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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * PWM framework driver for Cirrus Logic EP93xx4 *5 * Copyright (c) 2009 Matthieu Crapet <mcrapet@gmail.com>6 * Copyright (c) 2009, 2013 H Hartley Sweeten <hsweeten@visionengravers.com>7 *8 * EP9301/02 have only one channel:9 * platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)10 *11 * EP9307 has only one channel:12 * platform device ep93xx-pwm.0 - PWMOUT13 *14 * EP9312/15 have two channels:15 * platform device ep93xx-pwm.0 - PWMOUT16 * platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)17 */18 19#include <linux/module.h>20#include <linux/mod_devicetable.h>21#include <linux/platform_device.h>22#include <linux/slab.h>23#include <linux/clk.h>24#include <linux/err.h>25#include <linux/io.h>26#include <linux/pwm.h>27 28#include <asm/div64.h>29 30#define EP93XX_PWMx_TERM_COUNT 0x0031#define EP93XX_PWMx_DUTY_CYCLE 0x0432#define EP93XX_PWMx_ENABLE 0x0833#define EP93XX_PWMx_INVERT 0x0c34 35struct ep93xx_pwm {36 void __iomem *base;37 struct clk *clk;38};39 40static inline struct ep93xx_pwm *to_ep93xx_pwm(struct pwm_chip *chip)41{42 return pwmchip_get_drvdata(chip);43}44 45static int ep93xx_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,46 const struct pwm_state *state)47{48 int ret;49 struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);50 bool enabled = state->enabled;51 void __iomem *base = ep93xx_pwm->base;52 unsigned long long c;53 unsigned long period_cycles;54 unsigned long duty_cycles;55 unsigned long term;56 57 if (state->polarity != pwm->state.polarity) {58 if (enabled) {59 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);60 clk_disable_unprepare(ep93xx_pwm->clk);61 enabled = false;62 }63 64 /*65 * The clock needs to be enabled to access the PWM registers.66 * Polarity can only be changed when the PWM is disabled.67 */68 ret = clk_prepare_enable(ep93xx_pwm->clk);69 if (ret)70 return ret;71 72 if (state->polarity == PWM_POLARITY_INVERSED)73 writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT);74 else75 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT);76 77 clk_disable_unprepare(ep93xx_pwm->clk);78 }79 80 if (!state->enabled) {81 if (enabled) {82 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);83 clk_disable_unprepare(ep93xx_pwm->clk);84 }85 86 return 0;87 }88 89 /*90 * The clock needs to be enabled to access the PWM registers.91 * Configuration can be changed at any time.92 */93 if (!pwm_is_enabled(pwm)) {94 ret = clk_prepare_enable(ep93xx_pwm->clk);95 if (ret)96 return ret;97 }98 99 c = clk_get_rate(ep93xx_pwm->clk);100 c *= state->period;101 do_div(c, 1000000000);102 period_cycles = c;103 104 c = period_cycles;105 c *= state->duty_cycle;106 do_div(c, state->period);107 duty_cycles = c;108 109 if (period_cycles < 0x10000 && duty_cycles < 0x10000) {110 term = readw(base + EP93XX_PWMx_TERM_COUNT);111 112 /* Order is important if PWM is running */113 if (period_cycles > term) {114 writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);115 writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);116 } else {117 writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);118 writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);119 }120 ret = 0;121 } else {122 ret = -EINVAL;123 }124 125 if (!pwm_is_enabled(pwm))126 clk_disable_unprepare(ep93xx_pwm->clk);127 128 if (ret)129 return ret;130 131 if (!enabled) {132 ret = clk_prepare_enable(ep93xx_pwm->clk);133 if (ret)134 return ret;135 136 writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);137 }138 139 return 0;140}141 142static const struct pwm_ops ep93xx_pwm_ops = {143 .apply = ep93xx_pwm_apply,144};145 146static int ep93xx_pwm_probe(struct platform_device *pdev)147{148 struct pwm_chip *chip;149 struct ep93xx_pwm *ep93xx_pwm;150 int ret;151 152 chip = devm_pwmchip_alloc(&pdev->dev, 1, sizeof(*ep93xx_pwm));153 if (IS_ERR(chip))154 return PTR_ERR(chip);155 ep93xx_pwm = to_ep93xx_pwm(chip);156 157 ep93xx_pwm->base = devm_platform_ioremap_resource(pdev, 0);158 if (IS_ERR(ep93xx_pwm->base))159 return PTR_ERR(ep93xx_pwm->base);160 161 ep93xx_pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk");162 if (IS_ERR(ep93xx_pwm->clk))163 return PTR_ERR(ep93xx_pwm->clk);164 165 chip->ops = &ep93xx_pwm_ops;166 167 ret = devm_pwmchip_add(&pdev->dev, chip);168 if (ret < 0)169 return ret;170 171 return 0;172}173 174static const struct of_device_id ep93xx_pwm_of_ids[] = {175 { .compatible = "cirrus,ep9301-pwm" },176 { /* sentinel */}177};178MODULE_DEVICE_TABLE(of, ep93xx_pwm_of_ids);179 180static struct platform_driver ep93xx_pwm_driver = {181 .driver = {182 .name = "ep93xx-pwm",183 .of_match_table = ep93xx_pwm_of_ids,184 },185 .probe = ep93xx_pwm_probe,186};187module_platform_driver(ep93xx_pwm_driver);188 189MODULE_DESCRIPTION("Cirrus Logic EP93xx PWM driver");190MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>");191MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");192MODULE_ALIAS("platform:ep93xx-pwm");193MODULE_LICENSE("GPL");194