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 PWMTHRES                0x30
  33
  34 #define PWM_CLK_DIV_MAX         7
  35
  36 enum {
  37         MTK_CLK_MAIN = 0,
  38         MTK_CLK_TOP,
  39         MTK_CLK_PWM1,
  40         MTK_CLK_PWM2,
  41         MTK_CLK_PWM3,
  42         MTK_CLK_PWM4,
  43         MTK_CLK_PWM5,
  44         MTK_CLK_PWM6,
  45         MTK_CLK_PWM7,
  46         MTK_CLK_PWM8,
  47         MTK_CLK_MAX,
  48 };
  49
  50 static const char * const mtk_pwm_clk_name[MTK_CLK_MAX] = {
  51         "main", "top", "pwm1", "pwm2", "pwm3", "pwm4", "pwm5", "pwm6", "pwm7",
  52         "pwm8"
  53 };
  54
  55 struct mtk_pwm_platform_data {
  56         unsigned int num_pwms;
  57 };
  58
  59 /**
  60  * struct mtk_pwm_chip - struct representing PWM chip
  61  * @chip: linux PWM chip representation
  62  * @regs: base address of PWM chip
  63  * @clks: list of clocks
  64  */
  65 struct mtk_pwm_chip {
  66         struct pwm_chip chip;
  67         void __iomem *regs;
  68         struct clk *clks[MTK_CLK_MAX];
  69 };
  70
  71 static const unsigned int mtk_pwm_reg_offset[] = {
  72         0x0010, 0x0050, 0x0090, 0x00d0, 0x0110, 0x0150, 0x0190, 0x0220
  73 };
  74
  75 static inline struct mtk_pwm_chip *to_mtk_pwm_chip(struct pwm_chip *chip)
  76 {
  77         return container_of(chip, struct mtk_pwm_chip, chip);
  78 }
  79
  80 static int mtk_pwm_clk_enable(struct pwm_chip *chip, struct pwm_device *pwm)
  81 {
  82         struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
  83         int ret;
  84
  85         ret = clk_prepare_enable(pc->clks[MTK_CLK_TOP]);
  86         if (ret < 0)
  87                 return ret;
  88
  89         ret = clk_prepare_enable(pc->clks[MTK_CLK_MAIN]);
  90         if (ret < 0)
  91                 goto disable_clk_top;
  92
  93         ret = clk_prepare_enable(pc->clks[MTK_CLK_PWM1 + pwm->hwpwm]);
  94         if (ret < 0)
  95                 goto disable_clk_main;
  96
  97         return 0;
  98
  99 disable_clk_main:
 100         clk_disable_unprepare(pc->clks[MTK_CLK_MAIN]);
 101 disable_clk_top:
 102         clk_disable_unprepare(pc->clks[MTK_CLK_TOP]);
 103
 104         return ret;
 105 }
 106
 107 static void mtk_pwm_clk_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 108 {
 109         struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
 110
 111         clk_disable_unprepare(pc->clks[MTK_CLK_PWM1 + pwm->hwpwm]);
 112         clk_disable_unprepare(pc->clks[MTK_CLK_MAIN]);
 113         clk_disable_unprepare(pc->clks[MTK_CLK_TOP]);
 114 }
 115
 116 static inline u32 mtk_pwm_readl(struct mtk_pwm_chip *chip, unsigned int num,
 117                                 unsigned int offset)
 118 {
 119         return readl(chip->regs + mtk_pwm_reg_offset[num] + offset);
 120 }
 121
 122 static inline void mtk_pwm_writel(struct mtk_pwm_chip *chip,
 123                                   unsigned int num, unsigned int offset,
 124                                   u32 value)
 125 {
 126         writel(value, chip->regs + mtk_pwm_reg_offset[num] + offset);
 127 }
 128
 129 static int mtk_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 130                           int duty_ns, int period_ns)
 131 {
 132         struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
 133         struct clk *clk = pc->clks[MTK_CLK_PWM1 + pwm->hwpwm];
 134         u32 resolution, clkdiv = 0;
 135         int ret;
 136
 137         ret = mtk_pwm_clk_enable(chip, pwm);
 138         if (ret < 0)
 139                 return ret;
 140
 141         resolution = NSEC_PER_SEC / clk_get_rate(clk);
 142
 143         while (period_ns / resolution > 8191) {
 144                 resolution *= 2;
 145                 clkdiv++;
 146         }
 147
 148         if (clkdiv > PWM_CLK_DIV_MAX) {
 149                 mtk_pwm_clk_disable(chip, pwm);
 150                 dev_err(chip->dev, "period %d not supported\n", period_ns);
 151                 return -EINVAL;
 152         }
 153
 154         mtk_pwm_writel(pc, pwm->hwpwm, PWMCON, BIT(15) | clkdiv);
 155         mtk_pwm_writel(pc, pwm->hwpwm, PWMDWIDTH, period_ns / resolution);
 156         mtk_pwm_writel(pc, pwm->hwpwm, PWMTHRES, duty_ns / resolution);
 157
 158         mtk_pwm_clk_disable(chip, pwm);
 159
 160         return 0;
 161 }
 162
 163 static int mtk_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 164 {
 165         struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
 166         u32 value;
 167         int ret;
 168
 169         ret = mtk_pwm_clk_enable(chip, pwm);
 170         if (ret < 0)
 171                 return ret;
 172
 173         value = readl(pc->regs);
 174         value |= BIT(pwm->hwpwm);
 175         writel(value, pc->regs);
 176
 177         return 0;
 178 }
 179
 180 static void mtk_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 181 {
 182         struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
 183         u32 value;
 184
 185         value = readl(pc->regs);
 186         value &= ~BIT(pwm->hwpwm);
 187         writel(value, pc->regs);
 188
 189         mtk_pwm_clk_disable(chip, pwm);
 190 }
 191
 192 static const struct pwm_ops mtk_pwm_ops = {
 193         .config = mtk_pwm_config,
 194         .enable = mtk_pwm_enable,
 195         .disable = mtk_pwm_disable,
 196         .owner = THIS_MODULE,
 197 };
 198
 199 static int mtk_pwm_probe(struct platform_device *pdev)
 200 {
 201         const struct mtk_pwm_platform_data *data;
 202         struct mtk_pwm_chip *pc;
 203         struct resource *res;
 204         unsigned int i;
 205         int ret;
 206
 207         pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
 208         if (!pc)
 209                 return -ENOMEM;
 210
 211         data = of_device_get_match_data(&pdev->dev);
 212         if (data == NULL)
 213                 return -EINVAL;
 214
 215         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 216         pc->regs = devm_ioremap_resource(&pdev->dev, res);
 217         if (IS_ERR(pc->regs))
 218                 return PTR_ERR(pc->regs);
 219
 220         for (i = 0; i < data->num_pwms + 2; i++) {
 221                 pc->clks[i] = devm_clk_get(&pdev->dev, mtk_pwm_clk_name[i]);
 222                 if (IS_ERR(pc->clks[i])) {
 223                         dev_err(&pdev->dev, "clock: %s fail: %ld\n",
 224                                 mtk_pwm_clk_name[i], PTR_ERR(pc->clks[i]));
 225                         return PTR_ERR(pc->clks[i]);
 226                 }
 227         }
 228
 229         platform_set_drvdata(pdev, pc);
 230
 231         pc->chip.dev = &pdev->dev;
 232         pc->chip.ops = &mtk_pwm_ops;
 233         pc->chip.base = -1;
 234         pc->chip.npwm = data->num_pwms;
 235
 236         ret = pwmchip_add(&pc->chip);
 237         if (ret < 0) {
 238                 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
 239                 return ret;
 240         }
 241
 242         return 0;
 243 }
 244
 245 static int mtk_pwm_remove(struct platform_device *pdev)
 246 {
 247         struct mtk_pwm_chip *pc = platform_get_drvdata(pdev);
 248
 249         return pwmchip_remove(&pc->chip);
 250 }
 251
 252 static const struct mtk_pwm_platform_data mt2712_pwm_data = {
 253         .num_pwms = 8,
 254 };
 255
 256 static const struct mtk_pwm_platform_data mt7622_pwm_data = {
 257         .num_pwms = 6,
 258 };
 259
 260 static const struct mtk_pwm_platform_data mt7623_pwm_data = {
 261         .num_pwms = 5,
 262 };
 263
 264 static const struct of_device_id mtk_pwm_of_match[] = {
 265         { .compatible = "mediatek,mt2712-pwm", .data = &mt2712_pwm_data },
 266         { .compatible = "mediatek,mt7622-pwm", .data = &mt7622_pwm_data },
 267         { .compatible = "mediatek,mt7623-pwm", .data = &mt7623_pwm_data },
 268         { },
 269 };
 270 MODULE_DEVICE_TABLE(of, mtk_pwm_of_match);
 271
 272 static struct platform_driver mtk_pwm_driver = {
 273         .driver = {
 274                 .name = "mtk-pwm",
 275                 .of_match_table = mtk_pwm_of_match,
 276         },
 277         .probe = mtk_pwm_probe,
 278         .remove = mtk_pwm_remove,
 279 };
 280 module_platform_driver(mtk_pwm_driver);
 281
 282 MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
 283 MODULE_ALIAS("platform:mtk-pwm");
 284 MODULE_LICENSE("GPL");