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| 1 | /* |
| 2 | * Blackfin Pulse Width Modulation (PWM) core |
| 3 | * |
| 4 | * Copyright (c) 2011 Analog Devices Inc. |
| 5 | * |
| 6 | * Licensed under the GPL-2 or later. |
| 7 | */ |
| 8 | |
| 9 | #include <linux/module.h> |
| 10 | #include <linux/platform_device.h> |
| 11 | #include <linux/pwm.h> |
| 12 | #include <linux/slab.h> |
| 13 | |
| 14 | #include <asm/gptimers.h> |
| 15 | #include <asm/portmux.h> |
| 16 | |
| 17 | struct bfin_pwm_chip { |
| 18 | struct pwm_chip chip; |
| 19 | }; |
| 20 | |
| 21 | struct bfin_pwm { |
| 22 | unsigned short pin; |
| 23 | }; |
| 24 | |
| 25 | static const unsigned short pwm_to_gptimer_per[] = { |
| 26 | P_TMR0, P_TMR1, P_TMR2, P_TMR3, P_TMR4, P_TMR5, |
| 27 | P_TMR6, P_TMR7, P_TMR8, P_TMR9, P_TMR10, P_TMR11, |
| 28 | }; |
| 29 | |
| 30 | static int bfin_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) |
| 31 | { |
| 32 | struct bfin_pwm *priv; |
| 33 | int ret; |
| 34 | |
| 35 | if (pwm->hwpwm >= ARRAY_SIZE(pwm_to_gptimer_per)) |
| 36 | return -EINVAL; |
| 37 | |
| 38 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); |
| 39 | if (!priv) |
| 40 | return -ENOMEM; |
| 41 | |
| 42 | priv->pin = pwm_to_gptimer_per[pwm->hwpwm]; |
| 43 | |
| 44 | ret = peripheral_request(priv->pin, NULL); |
| 45 | if (ret) { |
| 46 | kfree(priv); |
| 47 | return ret; |
| 48 | } |
| 49 | |
| 50 | pwm_set_chip_data(pwm, priv); |
| 51 | |
| 52 | return 0; |
| 53 | } |
| 54 | |
| 55 | static void bfin_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) |
| 56 | { |
| 57 | struct bfin_pwm *priv = pwm_get_chip_data(pwm); |
| 58 | |
| 59 | if (priv) { |
| 60 | peripheral_free(priv->pin); |
| 61 | kfree(priv); |
| 62 | } |
| 63 | } |
| 64 | |
| 65 | static int bfin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, |
| 66 | int duty_ns, int period_ns) |
| 67 | { |
| 68 | struct bfin_pwm *priv = pwm_get_chip_data(pwm); |
| 69 | unsigned long period, duty; |
| 70 | unsigned long long val; |
| 71 | |
| 72 | if (duty_ns < 0 || duty_ns > period_ns) |
| 73 | return -EINVAL; |
| 74 | |
| 75 | val = (unsigned long long)get_sclk() * period_ns; |
| 76 | do_div(val, NSEC_PER_SEC); |
| 77 | period = val; |
| 78 | |
| 79 | val = (unsigned long long)period * duty_ns; |
| 80 | do_div(val, period_ns); |
| 81 | duty = period - val; |
| 82 | |
| 83 | if (duty >= period) |
| 84 | duty = period - 1; |
| 85 | |
| 86 | set_gptimer_config(priv->pin, TIMER_MODE_PWM | TIMER_PERIOD_CNT); |
| 87 | set_gptimer_pwidth(priv->pin, duty); |
| 88 | set_gptimer_period(priv->pin, period); |
| 89 | |
| 90 | return 0; |
| 91 | } |
| 92 | |
| 93 | static int bfin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) |
| 94 | { |
| 95 | struct bfin_pwm *priv = pwm_get_chip_data(pwm); |
| 96 | |
| 97 | enable_gptimer(priv->pin); |
| 98 | |
| 99 | return 0; |
| 100 | } |
| 101 | |
| 102 | static void bfin_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) |
| 103 | { |
| 104 | struct bfin_pwm *priv = pwm_get_chip_data(pwm); |
| 105 | |
| 106 | disable_gptimer(priv->pin); |
| 107 | } |
| 108 | |
| 109 | static struct pwm_ops bfin_pwm_ops = { |
| 110 | .request = bfin_pwm_request, |
| 111 | .free = bfin_pwm_free, |
| 112 | .config = bfin_pwm_config, |
| 113 | .enable = bfin_pwm_enable, |
| 114 | .disable = bfin_pwm_disable, |
| 115 | .owner = THIS_MODULE, |
| 116 | }; |
| 117 | |
| 118 | static int bfin_pwm_probe(struct platform_device *pdev) |
| 119 | { |
| 120 | struct bfin_pwm_chip *pwm; |
| 121 | int ret; |
| 122 | |
| 123 | pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); |
| 124 | if (!pwm) { |
| 125 | dev_err(&pdev->dev, "failed to allocate memory\n"); |
| 126 | return -ENOMEM; |
| 127 | } |
| 128 | |
| 129 | platform_set_drvdata(pdev, pwm); |
| 130 | |
| 131 | pwm->chip.dev = &pdev->dev; |
| 132 | pwm->chip.ops = &bfin_pwm_ops; |
| 133 | pwm->chip.base = -1; |
| 134 | pwm->chip.npwm = 12; |
| 135 | |
| 136 | ret = pwmchip_add(&pwm->chip); |
| 137 | if (ret < 0) { |
| 138 | dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); |
| 139 | return ret; |
| 140 | } |
| 141 | |
| 142 | return 0; |
| 143 | } |
| 144 | |
| 145 | static int __devexit bfin_pwm_remove(struct platform_device *pdev) |
| 146 | { |
| 147 | struct bfin_pwm_chip *pwm = platform_get_drvdata(pdev); |
| 148 | |
| 149 | return pwmchip_remove(&pwm->chip); |
| 150 | } |
| 151 | |
| 152 | static struct platform_driver bfin_pwm_driver = { |
| 153 | .driver = { |
| 154 | .name = "bfin-pwm", |
| 155 | }, |
| 156 | .probe = bfin_pwm_probe, |
| 157 | .remove = __devexit_p(bfin_pwm_remove), |
| 158 | }; |
| 159 | |
| 160 | module_platform_driver(bfin_pwm_driver); |
| 161 | |
| 162 | MODULE_LICENSE("GPL"); |
| 163 |
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Tags:
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