| Thomas Gleixner | 236b83a | 2019-05-23 11:14:59 +0200 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
| Sean Young | db3df87 | 2017-07-07 05:52:02 -0400 | [diff] [blame] | 2 | /* |
| 3 | * Copyright (C) 2017 Sean Young <sean@mess.org> |
| Sean Young | db3df87 | 2017-07-07 05:52:02 -0400 | [diff] [blame] | 4 | */ |
| 5 | |
| 6 | #include <linux/kernel.h> |
| 7 | #include <linux/module.h> |
| 8 | #include <linux/pwm.h> |
| 9 | #include <linux/delay.h> |
| 10 | #include <linux/slab.h> |
| 11 | #include <linux/of.h> |
| 12 | #include <linux/platform_device.h> |
| 13 | #include <media/rc-core.h> |
| 14 | |
| 15 | #define DRIVER_NAME "pwm-ir-tx" |
| 16 | #define DEVICE_NAME "PWM IR Transmitter" |
| 17 | |
| 18 | struct pwm_ir { |
| 19 | struct pwm_device *pwm; |
| 20 | unsigned int carrier; |
| 21 | unsigned int duty_cycle; |
| 22 | }; |
| 23 | |
| 24 | static const struct of_device_id pwm_ir_of_match[] = { |
| 25 | { .compatible = "pwm-ir-tx", }, |
| 26 | { }, |
| 27 | }; |
| 28 | MODULE_DEVICE_TABLE(of, pwm_ir_of_match); |
| 29 | |
| 30 | static int pwm_ir_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle) |
| 31 | { |
| 32 | struct pwm_ir *pwm_ir = dev->priv; |
| 33 | |
| 34 | pwm_ir->duty_cycle = duty_cycle; |
| 35 | |
| 36 | return 0; |
| 37 | } |
| 38 | |
| 39 | static int pwm_ir_set_carrier(struct rc_dev *dev, u32 carrier) |
| 40 | { |
| 41 | struct pwm_ir *pwm_ir = dev->priv; |
| 42 | |
| 43 | if (!carrier) |
| 44 | return -EINVAL; |
| 45 | |
| 46 | pwm_ir->carrier = carrier; |
| 47 | |
| 48 | return 0; |
| 49 | } |
| 50 | |
| 51 | static int pwm_ir_tx(struct rc_dev *dev, unsigned int *txbuf, |
| 52 | unsigned int count) |
| 53 | { |
| 54 | struct pwm_ir *pwm_ir = dev->priv; |
| 55 | struct pwm_device *pwm = pwm_ir->pwm; |
| 56 | int i, duty, period; |
| 57 | ktime_t edge; |
| 58 | long delta; |
| 59 | |
| 60 | period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, pwm_ir->carrier); |
| 61 | duty = DIV_ROUND_CLOSEST(pwm_ir->duty_cycle * period, 100); |
| 62 | |
| 63 | pwm_config(pwm, duty, period); |
| 64 | |
| 65 | edge = ktime_get(); |
| 66 | |
| 67 | for (i = 0; i < count; i++) { |
| 68 | if (i % 2) // space |
| 69 | pwm_disable(pwm); |
| 70 | else |
| 71 | pwm_enable(pwm); |
| 72 | |
| 73 | edge = ktime_add_us(edge, txbuf[i]); |
| 74 | delta = ktime_us_delta(edge, ktime_get()); |
| 75 | if (delta > 0) |
| 76 | usleep_range(delta, delta + 10); |
| 77 | } |
| 78 | |
| 79 | pwm_disable(pwm); |
| 80 | |
| 81 | return count; |
| 82 | } |
| 83 | |
| 84 | static int pwm_ir_probe(struct platform_device *pdev) |
| 85 | { |
| 86 | struct pwm_ir *pwm_ir; |
| 87 | struct rc_dev *rcdev; |
| 88 | int rc; |
| 89 | |
| 90 | pwm_ir = devm_kmalloc(&pdev->dev, sizeof(*pwm_ir), GFP_KERNEL); |
| 91 | if (!pwm_ir) |
| 92 | return -ENOMEM; |
| 93 | |
| 94 | pwm_ir->pwm = devm_pwm_get(&pdev->dev, NULL); |
| 95 | if (IS_ERR(pwm_ir->pwm)) |
| 96 | return PTR_ERR(pwm_ir->pwm); |
| 97 | |
| 98 | pwm_ir->carrier = 38000; |
| 99 | pwm_ir->duty_cycle = 50; |
| 100 | |
| 101 | rcdev = devm_rc_allocate_device(&pdev->dev, RC_DRIVER_IR_RAW_TX); |
| 102 | if (!rcdev) |
| 103 | return -ENOMEM; |
| 104 | |
| 105 | rcdev->priv = pwm_ir; |
| 106 | rcdev->driver_name = DRIVER_NAME; |
| 107 | rcdev->device_name = DEVICE_NAME; |
| 108 | rcdev->tx_ir = pwm_ir_tx; |
| 109 | rcdev->s_tx_duty_cycle = pwm_ir_set_duty_cycle; |
| 110 | rcdev->s_tx_carrier = pwm_ir_set_carrier; |
| 111 | |
| 112 | rc = devm_rc_register_device(&pdev->dev, rcdev); |
| 113 | if (rc < 0) |
| 114 | dev_err(&pdev->dev, "failed to register rc device\n"); |
| 115 | |
| 116 | return rc; |
| 117 | } |
| 118 | |
| 119 | static struct platform_driver pwm_ir_driver = { |
| 120 | .probe = pwm_ir_probe, |
| 121 | .driver = { |
| 122 | .name = DRIVER_NAME, |
| 123 | .of_match_table = of_match_ptr(pwm_ir_of_match), |
| 124 | }, |
| 125 | }; |
| 126 | module_platform_driver(pwm_ir_driver); |
| 127 | |
| 128 | MODULE_DESCRIPTION("PWM IR Transmitter"); |
| 129 | MODULE_AUTHOR("Sean Young <sean@mess.org>"); |
| 130 | MODULE_LICENSE("GPL"); |