drivers/pwm/pwm-ep93xx.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * PWM framework driver for Cirrus Logic EP93xx
   4  *
   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 - PWMOUT
  13  *
  14  * EP9312/15 have two channels:
  15  *   platform device ep93xx-pwm.0 - PWMOUT
  16  *   platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14)
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/slab.h>
  22 #include <linux/clk.h>
  23 #include <linux/err.h>
  24 #include <linux/io.h>
  25 #include <linux/pwm.h>
  26
  27 #include <asm/div64.h>
  28
  29 #include <linux/soc/cirrus/ep93xx.h>    /* for ep93xx_pwm_{acquire,release}_gpio() */
  30
  31 #define EP93XX_PWMx_TERM_COUNT  0x00
  32 #define EP93XX_PWMx_DUTY_CYCLE  0x04
  33 #define EP93XX_PWMx_ENABLE      0x08
  34 #define EP93XX_PWMx_INVERT      0x0c
  35
  36 struct ep93xx_pwm {
  37         void __iomem *base;
  38         struct clk *clk;
  39         struct pwm_chip chip;
  40 };
  41
  42 static inline struct ep93xx_pwm *to_ep93xx_pwm(struct pwm_chip *chip)
  43 {
  44         return container_of(chip, struct ep93xx_pwm, chip);
  45 }
  46
  47 static int ep93xx_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  48 {
  49         struct platform_device *pdev = to_platform_device(chip->dev);
  50
  51         return ep93xx_pwm_acquire_gpio(pdev);
  52 }
  53
  54 static void ep93xx_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
  55 {
  56         struct platform_device *pdev = to_platform_device(chip->dev);
  57
  58         ep93xx_pwm_release_gpio(pdev);
  59 }
  60
  61 static int ep93xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  62                              int duty_ns, int period_ns)
  63 {
  64         struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
  65         void __iomem *base = ep93xx_pwm->base;
  66         unsigned long long c;
  67         unsigned long period_cycles;
  68         unsigned long duty_cycles;
  69         unsigned long term;
  70         int ret = 0;
  71
  72         /*
  73          * The clock needs to be enabled to access the PWM registers.
  74          * Configuration can be changed at any time.
  75          */
  76         if (!pwm_is_enabled(pwm)) {
  77                 ret = clk_enable(ep93xx_pwm->clk);
  78                 if (ret)
  79                         return ret;
  80         }
  81
  82         c = clk_get_rate(ep93xx_pwm->clk);
  83         c *= period_ns;
  84         do_div(c, 1000000000);
  85         period_cycles = c;
  86
  87         c = period_cycles;
  88         c *= duty_ns;
  89         do_div(c, period_ns);
  90         duty_cycles = c;
  91
  92         if (period_cycles < 0x10000 && duty_cycles < 0x10000) {
  93                 term = readw(base + EP93XX_PWMx_TERM_COUNT);
  94
  95                 /* Order is important if PWM is running */
  96                 if (period_cycles > term) {
  97                         writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
  98                         writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
  99                 } else {
 100                         writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE);
 101                         writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT);
 102                 }
 103         } else {
 104                 ret = -EINVAL;
 105         }
 106
 107         if (!pwm_is_enabled(pwm))
 108                 clk_disable(ep93xx_pwm->clk);
 109
 110         return ret;
 111 }
 112
 113 static int ep93xx_pwm_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
 114                                enum pwm_polarity polarity)
 115 {
 116         struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
 117         int ret;
 118
 119         /*
 120          * The clock needs to be enabled to access the PWM registers.
 121          * Polarity can only be changed when the PWM is disabled.
 122          */
 123         ret = clk_enable(ep93xx_pwm->clk);
 124         if (ret)
 125                 return ret;
 126
 127         if (polarity == PWM_POLARITY_INVERSED)
 128                 writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT);
 129         else
 130                 writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT);
 131
 132         clk_disable(ep93xx_pwm->clk);
 133
 134         return 0;
 135 }
 136
 137 static int ep93xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 138 {
 139         struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
 140         int ret;
 141
 142         ret = clk_enable(ep93xx_pwm->clk);
 143         if (ret)
 144                 return ret;
 145
 146         writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
 147
 148         return 0;
 149 }
 150
 151 static void ep93xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 152 {
 153         struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip);
 154
 155         writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE);
 156         clk_disable(ep93xx_pwm->clk);
 157 }
 158
 159 static const struct pwm_ops ep93xx_pwm_ops = {
 160         .request = ep93xx_pwm_request,
 161         .free = ep93xx_pwm_free,
 162         .config = ep93xx_pwm_config,
 163         .set_polarity = ep93xx_pwm_polarity,
 164         .enable = ep93xx_pwm_enable,
 165         .disable = ep93xx_pwm_disable,
 166         .owner = THIS_MODULE,
 167 };
 168
 169 static int ep93xx_pwm_probe(struct platform_device *pdev)
 170 {
 171         struct ep93xx_pwm *ep93xx_pwm;
 172         int ret;
 173
 174         ep93xx_pwm = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_pwm), GFP_KERNEL);
 175         if (!ep93xx_pwm)
 176                 return -ENOMEM;
 177
 178         ep93xx_pwm->base = devm_platform_ioremap_resource(pdev, 0);
 179         if (IS_ERR(ep93xx_pwm->base))
 180                 return PTR_ERR(ep93xx_pwm->base);
 181
 182         ep93xx_pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk");
 183         if (IS_ERR(ep93xx_pwm->clk))
 184                 return PTR_ERR(ep93xx_pwm->clk);
 185
 186         ep93xx_pwm->chip.dev = &pdev->dev;
 187         ep93xx_pwm->chip.ops = &ep93xx_pwm_ops;
 188         ep93xx_pwm->chip.npwm = 1;
 189
 190         ret = pwmchip_add(&ep93xx_pwm->chip);
 191         if (ret < 0)
 192                 return ret;
 193
 194         platform_set_drvdata(pdev, ep93xx_pwm);
 195         return 0;
 196 }
 197
 198 static int ep93xx_pwm_remove(struct platform_device *pdev)
 199 {
 200         struct ep93xx_pwm *ep93xx_pwm = platform_get_drvdata(pdev);
 201
 202         return pwmchip_remove(&ep93xx_pwm->chip);
 203 }
 204
 205 static struct platform_driver ep93xx_pwm_driver = {
 206         .driver = {
 207                 .name = "ep93xx-pwm",
 208         },
 209         .probe = ep93xx_pwm_probe,
 210         .remove = ep93xx_pwm_remove,
 211 };
 212 module_platform_driver(ep93xx_pwm_driver);
 213
 214 MODULE_DESCRIPTION("Cirrus Logic EP93xx PWM driver");
 215 MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>");
 216 MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
 217 MODULE_ALIAS("platform:ep93xx-pwm");
 218 MODULE_LICENSE("GPL");