--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * MPRLS0025PA - Honeywell MicroPressure pressure sensor series driver
+ *
+ * Copyright (c) Andreas Klinger <ak@it-klinger.de>
+ *
+ * Data sheet:
+ * https://prod-edam.honeywell.com/content/dam/honeywell-edam/sps/siot/en-us/
+ * products/sensors/pressure-sensors/board-mount-pressure-sensors/
+ * micropressure-mpr-series/documents/
+ * sps-siot-mpr-series-datasheet-32332628-ciid-172626.pdf
+ *
+ * 7-bit I2C default slave address: 0x18
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/math64.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/units.h>
+
+#include <linux/gpio/consumer.h>
+
+#include <linux/iio/buffer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#include <linux/regulator/consumer.h>
+
+#include <asm/unaligned.h>
+
+/* bits in i2c status byte */
+#define MPR_I2C_POWER BIT(6) /* device is powered */
+#define MPR_I2C_BUSY BIT(5) /* device is busy */
+#define MPR_I2C_MEMORY BIT(2) /* integrity test passed */
+#define MPR_I2C_MATH BIT(0) /* internal math saturation */
+
+/*
+ * support _RAW sysfs interface:
+ *
+ * Calculation formula from the datasheet:
+ * pressure = (press_cnt - outputmin) * scale + pmin
+ * with:
+ * * pressure - measured pressure in Pascal
+ * * press_cnt - raw value read from sensor
+ * * pmin - minimum pressure range value of sensor (data->pmin)
+ * * pmax - maximum pressure range value of sensor (data->pmax)
+ * * outputmin - minimum numerical range raw value delivered by sensor
+ * (mpr_func_spec.output_min)
+ * * outputmax - maximum numerical range raw value delivered by sensor
+ * (mpr_func_spec.output_max)
+ * * scale - (pmax - pmin) / (outputmax - outputmin)
+ *
+ * formula of the userspace:
+ * pressure = (raw + offset) * scale
+ *
+ * Values given to the userspace in sysfs interface:
+ * * raw - press_cnt
+ * * offset - (-1 * outputmin) - pmin / scale
+ * note: With all sensors from the datasheet pmin = 0
+ * which reduces the offset to (-1 * outputmin)
+ */
+
+/*
+ * transfer function A: 10% to 90% of 2^24
+ * transfer function B: 2.5% to 22.5% of 2^24
+ * transfer function C: 20% to 80% of 2^24
+ */
+enum mpr_func_id {
+ MPR_FUNCTION_A,
+ MPR_FUNCTION_B,
+ MPR_FUNCTION_C,
+};
+
+struct mpr_func_spec {
+ u32 output_min;
+ u32 output_max;
+};
+
+static const struct mpr_func_spec mpr_func_spec[] = {
+ [MPR_FUNCTION_A] = {.output_min = 1677722, .output_max = 15099494},
+ [MPR_FUNCTION_B] = {.output_min = 419430, .output_max = 3774874},
+ [MPR_FUNCTION_C] = {.output_min = 3355443, .output_max = 13421773},
+};
+
+struct mpr_chan {
+ s32 pres; /* pressure value */
+ s64 ts; /* timestamp */
+};
+
+struct mpr_data {
+ struct i2c_client *client;
+ struct mutex lock; /*
+ * access to device during read
+ */
+ u32 pmin; /* minimal pressure in pascal */
+ u32 pmax; /* maximal pressure in pascal */
+ enum mpr_func_id function; /* transfer function */
+ u32 outmin; /*
+ * minimal numerical range raw
+ * value from sensor
+ */
+ u32 outmax; /*
+ * maximal numerical range raw
+ * value from sensor
+ */
+ int scale; /* int part of scale */
+ int scale2; /* nano part of scale */
+ int offset; /* int part of offset */
+ int offset2; /* nano part of offset */
+ struct gpio_desc *gpiod_reset; /* reset */
+ int irq; /*
+ * end of conversion irq;
+ * used to distinguish between
+ * irq mode and reading in a
+ * loop until data is ready
+ */
+ struct completion completion; /* handshake from irq to read */
+ struct mpr_chan chan; /*
+ * channel values for buffered
+ * mode
+ */
+};
+
+static const struct iio_chan_spec mpr_channels[] = {
+ {
+ .type = IIO_PRESSURE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE) |
+ BIT(IIO_CHAN_INFO_OFFSET),
+ .scan_index = 0,
+ .scan_type = {
+ .sign = 's',
+ .realbits = 32,
+ .storagebits = 32,
+ .endianness = IIO_CPU,
+ },
+ },
+ IIO_CHAN_SOFT_TIMESTAMP(1),
+};
+
+static void mpr_reset(struct mpr_data *data)
+{
+ if (data->gpiod_reset) {
+ gpiod_set_value(data->gpiod_reset, 0);
+ udelay(10);
+ gpiod_set_value(data->gpiod_reset, 1);
+ }
+}
+
+/**
+ * mpr_read_pressure() - Read pressure value from sensor via I2C
+ * @data: Pointer to private data struct.
+ * @press: Output value read from sensor.
+ *
+ * Reading from the sensor by sending and receiving I2C telegrams.
+ *
+ * If there is an end of conversion (EOC) interrupt registered the function
+ * waits for a maximum of one second for the interrupt.
+ *
+ * Context: The function can sleep and data->lock should be held when calling it
+ * Return:
+ * * 0 - OK, the pressure value could be read
+ * * -ETIMEDOUT - Timeout while waiting for the EOC interrupt or busy flag is
+ * still set after nloops attempts of reading
+ */
+static int mpr_read_pressure(struct mpr_data *data, s32 *press)
+{
+ struct device *dev = &data->client->dev;
+ int ret, i;
+ u8 wdata[] = {0xAA, 0x00, 0x00};
+ s32 status;
+ int nloops = 10;
+ u8 buf[4];
+
+ reinit_completion(&data->completion);
+
+ ret = i2c_master_send(data->client, wdata, sizeof(wdata));
+ if (ret < 0) {
+ dev_err(dev, "error while writing ret: %d\n", ret);
+ return ret;
+ }
+ if (ret != sizeof(wdata)) {
+ dev_err(dev, "received size doesn't fit - ret: %d / %u\n", ret,
+ (u32)sizeof(wdata));
+ return -EIO;
+ }
+
+ if (data->irq > 0) {
+ ret = wait_for_completion_timeout(&data->completion, HZ);
+ if (!ret) {
+ dev_err(dev, "timeout while waiting for eoc irq\n");
+ return -ETIMEDOUT;
+ }
+ } else {
+ /* wait until status indicates data is ready */
+ for (i = 0; i < nloops; i++) {
+ /*
+ * datasheet only says to wait at least 5 ms for the
+ * data but leave the maximum response time open
+ * --> let's try it nloops (10) times which seems to be
+ * quite long
+ */
+ usleep_range(5000, 10000);
+ status = i2c_smbus_read_byte(data->client);
+ if (status < 0) {
+ dev_err(dev,
+ "error while reading, status: %d\n",
+ status);
+ return status;
+ }
+ if (!(status & MPR_I2C_BUSY))
+ break;
+ }
+ if (i == nloops) {
+ dev_err(dev, "timeout while reading\n");
+ return -ETIMEDOUT;
+ }
+ }
+
+ ret = i2c_master_recv(data->client, buf, sizeof(buf));
+ if (ret < 0) {
+ dev_err(dev, "error in i2c_master_recv ret: %d\n", ret);
+ return ret;
+ }
+ if (ret != sizeof(buf)) {
+ dev_err(dev, "received size doesn't fit - ret: %d / %u\n", ret,
+ (u32)sizeof(buf));
+ return -EIO;
+ }
+
+ if (buf[0] & MPR_I2C_BUSY) {
+ /*
+ * it should never be the case that status still indicates
+ * business
+ */
+ dev_err(dev, "data still not ready: %08x\n", buf[0]);
+ return -ETIMEDOUT;
+ }
+
+ *press = get_unaligned_be24(&buf[1]);
+
+ dev_dbg(dev, "received: %*ph cnt: %d\n", ret, buf, *press);
+
+ return 0;
+}
+
+static irqreturn_t mpr_eoc_handler(int irq, void *p)
+{
+ struct mpr_data *data = p;
+
+ complete(&data->completion);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t mpr_trigger_handler(int irq, void *p)
+{
+ int ret;
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct mpr_data *data = iio_priv(indio_dev);
+
+ mutex_lock(&data->lock);
+ ret = mpr_read_pressure(data, &data->chan.pres);
+ if (ret < 0)
+ goto err;
+
+ iio_push_to_buffers_with_timestamp(indio_dev, &data->chan,
+ iio_get_time_ns(indio_dev));
+
+err:
+ mutex_unlock(&data->lock);
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
+static int mpr_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val, int *val2, long mask)
+{
+ int ret;
+ s32 pressure;
+ struct mpr_data *data = iio_priv(indio_dev);
+
+ if (chan->type != IIO_PRESSURE)
+ return -EINVAL;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&data->lock);
+ ret = mpr_read_pressure(data, &pressure);
+ mutex_unlock(&data->lock);
+ if (ret < 0)
+ return ret;
+ *val = pressure;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = data->scale;
+ *val2 = data->scale2;
+ return IIO_VAL_INT_PLUS_NANO;
+ case IIO_CHAN_INFO_OFFSET:
+ *val = data->offset;
+ *val2 = data->offset2;
+ return IIO_VAL_INT_PLUS_NANO;
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info mpr_info = {
+ .read_raw = &mpr_read_raw,
+};
+
+static int mpr_probe(struct i2c_client *client)
+{
+ int ret;
+ struct mpr_data *data;
+ struct iio_dev *indio_dev;
+ struct device *dev = &client->dev;
+ s64 scale, offset;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BYTE))
+ return dev_err_probe(dev, -EOPNOTSUPP,
+ "I2C functionality not supported\n");
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
+ if (!indio_dev)
+ return dev_err_probe(dev, -ENOMEM, "couldn't get iio_dev\n");
+
+ data = iio_priv(indio_dev);
+ data->client = client;
+ data->irq = client->irq;
+
+ mutex_init(&data->lock);
+ init_completion(&data->completion);
+
+ indio_dev->name = "mprls0025pa";
+ indio_dev->info = &mpr_info;
+ indio_dev->channels = mpr_channels;
+ indio_dev->num_channels = ARRAY_SIZE(mpr_channels);
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ ret = devm_regulator_get_enable(dev, "vdd");
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "can't get and enable vdd supply\n");
+
+ if (dev_fwnode(dev)) {
+ ret = device_property_read_u32(dev, "honeywell,pmin-pascal",
+ &data->pmin);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "honeywell,pmin-pascal could not be read\n");
+ ret = device_property_read_u32(dev, "honeywell,pmax-pascal",
+ &data->pmax);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "honeywell,pmax-pascal could not be read\n");
+ ret = device_property_read_u32(dev,
+ "honeywell,transfer-function", &data->function);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "honeywell,transfer-function could not be read\n");
+ if (data->function > MPR_FUNCTION_C)
+ return dev_err_probe(dev, -EINVAL,
+ "honeywell,transfer-function %d invalid\n",
+ data->function);
+ } else {
+ /* when loaded as i2c device we need to use default values */
+ dev_notice(dev, "firmware node not found; using defaults\n");
+ data->pmin = 0;
+ data->pmax = 172369; /* 25 psi */
+ data->function = MPR_FUNCTION_A;
+ }
+
+ data->outmin = mpr_func_spec[data->function].output_min;
+ data->outmax = mpr_func_spec[data->function].output_max;
+
+ /* use 64 bit calculation for preserving a reasonable precision */
+ scale = div_s64(((s64)(data->pmax - data->pmin)) * NANO,
+ data->outmax - data->outmin);
+ data->scale = div_s64_rem(scale, NANO, &data->scale2);
+ /*
+ * multiply with NANO before dividing by scale and later divide by NANO
+ * again.
+ */
+ offset = ((-1LL) * (s64)data->outmin) * NANO -
+ div_s64(div_s64((s64)data->pmin * NANO, scale), NANO);
+ data->offset = div_s64_rem(offset, NANO, &data->offset2);
+
+ if (data->irq > 0) {
+ ret = devm_request_irq(dev, data->irq, mpr_eoc_handler,
+ IRQF_TRIGGER_RISING, client->name, data);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "request irq %d failed\n", data->irq);
+ }
+
+ data->gpiod_reset = devm_gpiod_get_optional(dev, "reset",
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(data->gpiod_reset))
+ return dev_err_probe(dev, PTR_ERR(data->gpiod_reset),
+ "request reset-gpio failed\n");
+
+ mpr_reset(data);
+
+ ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
+ mpr_trigger_handler, NULL);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "iio triggered buffer setup failed\n");
+
+ ret = devm_iio_device_register(dev, indio_dev);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "unable to register iio device\n");
+
+ return 0;
+}
+
+static const struct of_device_id mpr_matches[] = {
+ { .compatible = "honeywell,mprls0025pa" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, mpr_matches);
+
+static const struct i2c_device_id mpr_id[] = {
+ { "mprls0025pa" },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, mpr_id);
+
+static struct i2c_driver mpr_driver = {
+ .probe = mpr_probe,
+ .id_table = mpr_id,
+ .driver = {
+ .name = "mprls0025pa",
+ .of_match_table = mpr_matches,
+ },
+};
+module_i2c_driver(mpr_driver);
+
+MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
+MODULE_DESCRIPTION("Honeywell MPRLS0025PA I2C driver");
+MODULE_LICENSE("GPL");
projects / mirror_ubuntu-kernels.git / commitdiff