linux/drivers/pwm/pwm-mtk-disp.c
<<
>>
Prefs
   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * MediaTek display pulse-width-modulation controller driver.
   4 * Copyright (c) 2015 MediaTek Inc.
   5 * Author: YH Huang <yh.huang@mediatek.com>
   6 */
   7
   8#include <linux/bitfield.h>
   9#include <linux/clk.h>
  10#include <linux/err.h>
  11#include <linux/io.h>
  12#include <linux/module.h>
  13#include <linux/of.h>
  14#include <linux/of_device.h>
  15#include <linux/platform_device.h>
  16#include <linux/pwm.h>
  17#include <linux/slab.h>
  18
  19#define DISP_PWM_EN             0x00
  20
  21#define PWM_CLKDIV_SHIFT        16
  22#define PWM_CLKDIV_MAX          0x3ff
  23#define PWM_CLKDIV_MASK         (PWM_CLKDIV_MAX << PWM_CLKDIV_SHIFT)
  24
  25#define PWM_PERIOD_BIT_WIDTH    12
  26#define PWM_PERIOD_MASK         ((1 << PWM_PERIOD_BIT_WIDTH) - 1)
  27
  28#define PWM_HIGH_WIDTH_SHIFT    16
  29#define PWM_HIGH_WIDTH_MASK     (0x1fff << PWM_HIGH_WIDTH_SHIFT)
  30
  31struct mtk_pwm_data {
  32        u32 enable_mask;
  33        unsigned int con0;
  34        u32 con0_sel;
  35        unsigned int con1;
  36
  37        bool has_commit;
  38        unsigned int commit;
  39        unsigned int commit_mask;
  40
  41        unsigned int bls_debug;
  42        u32 bls_debug_mask;
  43};
  44
  45struct mtk_disp_pwm {
  46        struct pwm_chip chip;
  47        const struct mtk_pwm_data *data;
  48        struct clk *clk_main;
  49        struct clk *clk_mm;
  50        void __iomem *base;
  51        bool enabled;
  52};
  53
  54static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip)
  55{
  56        return container_of(chip, struct mtk_disp_pwm, chip);
  57}
  58
  59static void mtk_disp_pwm_update_bits(struct mtk_disp_pwm *mdp, u32 offset,
  60                                     u32 mask, u32 data)
  61{
  62        void __iomem *address = mdp->base + offset;
  63        u32 value;
  64
  65        value = readl(address);
  66        value &= ~mask;
  67        value |= data;
  68        writel(value, address);
  69}
  70
  71static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
  72                              const struct pwm_state *state)
  73{
  74        struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
  75        u32 clk_div, period, high_width, value;
  76        u64 div, rate;
  77        int err;
  78
  79        if (state->polarity != PWM_POLARITY_NORMAL)
  80                return -EINVAL;
  81
  82        if (!state->enabled) {
  83                mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
  84                                         0x0);
  85
  86                if (mdp->enabled) {
  87                        clk_disable_unprepare(mdp->clk_mm);
  88                        clk_disable_unprepare(mdp->clk_main);
  89                }
  90
  91                mdp->enabled = false;
  92                return 0;
  93        }
  94
  95        if (!mdp->enabled) {
  96                err = clk_prepare_enable(mdp->clk_main);
  97                if (err < 0) {
  98                        dev_err(chip->dev, "Can't enable mdp->clk_main: %pe\n",
  99                                ERR_PTR(err));
 100                        return err;
 101                }
 102
 103                err = clk_prepare_enable(mdp->clk_mm);
 104                if (err < 0) {
 105                        dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n",
 106                                ERR_PTR(err));
 107                        clk_disable_unprepare(mdp->clk_main);
 108                        return err;
 109                }
 110        }
 111
 112        /*
 113         * Find period, high_width and clk_div to suit duty_ns and period_ns.
 114         * Calculate proper div value to keep period value in the bound.
 115         *
 116         * period_ns = 10^9 * (clk_div + 1) * (period + 1) / PWM_CLK_RATE
 117         * duty_ns = 10^9 * (clk_div + 1) * high_width / PWM_CLK_RATE
 118         *
 119         * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1
 120         * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1))
 121         */
 122        rate = clk_get_rate(mdp->clk_main);
 123        clk_div = mul_u64_u64_div_u64(state->period, rate, NSEC_PER_SEC) >>
 124                          PWM_PERIOD_BIT_WIDTH;
 125        if (clk_div > PWM_CLKDIV_MAX) {
 126                if (!mdp->enabled) {
 127                        clk_disable_unprepare(mdp->clk_mm);
 128                        clk_disable_unprepare(mdp->clk_main);
 129                }
 130                return -EINVAL;
 131        }
 132
 133        div = NSEC_PER_SEC * (clk_div + 1);
 134        period = mul_u64_u64_div_u64(state->period, rate, div);
 135        if (period > 0)
 136                period--;
 137
 138        high_width = mul_u64_u64_div_u64(state->duty_cycle, rate, div);
 139        value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
 140
 141        mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
 142                                 PWM_CLKDIV_MASK,
 143                                 clk_div << PWM_CLKDIV_SHIFT);
 144        mtk_disp_pwm_update_bits(mdp, mdp->data->con1,
 145                                 PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK,
 146                                 value);
 147
 148        if (mdp->data->has_commit) {
 149                mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
 150                                         mdp->data->commit_mask,
 151                                         mdp->data->commit_mask);
 152                mtk_disp_pwm_update_bits(mdp, mdp->data->commit,
 153                                         mdp->data->commit_mask,
 154                                         0x0);
 155        } else {
 156                /*
 157                 * For MT2701, disable double buffer before writing register
 158                 * and select manual mode and use PWM_PERIOD/PWM_HIGH_WIDTH.
 159                 */
 160                mtk_disp_pwm_update_bits(mdp, mdp->data->bls_debug,
 161                                         mdp->data->bls_debug_mask,
 162                                         mdp->data->bls_debug_mask);
 163                mtk_disp_pwm_update_bits(mdp, mdp->data->con0,
 164                                         mdp->data->con0_sel,
 165                                         mdp->data->con0_sel);
 166        }
 167
 168        mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, mdp->data->enable_mask,
 169                                 mdp->data->enable_mask);
 170        mdp->enabled = true;
 171
 172        return 0;
 173}
 174
 175static void mtk_disp_pwm_get_state(struct pwm_chip *chip,
 176                                   struct pwm_device *pwm,
 177                                   struct pwm_state *state)
 178{
 179        struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
 180        u64 rate, period, high_width;
 181        u32 clk_div, con0, con1;
 182        int err;
 183
 184        err = clk_prepare_enable(mdp->clk_main);
 185        if (err < 0) {
 186                dev_err(chip->dev, "Can't enable mdp->clk_main: %pe\n", ERR_PTR(err));
 187                return;
 188        }
 189
 190        err = clk_prepare_enable(mdp->clk_mm);
 191        if (err < 0) {
 192                dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n", ERR_PTR(err));
 193                clk_disable_unprepare(mdp->clk_main);
 194                return;
 195        }
 196
 197        rate = clk_get_rate(mdp->clk_main);
 198        con0 = readl(mdp->base + mdp->data->con0);
 199        con1 = readl(mdp->base + mdp->data->con1);
 200        state->enabled = !!(con0 & BIT(0));
 201        clk_div = FIELD_GET(PWM_CLKDIV_MASK, con0);
 202        period = FIELD_GET(PWM_PERIOD_MASK, con1);
 203        /*
 204         * period has 12 bits, clk_div 11 and NSEC_PER_SEC has 30,
 205         * so period * (clk_div + 1) * NSEC_PER_SEC doesn't overflow.
 206         */
 207        state->period = DIV64_U64_ROUND_UP(period * (clk_div + 1) * NSEC_PER_SEC, rate);
 208        high_width = FIELD_GET(PWM_HIGH_WIDTH_MASK, con1);
 209        state->duty_cycle = DIV64_U64_ROUND_UP(high_width * (clk_div + 1) * NSEC_PER_SEC,
 210                                               rate);
 211        state->polarity = PWM_POLARITY_NORMAL;
 212        clk_disable_unprepare(mdp->clk_mm);
 213        clk_disable_unprepare(mdp->clk_main);
 214}
 215
 216static const struct pwm_ops mtk_disp_pwm_ops = {
 217        .apply = mtk_disp_pwm_apply,
 218        .get_state = mtk_disp_pwm_get_state,
 219        .owner = THIS_MODULE,
 220};
 221
 222static int mtk_disp_pwm_probe(struct platform_device *pdev)
 223{
 224        struct mtk_disp_pwm *mdp;
 225        int ret;
 226
 227        mdp = devm_kzalloc(&pdev->dev, sizeof(*mdp), GFP_KERNEL);
 228        if (!mdp)
 229                return -ENOMEM;
 230
 231        mdp->data = of_device_get_match_data(&pdev->dev);
 232
 233        mdp->base = devm_platform_ioremap_resource(pdev, 0);
 234        if (IS_ERR(mdp->base))
 235                return PTR_ERR(mdp->base);
 236
 237        mdp->clk_main = devm_clk_get(&pdev->dev, "main");
 238        if (IS_ERR(mdp->clk_main))
 239                return PTR_ERR(mdp->clk_main);
 240
 241        mdp->clk_mm = devm_clk_get(&pdev->dev, "mm");
 242        if (IS_ERR(mdp->clk_mm))
 243                return PTR_ERR(mdp->clk_mm);
 244
 245        mdp->chip.dev = &pdev->dev;
 246        mdp->chip.ops = &mtk_disp_pwm_ops;
 247        mdp->chip.npwm = 1;
 248
 249        ret = pwmchip_add(&mdp->chip);
 250        if (ret < 0) {
 251                dev_err(&pdev->dev, "pwmchip_add() failed: %pe\n", ERR_PTR(ret));
 252                return ret;
 253        }
 254
 255        platform_set_drvdata(pdev, mdp);
 256
 257        return 0;
 258}
 259
 260static int mtk_disp_pwm_remove(struct platform_device *pdev)
 261{
 262        struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev);
 263
 264        pwmchip_remove(&mdp->chip);
 265
 266        return 0;
 267}
 268
 269static const struct mtk_pwm_data mt2701_pwm_data = {
 270        .enable_mask = BIT(16),
 271        .con0 = 0xa8,
 272        .con0_sel = 0x2,
 273        .con1 = 0xac,
 274        .has_commit = false,
 275        .bls_debug = 0xb0,
 276        .bls_debug_mask = 0x3,
 277};
 278
 279static const struct mtk_pwm_data mt8173_pwm_data = {
 280        .enable_mask = BIT(0),
 281        .con0 = 0x10,
 282        .con0_sel = 0x0,
 283        .con1 = 0x14,
 284        .has_commit = true,
 285        .commit = 0x8,
 286        .commit_mask = 0x1,
 287};
 288
 289static const struct mtk_pwm_data mt8183_pwm_data = {
 290        .enable_mask = BIT(0),
 291        .con0 = 0x18,
 292        .con0_sel = 0x0,
 293        .con1 = 0x1c,
 294        .has_commit = false,
 295        .bls_debug = 0x80,
 296        .bls_debug_mask = 0x3,
 297};
 298
 299static const struct of_device_id mtk_disp_pwm_of_match[] = {
 300        { .compatible = "mediatek,mt2701-disp-pwm", .data = &mt2701_pwm_data},
 301        { .compatible = "mediatek,mt6595-disp-pwm", .data = &mt8173_pwm_data},
 302        { .compatible = "mediatek,mt8173-disp-pwm", .data = &mt8173_pwm_data},
 303        { .compatible = "mediatek,mt8183-disp-pwm", .data = &mt8183_pwm_data},
 304        { }
 305};
 306MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match);
 307
 308static struct platform_driver mtk_disp_pwm_driver = {
 309        .driver = {
 310                .name = "mediatek-disp-pwm",
 311                .of_match_table = mtk_disp_pwm_of_match,
 312        },
 313        .probe = mtk_disp_pwm_probe,
 314        .remove = mtk_disp_pwm_remove,
 315};
 316module_platform_driver(mtk_disp_pwm_driver);
 317
 318MODULE_AUTHOR("YH Huang <yh.huang@mediatek.com>");
 319MODULE_DESCRIPTION("MediaTek SoC display PWM driver");
 320MODULE_LICENSE("GPL v2");
 321