drivers/pwm/pwm-mediatek.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * MediaTek Pulse Width Modulator driver
   4  *
   5  * Copyright (C) 2015 John Crispin <blogic@openwrt.org>
   6  * Copyright (C) 2017 Zhi Mao <zhi.mao@mediatek.com>
   7  *
   8  */
   9
  10 #include <linux/err.h>
  11 #include <linux/io.h>
  12 #include <linux/ioport.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/clk.h>
  16 #include <linux/of.h>
  17 #include <linux/of_device.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/pwm.h>
  20 #include <linux/slab.h>
  21 #include <linux/types.h>
  22
  23 /* PWM registers and bits definitions */
  24 #define PWMCON                  0x00
  25 #define PWMHDUR                 0x04
  26 #define PWMLDUR                 0x08
  27 #define PWMGDUR                 0x0c
  28 #define PWMWAVENUM              0x28
  29 #define PWMDWIDTH               0x2c
  30 #define PWM45DWIDTH_FIXUP       0x30
  31 #define PWMTHRES                0x30
  32 #define PWM45THRES_FIXUP        0x34
  33 #define PWM_CK_26M_SEL          0x210
  34
  35 #define PWM_CLK_DIV_MAX         7
  36
  37 struct pwm_mediatek_of_data {
  38         unsigned int num_pwms;
  39         bool pwm45_fixup;
  40         bool has_ck_26m_sel;
  41 };
  42
  43 /**
  44  * struct pwm_mediatek_chip - struct representing PWM chip
  45  * @chip: linux PWM chip representation
  46  * @regs: base address of PWM chip
  47  * @clk_top: the top clock generator
  48  * @clk_main: the clock used by PWM core
  49  * @clk_pwms: the clock used by each PWM channel
  50  * @clk_freq: the fix clock frequency of legacy MIPS SoC
  51  * @soc: pointer to chip's platform data
  52  */
  53 struct pwm_mediatek_chip {
  54         struct pwm_chip chip;
  55         void __iomem *regs;
  56         struct clk *clk_top;
  57         struct clk *clk_main;
  58         struct clk **clk_pwms;
  59         const struct pwm_mediatek_of_data *soc;
  60 };
  61
  62 static const unsigned int pwm_mediatek_reg_offset[] = {
  63         0x0010, 0x0050, 0x0090, 0x00d0, 0x0110, 0x0150, 0x0190, 0x0220
  64 };
  65
  66 static inline struct pwm_mediatek_chip *
  67 to_pwm_mediatek_chip(struct pwm_chip *chip)
  68 {
  69         return container_of(chip, struct pwm_mediatek_chip, chip);
  70 }
  71
  72 static int pwm_mediatek_clk_enable(struct pwm_chip *chip,
  73                                    struct pwm_device *pwm)
  74 {
  75         struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip);
  76         int ret;
  77
  78         ret = clk_prepare_enable(pc->clk_top);
  79         if (ret < 0)
  80                 return ret;
  81
  82         ret = clk_prepare_enable(pc->clk_main);
  83         if (ret < 0)
  84                 goto disable_clk_top;
  85
  86         ret = clk_prepare_enable(pc->clk_pwms[pwm->hwpwm]);
  87         if (ret < 0)
  88                 goto disable_clk_main;
  89
  90         return 0;
  91
  92 disable_clk_main:
  93         clk_disable_unprepare(pc->clk_main);
  94 disable_clk_top:
  95         clk_disable_unprepare(pc->clk_top);
  96
  97         return ret;
  98 }
  99
 100 static void pwm_mediatek_clk_disable(struct pwm_chip *chip,
 101                                      struct pwm_device *pwm)
 102 {
 103         struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip);
 104
 105         clk_disable_unprepare(pc->clk_pwms[pwm->hwpwm]);
 106         clk_disable_unprepare(pc->clk_main);
 107         clk_disable_unprepare(pc->clk_top);
 108 }
 109
 110 static inline void pwm_mediatek_writel(struct pwm_mediatek_chip *chip,
 111                                        unsigned int num, unsigned int offset,
 112                                        u32 value)
 113 {
 114         writel(value, chip->regs + pwm_mediatek_reg_offset[num] + offset);
 115 }
 116
 117 static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm,
 118                                int duty_ns, int period_ns)
 119 {
 120         struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip);
 121         u32 clkdiv = 0, cnt_period, cnt_duty, reg_width = PWMDWIDTH,
 122             reg_thres = PWMTHRES;
 123         u64 resolution;
 124         int ret;
 125
 126         ret = pwm_mediatek_clk_enable(chip, pwm);
 127
 128         if (ret < 0)
 129                 return ret;
 130
 131         /* Make sure we use the bus clock and not the 26MHz clock */
 132         if (pc->soc->has_ck_26m_sel)
 133                 writel(0, pc->regs + PWM_CK_26M_SEL);
 134
 135         /* Using resolution in picosecond gets accuracy higher */
 136         resolution = (u64)NSEC_PER_SEC * 1000;
 137         do_div(resolution, clk_get_rate(pc->clk_pwms[pwm->hwpwm]));
 138
 139         cnt_period = DIV_ROUND_CLOSEST_ULL((u64)period_ns * 1000, resolution);
 140         while (cnt_period > 8191) {
 141                 resolution *= 2;
 142                 clkdiv++;
 143                 cnt_period = DIV_ROUND_CLOSEST_ULL((u64)period_ns * 1000,
 144                                                    resolution);
 145         }
 146
 147         if (clkdiv > PWM_CLK_DIV_MAX) {
 148                 pwm_mediatek_clk_disable(chip, pwm);
 149                 dev_err(chip->dev, "period %d not supported\n", period_ns);
 150                 return -EINVAL;
 151         }
 152
 153         if (pc->soc->pwm45_fixup && pwm->hwpwm > 2) {
 154                 /*
 155                  * PWM[4,5] has distinct offset for PWMDWIDTH and PWMTHRES
 156                  * from the other PWMs on MT7623.
 157                  */
 158                 reg_width = PWM45DWIDTH_FIXUP;
 159                 reg_thres = PWM45THRES_FIXUP;
 160         }
 161
 162         cnt_duty = DIV_ROUND_CLOSEST_ULL((u64)duty_ns * 1000, resolution);
 163         pwm_mediatek_writel(pc, pwm->hwpwm, PWMCON, BIT(15) | clkdiv);
 164         pwm_mediatek_writel(pc, pwm->hwpwm, reg_width, cnt_period);
 165         pwm_mediatek_writel(pc, pwm->hwpwm, reg_thres, cnt_duty);
 166
 167         pwm_mediatek_clk_disable(chip, pwm);
 168
 169         return 0;
 170 }
 171
 172 static int pwm_mediatek_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 173 {
 174         struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip);
 175         u32 value;
 176         int ret;
 177
 178         ret = pwm_mediatek_clk_enable(chip, pwm);
 179         if (ret < 0)
 180                 return ret;
 181
 182         value = readl(pc->regs);
 183         value |= BIT(pwm->hwpwm);
 184         writel(value, pc->regs);
 185
 186         return 0;
 187 }
 188
 189 static void pwm_mediatek_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 190 {
 191         struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip);
 192         u32 value;
 193
 194         value = readl(pc->regs);
 195         value &= ~BIT(pwm->hwpwm);
 196         writel(value, pc->regs);
 197
 198         pwm_mediatek_clk_disable(chip, pwm);
 199 }
 200
 201 static const struct pwm_ops pwm_mediatek_ops = {
 202         .config = pwm_mediatek_config,
 203         .enable = pwm_mediatek_enable,
 204         .disable = pwm_mediatek_disable,
 205         .owner = THIS_MODULE,
 206 };
 207
 208 static int pwm_mediatek_probe(struct platform_device *pdev)
 209 {
 210         struct pwm_mediatek_chip *pc;
 211         unsigned int i;
 212         int ret;
 213
 214         pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
 215         if (!pc)
 216                 return -ENOMEM;
 217
 218         pc->soc = of_device_get_match_data(&pdev->dev);
 219
 220         pc->regs = devm_platform_ioremap_resource(pdev, 0);
 221         if (IS_ERR(pc->regs))
 222                 return PTR_ERR(pc->regs);
 223
 224         pc->clk_pwms = devm_kcalloc(&pdev->dev, pc->soc->num_pwms,
 225                                     sizeof(*pc->clk_pwms), GFP_KERNEL);
 226         if (!pc->clk_pwms)
 227                 return -ENOMEM;
 228
 229         pc->clk_top = devm_clk_get(&pdev->dev, "top");
 230         if (IS_ERR(pc->clk_top)) {
 231                 dev_err(&pdev->dev, "clock: top fail: %ld\n",
 232                         PTR_ERR(pc->clk_top));
 233                 return PTR_ERR(pc->clk_top);
 234         }
 235
 236         pc->clk_main = devm_clk_get(&pdev->dev, "main");
 237         if (IS_ERR(pc->clk_main)) {
 238                 dev_err(&pdev->dev, "clock: main fail: %ld\n",
 239                         PTR_ERR(pc->clk_main));
 240                 return PTR_ERR(pc->clk_main);
 241         }
 242
 243         for (i = 0; i < pc->soc->num_pwms; i++) {
 244                 char name[8];
 245
 246                 snprintf(name, sizeof(name), "pwm%d", i + 1);
 247
 248                 pc->clk_pwms[i] = devm_clk_get(&pdev->dev, name);
 249                 if (IS_ERR(pc->clk_pwms[i])) {
 250                         dev_err(&pdev->dev, "clock: %s fail: %ld\n",
 251                                 name, PTR_ERR(pc->clk_pwms[i]));
 252                         return PTR_ERR(pc->clk_pwms[i]);
 253                 }
 254         }
 255
 256         pc->chip.dev = &pdev->dev;
 257         pc->chip.ops = &pwm_mediatek_ops;
 258         pc->chip.npwm = pc->soc->num_pwms;
 259
 260         ret = devm_pwmchip_add(&pdev->dev, &pc->chip);
 261         if (ret < 0) {
 262                 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
 263                 return ret;
 264         }
 265
 266         return 0;
 267 }
 268
 269 static const struct pwm_mediatek_of_data mt2712_pwm_data = {
 270         .num_pwms = 8,
 271         .pwm45_fixup = false,
 272         .has_ck_26m_sel = false,
 273 };
 274
 275 static const struct pwm_mediatek_of_data mt7622_pwm_data = {
 276         .num_pwms = 6,
 277         .pwm45_fixup = false,
 278         .has_ck_26m_sel = false,
 279 };
 280
 281 static const struct pwm_mediatek_of_data mt7623_pwm_data = {
 282         .num_pwms = 5,
 283         .pwm45_fixup = true,
 284         .has_ck_26m_sel = false,
 285 };
 286
 287 static const struct pwm_mediatek_of_data mt7628_pwm_data = {
 288         .num_pwms = 4,
 289         .pwm45_fixup = true,
 290         .has_ck_26m_sel = false,
 291 };
 292
 293 static const struct pwm_mediatek_of_data mt7629_pwm_data = {
 294         .num_pwms = 1,
 295         .pwm45_fixup = false,
 296         .has_ck_26m_sel = false,
 297 };
 298
 299 static const struct pwm_mediatek_of_data mt8183_pwm_data = {
 300         .num_pwms = 4,
 301         .pwm45_fixup = false,
 302         .has_ck_26m_sel = true,
 303 };
 304
 305 static const struct pwm_mediatek_of_data mt8516_pwm_data = {
 306         .num_pwms = 5,
 307         .pwm45_fixup = false,
 308         .has_ck_26m_sel = true,
 309 };
 310
 311 static const struct of_device_id pwm_mediatek_of_match[] = {
 312         { .compatible = "mediatek,mt2712-pwm", .data = &mt2712_pwm_data },
 313         { .compatible = "mediatek,mt7622-pwm", .data = &mt7622_pwm_data },
 314         { .compatible = "mediatek,mt7623-pwm", .data = &mt7623_pwm_data },
 315         { .compatible = "mediatek,mt7628-pwm", .data = &mt7628_pwm_data },
 316         { .compatible = "mediatek,mt7629-pwm", .data = &mt7629_pwm_data },
 317         { .compatible = "mediatek,mt8183-pwm", .data = &mt8183_pwm_data },
 318         { .compatible = "mediatek,mt8516-pwm", .data = &mt8516_pwm_data },
 319         { },
 320 };
 321 MODULE_DEVICE_TABLE(of, pwm_mediatek_of_match);
 322
 323 static struct platform_driver pwm_mediatek_driver = {
 324         .driver = {
 325                 .name = "pwm-mediatek",
 326                 .of_match_table = pwm_mediatek_of_match,
 327         },
 328         .probe = pwm_mediatek_probe,
 329 };
 330 module_platform_driver(pwm_mediatek_driver);
 331
 332 MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
 333 MODULE_LICENSE("GPL v2");