| Message ID | 20200414184930.5576-3-mani@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add Reset and Wakeup support for CCS811 | expand |
On Tue, Apr 14, 2020 at 9:49 PM <mani@kernel.org> wrote: > > From: Manivannan Sadhasivam <mani@kernel.org> > > CCS811 VOC sensor exposes nRESET and nWAKE pins which can be connected > to GPIO pins of the host controller. These pins can be used to externally > release the device from reset and also to wake it up before any I2C > transaction. The initial driver support assumed that the nRESET pin is not > connected and the nWAKE pin is tied to ground. > > This commit improves it by adding support for controlling those two pins > externally using a host controller. For the case of reset, if the hardware > reset is not available, the mechanism to do software reset is also added. > > As a side effect of doing this, the IIO device allocation needs to be > slightly moved to top of probe to make use of priv data early. > LGTM, Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> > Signed-off-by: Manivannan Sadhasivam <mani@kernel.org> > --- > drivers/iio/chemical/ccs811.c | 105 ++++++++++++++++++++++++++++++---- > 1 file changed, 94 insertions(+), 11 deletions(-) > > diff --git a/drivers/iio/chemical/ccs811.c b/drivers/iio/chemical/ccs811.c > index 2ebdfc35bcda..1500e4b0dfbd 100644 > --- a/drivers/iio/chemical/ccs811.c > +++ b/drivers/iio/chemical/ccs811.c > @@ -16,6 +16,7 @@ > */ > > #include <linux/delay.h> > +#include <linux/gpio/consumer.h> > #include <linux/i2c.h> > #include <linux/iio/iio.h> > #include <linux/iio/buffer.h> > @@ -36,6 +37,7 @@ > #define CCS811_ERR 0xE0 > /* Used to transition from boot to application mode */ > #define CCS811_APP_START 0xF4 > +#define CCS811_SW_RESET 0xFF > > /* Status register flags */ > #define CCS811_STATUS_ERROR BIT(0) > @@ -74,6 +76,7 @@ struct ccs811_data { > struct mutex lock; /* Protect readings */ > struct ccs811_reading buffer; > struct iio_trigger *drdy_trig; > + struct gpio_desc *wakeup_gpio; > bool drdy_trig_on; > }; > > @@ -166,10 +169,25 @@ static int ccs811_setup(struct i2c_client *client) > CCS811_MODE_IAQ_1SEC); > } > > +static void ccs811_set_wakeup(struct ccs811_data *data, bool enable) > +{ > + if (!data->wakeup_gpio) > + return; > + > + gpiod_set_value(data->wakeup_gpio, enable); > + > + if (enable) > + usleep_range(50, 60); > + else > + usleep_range(20, 30); > +} > + > static int ccs811_get_measurement(struct ccs811_data *data) > { > int ret, tries = 11; > > + ccs811_set_wakeup(data, true); > + > /* Maximum waiting time: 1s, as measurements are made every second */ > while (tries-- > 0) { > ret = i2c_smbus_read_byte_data(data->client, CCS811_STATUS); > @@ -183,9 +201,12 @@ static int ccs811_get_measurement(struct ccs811_data *data) > if (!(ret & CCS811_STATUS_DATA_READY)) > return -EIO; > > - return i2c_smbus_read_i2c_block_data(data->client, > + ret = i2c_smbus_read_i2c_block_data(data->client, > CCS811_ALG_RESULT_DATA, 8, > (char *)&data->buffer); > + ccs811_set_wakeup(data, false); > + > + return ret; > } > > static int ccs811_read_raw(struct iio_dev *indio_dev, > @@ -336,6 +357,45 @@ static irqreturn_t ccs811_data_rdy_trigger_poll(int irq, void *private) > return IRQ_HANDLED; > } > > +static int ccs811_reset(struct i2c_client *client) > +{ > + struct gpio_desc *reset_gpio; > + int ret; > + > + reset_gpio = devm_gpiod_get_optional(&client->dev, "reset", > + GPIOD_OUT_LOW); > + if (IS_ERR(reset_gpio)) > + return PTR_ERR(reset_gpio); > + > + /* Try to reset using nRESET pin if available else do SW reset */ > + if (reset_gpio) { > + gpiod_set_value(reset_gpio, 1); > + usleep_range(20, 30); > + gpiod_set_value(reset_gpio, 0); > + } else { > + /* > + * As per the datasheet, this sequence of values needs to be > + * written to the SW_RESET register for triggering the soft > + * reset in the device and placing it in boot mode. > + */ > + static const u8 reset_seq[] = { > + 0x11, 0xE5, 0x72, 0x8A, > + }; > + > + ret = i2c_smbus_write_i2c_block_data(client, CCS811_SW_RESET, > + sizeof(reset_seq), reset_seq); > + if (ret < 0) { > + dev_err(&client->dev, "Failed to reset sensor\n"); > + return ret; > + } > + } > + > + /* tSTART delay required after reset */ > + usleep_range(1000, 2000); > + > + return 0; > +} > + > static int ccs811_probe(struct i2c_client *client, > const struct i2c_device_id *id) > { > @@ -348,36 +408,59 @@ static int ccs811_probe(struct i2c_client *client, > | I2C_FUNC_SMBUS_READ_I2C_BLOCK)) > return -EOPNOTSUPP; > > + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); > + if (!indio_dev) > + return -ENOMEM; > + > + data = iio_priv(indio_dev); > + i2c_set_clientdata(client, indio_dev); > + data->client = client; > + > + data->wakeup_gpio = devm_gpiod_get_optional(&client->dev, "wakeup", > + GPIOD_OUT_HIGH); > + if (IS_ERR(data->wakeup_gpio)) > + return PTR_ERR(data->wakeup_gpio); > + > + ccs811_set_wakeup(data, true); > + > + ret = ccs811_reset(client); > + if (ret) { > + ccs811_set_wakeup(data, false); > + return ret; > + } > + > /* Check hardware id (should be 0x81 for this family of devices) */ > ret = i2c_smbus_read_byte_data(client, CCS811_HW_ID); > - if (ret < 0) > + if (ret < 0) { > + ccs811_set_wakeup(data, false); > return ret; > + } > > if (ret != CCS811_HW_ID_VALUE) { > dev_err(&client->dev, "hardware id doesn't match CCS81x\n"); > + ccs811_set_wakeup(data, false); > return -ENODEV; > } > > ret = i2c_smbus_read_byte_data(client, CCS811_HW_VERSION); > - if (ret < 0) > + if (ret < 0) { > + ccs811_set_wakeup(data, false); > return ret; > + } > > if ((ret & CCS811_HW_VERSION_MASK) != CCS811_HW_VERSION_VALUE) { > dev_err(&client->dev, "no CCS811 sensor\n"); > + ccs811_set_wakeup(data, false); > return -ENODEV; > } > > - indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); > - if (!indio_dev) > - return -ENOMEM; > - > ret = ccs811_setup(client); > - if (ret < 0) > + if (ret < 0) { > + ccs811_set_wakeup(data, false); > return ret; > + } > > - data = iio_priv(indio_dev); > - i2c_set_clientdata(client, indio_dev); > - data->client = client; > + ccs811_set_wakeup(data, false); > > mutex_init(&data->lock); > > -- > 2.17.1 >
diff --git a/drivers/iio/chemical/ccs811.c b/drivers/iio/chemical/ccs811.c index 2ebdfc35bcda..1500e4b0dfbd 100644 --- a/drivers/iio/chemical/ccs811.c +++ b/drivers/iio/chemical/ccs811.c @@ -16,6 +16,7 @@ */ #include <linux/delay.h> +#include <linux/gpio/consumer.h> #include <linux/i2c.h> #include <linux/iio/iio.h> #include <linux/iio/buffer.h> @@ -36,6 +37,7 @@ #define CCS811_ERR 0xE0 /* Used to transition from boot to application mode */ #define CCS811_APP_START 0xF4 +#define CCS811_SW_RESET 0xFF /* Status register flags */ #define CCS811_STATUS_ERROR BIT(0) @@ -74,6 +76,7 @@ struct ccs811_data { struct mutex lock; /* Protect readings */ struct ccs811_reading buffer; struct iio_trigger *drdy_trig; + struct gpio_desc *wakeup_gpio; bool drdy_trig_on; }; @@ -166,10 +169,25 @@ static int ccs811_setup(struct i2c_client *client) CCS811_MODE_IAQ_1SEC); } +static void ccs811_set_wakeup(struct ccs811_data *data, bool enable) +{ + if (!data->wakeup_gpio) + return; + + gpiod_set_value(data->wakeup_gpio, enable); + + if (enable) + usleep_range(50, 60); + else + usleep_range(20, 30); +} + static int ccs811_get_measurement(struct ccs811_data *data) { int ret, tries = 11; + ccs811_set_wakeup(data, true); + /* Maximum waiting time: 1s, as measurements are made every second */ while (tries-- > 0) { ret = i2c_smbus_read_byte_data(data->client, CCS811_STATUS); @@ -183,9 +201,12 @@ static int ccs811_get_measurement(struct ccs811_data *data) if (!(ret & CCS811_STATUS_DATA_READY)) return -EIO; - return i2c_smbus_read_i2c_block_data(data->client, + ret = i2c_smbus_read_i2c_block_data(data->client, CCS811_ALG_RESULT_DATA, 8, (char *)&data->buffer); + ccs811_set_wakeup(data, false); + + return ret; } static int ccs811_read_raw(struct iio_dev *indio_dev, @@ -336,6 +357,45 @@ static irqreturn_t ccs811_data_rdy_trigger_poll(int irq, void *private) return IRQ_HANDLED; } +static int ccs811_reset(struct i2c_client *client) +{ + struct gpio_desc *reset_gpio; + int ret; + + reset_gpio = devm_gpiod_get_optional(&client->dev, "reset", + GPIOD_OUT_LOW); + if (IS_ERR(reset_gpio)) + return PTR_ERR(reset_gpio); + + /* Try to reset using nRESET pin if available else do SW reset */ + if (reset_gpio) { + gpiod_set_value(reset_gpio, 1); + usleep_range(20, 30); + gpiod_set_value(reset_gpio, 0); + } else { + /* + * As per the datasheet, this sequence of values needs to be + * written to the SW_RESET register for triggering the soft + * reset in the device and placing it in boot mode. + */ + static const u8 reset_seq[] = { + 0x11, 0xE5, 0x72, 0x8A, + }; + + ret = i2c_smbus_write_i2c_block_data(client, CCS811_SW_RESET, + sizeof(reset_seq), reset_seq); + if (ret < 0) { + dev_err(&client->dev, "Failed to reset sensor\n"); + return ret; + } + } + + /* tSTART delay required after reset */ + usleep_range(1000, 2000); + + return 0; +} + static int ccs811_probe(struct i2c_client *client, const struct i2c_device_id *id) { @@ -348,36 +408,59 @@ static int ccs811_probe(struct i2c_client *client, | I2C_FUNC_SMBUS_READ_I2C_BLOCK)) return -EOPNOTSUPP; + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + + data = iio_priv(indio_dev); + i2c_set_clientdata(client, indio_dev); + data->client = client; + + data->wakeup_gpio = devm_gpiod_get_optional(&client->dev, "wakeup", + GPIOD_OUT_HIGH); + if (IS_ERR(data->wakeup_gpio)) + return PTR_ERR(data->wakeup_gpio); + + ccs811_set_wakeup(data, true); + + ret = ccs811_reset(client); + if (ret) { + ccs811_set_wakeup(data, false); + return ret; + } + /* Check hardware id (should be 0x81 for this family of devices) */ ret = i2c_smbus_read_byte_data(client, CCS811_HW_ID); - if (ret < 0) + if (ret < 0) { + ccs811_set_wakeup(data, false); return ret; + } if (ret != CCS811_HW_ID_VALUE) { dev_err(&client->dev, "hardware id doesn't match CCS81x\n"); + ccs811_set_wakeup(data, false); return -ENODEV; } ret = i2c_smbus_read_byte_data(client, CCS811_HW_VERSION); - if (ret < 0) + if (ret < 0) { + ccs811_set_wakeup(data, false); return ret; + } if ((ret & CCS811_HW_VERSION_MASK) != CCS811_HW_VERSION_VALUE) { dev_err(&client->dev, "no CCS811 sensor\n"); + ccs811_set_wakeup(data, false); return -ENODEV; } - indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); - if (!indio_dev) - return -ENOMEM; - ret = ccs811_setup(client); - if (ret < 0) + if (ret < 0) { + ccs811_set_wakeup(data, false); return ret; + } - data = iio_priv(indio_dev); - i2c_set_clientdata(client, indio_dev); - data->client = client; + ccs811_set_wakeup(data, false); mutex_init(&data->lock);