drivers/pwm/pwm-berlin.c

   1 /*
   2  * Marvell Berlin PWM driver
   3  *
   4  * Copyright (C) 2015 Marvell Technology Group Ltd.
   5  *
   6  * Author: Antoine Tenart <antoine.tenart@free-electrons.com>
   7  *
   8  * This file is licensed under the terms of the GNU General Public
   9  * License version 2. This program is licensed "as is" without any
  10  * warranty of any kind, whether express or implied.
  11  */
  12
  13 #include <linux/clk.h>
  14 #include <linux/io.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/pwm.h>
  19 #include <linux/slab.h>
  20
  21 #define BERLIN_PWM_EN                   0x0
  22 #define  BERLIN_PWM_ENABLE              BIT(0)
  23 #define BERLIN_PWM_CONTROL              0x4
  24 #define  BERLIN_PWM_PRESCALE_MASK       0x7
  25 #define  BERLIN_PWM_PRESCALE_MAX        4096
  26 #define  BERLIN_PWM_INVERT_POLARITY     BIT(3)
  27 #define BERLIN_PWM_DUTY                 0x8
  28 #define BERLIN_PWM_TCNT                 0xc
  29 #define  BERLIN_PWM_MAX_TCNT            65535
  30
  31 struct berlin_pwm_channel {
  32         u32 enable;
  33         u32 ctrl;
  34         u32 duty;
  35         u32 tcnt;
  36 };
  37
  38 struct berlin_pwm_chip {
  39         struct pwm_chip chip;
  40         struct clk *clk;
  41         void __iomem *base;
  42 };
  43
  44 static inline struct berlin_pwm_chip *to_berlin_pwm_chip(struct pwm_chip *chip)
  45 {
  46         return container_of(chip, struct berlin_pwm_chip, chip);
  47 }
  48
  49 static const u32 prescaler_table[] = {
  50         1, 4, 8, 16, 64, 256, 1024, 4096
  51 };
  52
  53 static inline u32 berlin_pwm_readl(struct berlin_pwm_chip *chip,
  54                                    unsigned int channel, unsigned long offset)
  55 {
  56         return readl_relaxed(chip->base + channel * 0x10 + offset);
  57 }
  58
  59 static inline void berlin_pwm_writel(struct berlin_pwm_chip *chip,
  60                                      unsigned int channel, u32 value,
  61                                      unsigned long offset)
  62 {
  63         writel_relaxed(value, chip->base + channel * 0x10 + offset);
  64 }
  65
  66 static int berlin_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  67 {
  68         struct berlin_pwm_channel *channel;
  69
  70         channel = kzalloc(sizeof(*channel), GFP_KERNEL);
  71         if (!channel)
  72                 return -ENOMEM;
  73
  74         return pwm_set_chip_data(pwm, channel);
  75 }
  76
  77 static void berlin_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
  78 {
  79         struct berlin_pwm_channel *channel = pwm_get_chip_data(pwm);
  80
  81         pwm_set_chip_data(pwm, NULL);
  82         kfree(channel);
  83 }
  84
  85 static int berlin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm_dev,
  86                              int duty_ns, int period_ns)
  87 {
  88         struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
  89         unsigned int prescale;
  90         u32 value, duty, period;
  91         u64 cycles, tmp;
  92
  93         cycles = clk_get_rate(pwm->clk);
  94         cycles *= period_ns;
  95         do_div(cycles, NSEC_PER_SEC);
  96
  97         for (prescale = 0; prescale < ARRAY_SIZE(prescaler_table); prescale++) {
  98                 tmp = cycles;
  99                 do_div(tmp, prescaler_table[prescale]);
 100
 101                 if (tmp <= BERLIN_PWM_MAX_TCNT)
 102                         break;
 103         }
 104
 105         if (tmp > BERLIN_PWM_MAX_TCNT)
 106                 return -ERANGE;
 107
 108         period = tmp;
 109         cycles = tmp * duty_ns;
 110         do_div(cycles, period_ns);
 111         duty = cycles;
 112
 113         value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL);
 114         value &= ~BERLIN_PWM_PRESCALE_MASK;
 115         value |= prescale;
 116         berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL);
 117
 118         berlin_pwm_writel(pwm, pwm_dev->hwpwm, duty, BERLIN_PWM_DUTY);
 119         berlin_pwm_writel(pwm, pwm_dev->hwpwm, period, BERLIN_PWM_TCNT);
 120
 121         return 0;
 122 }
 123
 124 static int berlin_pwm_set_polarity(struct pwm_chip *chip,
 125                                    struct pwm_device *pwm_dev,
 126                                    enum pwm_polarity polarity)
 127 {
 128         struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
 129         u32 value;
 130
 131         value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL);
 132
 133         if (polarity == PWM_POLARITY_NORMAL)
 134                 value &= ~BERLIN_PWM_INVERT_POLARITY;
 135         else
 136                 value |= BERLIN_PWM_INVERT_POLARITY;
 137
 138         berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL);
 139
 140         return 0;
 141 }
 142
 143 static int berlin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm_dev)
 144 {
 145         struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
 146         u32 value;
 147
 148         value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN);
 149         value |= BERLIN_PWM_ENABLE;
 150         berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN);
 151
 152         return 0;
 153 }
 154
 155 static void berlin_pwm_disable(struct pwm_chip *chip,
 156                                struct pwm_device *pwm_dev)
 157 {
 158         struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
 159         u32 value;
 160
 161         value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN);
 162         value &= ~BERLIN_PWM_ENABLE;
 163         berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN);
 164 }
 165
 166 static const struct pwm_ops berlin_pwm_ops = {
 167         .request = berlin_pwm_request,
 168         .free = berlin_pwm_free,
 169         .config = berlin_pwm_config,
 170         .set_polarity = berlin_pwm_set_polarity,
 171         .enable = berlin_pwm_enable,
 172         .disable = berlin_pwm_disable,
 173         .owner = THIS_MODULE,
 174 };
 175
 176 static const struct of_device_id berlin_pwm_match[] = {
 177         { .compatible = "marvell,berlin-pwm" },
 178         { },
 179 };
 180 MODULE_DEVICE_TABLE(of, berlin_pwm_match);
 181
 182 static int berlin_pwm_probe(struct platform_device *pdev)
 183 {
 184         struct berlin_pwm_chip *pwm;
 185         struct resource *res;
 186         int ret;
 187
 188         pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
 189         if (!pwm)
 190                 return -ENOMEM;
 191
 192         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 193         pwm->base = devm_ioremap_resource(&pdev->dev, res);
 194         if (IS_ERR(pwm->base))
 195                 return PTR_ERR(pwm->base);
 196
 197         pwm->clk = devm_clk_get(&pdev->dev, NULL);
 198         if (IS_ERR(pwm->clk))
 199                 return PTR_ERR(pwm->clk);
 200
 201         ret = clk_prepare_enable(pwm->clk);
 202         if (ret)
 203                 return ret;
 204
 205         pwm->chip.dev = &pdev->dev;
 206         pwm->chip.ops = &berlin_pwm_ops;
 207         pwm->chip.base = -1;
 208         pwm->chip.npwm = 4;
 209         pwm->chip.of_xlate = of_pwm_xlate_with_flags;
 210         pwm->chip.of_pwm_n_cells = 3;
 211
 212         ret = pwmchip_add(&pwm->chip);
 213         if (ret < 0) {
 214                 dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
 215                 clk_disable_unprepare(pwm->clk);
 216                 return ret;
 217         }
 218
 219         platform_set_drvdata(pdev, pwm);
 220
 221         return 0;
 222 }
 223
 224 static int berlin_pwm_remove(struct platform_device *pdev)
 225 {
 226         struct berlin_pwm_chip *pwm = platform_get_drvdata(pdev);
 227         int ret;
 228
 229         ret = pwmchip_remove(&pwm->chip);
 230         clk_disable_unprepare(pwm->clk);
 231
 232         return ret;
 233 }
 234
 235 #ifdef CONFIG_PM_SLEEP
 236 static int berlin_pwm_suspend(struct device *dev)
 237 {
 238         struct berlin_pwm_chip *pwm = dev_get_drvdata(dev);
 239         unsigned int i;
 240
 241         for (i = 0; i < pwm->chip.npwm; i++) {
 242                 struct berlin_pwm_channel *channel;
 243
 244                 channel = pwm_get_chip_data(&pwm->chip.pwms[i]);
 245                 if (!channel)
 246                         continue;
 247
 248                 channel->enable = berlin_pwm_readl(pwm, i, BERLIN_PWM_ENABLE);
 249                 channel->ctrl = berlin_pwm_readl(pwm, i, BERLIN_PWM_CONTROL);
 250                 channel->duty = berlin_pwm_readl(pwm, i, BERLIN_PWM_DUTY);
 251                 channel->tcnt = berlin_pwm_readl(pwm, i, BERLIN_PWM_TCNT);
 252         }
 253
 254         clk_disable_unprepare(pwm->clk);
 255
 256         return 0;
 257 }
 258
 259 static int berlin_pwm_resume(struct device *dev)
 260 {
 261         struct berlin_pwm_chip *pwm = dev_get_drvdata(dev);
 262         unsigned int i;
 263         int ret;
 264
 265         ret = clk_prepare_enable(pwm->clk);
 266         if (ret)
 267                 return ret;
 268
 269         for (i = 0; i < pwm->chip.npwm; i++) {
 270                 struct berlin_pwm_channel *channel;
 271
 272                 channel = pwm_get_chip_data(&pwm->chip.pwms[i]);
 273                 if (!channel)
 274                         continue;
 275
 276                 berlin_pwm_writel(pwm, i, channel->ctrl, BERLIN_PWM_CONTROL);
 277                 berlin_pwm_writel(pwm, i, channel->duty, BERLIN_PWM_DUTY);
 278                 berlin_pwm_writel(pwm, i, channel->tcnt, BERLIN_PWM_TCNT);
 279                 berlin_pwm_writel(pwm, i, channel->enable, BERLIN_PWM_ENABLE);
 280         }
 281
 282         return 0;
 283 }
 284 #endif
 285
 286 static SIMPLE_DEV_PM_OPS(berlin_pwm_pm_ops, berlin_pwm_suspend,
 287                          berlin_pwm_resume);
 288
 289 static struct platform_driver berlin_pwm_driver = {
 290         .probe = berlin_pwm_probe,
 291         .remove = berlin_pwm_remove,
 292         .driver = {
 293                 .name = "berlin-pwm",
 294                 .of_match_table = berlin_pwm_match,
 295                 .pm = &berlin_pwm_pm_ops,
 296         },
 297 };
 298 module_platform_driver(berlin_pwm_driver);
 299
 300 MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>");
 301 MODULE_DESCRIPTION("Marvell Berlin PWM driver");
 302 MODULE_LICENSE("GPL v2");