iio: accel: mxc4005: Reset chip on probe() and resume()

On some designs the chip is not properly reset when powered up at boot or
after a suspend/resume cycle.

Use the sw-reset feature to ensure that the chip is in a clean state
after probe() / resume() and in the case of resume() restore the settings
(scale, trigger-enabled).

Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218578
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20240326113700.56725-3-hdegoede@redhat.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/accel/mxc4005.c b/drivers/iio/accel/mxc4005.c
index 111f4bcf24ad66f437a567e3d9219482724b076e..63c3566a533bd89429b0104a563f1acc72280ad7 100644 (file)
--- a/drivers/iio/accel/mxc4005.c
+++ b/drivers/iio/accel/mxc4005.c
@@ -5,6 +5,7 @@
  * Copyright (c) 2014, Intel Corporation.
  */
 
+#include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/i2c.h>
 #include <linux/iio/iio.h>
@@ -36,6 +37,7 @@
 
 #define MXC4005_REG_INT_CLR1           0x01
 #define MXC4005_REG_INT_CLR1_BIT_DRDYC 0x01
+#define MXC4005_REG_INT_CLR1_SW_RST    0x10
 
 #define MXC4005_REG_CONTROL            0x0D
 #define MXC4005_REG_CONTROL_MASK_FSR   GENMASK(6, 5)
@@ -43,6 +45,9 @@
 
 #define MXC4005_REG_DEVICE_ID          0x0E
 
+/* Datasheet does not specify a reset time, this is a conservative guess */
+#define MXC4005_RESET_TIME_US          2000
+
 enum mxc4005_axis {
        AXIS_X,
        AXIS_Y,
@@ -66,6 +71,8 @@ struct mxc4005_data {
                s64 timestamp __aligned(8);
        } scan;
        bool trigger_enabled;
+       unsigned int control;
+       unsigned int int_mask1;
 };
 
 /*
@@ -349,6 +356,7 @@ static int mxc4005_set_trigger_state(struct iio_trigger *trig,
                return ret;
        }
 
+       data->int_mask1 = val;
        data->trigger_enabled = state;
        mutex_unlock(&data->mutex);
 
@@ -384,6 +392,13 @@ static int mxc4005_chip_init(struct mxc4005_data *data)
 
        dev_dbg(data->dev, "MXC4005 chip id %02x\n", reg);
 
+       ret = regmap_write(data->regmap, MXC4005_REG_INT_CLR1,
+                          MXC4005_REG_INT_CLR1_SW_RST);
+       if (ret < 0)
+               return dev_err_probe(data->dev, ret, "resetting chip\n");
+
+       fsleep(MXC4005_RESET_TIME_US);
+
        ret = regmap_write(data->regmap, MXC4005_REG_INT_MASK0, 0);
        if (ret < 0)
                return dev_err_probe(data->dev, ret, "writing INT_MASK0\n");
@@ -479,6 +494,58 @@ static int mxc4005_probe(struct i2c_client *client)
        return devm_iio_device_register(&client->dev, indio_dev);
 }
 
+static int mxc4005_suspend(struct device *dev)
+{
+       struct iio_dev *indio_dev = dev_get_drvdata(dev);
+       struct mxc4005_data *data = iio_priv(indio_dev);
+       int ret;
+
+       /* Save control to restore it on resume */
+       ret = regmap_read(data->regmap, MXC4005_REG_CONTROL, &data->control);
+       if (ret < 0)
+               dev_err(data->dev, "failed to read reg_control\n");
+
+       return ret;
+}
+
+static int mxc4005_resume(struct device *dev)
+{
+       struct iio_dev *indio_dev = dev_get_drvdata(dev);
+       struct mxc4005_data *data = iio_priv(indio_dev);
+       int ret;
+
+       ret = regmap_write(data->regmap, MXC4005_REG_INT_CLR1,
+                          MXC4005_REG_INT_CLR1_SW_RST);
+       if (ret) {
+               dev_err(data->dev, "failed to reset chip: %d\n", ret);
+               return ret;
+       }
+
+       fsleep(MXC4005_RESET_TIME_US);
+
+       ret = regmap_write(data->regmap, MXC4005_REG_CONTROL, data->control);
+       if (ret) {
+               dev_err(data->dev, "failed to restore control register\n");
+               return ret;
+       }
+
+       ret = regmap_write(data->regmap, MXC4005_REG_INT_MASK0, 0);
+       if (ret) {
+               dev_err(data->dev, "failed to restore interrupt 0 mask\n");
+               return ret;
+       }
+
+       ret = regmap_write(data->regmap, MXC4005_REG_INT_MASK1, data->int_mask1);
+       if (ret) {
+               dev_err(data->dev, "failed to restore interrupt 1 mask\n");
+               return ret;
+       }
+
+       return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(mxc4005_pm_ops, mxc4005_suspend, mxc4005_resume);
+
 static const struct acpi_device_id mxc4005_acpi_match[] = {
        {"MXC4005",     0},
        {"MXC6655",     0},
@@ -506,6 +573,7 @@ static struct i2c_driver mxc4005_driver = {
                .name = MXC4005_DRV_NAME,
                .acpi_match_table = mxc4005_acpi_match,
                .of_match_table = mxc4005_of_match,
+               .pm = pm_sleep_ptr(&mxc4005_pm_ops),
        },
        .probe          = mxc4005_probe,
        .id_table       = mxc4005_id,