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| 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 | |
| 24 | #include <asm/mach-jz4740/gpio.h> |
| 25 | #include <asm/mach-jz4740/timer.h> |
| 26 | |
| 27 | #define NUM_PWM 8 |
| 28 | |
| 29 | static const unsigned int jz4740_pwm_gpio_list[NUM_PWM] = { |
| 30 | JZ_GPIO_PWM0, |
| 31 | JZ_GPIO_PWM1, |
| 32 | JZ_GPIO_PWM2, |
| 33 | JZ_GPIO_PWM3, |
| 34 | JZ_GPIO_PWM4, |
| 35 | JZ_GPIO_PWM5, |
| 36 | JZ_GPIO_PWM6, |
| 37 | JZ_GPIO_PWM7, |
| 38 | }; |
| 39 | |
| 40 | struct jz4740_pwm_chip { |
| 41 | struct pwm_chip chip; |
| 42 | struct clk *clk; |
| 43 | }; |
| 44 | |
| 45 | static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip) |
| 46 | { |
| 47 | return container_of(chip, struct jz4740_pwm_chip, chip); |
| 48 | } |
| 49 | |
| 50 | static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) |
| 51 | { |
| 52 | unsigned int gpio = jz4740_pwm_gpio_list[pwm->hwpwm]; |
| 53 | int ret; |
| 54 | |
| 55 | /* |
| 56 | * Timers 0 and 1 are used for system tasks, so they are unavailable |
| 57 | * for use as PWMs. |
| 58 | */ |
| 59 | if (pwm->hwpwm < 2) |
| 60 | return -EBUSY; |
| 61 | |
| 62 | ret = gpio_request(gpio, pwm->label); |
| 63 | if (ret) { |
| 64 | dev_err(chip->dev, "Failed to request GPIO#%u for PWM: %d\n", |
| 65 | gpio, ret); |
| 66 | return ret; |
| 67 | } |
| 68 | |
| 69 | jz_gpio_set_function(gpio, JZ_GPIO_FUNC_PWM); |
| 70 | |
| 71 | jz4740_timer_start(pwm->hwpwm); |
| 72 | |
| 73 | return 0; |
| 74 | } |
| 75 | |
| 76 | static void jz4740_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) |
| 77 | { |
| 78 | unsigned int gpio = jz4740_pwm_gpio_list[pwm->hwpwm]; |
| 79 | |
| 80 | jz4740_timer_set_ctrl(pwm->hwpwm, 0); |
| 81 | |
| 82 | jz_gpio_set_function(gpio, JZ_GPIO_FUNC_NONE); |
| 83 | gpio_free(gpio); |
| 84 | |
| 85 | jz4740_timer_stop(pwm->hwpwm); |
| 86 | } |
| 87 | |
| 88 | static int jz4740_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) |
| 89 | { |
| 90 | uint32_t ctrl = jz4740_timer_get_ctrl(pwm->pwm); |
| 91 | |
| 92 | ctrl |= JZ_TIMER_CTRL_PWM_ENABLE; |
| 93 | jz4740_timer_set_ctrl(pwm->hwpwm, ctrl); |
| 94 | jz4740_timer_enable(pwm->hwpwm); |
| 95 | |
| 96 | return 0; |
| 97 | } |
| 98 | |
| 99 | static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) |
| 100 | { |
| 101 | uint32_t ctrl = jz4740_timer_get_ctrl(pwm->hwpwm); |
| 102 | |
| 103 | ctrl &= ~JZ_TIMER_CTRL_PWM_ENABLE; |
| 104 | jz4740_timer_disable(pwm->hwpwm); |
| 105 | jz4740_timer_set_ctrl(pwm->hwpwm, ctrl); |
| 106 | } |
| 107 | |
| 108 | static int jz4740_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, |
| 109 | int duty_ns, int period_ns) |
| 110 | { |
| 111 | struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip); |
| 112 | unsigned long long tmp; |
| 113 | unsigned long period, duty; |
| 114 | unsigned int prescaler = 0; |
| 115 | uint16_t ctrl; |
| 116 | bool is_enabled; |
| 117 | |
| 118 | tmp = (unsigned long long)clk_get_rate(jz4740->clk) * period_ns; |
| 119 | do_div(tmp, 1000000000); |
| 120 | period = tmp; |
| 121 | |
| 122 | while (period > 0xffff && prescaler < 6) { |
| 123 | period >>= 2; |
| 124 | ++prescaler; |
| 125 | } |
| 126 | |
| 127 | if (prescaler == 6) |
| 128 | return -EINVAL; |
| 129 | |
| 130 | tmp = (unsigned long long)period * duty_ns; |
| 131 | do_div(tmp, period_ns); |
| 132 | duty = period - tmp; |
| 133 | |
| 134 | if (duty >= period) |
| 135 | duty = period - 1; |
| 136 | |
| 137 | is_enabled = jz4740_timer_is_enabled(pwm->hwpwm); |
| 138 | if (is_enabled) |
| 139 | jz4740_pwm_disable(chip, pwm); |
| 140 | |
| 141 | jz4740_timer_set_count(pwm->hwpwm, 0); |
| 142 | jz4740_timer_set_duty(pwm->hwpwm, duty); |
| 143 | jz4740_timer_set_period(pwm->hwpwm, period); |
| 144 | |
| 145 | ctrl = JZ_TIMER_CTRL_PRESCALER(prescaler) | JZ_TIMER_CTRL_SRC_EXT | |
| 146 | JZ_TIMER_CTRL_PWM_ABBRUPT_SHUTDOWN; |
| 147 | |
| 148 | jz4740_timer_set_ctrl(pwm->hwpwm, ctrl); |
| 149 | |
| 150 | if (is_enabled) |
| 151 | jz4740_pwm_enable(chip, pwm); |
| 152 | |
| 153 | return 0; |
| 154 | } |
| 155 | |
| 156 | static const struct pwm_ops jz4740_pwm_ops = { |
| 157 | .request = jz4740_pwm_request, |
| 158 | .free = jz4740_pwm_free, |
| 159 | .config = jz4740_pwm_config, |
| 160 | .enable = jz4740_pwm_enable, |
| 161 | .disable = jz4740_pwm_disable, |
| 162 | .owner = THIS_MODULE, |
| 163 | }; |
| 164 | |
| 165 | static int __devinit jz4740_pwm_probe(struct platform_device *pdev) |
| 166 | { |
| 167 | struct jz4740_pwm_chip *jz4740; |
| 168 | int ret; |
| 169 | |
| 170 | jz4740 = devm_kzalloc(&pdev->dev, sizeof(*jz4740), GFP_KERNEL); |
| 171 | if (!jz4740) |
| 172 | return -ENOMEM; |
| 173 | |
| 174 | jz4740->clk = clk_get(NULL, "ext"); |
| 175 | if (IS_ERR(jz4740->clk)) |
| 176 | return PTR_ERR(jz4740->clk); |
| 177 | |
| 178 | jz4740->chip.dev = &pdev->dev; |
| 179 | jz4740->chip.ops = &jz4740_pwm_ops; |
| 180 | jz4740->chip.npwm = NUM_PWM; |
| 181 | jz4740->chip.base = -1; |
| 182 | |
| 183 | ret = pwmchip_add(&jz4740->chip); |
| 184 | if (ret < 0) { |
| 185 | clk_put(jz4740->clk); |
| 186 | return ret; |
| 187 | } |
| 188 | |
| 189 | platform_set_drvdata(pdev, jz4740); |
| 190 | |
| 191 | return 0; |
| 192 | } |
| 193 | |
| 194 | static int __devexit jz4740_pwm_remove(struct platform_device *pdev) |
| 195 | { |
| 196 | struct jz4740_pwm_chip *jz4740 = platform_get_drvdata(pdev); |
| 197 | int ret; |
| 198 | |
| 199 | ret = pwmchip_remove(&jz4740->chip); |
| 200 | if (ret < 0) |
| 201 | return ret; |
| 202 | |
| 203 | clk_put(jz4740->clk); |
| 204 | |
| 205 | return 0; |
| 206 | } |
| 207 | |
| 208 | static struct platform_driver jz4740_pwm_driver = { |
| 209 | .driver = { |
| 210 | .name = "jz4740-pwm", |
| 211 | .owner = THIS_MODULE, |
| 212 | }, |
| 213 | .probe = jz4740_pwm_probe, |
| 214 | .remove = __devexit_p(jz4740_pwm_remove), |
| 215 | }; |
| 216 | module_platform_driver(jz4740_pwm_driver); |
| 217 | |
| 218 | MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); |
| 219 | MODULE_DESCRIPTION("Ingenic JZ4740 PWM driver"); |
| 220 | MODULE_ALIAS("platform:jz4740-pwm"); |
| 221 | MODULE_LICENSE("GPL"); |
| 222 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
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jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
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jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9
