drivers/pwm/pwm-mtk-disp.c

   1 /*
   2  * MediaTek display pulse-width-modulation controller driver.
   3  * Copyright (c) 2015 MediaTek Inc.
   4  * Author: YH Huang <yh.huang@mediatek.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/clk.h>
  17 #include <linux/err.h>
  18 #include <linux/io.h>
  19 #include <linux/module.h>
  20 #include <linux/of.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/pwm.h>
  23 #include <linux/slab.h>
  24
  25 #define DISP_PWM_EN             0x00
  26 #define PWM_ENABLE_MASK         BIT(0)
  27
  28 #define DISP_PWM_COMMIT         0x08
  29 #define PWM_COMMIT_MASK         BIT(0)
  30
  31 #define DISP_PWM_CON_0          0x10
  32 #define PWM_CLKDIV_SHIFT        16
  33 #define PWM_CLKDIV_MAX          0x3ff
  34 #define PWM_CLKDIV_MASK         (PWM_CLKDIV_MAX << PWM_CLKDIV_SHIFT)
  35
  36 #define DISP_PWM_CON_1          0x14
  37 #define PWM_PERIOD_BIT_WIDTH    12
  38 #define PWM_PERIOD_MASK         ((1 << PWM_PERIOD_BIT_WIDTH) - 1)
  39
  40 #define PWM_HIGH_WIDTH_SHIFT    16
  41 #define PWM_HIGH_WIDTH_MASK     (0x1fff << PWM_HIGH_WIDTH_SHIFT)
  42
  43 struct mtk_disp_pwm {
  44         struct pwm_chip chip;
  45         struct clk *clk_main;
  46         struct clk *clk_mm;
  47         void __iomem *base;
  48 };
  49
  50 static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip)
  51 {
  52         return container_of(chip, struct mtk_disp_pwm, chip);
  53 }
  54
  55 static void mtk_disp_pwm_update_bits(struct mtk_disp_pwm *mdp, u32 offset,
  56                                      u32 mask, u32 data)
  57 {
  58         void __iomem *address = mdp->base + offset;
  59         u32 value;
  60
  61         value = readl(address);
  62         value &= ~mask;
  63         value |= data;
  64         writel(value, address);
  65 }
  66
  67 static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  68                                int duty_ns, int period_ns)
  69 {
  70         struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
  71         u32 clk_div, period, high_width, value;
  72         u64 div, rate;
  73         int err;
  74
  75         /*
  76          * Find period, high_width and clk_div to suit duty_ns and period_ns.
  77          * Calculate proper div value to keep period value in the bound.
  78          *
  79          * period_ns = 10^9 * (clk_div + 1) * (period + 1) / PWM_CLK_RATE
  80          * duty_ns = 10^9 * (clk_div + 1) * high_width / PWM_CLK_RATE
  81          *
  82          * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1
  83          * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1))
  84          */
  85         rate = clk_get_rate(mdp->clk_main);
  86         clk_div = div_u64(rate * period_ns, NSEC_PER_SEC) >>
  87                           PWM_PERIOD_BIT_WIDTH;
  88         if (clk_div > PWM_CLKDIV_MAX)
  89                 return -EINVAL;
  90
  91         div = NSEC_PER_SEC * (clk_div + 1);
  92         period = div64_u64(rate * period_ns, div);
  93         if (period > 0)
  94                 period--;
  95
  96         high_width = div64_u64(rate * duty_ns, div);
  97         value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
  98
  99         err = clk_enable(mdp->clk_main);
 100         if (err < 0)
 101                 return err;
 102
 103         err = clk_enable(mdp->clk_mm);
 104         if (err < 0) {
 105                 clk_disable(mdp->clk_main);
 106                 return err;
 107         }
 108
 109         mtk_disp_pwm_update_bits(mdp, DISP_PWM_CON_0, PWM_CLKDIV_MASK,
 110                                  clk_div << PWM_CLKDIV_SHIFT);
 111         mtk_disp_pwm_update_bits(mdp, DISP_PWM_CON_1,
 112                                  PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK, value);
 113         mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT, PWM_COMMIT_MASK, 1);
 114         mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT, PWM_COMMIT_MASK, 0);
 115
 116         clk_disable(mdp->clk_mm);
 117         clk_disable(mdp->clk_main);
 118
 119         return 0;
 120 }
 121
 122 static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 123 {
 124         struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
 125         int err;
 126
 127         err = clk_enable(mdp->clk_main);
 128         if (err < 0)
 129                 return err;
 130
 131         err = clk_enable(mdp->clk_mm);
 132         if (err < 0) {
 133                 clk_disable(mdp->clk_main);
 134                 return err;
 135         }
 136
 137         mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, PWM_ENABLE_MASK, 1);
 138
 139         return 0;
 140 }
 141
 142 static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 143 {
 144         struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
 145
 146         mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, PWM_ENABLE_MASK, 0);
 147
 148         clk_disable(mdp->clk_mm);
 149         clk_disable(mdp->clk_main);
 150 }
 151
 152 static const struct pwm_ops mtk_disp_pwm_ops = {
 153         .config = mtk_disp_pwm_config,
 154         .enable = mtk_disp_pwm_enable,
 155         .disable = mtk_disp_pwm_disable,
 156         .owner = THIS_MODULE,
 157 };
 158
 159 static int mtk_disp_pwm_probe(struct platform_device *pdev)
 160 {
 161         struct mtk_disp_pwm *mdp;
 162         struct resource *r;
 163         int ret;
 164
 165         mdp = devm_kzalloc(&pdev->dev, sizeof(*mdp), GFP_KERNEL);
 166         if (!mdp)
 167                 return -ENOMEM;
 168
 169         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 170         mdp->base = devm_ioremap_resource(&pdev->dev, r);
 171         if (IS_ERR(mdp->base))
 172                 return PTR_ERR(mdp->base);
 173
 174         mdp->clk_main = devm_clk_get(&pdev->dev, "main");
 175         if (IS_ERR(mdp->clk_main))
 176                 return PTR_ERR(mdp->clk_main);
 177
 178         mdp->clk_mm = devm_clk_get(&pdev->dev, "mm");
 179         if (IS_ERR(mdp->clk_mm))
 180                 return PTR_ERR(mdp->clk_mm);
 181
 182         ret = clk_prepare(mdp->clk_main);
 183         if (ret < 0)
 184                 return ret;
 185
 186         ret = clk_prepare(mdp->clk_mm);
 187         if (ret < 0)
 188                 goto disable_clk_main;
 189
 190         mdp->chip.dev = &pdev->dev;
 191         mdp->chip.ops = &mtk_disp_pwm_ops;
 192         mdp->chip.base = -1;
 193         mdp->chip.npwm = 1;
 194
 195         ret = pwmchip_add(&mdp->chip);
 196         if (ret < 0) {
 197                 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
 198                 goto disable_clk_mm;
 199         }
 200
 201         platform_set_drvdata(pdev, mdp);
 202
 203         return 0;
 204
 205 disable_clk_mm:
 206         clk_unprepare(mdp->clk_mm);
 207 disable_clk_main:
 208         clk_unprepare(mdp->clk_main);
 209         return ret;
 210 }
 211
 212 static int mtk_disp_pwm_remove(struct platform_device *pdev)
 213 {
 214         struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev);
 215         int ret;
 216
 217         ret = pwmchip_remove(&mdp->chip);
 218         clk_unprepare(mdp->clk_mm);
 219         clk_unprepare(mdp->clk_main);
 220
 221         return ret;
 222 }
 223
 224 static const struct of_device_id mtk_disp_pwm_of_match[] = {
 225         { .compatible = "mediatek,mt8173-disp-pwm" },
 226         { .compatible = "mediatek,mt6595-disp-pwm" },
 227         { }
 228 };
 229 MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match);
 230
 231 static struct platform_driver mtk_disp_pwm_driver = {
 232         .driver = {
 233                 .name = "mediatek-disp-pwm",
 234                 .of_match_table = mtk_disp_pwm_of_match,
 235         },
 236         .probe = mtk_disp_pwm_probe,
 237         .remove = mtk_disp_pwm_remove,
 238 };
 239 module_platform_driver(mtk_disp_pwm_driver);
 240
 241 MODULE_AUTHOR("YH Huang <yh.huang@mediatek.com>");
 242 MODULE_DESCRIPTION("MediaTek SoC display PWM driver");
 243 MODULE_LICENSE("GPL v2");