1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * STMicroelectronics hts221 sensor driver
4  *
5  * Copyright 2016 STMicroelectronics Inc.
6  *
7  * Lorenzo Bianconi <lorenzo.bianconi@st.com>
8  */
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/device.h>
12 #include <linux/interrupt.h>
13 #include <linux/irqreturn.h>
14 #include <linux/regmap.h>
15 #include <linux/bitfield.h>
16 
17 #include <linux/iio/iio.h>
18 #include <linux/iio/trigger.h>
19 #include <linux/iio/events.h>
20 #include <linux/iio/trigger_consumer.h>
21 #include <linux/iio/triggered_buffer.h>
22 #include <linux/iio/buffer.h>
23 
24 #include <linux/platform_data/st_sensors_pdata.h>
25 
26 #include "hts221.h"
27 
28 #define HTS221_REG_DRDY_HL_ADDR		0x22
29 #define HTS221_REG_DRDY_HL_MASK		BIT(7)
30 #define HTS221_REG_DRDY_PP_OD_ADDR	0x22
31 #define HTS221_REG_DRDY_PP_OD_MASK	BIT(6)
32 #define HTS221_REG_DRDY_EN_ADDR		0x22
33 #define HTS221_REG_DRDY_EN_MASK		BIT(2)
34 #define HTS221_REG_STATUS_ADDR		0x27
35 #define HTS221_RH_DRDY_MASK		BIT(1)
36 #define HTS221_TEMP_DRDY_MASK		BIT(0)
37 
38 static int hts221_trig_set_state(struct iio_trigger *trig, bool state)
39 {
40 	struct iio_dev *iio_dev = iio_trigger_get_drvdata(trig);
41 	struct hts221_hw *hw = iio_priv(iio_dev);
42 
43 	return regmap_update_bits(hw->regmap, HTS221_REG_DRDY_EN_ADDR,
44 				  HTS221_REG_DRDY_EN_MASK,
45 				  FIELD_PREP(HTS221_REG_DRDY_EN_MASK, state));
46 }
47 
48 static const struct iio_trigger_ops hts221_trigger_ops = {
49 	.set_trigger_state = hts221_trig_set_state,
50 };
51 
52 static irqreturn_t hts221_trigger_handler_thread(int irq, void *private)
53 {
54 	struct hts221_hw *hw = private;
55 	int err, status;
56 
57 	err = regmap_read(hw->regmap, HTS221_REG_STATUS_ADDR, &status);
58 	if (err < 0)
59 		return IRQ_HANDLED;
60 
61 	/*
62 	 * H_DA bit (humidity data available) is routed to DRDY line.
63 	 * Humidity sample is computed after temperature one.
64 	 * Here we can assume data channels are both available if H_DA bit
65 	 * is set in status register
66 	 */
67 	if (!(status & HTS221_RH_DRDY_MASK))
68 		return IRQ_NONE;
69 
70 	iio_trigger_poll_chained(hw->trig);
71 
72 	return IRQ_HANDLED;
73 }
74 
75 int hts221_allocate_trigger(struct iio_dev *iio_dev)
76 {
77 	struct hts221_hw *hw = iio_priv(iio_dev);
78 	struct st_sensors_platform_data *pdata = dev_get_platdata(hw->dev);
79 	bool irq_active_low = false, open_drain = false;
80 	unsigned long irq_type;
81 	int err;
82 
83 	irq_type = irqd_get_trigger_type(irq_get_irq_data(hw->irq));
84 
85 	switch (irq_type) {
86 	case IRQF_TRIGGER_HIGH:
87 	case IRQF_TRIGGER_RISING:
88 		break;
89 	case IRQF_TRIGGER_LOW:
90 	case IRQF_TRIGGER_FALLING:
91 		irq_active_low = true;
92 		break;
93 	default:
94 		dev_info(hw->dev,
95 			 "mode %lx unsupported, using IRQF_TRIGGER_RISING\n",
96 			 irq_type);
97 		irq_type = IRQF_TRIGGER_RISING;
98 		break;
99 	}
100 
101 	err = regmap_update_bits(hw->regmap, HTS221_REG_DRDY_HL_ADDR,
102 				 HTS221_REG_DRDY_HL_MASK,
103 				 FIELD_PREP(HTS221_REG_DRDY_HL_MASK,
104 					    irq_active_low));
105 	if (err < 0)
106 		return err;
107 
108 	if (device_property_read_bool(hw->dev, "drive-open-drain") ||
109 	    (pdata && pdata->open_drain)) {
110 		irq_type |= IRQF_SHARED;
111 		open_drain = true;
112 	}
113 
114 	err = regmap_update_bits(hw->regmap, HTS221_REG_DRDY_PP_OD_ADDR,
115 				 HTS221_REG_DRDY_PP_OD_MASK,
116 				 FIELD_PREP(HTS221_REG_DRDY_PP_OD_MASK,
117 					    open_drain));
118 	if (err < 0)
119 		return err;
120 
121 	err = devm_request_threaded_irq(hw->dev, hw->irq, NULL,
122 					hts221_trigger_handler_thread,
123 					irq_type | IRQF_ONESHOT,
124 					hw->name, hw);
125 	if (err) {
126 		dev_err(hw->dev, "failed to request trigger irq %d\n",
127 			hw->irq);
128 		return err;
129 	}
130 
131 	hw->trig = devm_iio_trigger_alloc(hw->dev, "%s-trigger",
132 					  iio_dev->name);
133 	if (!hw->trig)
134 		return -ENOMEM;
135 
136 	iio_trigger_set_drvdata(hw->trig, iio_dev);
137 	hw->trig->ops = &hts221_trigger_ops;
138 	hw->trig->dev.parent = hw->dev;
139 	iio_dev->trig = iio_trigger_get(hw->trig);
140 
141 	return devm_iio_trigger_register(hw->dev, hw->trig);
142 }
143 
144 static int hts221_buffer_preenable(struct iio_dev *iio_dev)
145 {
146 	return hts221_set_enable(iio_priv(iio_dev), true);
147 }
148 
149 static int hts221_buffer_postdisable(struct iio_dev *iio_dev)
150 {
151 	return hts221_set_enable(iio_priv(iio_dev), false);
152 }
153 
154 static const struct iio_buffer_setup_ops hts221_buffer_ops = {
155 	.preenable = hts221_buffer_preenable,
156 	.postdisable = hts221_buffer_postdisable,
157 };
158 
159 static irqreturn_t hts221_buffer_handler_thread(int irq, void *p)
160 {
161 	struct iio_poll_func *pf = p;
162 	struct iio_dev *iio_dev = pf->indio_dev;
163 	struct hts221_hw *hw = iio_priv(iio_dev);
164 	struct iio_chan_spec const *ch;
165 	int err;
166 
167 	/* humidity data */
168 	ch = &iio_dev->channels[HTS221_SENSOR_H];
169 	err = regmap_bulk_read(hw->regmap, ch->address,
170 			       &hw->scan.channels[0],
171 			       sizeof(hw->scan.channels[0]));
172 	if (err < 0)
173 		goto out;
174 
175 	/* temperature data */
176 	ch = &iio_dev->channels[HTS221_SENSOR_T];
177 	err = regmap_bulk_read(hw->regmap, ch->address,
178 			       &hw->scan.channels[1],
179 			       sizeof(hw->scan.channels[1]));
180 	if (err < 0)
181 		goto out;
182 
183 	iio_push_to_buffers_with_timestamp(iio_dev, &hw->scan,
184 					   iio_get_time_ns(iio_dev));
185 
186 out:
187 	iio_trigger_notify_done(hw->trig);
188 
189 	return IRQ_HANDLED;
190 }
191 
192 int hts221_allocate_buffers(struct iio_dev *iio_dev)
193 {
194 	struct hts221_hw *hw = iio_priv(iio_dev);
195 	return devm_iio_triggered_buffer_setup(hw->dev, iio_dev,
196 					NULL, hts221_buffer_handler_thread,
197 					&hts221_buffer_ops);
198 }
199 
200 MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi@st.com>");
201 MODULE_DESCRIPTION("STMicroelectronics hts221 buffer driver");
202 MODULE_LICENSE("GPL v2");
203