Mike Frysinger | 006669e | 2011-06-15 16:55:39 -0400 | [diff] [blame] | 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/pwm.h> |
| 11 | #include <linux/slab.h> |
| 12 | |
| 13 | #include <asm/gptimers.h> |
| 14 | #include <asm/portmux.h> |
| 15 | |
| 16 | struct pwm_device { |
| 17 | unsigned id; |
| 18 | unsigned short pin; |
| 19 | }; |
| 20 | |
| 21 | static const unsigned short pwm_to_gptimer_per[] = { |
| 22 | P_TMR0, P_TMR1, P_TMR2, P_TMR3, P_TMR4, P_TMR5, |
| 23 | P_TMR6, P_TMR7, P_TMR8, P_TMR9, P_TMR10, P_TMR11, |
| 24 | }; |
| 25 | |
| 26 | struct pwm_device *pwm_request(int pwm_id, const char *label) |
| 27 | { |
| 28 | struct pwm_device *pwm; |
| 29 | int ret; |
| 30 | |
| 31 | /* XXX: pwm_id really should be unsigned */ |
| 32 | if (pwm_id < 0) |
| 33 | return NULL; |
| 34 | |
| 35 | pwm = kzalloc(sizeof(*pwm), GFP_KERNEL); |
| 36 | if (!pwm) |
| 37 | return pwm; |
| 38 | |
| 39 | pwm->id = pwm_id; |
| 40 | if (pwm->id >= ARRAY_SIZE(pwm_to_gptimer_per)) |
| 41 | goto err; |
| 42 | |
| 43 | pwm->pin = pwm_to_gptimer_per[pwm->id]; |
| 44 | ret = peripheral_request(pwm->pin, label); |
| 45 | if (ret) |
| 46 | goto err; |
| 47 | |
| 48 | return pwm; |
| 49 | err: |
| 50 | kfree(pwm); |
| 51 | return NULL; |
| 52 | } |
| 53 | EXPORT_SYMBOL(pwm_request); |
| 54 | |
| 55 | void pwm_free(struct pwm_device *pwm) |
| 56 | { |
| 57 | peripheral_free(pwm->pin); |
| 58 | kfree(pwm); |
| 59 | } |
| 60 | EXPORT_SYMBOL(pwm_free); |
| 61 | |
| 62 | int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) |
| 63 | { |
| 64 | unsigned long period, duty; |
| 65 | unsigned long long val; |
| 66 | |
| 67 | if (duty_ns < 0 || duty_ns > period_ns) |
| 68 | return -EINVAL; |
| 69 | |
| 70 | val = (unsigned long long)get_sclk() * period_ns; |
| 71 | do_div(val, NSEC_PER_SEC); |
| 72 | period = val; |
| 73 | |
| 74 | val = (unsigned long long)period * duty_ns; |
| 75 | do_div(val, period_ns); |
| 76 | duty = period - val; |
| 77 | |
| 78 | if (duty >= period) |
| 79 | duty = period - 1; |
| 80 | |
| 81 | set_gptimer_config(pwm->id, TIMER_MODE_PWM | TIMER_PERIOD_CNT); |
| 82 | set_gptimer_pwidth(pwm->id, duty); |
| 83 | set_gptimer_period(pwm->id, period); |
| 84 | |
| 85 | return 0; |
| 86 | } |
| 87 | EXPORT_SYMBOL(pwm_config); |
| 88 | |
| 89 | int pwm_enable(struct pwm_device *pwm) |
| 90 | { |
| 91 | enable_gptimer(pwm->id); |
| 92 | return 0; |
| 93 | } |
| 94 | EXPORT_SYMBOL(pwm_enable); |
| 95 | |
| 96 | void pwm_disable(struct pwm_device *pwm) |
| 97 | { |
| 98 | disable_gptimer(pwm->id); |
| 99 | } |
| 100 | EXPORT_SYMBOL(pwm_disable); |