Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de> |
| 3 | * JZ4740 platform PWM support |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License as published by the |
| 7 | * Free Software Foundation; either version 2 of the License, or (at your |
| 8 | * option) any later version. |
| 9 | * |
| 10 | * You should have received a copy of the GNU General Public License along |
| 11 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 12 | * 675 Mass Ave, Cambridge, MA 02139, USA. |
| 13 | * |
| 14 | */ |
| 15 | |
| 16 | #include <linux/clk.h> |
| 17 | #include <linux/err.h> |
| 18 | #include <linux/gpio.h> |
| 19 | #include <linux/kernel.h> |
| 20 | #include <linux/module.h> |
| 21 | #include <linux/platform_device.h> |
| 22 | #include <linux/pwm.h> |
| 23 | |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 24 | #include <asm/mach-jz4740/timer.h> |
| 25 | |
| 26 | #define NUM_PWM 8 |
| 27 | |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 28 | struct jz4740_pwm_chip { |
| 29 | struct pwm_chip chip; |
| 30 | struct clk *clk; |
| 31 | }; |
| 32 | |
| 33 | static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip) |
| 34 | { |
| 35 | return container_of(chip, struct jz4740_pwm_chip, chip); |
| 36 | } |
| 37 | |
| 38 | static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) |
| 39 | { |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 40 | /* |
| 41 | * Timers 0 and 1 are used for system tasks, so they are unavailable |
| 42 | * for use as PWMs. |
| 43 | */ |
| 44 | if (pwm->hwpwm < 2) |
| 45 | return -EBUSY; |
| 46 | |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 47 | jz4740_timer_start(pwm->hwpwm); |
| 48 | |
| 49 | return 0; |
| 50 | } |
| 51 | |
| 52 | static void jz4740_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) |
| 53 | { |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 54 | jz4740_timer_set_ctrl(pwm->hwpwm, 0); |
| 55 | |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 56 | jz4740_timer_stop(pwm->hwpwm); |
| 57 | } |
| 58 | |
| 59 | static int jz4740_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) |
| 60 | { |
| 61 | uint32_t ctrl = jz4740_timer_get_ctrl(pwm->pwm); |
| 62 | |
| 63 | ctrl |= JZ_TIMER_CTRL_PWM_ENABLE; |
| 64 | jz4740_timer_set_ctrl(pwm->hwpwm, ctrl); |
| 65 | jz4740_timer_enable(pwm->hwpwm); |
| 66 | |
| 67 | return 0; |
| 68 | } |
| 69 | |
| 70 | static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) |
| 71 | { |
| 72 | uint32_t ctrl = jz4740_timer_get_ctrl(pwm->hwpwm); |
| 73 | |
| 74 | ctrl &= ~JZ_TIMER_CTRL_PWM_ENABLE; |
| 75 | jz4740_timer_disable(pwm->hwpwm); |
| 76 | jz4740_timer_set_ctrl(pwm->hwpwm, ctrl); |
| 77 | } |
| 78 | |
| 79 | static int jz4740_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, |
| 80 | int duty_ns, int period_ns) |
| 81 | { |
| 82 | struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip); |
| 83 | unsigned long long tmp; |
| 84 | unsigned long period, duty; |
| 85 | unsigned int prescaler = 0; |
| 86 | uint16_t ctrl; |
| 87 | bool is_enabled; |
| 88 | |
| 89 | tmp = (unsigned long long)clk_get_rate(jz4740->clk) * period_ns; |
| 90 | do_div(tmp, 1000000000); |
| 91 | period = tmp; |
| 92 | |
| 93 | while (period > 0xffff && prescaler < 6) { |
| 94 | period >>= 2; |
| 95 | ++prescaler; |
| 96 | } |
| 97 | |
| 98 | if (prescaler == 6) |
| 99 | return -EINVAL; |
| 100 | |
| 101 | tmp = (unsigned long long)period * duty_ns; |
| 102 | do_div(tmp, period_ns); |
| 103 | duty = period - tmp; |
| 104 | |
| 105 | if (duty >= period) |
| 106 | duty = period - 1; |
| 107 | |
| 108 | is_enabled = jz4740_timer_is_enabled(pwm->hwpwm); |
| 109 | if (is_enabled) |
| 110 | jz4740_pwm_disable(chip, pwm); |
| 111 | |
| 112 | jz4740_timer_set_count(pwm->hwpwm, 0); |
| 113 | jz4740_timer_set_duty(pwm->hwpwm, duty); |
| 114 | jz4740_timer_set_period(pwm->hwpwm, period); |
| 115 | |
| 116 | ctrl = JZ_TIMER_CTRL_PRESCALER(prescaler) | JZ_TIMER_CTRL_SRC_EXT | |
| 117 | JZ_TIMER_CTRL_PWM_ABBRUPT_SHUTDOWN; |
| 118 | |
| 119 | jz4740_timer_set_ctrl(pwm->hwpwm, ctrl); |
| 120 | |
| 121 | if (is_enabled) |
| 122 | jz4740_pwm_enable(chip, pwm); |
| 123 | |
| 124 | return 0; |
| 125 | } |
| 126 | |
| 127 | static const struct pwm_ops jz4740_pwm_ops = { |
| 128 | .request = jz4740_pwm_request, |
| 129 | .free = jz4740_pwm_free, |
| 130 | .config = jz4740_pwm_config, |
| 131 | .enable = jz4740_pwm_enable, |
| 132 | .disable = jz4740_pwm_disable, |
| 133 | .owner = THIS_MODULE, |
| 134 | }; |
| 135 | |
Bill Pemberton | 3e9fe83 | 2012-11-19 13:23:14 -0500 | [diff] [blame] | 136 | static int jz4740_pwm_probe(struct platform_device *pdev) |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 137 | { |
| 138 | struct jz4740_pwm_chip *jz4740; |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 139 | |
| 140 | jz4740 = devm_kzalloc(&pdev->dev, sizeof(*jz4740), GFP_KERNEL); |
| 141 | if (!jz4740) |
| 142 | return -ENOMEM; |
| 143 | |
Lars-Peter Clausen | 0dc1135 | 2013-12-07 18:13:16 +0100 | [diff] [blame] | 144 | jz4740->clk = devm_clk_get(&pdev->dev, "ext"); |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 145 | if (IS_ERR(jz4740->clk)) |
| 146 | return PTR_ERR(jz4740->clk); |
| 147 | |
| 148 | jz4740->chip.dev = &pdev->dev; |
| 149 | jz4740->chip.ops = &jz4740_pwm_ops; |
| 150 | jz4740->chip.npwm = NUM_PWM; |
| 151 | jz4740->chip.base = -1; |
| 152 | |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 153 | platform_set_drvdata(pdev, jz4740); |
| 154 | |
Lars-Peter Clausen | 0dc1135 | 2013-12-07 18:13:16 +0100 | [diff] [blame] | 155 | return pwmchip_add(&jz4740->chip); |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 156 | } |
| 157 | |
Bill Pemberton | 77f3791 | 2012-11-19 13:26:09 -0500 | [diff] [blame] | 158 | static int jz4740_pwm_remove(struct platform_device *pdev) |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 159 | { |
| 160 | struct jz4740_pwm_chip *jz4740 = platform_get_drvdata(pdev); |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 161 | |
Lars-Peter Clausen | 0dc1135 | 2013-12-07 18:13:16 +0100 | [diff] [blame] | 162 | return pwmchip_remove(&jz4740->chip); |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 163 | } |
| 164 | |
| 165 | static struct platform_driver jz4740_pwm_driver = { |
| 166 | .driver = { |
| 167 | .name = "jz4740-pwm", |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 168 | }, |
| 169 | .probe = jz4740_pwm_probe, |
Bill Pemberton | fd10911 | 2012-11-19 13:21:28 -0500 | [diff] [blame] | 170 | .remove = jz4740_pwm_remove, |
Thierry Reding | f6b8a57 | 2012-08-22 10:01:24 +0200 | [diff] [blame] | 171 | }; |
| 172 | module_platform_driver(jz4740_pwm_driver); |
| 173 | |
| 174 | MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); |
| 175 | MODULE_DESCRIPTION("Ingenic JZ4740 PWM driver"); |
| 176 | MODULE_ALIAS("platform:jz4740-pwm"); |
| 177 | MODULE_LICENSE("GPL"); |