1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) 2008 Nokia Corporation 4 * 5 * Based on lirc_serial.c 6 */ 7 #include <linux/clk.h> 8 #include <linux/module.h> 9 #include <linux/platform_device.h> 10 #include <linux/wait.h> 11 #include <linux/pwm.h> 12 #include <linux/of.h> 13 #include <linux/hrtimer.h> 14 15 #include <media/rc-core.h> 16 17 #define WBUF_LEN 256 18 19 struct ir_rx51 { 20 struct rc_dev *rcdev; 21 struct pwm_device *pwm; 22 struct pwm_state state; 23 struct hrtimer timer; 24 struct device *dev; 25 wait_queue_head_t wqueue; 26 27 unsigned int freq; /* carrier frequency */ 28 unsigned int duty_cycle; /* carrier duty cycle */ 29 int wbuf[WBUF_LEN]; 30 int wbuf_index; 31 unsigned long device_is_open; 32 }; 33 34 static inline void ir_rx51_on(struct ir_rx51 *ir_rx51) 35 { 36 ir_rx51->state.enabled = true; 37 pwm_apply_state(ir_rx51->pwm, &ir_rx51->state); 38 } 39 40 static inline void ir_rx51_off(struct ir_rx51 *ir_rx51) 41 { 42 ir_rx51->state.enabled = false; 43 pwm_apply_state(ir_rx51->pwm, &ir_rx51->state); 44 } 45 46 static int init_timing_params(struct ir_rx51 *ir_rx51) 47 { 48 ir_rx51->state.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, ir_rx51->freq); 49 pwm_set_relative_duty_cycle(&ir_rx51->state, ir_rx51->duty_cycle, 100); 50 51 return 0; 52 } 53 54 static enum hrtimer_restart ir_rx51_timer_cb(struct hrtimer *timer) 55 { 56 struct ir_rx51 *ir_rx51 = container_of(timer, struct ir_rx51, timer); 57 ktime_t now; 58 59 if (ir_rx51->wbuf_index < 0) { 60 dev_err_ratelimited(ir_rx51->dev, 61 "BUG wbuf_index has value of %i\n", 62 ir_rx51->wbuf_index); 63 goto end; 64 } 65 66 /* 67 * If we happen to hit an odd latency spike, loop through the 68 * pulses until we catch up. 69 */ 70 do { 71 u64 ns; 72 73 if (ir_rx51->wbuf_index >= WBUF_LEN) 74 goto end; 75 if (ir_rx51->wbuf[ir_rx51->wbuf_index] == -1) 76 goto end; 77 78 if (ir_rx51->wbuf_index % 2) 79 ir_rx51_off(ir_rx51); 80 else 81 ir_rx51_on(ir_rx51); 82 83 ns = US_TO_NS(ir_rx51->wbuf[ir_rx51->wbuf_index]); 84 hrtimer_add_expires_ns(timer, ns); 85 86 ir_rx51->wbuf_index++; 87 88 now = timer->base->get_time(); 89 90 } while (hrtimer_get_expires_tv64(timer) < now); 91 92 return HRTIMER_RESTART; 93 end: 94 /* Stop TX here */ 95 ir_rx51_off(ir_rx51); 96 ir_rx51->wbuf_index = -1; 97 98 wake_up_interruptible(&ir_rx51->wqueue); 99 100 return HRTIMER_NORESTART; 101 } 102 103 static int ir_rx51_tx(struct rc_dev *dev, unsigned int *buffer, 104 unsigned int count) 105 { 106 struct ir_rx51 *ir_rx51 = dev->priv; 107 108 if (count > WBUF_LEN) 109 return -EINVAL; 110 111 memcpy(ir_rx51->wbuf, buffer, count * sizeof(unsigned int)); 112 113 /* Wait any pending transfers to finish */ 114 wait_event_interruptible(ir_rx51->wqueue, ir_rx51->wbuf_index < 0); 115 116 init_timing_params(ir_rx51); 117 if (count < WBUF_LEN) 118 ir_rx51->wbuf[count] = -1; /* Insert termination mark */ 119 120 /* 121 * REVISIT: Adjust latency requirements so the device doesn't go in too 122 * deep sleep states with pm_qos_add_request(). 123 */ 124 125 ir_rx51_on(ir_rx51); 126 ir_rx51->wbuf_index = 1; 127 hrtimer_start(&ir_rx51->timer, 128 ns_to_ktime(US_TO_NS(ir_rx51->wbuf[0])), 129 HRTIMER_MODE_REL); 130 /* 131 * Don't return back to the userspace until the transfer has 132 * finished 133 */ 134 wait_event_interruptible(ir_rx51->wqueue, ir_rx51->wbuf_index < 0); 135 136 /* REVISIT: Remove pm_qos constraint, we can sleep again */ 137 138 return count; 139 } 140 141 static int ir_rx51_open(struct rc_dev *dev) 142 { 143 struct ir_rx51 *ir_rx51 = dev->priv; 144 145 if (test_and_set_bit(1, &ir_rx51->device_is_open)) 146 return -EBUSY; 147 148 ir_rx51->pwm = pwm_get(ir_rx51->dev, NULL); 149 if (IS_ERR(ir_rx51->pwm)) { 150 int res = PTR_ERR(ir_rx51->pwm); 151 152 dev_err(ir_rx51->dev, "pwm_get failed: %d\n", res); 153 return res; 154 } 155 156 return 0; 157 } 158 159 static void ir_rx51_release(struct rc_dev *dev) 160 { 161 struct ir_rx51 *ir_rx51 = dev->priv; 162 163 hrtimer_cancel(&ir_rx51->timer); 164 ir_rx51_off(ir_rx51); 165 pwm_put(ir_rx51->pwm); 166 167 clear_bit(1, &ir_rx51->device_is_open); 168 } 169 170 static struct ir_rx51 ir_rx51 = { 171 .duty_cycle = 50, 172 .wbuf_index = -1, 173 }; 174 175 static int ir_rx51_set_duty_cycle(struct rc_dev *dev, u32 duty) 176 { 177 struct ir_rx51 *ir_rx51 = dev->priv; 178 179 ir_rx51->duty_cycle = duty; 180 181 return 0; 182 } 183 184 static int ir_rx51_set_tx_carrier(struct rc_dev *dev, u32 carrier) 185 { 186 struct ir_rx51 *ir_rx51 = dev->priv; 187 188 if (carrier > 500000 || carrier < 20000) 189 return -EINVAL; 190 191 ir_rx51->freq = carrier; 192 193 return 0; 194 } 195 196 #ifdef CONFIG_PM 197 198 static int ir_rx51_suspend(struct platform_device *dev, pm_message_t state) 199 { 200 /* 201 * In case the device is still open, do not suspend. Normally 202 * this should not be a problem as lircd only keeps the device 203 * open only for short periods of time. We also don't want to 204 * get involved with race conditions that might happen if we 205 * were in a middle of a transmit. Thus, we defer any suspend 206 * actions until transmit has completed. 207 */ 208 if (test_and_set_bit(1, &ir_rx51.device_is_open)) 209 return -EAGAIN; 210 211 clear_bit(1, &ir_rx51.device_is_open); 212 213 return 0; 214 } 215 216 static int ir_rx51_resume(struct platform_device *dev) 217 { 218 return 0; 219 } 220 221 #else 222 223 #define ir_rx51_suspend NULL 224 #define ir_rx51_resume NULL 225 226 #endif /* CONFIG_PM */ 227 228 static int ir_rx51_probe(struct platform_device *dev) 229 { 230 struct pwm_device *pwm; 231 struct rc_dev *rcdev; 232 233 pwm = pwm_get(&dev->dev, NULL); 234 if (IS_ERR(pwm)) 235 return dev_err_probe(&dev->dev, PTR_ERR(pwm), "pwm_get failed\n"); 236 237 /* Use default, in case userspace does not set the carrier */ 238 ir_rx51.freq = DIV_ROUND_CLOSEST_ULL(pwm_get_period(pwm), NSEC_PER_SEC); 239 pwm_init_state(pwm, &ir_rx51.state); 240 pwm_put(pwm); 241 242 hrtimer_init(&ir_rx51.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 243 ir_rx51.timer.function = ir_rx51_timer_cb; 244 245 ir_rx51.dev = &dev->dev; 246 247 rcdev = devm_rc_allocate_device(&dev->dev, RC_DRIVER_IR_RAW_TX); 248 if (!rcdev) 249 return -ENOMEM; 250 251 rcdev->priv = &ir_rx51; 252 rcdev->open = ir_rx51_open; 253 rcdev->close = ir_rx51_release; 254 rcdev->tx_ir = ir_rx51_tx; 255 rcdev->s_tx_duty_cycle = ir_rx51_set_duty_cycle; 256 rcdev->s_tx_carrier = ir_rx51_set_tx_carrier; 257 rcdev->driver_name = KBUILD_MODNAME; 258 259 ir_rx51.rcdev = rcdev; 260 261 return devm_rc_register_device(&dev->dev, ir_rx51.rcdev); 262 } 263 264 static const struct of_device_id ir_rx51_match[] = { 265 { 266 .compatible = "nokia,n900-ir", 267 }, 268 {}, 269 }; 270 MODULE_DEVICE_TABLE(of, ir_rx51_match); 271 272 static struct platform_driver ir_rx51_platform_driver = { 273 .probe = ir_rx51_probe, 274 .suspend = ir_rx51_suspend, 275 .resume = ir_rx51_resume, 276 .driver = { 277 .name = KBUILD_MODNAME, 278 .of_match_table = of_match_ptr(ir_rx51_match), 279 }, 280 }; 281 module_platform_driver(ir_rx51_platform_driver); 282 283 MODULE_DESCRIPTION("IR TX driver for Nokia RX51"); 284 MODULE_AUTHOR("Nokia Corporation"); 285 MODULE_LICENSE("GPL"); 286