--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for the RP1 ADC and temperature sensor
+ * Copyright (C) 2023 Raspberry Pi Ltd.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#define MODULE_NAME "rp1-adc"
+
+#define RP1_ADC_CS 0x00
+#define RP1_ADC_RESULT 0x04
+#define RP1_ADC_FCS 0x08
+#define RP1_ADC_FIFO 0x0c
+#define RP1_ADC_DIV 0x10
+
+#define RP1_ADC_INTR 0x14
+#define RP1_ADC_INTE 0x18
+#define RP1_ADC_INTF 0x1c
+#define RP1_ADC_INTS 0x20
+
+#define RP1_ADC_RWTYPE_SET 0x2000
+#define RP1_ADC_RWTYPE_CLR 0x3000
+
+#define RP1_ADC_CS_RROBIN_MASK 0x1f
+#define RP1_ADC_CS_RROBIN_SHIFT 16
+#define RP1_ADC_CS_AINSEL_MASK 0x7
+#define RP1_ADC_CS_AINSEL_SHIFT 12
+#define RP1_ADC_CS_ERR_STICKY 0x400
+#define RP1_ADC_CS_ERR 0x200
+#define RP1_ADC_CS_READY 0x100
+#define RP1_ADC_CS_START_MANY 0x8
+#define RP1_ADC_CS_START_ONCE 0x4
+#define RP1_ADC_CS_TS_EN 0x2
+#define RP1_ADC_CS_EN 0x1
+
+#define RP1_ADC_FCS_THRESH_MASK 0xf
+#define RP1_ADC_FCS_THRESH_SHIFT 24
+#define RP1_ADC_FCS_LEVEL_MASK 0xf
+#define RP1_ADC_FCS_LEVEL_SHIFT 16
+#define RP1_ADC_FCS_OVER 0x800
+#define RP1_ADC_FCS_UNDER 0x400
+#define RP1_ADC_FCS_FULL 0x200
+#define RP1_ADC_FCS_EMPTY 0x100
+#define RP1_ADC_FCS_DREQ_EN 0x8
+#define RP1_ADC_FCS_ERR 0x4
+#define RP1_ADC_FCS_SHIFR 0x2
+#define RP1_ADC_FCS_EN 0x1
+
+#define RP1_ADC_FIFO_ERR 0x8000
+#define RP1_ADC_FIFO_VAL_MASK 0xfff
+
+#define RP1_ADC_DIV_INT_MASK 0xffff
+#define RP1_ADC_DIV_INT_SHIFT 8
+#define RP1_ADC_DIV_FRAC_MASK 0xff
+#define RP1_ADC_DIV_FRAC_SHIFT 0
+
+struct rp1_adc_data {
+ void __iomem *base;
+ spinlock_t lock;
+ struct device *hwmon_dev;
+ int vref_mv;
+};
+
+static int rp1_adc_ready_wait(struct rp1_adc_data *data)
+{
+ int retries = 10;
+
+ while (retries && !(readl(data->base + RP1_ADC_CS) & RP1_ADC_CS_READY))
+ retries--;
+
+ return retries ? 0 : -EIO;
+}
+
+static int rp1_adc_read(struct rp1_adc_data *data,
+ struct device_attribute *devattr, unsigned int *val)
+{
+ struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+ int channel = attr->index;
+ int ret;
+
+ spin_lock(&data->lock);
+
+ writel(RP1_ADC_CS_AINSEL_MASK << RP1_ADC_CS_AINSEL_SHIFT,
+ data->base + RP1_ADC_RWTYPE_CLR + RP1_ADC_CS);
+ writel(channel << RP1_ADC_CS_AINSEL_SHIFT,
+ data->base + RP1_ADC_RWTYPE_SET + RP1_ADC_CS);
+ writel(RP1_ADC_CS_START_ONCE,
+ data->base + RP1_ADC_RWTYPE_SET + RP1_ADC_CS);
+
+ ret = rp1_adc_ready_wait(data);
+ if (!ret)
+ *val = readl(data->base + RP1_ADC_RESULT);
+
+ spin_unlock(&data->lock);
+
+ return ret;
+}
+
+static int rp1_adc_to_mv(struct rp1_adc_data *data, unsigned int val)
+{
+ return ((u64)data->vref_mv * val) / 0xfff;
+}
+
+static ssize_t rp1_adc_show(struct device *dev,
+ struct device_attribute *devattr,
+ char *buf)
+{
+ struct rp1_adc_data *data = dev_get_drvdata(dev);
+ unsigned int val;
+ int ret;
+
+ ret = rp1_adc_read(data, devattr, &val);
+ if (ret)
+ return ret;
+
+ return sprintf(buf, "%d\n", rp1_adc_to_mv(data, val));
+}
+
+static ssize_t rp1_adc_temp_show(struct device *dev,
+ struct device_attribute *devattr,
+ char *buf)
+{
+ struct rp1_adc_data *data = dev_get_drvdata(dev);
+ unsigned int val;
+ int ret, mv, mc;
+
+ writel(RP1_ADC_CS_TS_EN,
+ data->base + RP1_ADC_RWTYPE_SET + RP1_ADC_CS);
+ ret = rp1_adc_read(data, devattr, &val);
+ if (ret)
+ return ret;
+
+ mv = rp1_adc_to_mv(data, val);
+
+ /* T = 27 - (ADC_voltage - 0.706)/0.001721 */
+
+ mc = 27000 - DIV_ROUND_CLOSEST((mv - 706) * (s64)1000000, 1721);
+
+ return sprintf(buf, "%d\n", mc);
+}
+
+static ssize_t rp1_adc_raw_show(struct device *dev,
+ struct device_attribute *devattr,
+ char *buf)
+{
+ struct rp1_adc_data *data = dev_get_drvdata(dev);
+ unsigned int val;
+ int ret = rp1_adc_read(data, devattr, &val);
+
+ if (ret)
+ return ret;
+
+ return sprintf(buf, "%u\n", val);
+}
+
+static ssize_t rp1_adc_temp_raw_show(struct device *dev,
+ struct device_attribute *devattr,
+ char *buf)
+{
+ struct rp1_adc_data *data = dev_get_drvdata(dev);
+ unsigned int val;
+ int ret = rp1_adc_read(data, devattr, &val);
+
+ if (ret)
+ return ret;
+
+ return sprintf(buf, "%u\n", val);
+}
+
+static SENSOR_DEVICE_ATTR_RO(in1_input, rp1_adc, 0);
+static SENSOR_DEVICE_ATTR_RO(in2_input, rp1_adc, 1);
+static SENSOR_DEVICE_ATTR_RO(in3_input, rp1_adc, 2);
+static SENSOR_DEVICE_ATTR_RO(in4_input, rp1_adc, 3);
+static SENSOR_DEVICE_ATTR_RO(temp1_input, rp1_adc_temp, 4);
+static SENSOR_DEVICE_ATTR_RO(in1_raw, rp1_adc_raw, 0);
+static SENSOR_DEVICE_ATTR_RO(in2_raw, rp1_adc_raw, 1);
+static SENSOR_DEVICE_ATTR_RO(in3_raw, rp1_adc_raw, 2);
+static SENSOR_DEVICE_ATTR_RO(in4_raw, rp1_adc_raw, 3);
+static SENSOR_DEVICE_ATTR_RO(temp1_raw, rp1_adc_temp_raw, 4);
+
+static struct attribute *rp1_adc_attrs[] = {
+ &sensor_dev_attr_in1_input.dev_attr.attr,
+ &sensor_dev_attr_in2_input.dev_attr.attr,
+ &sensor_dev_attr_in3_input.dev_attr.attr,
+ &sensor_dev_attr_in4_input.dev_attr.attr,
+ &sensor_dev_attr_temp1_input.dev_attr.attr,
+ &sensor_dev_attr_in1_raw.dev_attr.attr,
+ &sensor_dev_attr_in2_raw.dev_attr.attr,
+ &sensor_dev_attr_in3_raw.dev_attr.attr,
+ &sensor_dev_attr_in4_raw.dev_attr.attr,
+ &sensor_dev_attr_temp1_raw.dev_attr.attr,
+ NULL
+};
+
+static umode_t rp1_adc_is_visible(struct kobject *kobj,
+ struct attribute *attr, int index)
+{
+ return 0444;
+}
+
+static const struct attribute_group rp1_adc_group = {
+ .attrs = rp1_adc_attrs,
+ .is_visible = rp1_adc_is_visible,
+};
+__ATTRIBUTE_GROUPS(rp1_adc);
+
+static int __init rp1_adc_probe(struct platform_device *pdev)
+{
+ struct rp1_adc_data *data;
+ struct regulator *reg;
+ struct clk *clk;
+ int vref_uv, ret;
+
+ data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ spin_lock_init(&data->lock);
+
+ data->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(data->base))
+ return PTR_ERR(data->base);
+
+ platform_set_drvdata(pdev, data);
+
+ clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(clk))
+ return -ENODEV;
+
+ clk_set_rate(clk, 50000000);
+ clk_prepare_enable(clk);
+
+ reg = devm_regulator_get(&pdev->dev, "vref");
+ if (IS_ERR(reg))
+ return PTR_ERR(reg);
+
+ vref_uv = regulator_get_voltage(reg);
+ data->vref_mv = DIV_ROUND_CLOSEST(vref_uv, 1000);
+
+ data->hwmon_dev =
+ devm_hwmon_device_register_with_groups(&pdev->dev,
+ "rp1_adc",
+ data,
+ rp1_adc_groups);
+ if (IS_ERR(data->hwmon_dev)) {
+ ret = PTR_ERR(data->hwmon_dev);
+ dev_err(&pdev->dev, "hwmon_device_register failed with %d.\n", ret);
+ goto err_register;
+ }
+
+ /* Disable interrupts */
+ writel(0, data->base + RP1_ADC_INTE);
+
+ /* Enable the block, clearing any sticky error */
+ writel(RP1_ADC_CS_EN | RP1_ADC_CS_ERR_STICKY, data->base + RP1_ADC_CS);
+
+ return 0;
+
+err_register:
+ sysfs_remove_group(&pdev->dev.kobj, &rp1_adc_group);
+
+ return ret;
+}
+
+static int rp1_adc_remove(struct platform_device *pdev)
+{
+ struct rp1_adc_data *data = platform_get_drvdata(pdev);
+
+ hwmon_device_unregister(data->hwmon_dev);
+
+ return 0;
+}
+
+static const struct of_device_id rp1_adc_dt_ids[] = {
+ { .compatible = "raspberrypi,rp1-adc", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, rp1_adc_dt_ids);
+
+static struct platform_driver rp1_adc_driver = {
+ .remove = rp1_adc_remove,
+ .driver = {
+ .name = MODULE_NAME,
+ .of_match_table = rp1_adc_dt_ids,
+ },
+};
+
+module_platform_driver_probe(rp1_adc_driver, rp1_adc_probe);
+
+MODULE_DESCRIPTION("RP1 ADC driver");
+MODULE_AUTHOR("Phil Elwell <phil@raspberrypi.com>");
+MODULE_LICENSE("GPL");
projects / platform / kernel / linux-rpi.git / commitdiff