drivers/pwm/pwm-rcar.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * R-Car PWM Timer driver
   4  *
   5  * Copyright (C) 2015 Renesas Electronics Corporation
   6  *
   7  * Limitations:
   8  * - The hardware cannot generate a 0% duty cycle.
   9  */
  10
  11 #include <linux/clk.h>
  12 #include <linux/err.h>
  13 #include <linux/io.h>
  14 #include <linux/log2.h>
  15 #include <linux/math64.h>
  16 #include <linux/module.h>
  17 #include <linux/of.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/pm_runtime.h>
  20 #include <linux/pwm.h>
  21 #include <linux/slab.h>
  22
  23 #define RCAR_PWM_MAX_DIVISION   24
  24 #define RCAR_PWM_MAX_CYCLE      1023
  25
  26 #define RCAR_PWMCR              0x00
  27 #define  RCAR_PWMCR_CC0_MASK    0x000f0000
  28 #define  RCAR_PWMCR_CC0_SHIFT   16
  29 #define  RCAR_PWMCR_CCMD        BIT(15)
  30 #define  RCAR_PWMCR_SYNC        BIT(11)
  31 #define  RCAR_PWMCR_SS0         BIT(4)
  32 #define  RCAR_PWMCR_EN0         BIT(0)
  33
  34 #define RCAR_PWMCNT             0x04
  35 #define  RCAR_PWMCNT_CYC0_MASK  0x03ff0000
  36 #define  RCAR_PWMCNT_CYC0_SHIFT 16
  37 #define  RCAR_PWMCNT_PH0_MASK   0x000003ff
  38 #define  RCAR_PWMCNT_PH0_SHIFT  0
  39
  40 struct rcar_pwm_chip {
  41         struct pwm_chip chip;
  42         void __iomem *base;
  43         struct clk *clk;
  44 };
  45
  46 static inline struct rcar_pwm_chip *to_rcar_pwm_chip(struct pwm_chip *chip)
  47 {
  48         return container_of(chip, struct rcar_pwm_chip, chip);
  49 }
  50
  51 static void rcar_pwm_write(struct rcar_pwm_chip *rp, u32 data,
  52                            unsigned int offset)
  53 {
  54         writel(data, rp->base + offset);
  55 }
  56
  57 static u32 rcar_pwm_read(struct rcar_pwm_chip *rp, unsigned int offset)
  58 {
  59         return readl(rp->base + offset);
  60 }
  61
  62 static void rcar_pwm_update(struct rcar_pwm_chip *rp, u32 mask, u32 data,
  63                             unsigned int offset)
  64 {
  65         u32 value;
  66
  67         value = rcar_pwm_read(rp, offset);
  68         value &= ~mask;
  69         value |= data & mask;
  70         rcar_pwm_write(rp, value, offset);
  71 }
  72
  73 static int rcar_pwm_get_clock_division(struct rcar_pwm_chip *rp, int period_ns)
  74 {
  75         unsigned long clk_rate = clk_get_rate(rp->clk);
  76         u64 div, tmp;
  77
  78         if (clk_rate == 0)
  79                 return -EINVAL;
  80
  81         div = (u64)NSEC_PER_SEC * RCAR_PWM_MAX_CYCLE;
  82         tmp = (u64)period_ns * clk_rate + div - 1;
  83         tmp = div64_u64(tmp, div);
  84         div = ilog2(tmp - 1) + 1;
  85
  86         return (div <= RCAR_PWM_MAX_DIVISION) ? div : -ERANGE;
  87 }
  88
  89 static void rcar_pwm_set_clock_control(struct rcar_pwm_chip *rp,
  90                                        unsigned int div)
  91 {
  92         u32 value;
  93
  94         value = rcar_pwm_read(rp, RCAR_PWMCR);
  95         value &= ~(RCAR_PWMCR_CCMD | RCAR_PWMCR_CC0_MASK);
  96
  97         if (div & 1)
  98                 value |= RCAR_PWMCR_CCMD;
  99
 100         div >>= 1;
 101
 102         value |= div << RCAR_PWMCR_CC0_SHIFT;
 103         rcar_pwm_write(rp, value, RCAR_PWMCR);
 104 }
 105
 106 static int rcar_pwm_set_counter(struct rcar_pwm_chip *rp, int div, int duty_ns,
 107                                 int period_ns)
 108 {
 109         unsigned long long one_cycle, tmp;      /* 0.01 nanoseconds */
 110         unsigned long clk_rate = clk_get_rate(rp->clk);
 111         u32 cyc, ph;
 112
 113         one_cycle = NSEC_PER_SEC * 100ULL << div;
 114         do_div(one_cycle, clk_rate);
 115
 116         tmp = period_ns * 100ULL;
 117         do_div(tmp, one_cycle);
 118         cyc = (tmp << RCAR_PWMCNT_CYC0_SHIFT) & RCAR_PWMCNT_CYC0_MASK;
 119
 120         tmp = duty_ns * 100ULL;
 121         do_div(tmp, one_cycle);
 122         ph = tmp & RCAR_PWMCNT_PH0_MASK;
 123
 124         /* Avoid prohibited setting */
 125         if (cyc == 0 || ph == 0)
 126                 return -EINVAL;
 127
 128         rcar_pwm_write(rp, cyc | ph, RCAR_PWMCNT);
 129
 130         return 0;
 131 }
 132
 133 static int rcar_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 134 {
 135         return pm_runtime_get_sync(chip->dev);
 136 }
 137
 138 static void rcar_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 139 {
 140         pm_runtime_put(chip->dev);
 141 }
 142
 143 static int rcar_pwm_enable(struct rcar_pwm_chip *rp)
 144 {
 145         u32 value;
 146
 147         /* Don't enable the PWM device if CYC0 or PH0 is 0 */
 148         value = rcar_pwm_read(rp, RCAR_PWMCNT);
 149         if ((value & RCAR_PWMCNT_CYC0_MASK) == 0 ||
 150             (value & RCAR_PWMCNT_PH0_MASK) == 0)
 151                 return -EINVAL;
 152
 153         rcar_pwm_update(rp, RCAR_PWMCR_EN0, RCAR_PWMCR_EN0, RCAR_PWMCR);
 154
 155         return 0;
 156 }
 157
 158 static void rcar_pwm_disable(struct rcar_pwm_chip *rp)
 159 {
 160         rcar_pwm_update(rp, RCAR_PWMCR_EN0, 0, RCAR_PWMCR);
 161 }
 162
 163 static int rcar_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 164                           const struct pwm_state *state)
 165 {
 166         struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
 167         int div, ret;
 168
 169         /* This HW/driver only supports normal polarity */
 170         if (state->polarity != PWM_POLARITY_NORMAL)
 171                 return -EINVAL;
 172
 173         if (!state->enabled) {
 174                 rcar_pwm_disable(rp);
 175                 return 0;
 176         }
 177
 178         div = rcar_pwm_get_clock_division(rp, state->period);
 179         if (div < 0)
 180                 return div;
 181
 182         rcar_pwm_update(rp, RCAR_PWMCR_SYNC, RCAR_PWMCR_SYNC, RCAR_PWMCR);
 183
 184         ret = rcar_pwm_set_counter(rp, div, state->duty_cycle, state->period);
 185         if (!ret)
 186                 rcar_pwm_set_clock_control(rp, div);
 187
 188         /* The SYNC should be set to 0 even if rcar_pwm_set_counter failed */
 189         rcar_pwm_update(rp, RCAR_PWMCR_SYNC, 0, RCAR_PWMCR);
 190
 191         if (!ret)
 192                 ret = rcar_pwm_enable(rp);
 193
 194         return ret;
 195 }
 196
 197 static const struct pwm_ops rcar_pwm_ops = {
 198         .request = rcar_pwm_request,
 199         .free = rcar_pwm_free,
 200         .apply = rcar_pwm_apply,
 201         .owner = THIS_MODULE,
 202 };
 203
 204 static int rcar_pwm_probe(struct platform_device *pdev)
 205 {
 206         struct rcar_pwm_chip *rcar_pwm;
 207         int ret;
 208
 209         rcar_pwm = devm_kzalloc(&pdev->dev, sizeof(*rcar_pwm), GFP_KERNEL);
 210         if (rcar_pwm == NULL)
 211                 return -ENOMEM;
 212
 213         rcar_pwm->base = devm_platform_ioremap_resource(pdev, 0);
 214         if (IS_ERR(rcar_pwm->base))
 215                 return PTR_ERR(rcar_pwm->base);
 216
 217         rcar_pwm->clk = devm_clk_get(&pdev->dev, NULL);
 218         if (IS_ERR(rcar_pwm->clk)) {
 219                 dev_err(&pdev->dev, "cannot get clock\n");
 220                 return PTR_ERR(rcar_pwm->clk);
 221         }
 222
 223         platform_set_drvdata(pdev, rcar_pwm);
 224
 225         rcar_pwm->chip.dev = &pdev->dev;
 226         rcar_pwm->chip.ops = &rcar_pwm_ops;
 227         rcar_pwm->chip.npwm = 1;
 228
 229         pm_runtime_enable(&pdev->dev);
 230
 231         ret = pwmchip_add(&rcar_pwm->chip);
 232         if (ret < 0) {
 233                 dev_err(&pdev->dev, "failed to register PWM chip: %d\n", ret);
 234                 pm_runtime_disable(&pdev->dev);
 235                 return ret;
 236         }
 237
 238         return 0;
 239 }
 240
 241 static void rcar_pwm_remove(struct platform_device *pdev)
 242 {
 243         struct rcar_pwm_chip *rcar_pwm = platform_get_drvdata(pdev);
 244
 245         pwmchip_remove(&rcar_pwm->chip);
 246
 247         pm_runtime_disable(&pdev->dev);
 248 }
 249
 250 static const struct of_device_id rcar_pwm_of_table[] = {
 251         { .compatible = "renesas,pwm-rcar", },
 252         { },
 253 };
 254 MODULE_DEVICE_TABLE(of, rcar_pwm_of_table);
 255
 256 static struct platform_driver rcar_pwm_driver = {
 257         .probe = rcar_pwm_probe,
 258         .remove_new = rcar_pwm_remove,
 259         .driver = {
 260                 .name = "pwm-rcar",
 261                 .of_match_table = rcar_pwm_of_table,
 262         }
 263 };
 264 module_platform_driver(rcar_pwm_driver);
 265
 266 MODULE_AUTHOR("Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>");
 267 MODULE_DESCRIPTION("Renesas PWM Timer Driver");
 268 MODULE_LICENSE("GPL v2");
 269 MODULE_ALIAS("platform:pwm-rcar");