1 // SPDX-License-Identifier: GPL-2.0+
3 * Driver for the RP1 ADC and temperature sensor
4 * Copyright (C) 2023 Raspberry Pi Ltd.
9 #include <linux/hwmon.h>
10 #include <linux/hwmon-sysfs.h>
12 #include <linux/module.h>
13 #include <linux/mod_devicetable.h>
14 #include <linux/platform_device.h>
15 #include <linux/regulator/consumer.h>
17 #define MODULE_NAME "rp1-adc"
19 #define RP1_ADC_CS 0x00
20 #define RP1_ADC_RESULT 0x04
21 #define RP1_ADC_FCS 0x08
22 #define RP1_ADC_FIFO 0x0c
23 #define RP1_ADC_DIV 0x10
25 #define RP1_ADC_INTR 0x14
26 #define RP1_ADC_INTE 0x18
27 #define RP1_ADC_INTF 0x1c
28 #define RP1_ADC_INTS 0x20
30 #define RP1_ADC_RWTYPE_SET 0x2000
31 #define RP1_ADC_RWTYPE_CLR 0x3000
33 #define RP1_ADC_CS_RROBIN_MASK 0x1f
34 #define RP1_ADC_CS_RROBIN_SHIFT 16
35 #define RP1_ADC_CS_AINSEL_MASK 0x7
36 #define RP1_ADC_CS_AINSEL_SHIFT 12
37 #define RP1_ADC_CS_ERR_STICKY 0x400
38 #define RP1_ADC_CS_ERR 0x200
39 #define RP1_ADC_CS_READY 0x100
40 #define RP1_ADC_CS_START_MANY 0x8
41 #define RP1_ADC_CS_START_ONCE 0x4
42 #define RP1_ADC_CS_TS_EN 0x2
43 #define RP1_ADC_CS_EN 0x1
45 #define RP1_ADC_FCS_THRESH_MASK 0xf
46 #define RP1_ADC_FCS_THRESH_SHIFT 24
47 #define RP1_ADC_FCS_LEVEL_MASK 0xf
48 #define RP1_ADC_FCS_LEVEL_SHIFT 16
49 #define RP1_ADC_FCS_OVER 0x800
50 #define RP1_ADC_FCS_UNDER 0x400
51 #define RP1_ADC_FCS_FULL 0x200
52 #define RP1_ADC_FCS_EMPTY 0x100
53 #define RP1_ADC_FCS_DREQ_EN 0x8
54 #define RP1_ADC_FCS_ERR 0x4
55 #define RP1_ADC_FCS_SHIFR 0x2
56 #define RP1_ADC_FCS_EN 0x1
58 #define RP1_ADC_FIFO_ERR 0x8000
59 #define RP1_ADC_FIFO_VAL_MASK 0xfff
61 #define RP1_ADC_DIV_INT_MASK 0xffff
62 #define RP1_ADC_DIV_INT_SHIFT 8
63 #define RP1_ADC_DIV_FRAC_MASK 0xff
64 #define RP1_ADC_DIV_FRAC_SHIFT 0
69 struct device *hwmon_dev;
73 static int rp1_adc_ready_wait(struct rp1_adc_data *data)
77 while (retries && !(readl(data->base + RP1_ADC_CS) & RP1_ADC_CS_READY))
80 return retries ? 0 : -EIO;
83 static int rp1_adc_read(struct rp1_adc_data *data,
84 struct device_attribute *devattr, unsigned int *val)
86 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
87 int channel = attr->index;
90 spin_lock(&data->lock);
92 writel(RP1_ADC_CS_AINSEL_MASK << RP1_ADC_CS_AINSEL_SHIFT,
93 data->base + RP1_ADC_RWTYPE_CLR + RP1_ADC_CS);
94 writel(channel << RP1_ADC_CS_AINSEL_SHIFT,
95 data->base + RP1_ADC_RWTYPE_SET + RP1_ADC_CS);
96 writel(RP1_ADC_CS_START_ONCE,
97 data->base + RP1_ADC_RWTYPE_SET + RP1_ADC_CS);
99 ret = rp1_adc_ready_wait(data);
101 *val = readl(data->base + RP1_ADC_RESULT);
103 spin_unlock(&data->lock);
108 static int rp1_adc_to_mv(struct rp1_adc_data *data, unsigned int val)
110 return ((u64)data->vref_mv * val) / 0xfff;
113 static ssize_t rp1_adc_show(struct device *dev,
114 struct device_attribute *devattr,
117 struct rp1_adc_data *data = dev_get_drvdata(dev);
121 ret = rp1_adc_read(data, devattr, &val);
125 return sprintf(buf, "%d\n", rp1_adc_to_mv(data, val));
128 static ssize_t rp1_adc_temp_show(struct device *dev,
129 struct device_attribute *devattr,
132 struct rp1_adc_data *data = dev_get_drvdata(dev);
136 writel(RP1_ADC_CS_TS_EN,
137 data->base + RP1_ADC_RWTYPE_SET + RP1_ADC_CS);
138 ret = rp1_adc_read(data, devattr, &val);
142 mv = rp1_adc_to_mv(data, val);
144 /* T = 27 - (ADC_voltage - 0.706)/0.001721 */
146 mc = 27000 - DIV_ROUND_CLOSEST((mv - 706) * (s64)1000000, 1721);
148 return sprintf(buf, "%d\n", mc);
151 static ssize_t rp1_adc_raw_show(struct device *dev,
152 struct device_attribute *devattr,
155 struct rp1_adc_data *data = dev_get_drvdata(dev);
157 int ret = rp1_adc_read(data, devattr, &val);
162 return sprintf(buf, "%u\n", val);
165 static ssize_t rp1_adc_temp_raw_show(struct device *dev,
166 struct device_attribute *devattr,
169 struct rp1_adc_data *data = dev_get_drvdata(dev);
171 int ret = rp1_adc_read(data, devattr, &val);
176 return sprintf(buf, "%u\n", val);
179 static SENSOR_DEVICE_ATTR_RO(in1_input, rp1_adc, 0);
180 static SENSOR_DEVICE_ATTR_RO(in2_input, rp1_adc, 1);
181 static SENSOR_DEVICE_ATTR_RO(in3_input, rp1_adc, 2);
182 static SENSOR_DEVICE_ATTR_RO(in4_input, rp1_adc, 3);
183 static SENSOR_DEVICE_ATTR_RO(temp1_input, rp1_adc_temp, 4);
184 static SENSOR_DEVICE_ATTR_RO(in1_raw, rp1_adc_raw, 0);
185 static SENSOR_DEVICE_ATTR_RO(in2_raw, rp1_adc_raw, 1);
186 static SENSOR_DEVICE_ATTR_RO(in3_raw, rp1_adc_raw, 2);
187 static SENSOR_DEVICE_ATTR_RO(in4_raw, rp1_adc_raw, 3);
188 static SENSOR_DEVICE_ATTR_RO(temp1_raw, rp1_adc_temp_raw, 4);
190 static struct attribute *rp1_adc_attrs[] = {
191 &sensor_dev_attr_in1_input.dev_attr.attr,
192 &sensor_dev_attr_in2_input.dev_attr.attr,
193 &sensor_dev_attr_in3_input.dev_attr.attr,
194 &sensor_dev_attr_in4_input.dev_attr.attr,
195 &sensor_dev_attr_temp1_input.dev_attr.attr,
196 &sensor_dev_attr_in1_raw.dev_attr.attr,
197 &sensor_dev_attr_in2_raw.dev_attr.attr,
198 &sensor_dev_attr_in3_raw.dev_attr.attr,
199 &sensor_dev_attr_in4_raw.dev_attr.attr,
200 &sensor_dev_attr_temp1_raw.dev_attr.attr,
204 static umode_t rp1_adc_is_visible(struct kobject *kobj,
205 struct attribute *attr, int index)
210 static const struct attribute_group rp1_adc_group = {
211 .attrs = rp1_adc_attrs,
212 .is_visible = rp1_adc_is_visible,
214 __ATTRIBUTE_GROUPS(rp1_adc);
216 static int __init rp1_adc_probe(struct platform_device *pdev)
218 struct rp1_adc_data *data;
219 struct regulator *reg;
223 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
227 spin_lock_init(&data->lock);
229 data->base = devm_platform_ioremap_resource(pdev, 0);
230 if (IS_ERR(data->base))
231 return PTR_ERR(data->base);
233 platform_set_drvdata(pdev, data);
235 clk = devm_clk_get(&pdev->dev, NULL);
239 clk_set_rate(clk, 50000000);
240 clk_prepare_enable(clk);
242 reg = devm_regulator_get(&pdev->dev, "vref");
246 vref_uv = regulator_get_voltage(reg);
247 data->vref_mv = DIV_ROUND_CLOSEST(vref_uv, 1000);
250 devm_hwmon_device_register_with_groups(&pdev->dev,
254 if (IS_ERR(data->hwmon_dev)) {
255 ret = PTR_ERR(data->hwmon_dev);
256 dev_err(&pdev->dev, "hwmon_device_register failed with %d.\n", ret);
260 /* Disable interrupts */
261 writel(0, data->base + RP1_ADC_INTE);
263 /* Enable the block, clearing any sticky error */
264 writel(RP1_ADC_CS_EN | RP1_ADC_CS_ERR_STICKY, data->base + RP1_ADC_CS);
269 sysfs_remove_group(&pdev->dev.kobj, &rp1_adc_group);
274 static int rp1_adc_remove(struct platform_device *pdev)
276 struct rp1_adc_data *data = platform_get_drvdata(pdev);
278 hwmon_device_unregister(data->hwmon_dev);
283 static const struct of_device_id rp1_adc_dt_ids[] = {
284 { .compatible = "raspberrypi,rp1-adc", },
287 MODULE_DEVICE_TABLE(of, rp1_adc_dt_ids);
289 static struct platform_driver rp1_adc_driver = {
290 .remove = rp1_adc_remove,
293 .of_match_table = rp1_adc_dt_ids,
297 module_platform_driver_probe(rp1_adc_driver, rp1_adc_probe);
299 MODULE_DESCRIPTION("RP1 ADC driver");
300 MODULE_AUTHOR("Phil Elwell <phil@raspberrypi.com>");
301 MODULE_LICENSE("GPL");