1 /*
2  * STMicroelectronics hts221 sensor driver
3  *
4  * Copyright 2016 STMicroelectronics Inc.
5  *
6  * Lorenzo Bianconi <lorenzo.bianconi@st.com>
7  *
8  * Licensed under the GPL-2.
9  */
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/device.h>
13 #include <linux/interrupt.h>
14 #include <linux/irqreturn.h>
15 
16 #include <linux/iio/iio.h>
17 #include <linux/iio/trigger.h>
18 #include <linux/iio/events.h>
19 #include <linux/iio/trigger_consumer.h>
20 #include <linux/iio/triggered_buffer.h>
21 #include <linux/iio/buffer.h>
22 
23 #include "hts221.h"
24 
25 #define HTS221_REG_STATUS_ADDR		0x27
26 #define HTS221_RH_DRDY_MASK		BIT(1)
27 #define HTS221_TEMP_DRDY_MASK		BIT(0)
28 
29 static int hts221_trig_set_state(struct iio_trigger *trig, bool state)
30 {
31 	struct iio_dev *iio_dev = iio_trigger_get_drvdata(trig);
32 	struct hts221_hw *hw = iio_priv(iio_dev);
33 
34 	return hts221_config_drdy(hw, state);
35 }
36 
37 static const struct iio_trigger_ops hts221_trigger_ops = {
38 	.owner = THIS_MODULE,
39 	.set_trigger_state = hts221_trig_set_state,
40 };
41 
42 static irqreturn_t hts221_trigger_handler_thread(int irq, void *private)
43 {
44 	struct hts221_hw *hw = (struct hts221_hw *)private;
45 	u8 status;
46 	int err;
47 
48 	err = hw->tf->read(hw->dev, HTS221_REG_STATUS_ADDR, sizeof(status),
49 			   &status);
50 	if (err < 0)
51 		return IRQ_HANDLED;
52 
53 	/*
54 	 * H_DA bit (humidity data available) is routed to DRDY line.
55 	 * Humidity sample is computed after temperature one.
56 	 * Here we can assume data channels are both available if H_DA bit
57 	 * is set in status register
58 	 */
59 	if (!(status & HTS221_RH_DRDY_MASK))
60 		return IRQ_NONE;
61 
62 	iio_trigger_poll_chained(hw->trig);
63 
64 	return IRQ_HANDLED;
65 }
66 
67 int hts221_allocate_trigger(struct hts221_hw *hw)
68 {
69 	struct iio_dev *iio_dev = iio_priv_to_dev(hw);
70 	unsigned long irq_type;
71 	int err;
72 
73 	irq_type = irqd_get_trigger_type(irq_get_irq_data(hw->irq));
74 
75 	switch (irq_type) {
76 	case IRQF_TRIGGER_HIGH:
77 	case IRQF_TRIGGER_RISING:
78 		break;
79 	default:
80 		dev_info(hw->dev,
81 			 "mode %lx unsupported, using IRQF_TRIGGER_RISING\n",
82 			 irq_type);
83 		irq_type = IRQF_TRIGGER_RISING;
84 		break;
85 	}
86 
87 	err = devm_request_threaded_irq(hw->dev, hw->irq, NULL,
88 					hts221_trigger_handler_thread,
89 					irq_type | IRQF_ONESHOT,
90 					hw->name, hw);
91 	if (err) {
92 		dev_err(hw->dev, "failed to request trigger irq %d\n",
93 			hw->irq);
94 		return err;
95 	}
96 
97 	hw->trig = devm_iio_trigger_alloc(hw->dev, "%s-trigger",
98 					  iio_dev->name);
99 	if (!hw->trig)
100 		return -ENOMEM;
101 
102 	iio_trigger_set_drvdata(hw->trig, iio_dev);
103 	hw->trig->ops = &hts221_trigger_ops;
104 	hw->trig->dev.parent = hw->dev;
105 	iio_dev->trig = iio_trigger_get(hw->trig);
106 
107 	return devm_iio_trigger_register(hw->dev, hw->trig);
108 }
109 
110 static int hts221_buffer_preenable(struct iio_dev *iio_dev)
111 {
112 	return hts221_power_on(iio_priv(iio_dev));
113 }
114 
115 static int hts221_buffer_postdisable(struct iio_dev *iio_dev)
116 {
117 	return hts221_power_off(iio_priv(iio_dev));
118 }
119 
120 static const struct iio_buffer_setup_ops hts221_buffer_ops = {
121 	.preenable = hts221_buffer_preenable,
122 	.postenable = iio_triggered_buffer_postenable,
123 	.predisable = iio_triggered_buffer_predisable,
124 	.postdisable = hts221_buffer_postdisable,
125 };
126 
127 static irqreturn_t hts221_buffer_handler_thread(int irq, void *p)
128 {
129 	u8 buffer[ALIGN(2 * HTS221_DATA_SIZE, sizeof(s64)) + sizeof(s64)];
130 	struct iio_poll_func *pf = p;
131 	struct iio_dev *iio_dev = pf->indio_dev;
132 	struct hts221_hw *hw = iio_priv(iio_dev);
133 	struct iio_chan_spec const *ch;
134 	int err;
135 
136 	/* humidity data */
137 	ch = &iio_dev->channels[HTS221_SENSOR_H];
138 	err = hw->tf->read(hw->dev, ch->address, HTS221_DATA_SIZE,
139 			   buffer);
140 	if (err < 0)
141 		goto out;
142 
143 	/* temperature data */
144 	ch = &iio_dev->channels[HTS221_SENSOR_T];
145 	err = hw->tf->read(hw->dev, ch->address, HTS221_DATA_SIZE,
146 			   buffer + HTS221_DATA_SIZE);
147 	if (err < 0)
148 		goto out;
149 
150 	iio_push_to_buffers_with_timestamp(iio_dev, buffer,
151 					   iio_get_time_ns(iio_dev));
152 
153 out:
154 	iio_trigger_notify_done(hw->trig);
155 
156 	return IRQ_HANDLED;
157 }
158 
159 int hts221_allocate_buffers(struct hts221_hw *hw)
160 {
161 	return devm_iio_triggered_buffer_setup(hw->dev, iio_priv_to_dev(hw),
162 					NULL, hts221_buffer_handler_thread,
163 					&hts221_buffer_ops);
164 }
165 
166 MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@st.com>");
167 MODULE_DESCRIPTION("STMicroelectronics hts221 buffer driver");
168 MODULE_LICENSE("GPL v2");
169