* [PATCH v2 0/1] iio: proximity: lidar: optimize i2c transactions @ 2015-12-01 2:16 Matt Ranostay 2015-12-01 2:16 ` [PATCH v2 1/1] " Matt Ranostay 0 siblings, 1 reply; 3+ messages in thread From: Matt Ranostay @ 2015-12-01 2:16 UTC (permalink / raw) To: linux-iio, jic23; +Cc: Matt Ranostay Changes from v1: * allow smbus method as fallback if i2c mode isn't possible Matt Ranostay (1): iio: proximity: lidar: optimize i2c transactions drivers/iio/proximity/pulsedlight-lidar-lite-v2.c | 95 +++++++++++++++++------ 1 file changed, 70 insertions(+), 25 deletions(-) -- 1.9.1 ^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH v2 1/1] iio: proximity: lidar: optimize i2c transactions 2015-12-01 2:16 [PATCH v2 0/1] iio: proximity: lidar: optimize i2c transactions Matt Ranostay @ 2015-12-01 2:16 ` Matt Ranostay 2015-12-02 5:00 ` Matt Ranostay 0 siblings, 1 reply; 3+ messages in thread From: Matt Ranostay @ 2015-12-01 2:16 UTC (permalink / raw) To: linux-iio, jic23; +Cc: Matt Ranostay Optimize device tranactions using i2c transfers versus multiple possibly racey i2c_smbus_* function calls, and only one transaction for distance measurement. Falls back to smbus method if i2c functionality isn't available. Signed-off-by: Matt Ranostay <mranostay@gmail.com> --- drivers/iio/proximity/pulsedlight-lidar-lite-v2.c | 95 +++++++++++++++++------ 1 file changed, 70 insertions(+), 25 deletions(-) diff --git a/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c index 32f24f1..1cdcc5a 100644 --- a/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c +++ b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c @@ -36,8 +36,10 @@ #define LIDAR_REG_STATUS_INVALID BIT(3) #define LIDAR_REG_STATUS_READY BIT(0) -#define LIDAR_REG_DATA_HBYTE 0x0f -#define LIDAR_REG_DATA_LBYTE 0x10 +#define LIDAR_REG_DATA_HBYTE 0x0f +#define LIDAR_REG_DATA_LBYTE 0x10 +#define LIDAR_REG_DATA_WORD_READ BIT(7) + #define LIDAR_REG_PWR_CONTROL 0x65 #define LIDAR_DRV_NAME "lidar" @@ -46,6 +48,9 @@ struct lidar_data { struct iio_dev *indio_dev; struct i2c_client *client; + int (*xfer)(struct lidar_data *data, u8 reg, u8 *val, int len); + int i2c_enabled; + u16 buffer[8]; /* 2 byte distance + 8 byte timestamp */ }; @@ -64,7 +69,28 @@ static const struct iio_chan_spec lidar_channels[] = { IIO_CHAN_SOFT_TIMESTAMP(1), }; -static int lidar_read_byte(struct lidar_data *data, int reg) +static int lidar_i2c_xfer(struct lidar_data *data, u8 reg, u8 *val, int len) +{ + struct i2c_client *client = data->client; + struct i2c_msg msg[2]; + int ret; + + msg[0].addr = client->addr; + msg[0].flags = client->flags | I2C_M_STOP; + msg[0].len = 1; + msg[0].buf = (char *) ® + + msg[1].addr = client->addr; + msg[1].flags = client->flags | I2C_M_RD; + msg[1].len = len; + msg[1].buf = (char *) val; + + ret = i2c_transfer(client->adapter, msg, 2); + + return (ret == len) ? 0 : ret; +} + +static int lidar_smbus_xfer(struct lidar_data *data, u8 reg, u8 *val, int len) { struct i2c_client *client = data->client; int ret; @@ -74,17 +100,35 @@ static int lidar_read_byte(struct lidar_data *data, int reg) * so in turn i2c_smbus_read_byte_data cannot be used */ - ret = i2c_smbus_write_byte(client, reg); - if (ret < 0) { - dev_err(&client->dev, "cannot write addr value"); - return ret; + while (len--) { + ret = i2c_smbus_write_byte(client, reg++); + if (ret < 0) { + dev_err(&client->dev, "cannot write addr value"); + return ret; + } + + ret = i2c_smbus_read_byte(client); + if (ret < 0) { + dev_err(&client->dev, "cannot read data value"); + return ret; + } + + *(val++) = ret; } - ret = i2c_smbus_read_byte(client); + return 0; +} + +static int lidar_read_byte(struct lidar_data *data, u8 reg) +{ + int ret; + u8 val; + + ret = data->xfer(data, reg, &val, 1); if (ret < 0) - dev_err(&client->dev, "cannot read data value"); + return ret; - return ret; + return val; } static inline int lidar_write_control(struct lidar_data *data, int val) @@ -100,22 +144,14 @@ static inline int lidar_write_power(struct lidar_data *data, int val) static int lidar_read_measurement(struct lidar_data *data, u16 *reg) { - int ret; - int val; - - ret = lidar_read_byte(data, LIDAR_REG_DATA_HBYTE); - if (ret < 0) - return ret; - val = ret << 8; + int ret = data->xfer(data, LIDAR_REG_DATA_HBYTE | + (data->i2c_enabled ? LIDAR_REG_DATA_WORD_READ : 0), + (u8 *) reg, 2); - ret = lidar_read_byte(data, LIDAR_REG_DATA_LBYTE); - if (ret < 0) - return ret; + if (!ret) + *reg = be16_to_cpu(*reg); - val |= ret; - *reg = val; - - return 0; + return ret; } static int lidar_get_measurement(struct lidar_data *data, u16 *reg) @@ -237,6 +273,16 @@ static int lidar_probe(struct i2c_client *client, indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); if (!indio_dev) return -ENOMEM; + data = iio_priv(indio_dev); + + if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { + data->xfer = lidar_i2c_xfer; + data->i2c_enabled = 1; + } else if (i2c_check_functionality(client->adapter, + I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE)) + data->xfer = lidar_smbus_xfer; + else + return -ENOTSUPP; indio_dev->info = &lidar_info; indio_dev->name = LIDAR_DRV_NAME; @@ -244,7 +290,6 @@ static int lidar_probe(struct i2c_client *client, indio_dev->num_channels = ARRAY_SIZE(lidar_channels); indio_dev->modes = INDIO_DIRECT_MODE; - data = iio_priv(indio_dev); i2c_set_clientdata(client, indio_dev); data->client = client; -- 1.9.1 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2 1/1] iio: proximity: lidar: optimize i2c transactions 2015-12-01 2:16 ` [PATCH v2 1/1] " Matt Ranostay @ 2015-12-02 5:00 ` Matt Ranostay 0 siblings, 0 replies; 3+ messages in thread From: Matt Ranostay @ 2015-12-02 5:00 UTC (permalink / raw) To: linux-iio@vger.kernel.org, Jonathan Cameron; +Cc: Matt Ranostay Please ignore version... there is an issue within this patchset with the i2c_transfer return check. On Mon, Nov 30, 2015 at 6:16 PM, Matt Ranostay <mranostay@gmail.com> wrote: > Optimize device tranactions using i2c transfers versus multiple > possibly racey i2c_smbus_* function calls, and only one transaction > for distance measurement. Falls back to smbus method if i2c > functionality isn't available. > > Signed-off-by: Matt Ranostay <mranostay@gmail.com> > --- > drivers/iio/proximity/pulsedlight-lidar-lite-v2.c | 95 +++++++++++++++++------ > 1 file changed, 70 insertions(+), 25 deletions(-) > > diff --git a/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c > index 32f24f1..1cdcc5a 100644 > --- a/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c > +++ b/drivers/iio/proximity/pulsedlight-lidar-lite-v2.c > @@ -36,8 +36,10 @@ > #define LIDAR_REG_STATUS_INVALID BIT(3) > #define LIDAR_REG_STATUS_READY BIT(0) > > -#define LIDAR_REG_DATA_HBYTE 0x0f > -#define LIDAR_REG_DATA_LBYTE 0x10 > +#define LIDAR_REG_DATA_HBYTE 0x0f > +#define LIDAR_REG_DATA_LBYTE 0x10 > +#define LIDAR_REG_DATA_WORD_READ BIT(7) > + > #define LIDAR_REG_PWR_CONTROL 0x65 > > #define LIDAR_DRV_NAME "lidar" > @@ -46,6 +48,9 @@ struct lidar_data { > struct iio_dev *indio_dev; > struct i2c_client *client; > > + int (*xfer)(struct lidar_data *data, u8 reg, u8 *val, int len); > + int i2c_enabled; > + > u16 buffer[8]; /* 2 byte distance + 8 byte timestamp */ > }; > > @@ -64,7 +69,28 @@ static const struct iio_chan_spec lidar_channels[] = { > IIO_CHAN_SOFT_TIMESTAMP(1), > }; > > -static int lidar_read_byte(struct lidar_data *data, int reg) > +static int lidar_i2c_xfer(struct lidar_data *data, u8 reg, u8 *val, int len) > +{ > + struct i2c_client *client = data->client; > + struct i2c_msg msg[2]; > + int ret; > + > + msg[0].addr = client->addr; > + msg[0].flags = client->flags | I2C_M_STOP; > + msg[0].len = 1; > + msg[0].buf = (char *) ® > + > + msg[1].addr = client->addr; > + msg[1].flags = client->flags | I2C_M_RD; > + msg[1].len = len; > + msg[1].buf = (char *) val; > + > + ret = i2c_transfer(client->adapter, msg, 2); > + > + return (ret == len) ? 0 : ret; > +} > + > +static int lidar_smbus_xfer(struct lidar_data *data, u8 reg, u8 *val, int len) > { > struct i2c_client *client = data->client; > int ret; > @@ -74,17 +100,35 @@ static int lidar_read_byte(struct lidar_data *data, int reg) > * so in turn i2c_smbus_read_byte_data cannot be used > */ > > - ret = i2c_smbus_write_byte(client, reg); > - if (ret < 0) { > - dev_err(&client->dev, "cannot write addr value"); > - return ret; > + while (len--) { > + ret = i2c_smbus_write_byte(client, reg++); > + if (ret < 0) { > + dev_err(&client->dev, "cannot write addr value"); > + return ret; > + } > + > + ret = i2c_smbus_read_byte(client); > + if (ret < 0) { > + dev_err(&client->dev, "cannot read data value"); > + return ret; > + } > + > + *(val++) = ret; > } > > - ret = i2c_smbus_read_byte(client); > + return 0; > +} > + > +static int lidar_read_byte(struct lidar_data *data, u8 reg) > +{ > + int ret; > + u8 val; > + > + ret = data->xfer(data, reg, &val, 1); > if (ret < 0) > - dev_err(&client->dev, "cannot read data value"); > + return ret; > > - return ret; > + return val; > } > > static inline int lidar_write_control(struct lidar_data *data, int val) > @@ -100,22 +144,14 @@ static inline int lidar_write_power(struct lidar_data *data, int val) > > static int lidar_read_measurement(struct lidar_data *data, u16 *reg) > { > - int ret; > - int val; > - > - ret = lidar_read_byte(data, LIDAR_REG_DATA_HBYTE); > - if (ret < 0) > - return ret; > - val = ret << 8; > + int ret = data->xfer(data, LIDAR_REG_DATA_HBYTE | > + (data->i2c_enabled ? LIDAR_REG_DATA_WORD_READ : 0), > + (u8 *) reg, 2); > > - ret = lidar_read_byte(data, LIDAR_REG_DATA_LBYTE); > - if (ret < 0) > - return ret; > + if (!ret) > + *reg = be16_to_cpu(*reg); > > - val |= ret; > - *reg = val; > - > - return 0; > + return ret; > } > > static int lidar_get_measurement(struct lidar_data *data, u16 *reg) > @@ -237,6 +273,16 @@ static int lidar_probe(struct i2c_client *client, > indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); > if (!indio_dev) > return -ENOMEM; > + data = iio_priv(indio_dev); > + > + if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { > + data->xfer = lidar_i2c_xfer; > + data->i2c_enabled = 1; > + } else if (i2c_check_functionality(client->adapter, > + I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BYTE)) > + data->xfer = lidar_smbus_xfer; > + else > + return -ENOTSUPP; > > indio_dev->info = &lidar_info; > indio_dev->name = LIDAR_DRV_NAME; > @@ -244,7 +290,6 @@ static int lidar_probe(struct i2c_client *client, > indio_dev->num_channels = ARRAY_SIZE(lidar_channels); > indio_dev->modes = INDIO_DIRECT_MODE; > > - data = iio_priv(indio_dev); > i2c_set_clientdata(client, indio_dev); > > data->client = client; > -- > 1.9.1 > ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2015-12-02 5:00 UTC | newest] Thread overview: 3+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2015-12-01 2:16 [PATCH v2 0/1] iio: proximity: lidar: optimize i2c transactions Matt Ranostay 2015-12-01 2:16 ` [PATCH v2 1/1] " Matt Ranostay 2015-12-02 5:00 ` Matt Ranostay
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