EP9307 has only one channel: * platform device ep93xx-pwm.0 - PWMOUT * * EP9312/15 have two channels: * platform device ep93xx-pwm.0 - PWMOUT * platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include <linux/module.h> #include <linux/platform_device.h> #include <linux/slab.h> #include <linux/clk.h> #include <linux/err.h> #include <linux/io.h> #include <linux/pwm.h> #include <asm/div64.h> #include <mach/platform.h> /* for ep93xx_pwm_{acquire,release}_gpio() */ #define EP93XX_PWMx_TERM_COUNT 0x00 #define EP93XX_PWMx_DUTY_CYCLE 0x04 #define EP93XX_PWMx_ENABLE 0x08 #define EP93XX_PWMx_INVERT 0x0c struct ep93xx_pwm { void __iomem *base; struct clk *clk; struct pwm_chip chip; }; static inline struct ep93xx_pwm *to_ep93xx_pwm(struct pwm_chip *chip) { return container_of(chip, struct ep93xx_pwm, chip); } static int ep93xx_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) { struct platform_device *pdev = to_platform_device(chip->dev); return ep93xx_pwm_acquire_gpio(pdev); } static void ep93xx_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) { struct platform_device *pdev = to_platform_device(chip->dev); ep93xx_pwm_release_gpio(pdev); } static int ep93xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns) { struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); void __iomem *base = ep93xx_pwm->base; unsigned long long c; unsigned long period_cycles; unsigned long duty_cycles; unsigned long term; int ret = 0; /* * The clock needs to be enabled to access the PWM registers. * Configuration can be changed at any time. */ if (!pwm_is_enabled(pwm)) { ret = clk_enable(ep93xx_pwm->clk); if (ret) return ret; } c = clk_get_rate(ep93xx_pwm->clk); c *= period_ns; do_div(c, 1000000000); period_cycles = c; c = period_cycles; c *= duty_ns; do_div(c, period_ns); duty_cycles = c; if (period_cycles < 0x10000 && duty_cycles < 0x10000) { term = readw(base + EP93XX_PWMx_TERM_COUNT); /* Order is important if PWM is running */ if (period_cycles > term) { writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); } else { writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); } } else { ret = -EINVAL; } if (!pwm_is_enabled(pwm)) clk_disable(ep93xx_pwm->clk); return ret; } static int ep93xx_pwm_polarity(struct pwm_chip *chip, struct pwm_device *pwm, enum pwm_polarity polarity) { struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); int ret; /* * The clock needs to be enabled to access the PWM registers. * Polarity can only be changed when the PWM is disabled. */ ret = clk_enable(ep93xx_pwm->clk); if (ret) return ret; if (polarity == PWM_POLARITY_INVERSED) writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT); else writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT); clk_disable(ep93xx_pwm->clk); return 0; } static int ep93xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) { struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); int ret; ret = clk_enable(ep93xx_pwm->clk); if (ret) return ret; writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); return 0; } static void ep93xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) { struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); clk_disable(ep93xx_pwm->clk); } static const struct pwm_ops ep93xx_pwm_ops = { .request = ep93xx_pwm_request, .free = ep93xx_pwm_free, .config = ep93xx_pwm_config, .set_polarity = ep93xx_pwm_polarity, .enable = ep93xx_pwm_enable, .disable = ep93xx_pwm_disable, .owner = THIS_MODULE, }; static int ep93xx_pwm_probe(struct platform_device *pdev) { struct ep93xx_pwm *ep93xx_pwm; struct resource *res; int ret; ep93xx_pwm = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_pwm), GFP_KERNEL); if (!ep93xx_pwm) return -ENOMEM; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); ep93xx_pwm->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(ep93xx_pwm->base)) return PTR_ERR(ep93xx_pwm->base); ep93xx_pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk"); if (IS_ERR(ep93xx_pwm->clk)) return PTR_ERR(ep93xx_pwm->clk); ep93xx_pwm->chip.dev = &pdev->dev; ep93xx_pwm->chip.ops = &ep93xx_pwm_ops; ep93xx_pwm->chip.base = -1; ep93xx_pwm->chip.npwm = 1; ret = pwmchip_add(&ep93xx_pwm->chip); if (ret < 0) return ret; platform_set_drvdata(pdev, ep93xx_pwm); return 0; } static int ep93xx_pwm_remove(struct platform_device *pdev) { struct ep93xx_pwm *ep93xx_pwm = platform_get_drvdata(pdev); return pwmchip_remove(&ep93xx_pwm->chip); } static struct platform_driver ep93xx_pwm_driver = { .driver = { .name = "ep93xx-pwm", }, .probe = ep93xx_pwm_probe, .remove = ep93xx_pwm_remove, }; module_platform_driver(ep93xx_pwm_driver); MODULE_DESCRIPTION("Cirrus Logic EP93xx PWM driver"); MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>"); MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>"); MODULE_ALIAS("platform:ep93xx-pwm"); MODULE_LICENSE("GPL");