On Wed, Apr 18, 2018 at 03:34:09PM +0300, Heikki Krogerus wrote: > If the I2C adapter that the PD controller is attached to > does not support SMBus protocol, the driver needs to handle > block reads separately. The first byte returned in block > read protocol will show the total number of bytes. It needs > to be stripped away. > > This is handled separately in the driver only because right > now we have no way of requesting the used protocol with > regmap-i2c. This is in practice a workaround for what is > really a problem in regmap-i2c. The other option would have > been to register custom regmap, or not use regmap at all, > however, since the solution is very simple, I choose to use > it in this case for convenience. It is easy to remove once > we figure out how to handle this kind of cases in > regmap-i2c. > > Fixes: 0a4c005bd171 ("usb: typec: driver for TI TPS6598x USB Power Delivery > controllers") > Signed-off-by: Heikki Krogerus <heikki.kroge...@linux.intel.com> > --- > drivers/usb/typec/tps6598x.c | 42 ++++++++++++++++++++++++++++++------ > 1 file changed, 35 insertions(+), 7 deletions(-) > > diff --git a/drivers/usb/typec/tps6598x.c b/drivers/usb/typec/tps6598x.c > index 8b8406867c02..82f09cd9792d 100644 > --- a/drivers/usb/typec/tps6598x.c > +++ b/drivers/usb/typec/tps6598x.c > @@ -73,6 +73,7 @@ struct tps6598x { > struct device *dev; > struct regmap *regmap; > struct mutex lock; /* device lock */ > + u8 i2c_protocol:1; > > struct typec_port *port; > struct typec_partner *partner; > @@ -80,6 +81,23 @@ struct tps6598x { > struct typec_capability typec_cap; > }; > > +static int > +tps6598x_block_read(struct tps6598x *tps, u8 reg, void *val, ssize_t len) > +{ > + u8 data[len + 1]; > + int ret; > + > + if (!tps->i2c_protocol) > + return regmap_raw_read(tps->regmap, reg, val, len); > + > + ret = regmap_raw_read(tps->regmap, reg, data, sizeof(data)); > + if (ret) > + return ret; > +
Sanity check ? if (data[0] != len) return -Esomething; Other than that, Reviewed-by: Guenter Roeck <li...@roeck-us.net> > + memcpy(val, &data[1], len); > + return 0; > +} > + > static inline int tps6598x_read16(struct tps6598x *tps, u8 reg, u16 *val) > { > return regmap_raw_read(tps->regmap, reg, val, sizeof(u16)); > @@ -87,12 +105,12 @@ static inline int tps6598x_read16(struct tps6598x *tps, > u8 reg, u16 *val) > > static inline int tps6598x_read32(struct tps6598x *tps, u8 reg, u32 *val) > { > - return regmap_raw_read(tps->regmap, reg, val, sizeof(u32)); > + return tps6598x_block_read(tps, reg, val, sizeof(u32)); > } > > static inline int tps6598x_read64(struct tps6598x *tps, u8 reg, u64 *val) > { > - return regmap_raw_read(tps->regmap, reg, val, sizeof(u64)); > + return tps6598x_block_read(tps, reg, val, sizeof(u64)); > } > > static inline int tps6598x_write16(struct tps6598x *tps, u8 reg, u16 val) > @@ -121,8 +139,8 @@ static int tps6598x_read_partner_identity(struct tps6598x > *tps) > struct tps6598x_rx_identity_reg id; > int ret; > > - ret = regmap_raw_read(tps->regmap, TPS_REG_RX_IDENTITY_SOP, > - &id, sizeof(id)); > + ret = tps6598x_block_read(tps, TPS_REG_RX_IDENTITY_SOP, > + &id, sizeof(id)); > if (ret) > return ret; > > @@ -224,13 +242,13 @@ static int tps6598x_exec_cmd(struct tps6598x *tps, > const char *cmd, > } while (val); > > if (out_len) { > - ret = regmap_raw_read(tps->regmap, TPS_REG_DATA1, > - out_data, out_len); > + ret = tps6598x_block_read(tps, TPS_REG_DATA1, > + out_data, out_len); > if (ret) > return ret; > val = out_data[0]; > } else { > - ret = regmap_read(tps->regmap, TPS_REG_DATA1, &val); > + ret = tps6598x_block_read(tps, TPS_REG_DATA1, &val, sizeof(u8)); > if (ret) > return ret; > } > @@ -385,6 +403,16 @@ static int tps6598x_probe(struct i2c_client *client) > if (!vid) > return -ENODEV; > > + /* > + * Checking can the adapter handle SMBus protocol. If if can not, the > + * driver needs to take care of block reads separately. > + * > + * FIXME: Testing with I2C_FUNC_I2C. regmap-i2c uses I2C protocol > + * unconditionally if the adapter has I2C_FUNC_I2C set. > + */ > + if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) > + tps->i2c_protocol = true; > + > ret = tps6598x_read32(tps, TPS_REG_STATUS, &status); > if (ret < 0) > return ret; > -- > 2.17.0 > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html