Hi, Martin
>From Anson's iPhone 6
> 在 2019年1月8日，19:41，Martin Kepplinger <martink@xxxxxxxxx> 写道：
>
>> On 08.01.19 10:14, Anson Huang wrote:
>> The accelerometer's power supply could be controllable on some
>> platforms, such as i.MX6Q-SABRESD board, the mma8451's power supplies
>> are controlled by a GPIO fixed regulator, need to make sure the
>> regulators are enabled before any communication with mma8451, this
>> patch adds vdd/vddio regulator operation support.
>>
>> Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx>
>> Acked-by: Martin Kepplinger <martink@xxxxxxxxx>
>> ---
>> ChangeLog Since V6:
>> - separate the error handling of regulators get to make code easy to read.
>> ---
>> drivers/iio/accel/mma8452.c | 105 ++++++++++++++++++++++++++++++++++----------
>> 1 file changed, 83 insertions(+), 22 deletions(-)
>>
>> diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
>> index 421a0a8..3027811 100644
>> --- a/drivers/iio/accel/mma8452.c
>> +++ b/drivers/iio/accel/mma8452.c
>> @@ -31,6 +31,7 @@
>> #include <linux/of_device.h>
>> #include <linux/of_irq.h>
>> #include <linux/pm_runtime.h>
>> +#include <linux/regulator/consumer.h>
>>
>> #define MMA8452_STATUS 0x00
>> #define MMA8452_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))
>> @@ -107,6 +108,8 @@ struct mma8452_data {
>> u8 data_cfg;
>> const struct mma_chip_info *chip_info;
>> int sleep_val;
>> + struct regulator *vdd_reg;
>> + struct regulator *vddio_reg;
>> };
>>
>> /**
>> @@ -1534,9 +1537,39 @@ static int mma8452_probe(struct i2c_client *client,
>> mutex_init(&data->lock);
>> data->chip_info = match->data;
>>
>> + data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
>> + if (IS_ERR(data->vdd_reg)) {
>> + if (PTR_ERR(data->vdd_reg) == -EPROBE_DEFER)
>> + return -EPROBE_DEFER;
>> +
>> + dev_err(&client->dev, "failed to get VDD regulator!\n");
>> + return PTR_ERR(data->vdd_reg);
>> + }
>> +
>> + data->vddio_reg = devm_regulator_get(&client->dev, "vddio");
>> + if (IS_ERR(data->vddio_reg)) {
>> + if (PTR_ERR(data->vddio_reg) == -EPROBE_DEFER)
>> + return -EPROBE_DEFER;
>> +
>> + dev_err(&client->dev, "failed to get VDDIO regulator!\n");
>> + return PTR_ERR(data->vddio_reg);
>> + }
>> +
>> + ret = regulator_enable(data->vdd_reg);
>> + if (ret) {
>> + dev_err(&client->dev, "failed to enable VDD regulator!\n");
>> + return ret;
>> + }
>> +
>> + ret = regulator_enable(data->vddio_reg);
>> + if (ret) {
>> + dev_err(&client->dev, "failed to enable VDDIO regulator!\n");
>> + goto disable_regulator_vdd;
>> + }
>> +
>> ret = i2c_smbus_read_byte_data(client, MMA8452_WHO_AM_I);
>> if (ret < 0)
>> - return ret;
>> + goto disable_regulators;
>>
>> switch (ret) {
>> case MMA8451_DEVICE_ID:
>> @@ -1549,7 +1582,8 @@ static int mma8452_probe(struct i2c_client *client,
>> break;
>> /* else: fall through */
>> default:
>> - return -ENODEV;
>> + ret = -ENODEV;
>> + goto disable_regulators;
>> }
>>
>> dev_info(&client->dev, "registering %s accelerometer; ID 0x%x\n",
>> @@ -1566,13 +1600,13 @@ static int mma8452_probe(struct i2c_client *client,
>>
>> ret = mma8452_reset(client);
>> if (ret < 0)
>> - return ret;
>> + goto disable_regulators;
>>
>> data->data_cfg = MMA8452_DATA_CFG_FS_2G;
>> ret = i2c_smbus_write_byte_data(client, MMA8452_DATA_CFG,
>> data->data_cfg);
>> if (ret < 0)
>> - return ret;
>> + goto disable_regulators;
>>
>> /*
>> * By default set transient threshold to max to avoid events if
>> @@ -1581,7 +1615,7 @@ static int mma8452_probe(struct i2c_client *client,
>> ret = i2c_smbus_write_byte_data(client, MMA8452_TRANSIENT_THS,
>> MMA8452_TRANSIENT_THS_MASK);
>> if (ret < 0)
>> - return ret;
>> + goto disable_regulators;
>>
>> if (client->irq) {
>> int irq2;
>> @@ -1595,7 +1629,7 @@ static int mma8452_probe(struct i2c_client *client,
>> MMA8452_CTRL_REG5,
>> data->chip_info->all_events);
>> if (ret < 0)
>> - return ret;
>> + goto disable_regulators;
>>
>> dev_dbg(&client->dev, "using interrupt line INT1\n");
>> }
>> @@ -1604,11 +1638,11 @@ static int mma8452_probe(struct i2c_client *client,
>> MMA8452_CTRL_REG4,
>> data->chip_info->enabled_events);
>> if (ret < 0)
>> - return ret;
>> + goto disable_regulators;
>>
>> ret = mma8452_trigger_setup(indio_dev);
>> if (ret < 0)
>> - return ret;
>> + goto disable_regulators;
>> }
>>
>> data->ctrl_reg1 = MMA8452_CTRL_ACTIVE |
>> @@ -1661,12 +1695,19 @@ static int mma8452_probe(struct i2c_client *client,
>> trigger_cleanup:
>> mma8452_trigger_cleanup(indio_dev);
>>
>> +disable_regulators:
>> + regulator_disable(data->vddio_reg);
>> +
>> +disable_regulator_vdd:
>> + regulator_disable(data->vdd_reg);
>> +
>> return ret;
>> }
>>
>> static int mma8452_remove(struct i2c_client *client)
>> {
>> struct iio_dev *indio_dev = i2c_get_clientdata(client);
>> + struct mma8452_data *data = iio_priv(indio_dev);
>>
>> iio_device_unregister(indio_dev);
>>
>> @@ -1678,6 +1719,9 @@ static int mma8452_remove(struct i2c_client *client)
>> mma8452_trigger_cleanup(indio_dev);
>> mma8452_standby(iio_priv(indio_dev));
>>
>> + regulator_disable(data->vddio_reg);
>> + regulator_disable(data->vdd_reg);
>> +
>> return 0;
>> }
>>
>> @@ -1696,6 +1740,18 @@ static int mma8452_runtime_suspend(struct device *dev)
>> return -EAGAIN;
>> }
>>
>> + ret = regulator_disable(data->vddio_reg);
>> + if (ret) {
>> + dev_err(dev, "failed to disable VDDIO regulator\n");
>> + return ret;
>> + }
>> +
>> + ret = regulator_disable(data->vdd_reg);
>> + if (ret) {
>> + dev_err(dev, "failed to disable VDD regulator\n");
>> + return ret;
>> + }
>> +
>> return 0;
>> }
>>
>> @@ -1705,9 +1761,22 @@ static int mma8452_runtime_resume(struct device *dev)
>> struct mma8452_data *data = iio_priv(indio_dev);
>> int ret, sleep_val;
>>
>> + ret = regulator_enable(data->vdd_reg);
>> + if (ret) {
>> + dev_err(dev, "failed to enable VDD regulator\n");
>> + return ret;
>> + }
>> +
>> + ret = regulator_enable(data->vddio_reg);
>> + if (ret) {
>> + dev_err(dev, "failed to enable VDDIO regulator\n");
>> + regulator_disable(data->vdd_reg);
>> + return ret;
>> + }
>> +
>> ret = mma8452_active(data);
>> if (ret < 0)
>> - return ret;
>> + goto runtime_resume_failed;
>>
>> ret = mma8452_get_odr_index(data);
>> sleep_val = 1000 / mma8452_samp_freq[ret][0];
>> @@ -1717,25 +1786,17 @@ static int mma8452_runtime_resume(struct device *dev)
>> msleep_interruptible(sleep_val);
>>
>> return 0;
>> -}
>> -#endif
>>
>> -#ifdef CONFIG_PM_SLEEP
>> -static int mma8452_suspend(struct device *dev)
>> -{
>> - return mma8452_standby(iio_priv(i2c_get_clientdata(
>> - to_i2c_client(dev))));
>> -}
>> +runtime_resume_failed:
>> + regulator_disable(data->vddio_reg);
>> + regulator_disable(data->vdd_reg);
>>
>> -static int mma8452_resume(struct device *dev)
>> -{
>> - return mma8452_active(iio_priv(i2c_get_clientdata(
>> - to_i2c_client(dev))));
>> + return ret;
>> }
>> #endif
>>
>> static const struct dev_pm_ops mma8452_pm_ops = {
>> - SET_SYSTEM_SLEEP_PM_OPS(mma8452_suspend, mma8452_resume)
>> + SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
>
> Just a quesion: Isn't it semantically a different change to replace
> mma8452_suspend() and mma8452_resume()? If not, why is it needed here?
>
> other than that, lgtm.
It is because with regulator operation added, before system suspend, driver is in runtime suspend already, the suspend/resume callback need to deal with regulator again including error handling etc., and also need to disable runtime pm and re-enable it etc., this introduces too many complicated code/logic, also, the things suspend/resume callback does are actually same as runtime suspend/ resume, so just using pm_runtime_force_suspend/resume can save these duplicated operations and make code easy/clean.
Anson.
>
>> SET_RUNTIME_PM_OPS(mma8452_runtime_suspend,
>> mma8452_runtime_resume, NULL)
>> };
>>
>
