drivers/pwm/pwm-mediatek.c

   1 /*
   2  * Mediatek Pulse Width Modulator driver
   3  *
   4  * Copyright (C) 2015 John Crispin <blogic@openwrt.org>
   5  * Copyright (C) 2017 Zhi Mao <zhi.mao@mediatek.com>
   6  *
   7  * This file is licensed under the terms of the GNU General Public
   8  * License version 2. This program is licensed "as is" without any
   9  * warranty of any kind, whether express or implied.
  10  */
  11
  12 #include <linux/err.h>
  13 #include <linux/io.h>
  14 #include <linux/ioport.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/clk.h>
  18 #include <linux/of.h>
  19 #include <linux/of_device.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/pwm.h>
  22 #include <linux/slab.h>
  23 #include <linux/types.h>
  24
  25 /* PWM registers and bits definitions */
  26 #define PWMCON                  0x00
  27 #define PWMHDUR                 0x04
  28 #define PWMLDUR                 0x08
  29 #define PWMGDUR                 0x0c
  30 #define PWMWAVENUM              0x28
  31 #define PWMDWIDTH               0x2c
  32 #define PWM45DWIDTH_FIXUP       0x30
  33 #define PWMTHRES                0x30
  34 #define PWM45THRES_FIXUP        0x34
  35
  36 #define PWM_CLK_DIV_MAX         7
  37
  38 enum {
  39         MTK_CLK_MAIN = 0,
  40         MTK_CLK_TOP,
  41         MTK_CLK_PWM1,
  42         MTK_CLK_PWM2,
  43         MTK_CLK_PWM3,
  44         MTK_CLK_PWM4,
  45         MTK_CLK_PWM5,
  46         MTK_CLK_PWM6,
  47         MTK_CLK_PWM7,
  48         MTK_CLK_PWM8,
  49         MTK_CLK_MAX,
  50 };
  51
  52 static const char * const mtk_pwm_clk_name[MTK_CLK_MAX] = {
  53         "main", "top", "pwm1", "pwm2", "pwm3", "pwm4", "pwm5", "pwm6", "pwm7",
  54         "pwm8"
  55 };
  56
  57 struct mtk_pwm_platform_data {
  58         unsigned int num_pwms;
  59         bool pwm45_fixup;
  60 };
  61
  62 /**
  63  * struct mtk_pwm_chip - struct representing PWM chip
  64  * @chip: linux PWM chip representation
  65  * @regs: base address of PWM chip
  66  * @clks: list of clocks
  67  */
  68 struct mtk_pwm_chip {
  69         struct pwm_chip chip;
  70         void __iomem *regs;
  71         struct clk *clks[MTK_CLK_MAX];
  72         const struct mtk_pwm_platform_data *soc;
  73 };
  74
  75 static const unsigned int mtk_pwm_reg_offset[] = {
  76         0x0010, 0x0050, 0x0090, 0x00d0, 0x0110, 0x0150, 0x0190, 0x0220
  77 };
  78
  79 static inline struct mtk_pwm_chip *to_mtk_pwm_chip(struct pwm_chip *chip)
  80 {
  81         return container_of(chip, struct mtk_pwm_chip, chip);
  82 }
  83
  84 static int mtk_pwm_clk_enable(struct pwm_chip *chip, struct pwm_device *pwm)
  85 {
  86         struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
  87         int ret;
  88
  89         ret = clk_prepare_enable(pc->clks[MTK_CLK_TOP]);
  90         if (ret < 0)
  91                 return ret;
  92
  93         ret = clk_prepare_enable(pc->clks[MTK_CLK_MAIN]);
  94         if (ret < 0)
  95                 goto disable_clk_top;
  96
  97         ret = clk_prepare_enable(pc->clks[MTK_CLK_PWM1 + pwm->hwpwm]);
  98         if (ret < 0)
  99                 goto disable_clk_main;
 100
 101         return 0;
 102
 103 disable_clk_main:
 104         clk_disable_unprepare(pc->clks[MTK_CLK_MAIN]);
 105 disable_clk_top:
 106         clk_disable_unprepare(pc->clks[MTK_CLK_TOP]);
 107
 108         return ret;
 109 }
 110
 111 static void mtk_pwm_clk_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 112 {
 113         struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
 114
 115         clk_disable_unprepare(pc->clks[MTK_CLK_PWM1 + pwm->hwpwm]);
 116         clk_disable_unprepare(pc->clks[MTK_CLK_MAIN]);
 117         clk_disable_unprepare(pc->clks[MTK_CLK_TOP]);
 118 }
 119
 120 static inline u32 mtk_pwm_readl(struct mtk_pwm_chip *chip, unsigned int num,
 121                                 unsigned int offset)
 122 {
 123         return readl(chip->regs + mtk_pwm_reg_offset[num] + offset);
 124 }
 125
 126 static inline void mtk_pwm_writel(struct mtk_pwm_chip *chip,
 127                                   unsigned int num, unsigned int offset,
 128                                   u32 value)
 129 {
 130         writel(value, chip->regs + mtk_pwm_reg_offset[num] + offset);
 131 }
 132
 133 static int mtk_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 134                           int duty_ns, int period_ns)
 135 {
 136         struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
 137         struct clk *clk = pc->clks[MTK_CLK_PWM1 + pwm->hwpwm];
 138         u32 clkdiv = 0, cnt_period, cnt_duty, reg_width = PWMDWIDTH,
 139             reg_thres = PWMTHRES;
 140         u64 resolution;
 141         int ret;
 142
 143         ret = mtk_pwm_clk_enable(chip, pwm);
 144         if (ret < 0)
 145                 return ret;
 146
 147         /* Using resolution in picosecond gets accuracy higher */
 148         resolution = (u64)NSEC_PER_SEC * 1000;
 149         do_div(resolution, clk_get_rate(clk));
 150
 151         cnt_period = DIV_ROUND_CLOSEST_ULL((u64)period_ns * 1000, resolution);
 152         while (cnt_period > 8191) {
 153                 resolution *= 2;
 154                 clkdiv++;
 155                 cnt_period = DIV_ROUND_CLOSEST_ULL((u64)period_ns * 1000,
 156                                                    resolution);
 157         }
 158
 159         if (clkdiv > PWM_CLK_DIV_MAX) {
 160                 mtk_pwm_clk_disable(chip, pwm);
 161                 dev_err(chip->dev, "period %d not supported\n", period_ns);
 162                 return -EINVAL;
 163         }
 164
 165         if (pc->soc->pwm45_fixup && pwm->hwpwm > 2) {
 166                 /*
 167                  * PWM[4,5] has distinct offset for PWMDWIDTH and PWMTHRES
 168                  * from the other PWMs on MT7623.
 169                  */
 170                 reg_width = PWM45DWIDTH_FIXUP;
 171                 reg_thres = PWM45THRES_FIXUP;
 172         }
 173
 174         cnt_duty = DIV_ROUND_CLOSEST_ULL((u64)duty_ns * 1000, resolution);
 175         mtk_pwm_writel(pc, pwm->hwpwm, PWMCON, BIT(15) | clkdiv);
 176         mtk_pwm_writel(pc, pwm->hwpwm, reg_width, cnt_period);
 177         mtk_pwm_writel(pc, pwm->hwpwm, reg_thres, cnt_duty);
 178
 179         mtk_pwm_clk_disable(chip, pwm);
 180
 181         return 0;
 182 }
 183
 184 static int mtk_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 185 {
 186         struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
 187         u32 value;
 188         int ret;
 189
 190         ret = mtk_pwm_clk_enable(chip, pwm);
 191         if (ret < 0)
 192                 return ret;
 193
 194         value = readl(pc->regs);
 195         value |= BIT(pwm->hwpwm);
 196         writel(value, pc->regs);
 197
 198         return 0;
 199 }
 200
 201 static void mtk_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 202 {
 203         struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
 204         u32 value;
 205
 206         value = readl(pc->regs);
 207         value &= ~BIT(pwm->hwpwm);
 208         writel(value, pc->regs);
 209
 210         mtk_pwm_clk_disable(chip, pwm);
 211 }
 212
 213 static const struct pwm_ops mtk_pwm_ops = {
 214         .config = mtk_pwm_config,
 215         .enable = mtk_pwm_enable,
 216         .disable = mtk_pwm_disable,
 217         .owner = THIS_MODULE,
 218 };
 219
 220 static int mtk_pwm_probe(struct platform_device *pdev)
 221 {
 222         const struct mtk_pwm_platform_data *data;
 223         struct mtk_pwm_chip *pc;
 224         struct resource *res;
 225         unsigned int i;
 226         int ret;
 227
 228         pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
 229         if (!pc)
 230                 return -ENOMEM;
 231
 232         data = of_device_get_match_data(&pdev->dev);
 233         if (data == NULL)
 234                 return -EINVAL;
 235         pc->soc = data;
 236
 237         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 238         pc->regs = devm_ioremap_resource(&pdev->dev, res);
 239         if (IS_ERR(pc->regs))
 240                 return PTR_ERR(pc->regs);
 241
 242         for (i = 0; i < data->num_pwms + 2; i++) {
 243                 pc->clks[i] = devm_clk_get(&pdev->dev, mtk_pwm_clk_name[i]);
 244                 if (IS_ERR(pc->clks[i])) {
 245                         dev_err(&pdev->dev, "clock: %s fail: %ld\n",
 246                                 mtk_pwm_clk_name[i], PTR_ERR(pc->clks[i]));
 247                         return PTR_ERR(pc->clks[i]);
 248                 }
 249         }
 250
 251         platform_set_drvdata(pdev, pc);
 252
 253         pc->chip.dev = &pdev->dev;
 254         pc->chip.ops = &mtk_pwm_ops;
 255         pc->chip.base = -1;
 256         pc->chip.npwm = data->num_pwms;
 257
 258         ret = pwmchip_add(&pc->chip);
 259         if (ret < 0) {
 260                 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
 261                 return ret;
 262         }
 263
 264         return 0;
 265 }
 266
 267 static int mtk_pwm_remove(struct platform_device *pdev)
 268 {
 269         struct mtk_pwm_chip *pc = platform_get_drvdata(pdev);
 270
 271         return pwmchip_remove(&pc->chip);
 272 }
 273
 274 static const struct mtk_pwm_platform_data mt2712_pwm_data = {
 275         .num_pwms = 8,
 276         .pwm45_fixup = false,
 277 };
 278
 279 static const struct mtk_pwm_platform_data mt7622_pwm_data = {
 280         .num_pwms = 6,
 281         .pwm45_fixup = false,
 282 };
 283
 284 static const struct mtk_pwm_platform_data mt7623_pwm_data = {
 285         .num_pwms = 5,
 286         .pwm45_fixup = true,
 287 };
 288
 289 static const struct of_device_id mtk_pwm_of_match[] = {
 290         { .compatible = "mediatek,mt2712-pwm", .data = &mt2712_pwm_data },
 291         { .compatible = "mediatek,mt7622-pwm", .data = &mt7622_pwm_data },
 292         { .compatible = "mediatek,mt7623-pwm", .data = &mt7623_pwm_data },
 293         { },
 294 };
 295 MODULE_DEVICE_TABLE(of, mtk_pwm_of_match);
 296
 297 static struct platform_driver mtk_pwm_driver = {
 298         .driver = {
 299                 .name = "mtk-pwm",
 300                 .of_match_table = mtk_pwm_of_match,
 301         },
 302         .probe = mtk_pwm_probe,
 303         .remove = mtk_pwm_remove,
 304 };
 305 module_platform_driver(mtk_pwm_driver);
 306
 307 MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
 308 MODULE_LICENSE("GPL");