drivers/pwm/pwm-jz4740.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
   4  *  JZ4740 platform PWM support
   5  */
   6
   7 #include <linux/clk.h>
   8 #include <linux/err.h>
   9 #include <linux/gpio.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/of_device.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/pwm.h>
  15
  16 #include <asm/mach-jz4740/timer.h>
  17
  18 #define NUM_PWM 8
  19
  20 struct jz4740_pwm_chip {
  21         struct pwm_chip chip;
  22         struct clk *clk;
  23 };
  24
  25 static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip)
  26 {
  27         return container_of(chip, struct jz4740_pwm_chip, chip);
  28 }
  29
  30 static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  31 {
  32         /*
  33          * Timers 0 and 1 are used for system tasks, so they are unavailable
  34          * for use as PWMs.
  35          */
  36         if (pwm->hwpwm < 2)
  37                 return -EBUSY;
  38
  39         jz4740_timer_start(pwm->hwpwm);
  40
  41         return 0;
  42 }
  43
  44 static void jz4740_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
  45 {
  46         jz4740_timer_set_ctrl(pwm->hwpwm, 0);
  47
  48         jz4740_timer_stop(pwm->hwpwm);
  49 }
  50
  51 static int jz4740_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
  52 {
  53         uint32_t ctrl = jz4740_timer_get_ctrl(pwm->pwm);
  54
  55         ctrl |= JZ_TIMER_CTRL_PWM_ENABLE;
  56         jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
  57         jz4740_timer_enable(pwm->hwpwm);
  58
  59         return 0;
  60 }
  61
  62 static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
  63 {
  64         uint32_t ctrl = jz4740_timer_get_ctrl(pwm->hwpwm);
  65
  66         /* Disable PWM output.
  67          * In TCU2 mode (channel 1/2 on JZ4750+), this must be done before the
  68          * counter is stopped, while in TCU1 mode the order does not matter.
  69          */
  70         ctrl &= ~JZ_TIMER_CTRL_PWM_ENABLE;
  71         jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
  72
  73         /* Stop counter */
  74         jz4740_timer_disable(pwm->hwpwm);
  75 }
  76
  77 static int jz4740_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  78                              int duty_ns, int period_ns)
  79 {
  80         struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip);
  81         unsigned long long tmp;
  82         unsigned long period, duty;
  83         unsigned int prescaler = 0;
  84         uint16_t ctrl;
  85         bool is_enabled;
  86
  87         tmp = (unsigned long long)clk_get_rate(jz4740->clk) * period_ns;
  88         do_div(tmp, 1000000000);
  89         period = tmp;
  90
  91         while (period > 0xffff && prescaler < 6) {
  92                 period >>= 2;
  93                 ++prescaler;
  94         }
  95
  96         if (prescaler == 6)
  97                 return -EINVAL;
  98
  99         tmp = (unsigned long long)period * duty_ns;
 100         do_div(tmp, period_ns);
 101         duty = period - tmp;
 102
 103         if (duty >= period)
 104                 duty = period - 1;
 105
 106         is_enabled = jz4740_timer_is_enabled(pwm->hwpwm);
 107         if (is_enabled)
 108                 jz4740_pwm_disable(chip, pwm);
 109
 110         jz4740_timer_set_count(pwm->hwpwm, 0);
 111         jz4740_timer_set_duty(pwm->hwpwm, duty);
 112         jz4740_timer_set_period(pwm->hwpwm, period);
 113
 114         ctrl = JZ_TIMER_CTRL_PRESCALER(prescaler) | JZ_TIMER_CTRL_SRC_EXT |
 115                 JZ_TIMER_CTRL_PWM_ABBRUPT_SHUTDOWN;
 116
 117         jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
 118
 119         if (is_enabled)
 120                 jz4740_pwm_enable(chip, pwm);
 121
 122         return 0;
 123 }
 124
 125 static int jz4740_pwm_set_polarity(struct pwm_chip *chip,
 126                 struct pwm_device *pwm, enum pwm_polarity polarity)
 127 {
 128         uint32_t ctrl = jz4740_timer_get_ctrl(pwm->pwm);
 129
 130         switch (polarity) {
 131         case PWM_POLARITY_NORMAL:
 132                 ctrl &= ~JZ_TIMER_CTRL_PWM_ACTIVE_LOW;
 133                 break;
 134         case PWM_POLARITY_INVERSED:
 135                 ctrl |= JZ_TIMER_CTRL_PWM_ACTIVE_LOW;
 136                 break;
 137         }
 138
 139         jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
 140         return 0;
 141 }
 142
 143 static const struct pwm_ops jz4740_pwm_ops = {
 144         .request = jz4740_pwm_request,
 145         .free = jz4740_pwm_free,
 146         .config = jz4740_pwm_config,
 147         .set_polarity = jz4740_pwm_set_polarity,
 148         .enable = jz4740_pwm_enable,
 149         .disable = jz4740_pwm_disable,
 150         .owner = THIS_MODULE,
 151 };
 152
 153 static int jz4740_pwm_probe(struct platform_device *pdev)
 154 {
 155         struct jz4740_pwm_chip *jz4740;
 156
 157         jz4740 = devm_kzalloc(&pdev->dev, sizeof(*jz4740), GFP_KERNEL);
 158         if (!jz4740)
 159                 return -ENOMEM;
 160
 161         jz4740->clk = devm_clk_get(&pdev->dev, "ext");
 162         if (IS_ERR(jz4740->clk))
 163                 return PTR_ERR(jz4740->clk);
 164
 165         jz4740->chip.dev = &pdev->dev;
 166         jz4740->chip.ops = &jz4740_pwm_ops;
 167         jz4740->chip.npwm = NUM_PWM;
 168         jz4740->chip.base = -1;
 169         jz4740->chip.of_xlate = of_pwm_xlate_with_flags;
 170         jz4740->chip.of_pwm_n_cells = 3;
 171
 172         platform_set_drvdata(pdev, jz4740);
 173
 174         return pwmchip_add(&jz4740->chip);
 175 }
 176
 177 static int jz4740_pwm_remove(struct platform_device *pdev)
 178 {
 179         struct jz4740_pwm_chip *jz4740 = platform_get_drvdata(pdev);
 180
 181         return pwmchip_remove(&jz4740->chip);
 182 }
 183
 184 #ifdef CONFIG_OF
 185 static const struct of_device_id jz4740_pwm_dt_ids[] = {
 186         { .compatible = "ingenic,jz4740-pwm", },
 187         { .compatible = "ingenic,jz4770-pwm", },
 188         { .compatible = "ingenic,jz4780-pwm", },
 189         {},
 190 };
 191 MODULE_DEVICE_TABLE(of, jz4740_pwm_dt_ids);
 192 #endif
 193
 194 static struct platform_driver jz4740_pwm_driver = {
 195         .driver = {
 196                 .name = "jz4740-pwm",
 197                 .of_match_table = of_match_ptr(jz4740_pwm_dt_ids),
 198         },
 199         .probe = jz4740_pwm_probe,
 200         .remove = jz4740_pwm_remove,
 201 };
 202 module_platform_driver(jz4740_pwm_driver);
 203
 204 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 205 MODULE_DESCRIPTION("Ingenic JZ4740 PWM driver");
 206 MODULE_ALIAS("platform:jz4740-pwm");
 207 MODULE_LICENSE("GPL");