| Message ID | 20240122180551.34429-1-francesco@dolcini.it (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v2] treewide, serdev: change receive_buf() return type to size_t | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On Mon, 22 Jan 2024, Francesco Dolcini wrote: > From: Francesco Dolcini <francesco.dolcini@toradex.com> > > receive_buf() is called from ttyport_receive_buf() that expects values > ">= 0" from serdev_controller_receive_buf(), change its return type from > ssize_t to size_t. > > The need for this clean-up was noticed while fixing a warning, see > commit 94d053942544 ("Bluetooth: btnxpuart: fix recv_buf() return value"). > Changing the callback prototype to return an unsigned seems the best way > to document the API and ensure that is properly used. > > GNSS drivers implementation of serdev receive_buf() callback return > directly the return value of gnss_insert_raw(). gnss_insert_raw() > returns a signed int, however this is not an issue since the value > returned is always positive, because of the kfifo_in() implementation. > gnss_insert_raw() could be changed to return also an unsigned, however > this is not implemented here as request by the GNSS maintainer Johan > Hovold. > > Suggested-by: Jiri Slaby <jirislaby@kernel.org> > Link: https://lore.kernel.org/all/087be419-ec6b-47ad-851a-5e1e3ea5cfcc@kernel.org/ > Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com> > Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> #for-iio Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
On Mon, Jan 22, 2024 at 12:06 PM Francesco Dolcini <francesco@dolcini.it> wrote: > > From: Francesco Dolcini <francesco.dolcini@toradex.com> > > receive_buf() is called from ttyport_receive_buf() that expects values > ">= 0" from serdev_controller_receive_buf(), change its return type from > ssize_t to size_t. > > The need for this clean-up was noticed while fixing a warning, see > commit 94d053942544 ("Bluetooth: btnxpuart: fix recv_buf() return value"). > Changing the callback prototype to return an unsigned seems the best way > to document the API and ensure that is properly used. > > GNSS drivers implementation of serdev receive_buf() callback return > directly the return value of gnss_insert_raw(). gnss_insert_raw() > returns a signed int, however this is not an issue since the value > returned is always positive, because of the kfifo_in() implementation. > gnss_insert_raw() could be changed to return also an unsigned, however > this is not implemented here as request by the GNSS maintainer Johan > Hovold. > > Suggested-by: Jiri Slaby <jirislaby@kernel.org> > Link: https://lore.kernel.org/all/087be419-ec6b-47ad-851a-5e1e3ea5cfcc@kernel.org/ > Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com> > Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> #for-iio > --- > v1: > - https://lore.kernel.org/all/20231214170146.641783-1-francesco@dolcini.it/ > v2: > - rebased on 6.8-rc1 > - add acked-by Jonathan > - do not change gnss_insert_raw() > - do not change the code style of the gnss code > - commit message improvements, explain the reasons for doing only minimal > changes on the GNSS part > --- > drivers/bluetooth/btmtkuart.c | 4 ++-- > drivers/bluetooth/btnxpuart.c | 4 ++-- > drivers/bluetooth/hci_serdev.c | 4 ++-- > drivers/gnss/serial.c | 2 +- > drivers/gnss/sirf.c | 2 +- > drivers/greybus/gb-beagleplay.c | 6 +++--- > drivers/iio/chemical/pms7003.c | 4 ++-- > drivers/iio/chemical/scd30_serial.c | 4 ++-- > drivers/iio/chemical/sps30_serial.c | 4 ++-- > drivers/iio/imu/bno055/bno055_ser_core.c | 4 ++-- > drivers/mfd/rave-sp.c | 4 ++-- > drivers/net/ethernet/qualcomm/qca_uart.c | 2 +- > drivers/nfc/pn533/uart.c | 4 ++-- > drivers/nfc/s3fwrn5/uart.c | 4 ++-- > drivers/platform/chrome/cros_ec_uart.c | 4 ++-- > drivers/platform/surface/aggregator/core.c | 4 ++-- > drivers/tty/serdev/serdev-ttyport.c | 10 ++++------ > include/linux/serdev.h | 8 ++++---- > sound/drivers/serial-generic.c | 4 ++-- > 19 files changed, 40 insertions(+), 42 deletions(-) Reviewed-by: Rob Herring <robh@kernel.org>
On 1/22/24 19:05, Francesco Dolcini wrote: > From: Francesco Dolcini <francesco.dolcini@toradex.com> > > receive_buf() is called from ttyport_receive_buf() that expects values > ">= 0" from serdev_controller_receive_buf(), change its return type from > ssize_t to size_t. > > The need for this clean-up was noticed while fixing a warning, see > commit 94d053942544 ("Bluetooth: btnxpuart: fix recv_buf() return value"). > Changing the callback prototype to return an unsigned seems the best way > to document the API and ensure that is properly used. > > GNSS drivers implementation of serdev receive_buf() callback return > directly the return value of gnss_insert_raw(). gnss_insert_raw() > returns a signed int, however this is not an issue since the value > returned is always positive, because of the kfifo_in() implementation. > gnss_insert_raw() could be changed to return also an unsigned, however > this is not implemented here as request by the GNSS maintainer Johan > Hovold. > > Suggested-by: Jiri Slaby <jirislaby@kernel.org> > Link: https://lore.kernel.org/all/087be419-ec6b-47ad-851a-5e1e3ea5cfcc@kernel.org/ > Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com> > Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> #for-iio Acked-by: Maximilian Luz <luzmaximilian@gmail.com> # for platform/surface > --- > v1: > - https://lore.kernel.org/all/20231214170146.641783-1-francesco@dolcini.it/ > v2: > - rebased on 6.8-rc1 > - add acked-by Jonathan > - do not change gnss_insert_raw() > - do not change the code style of the gnss code > - commit message improvements, explain the reasons for doing only minimal > changes on the GNSS part > --- > drivers/bluetooth/btmtkuart.c | 4 ++-- > drivers/bluetooth/btnxpuart.c | 4 ++-- > drivers/bluetooth/hci_serdev.c | 4 ++-- > drivers/gnss/serial.c | 2 +- > drivers/gnss/sirf.c | 2 +- > drivers/greybus/gb-beagleplay.c | 6 +++--- > drivers/iio/chemical/pms7003.c | 4 ++-- > drivers/iio/chemical/scd30_serial.c | 4 ++-- > drivers/iio/chemical/sps30_serial.c | 4 ++-- > drivers/iio/imu/bno055/bno055_ser_core.c | 4 ++-- > drivers/mfd/rave-sp.c | 4 ++-- > drivers/net/ethernet/qualcomm/qca_uart.c | 2 +- > drivers/nfc/pn533/uart.c | 4 ++-- > drivers/nfc/s3fwrn5/uart.c | 4 ++-- > drivers/platform/chrome/cros_ec_uart.c | 4 ++-- > drivers/platform/surface/aggregator/core.c | 4 ++-- > drivers/tty/serdev/serdev-ttyport.c | 10 ++++------ > include/linux/serdev.h | 8 ++++---- > sound/drivers/serial-generic.c | 4 ++-- > 19 files changed, 40 insertions(+), 42 deletions(-) > > diff --git a/drivers/bluetooth/btmtkuart.c b/drivers/bluetooth/btmtkuart.c > index 3c84fcbda01a..e6bc4a73c9fc 100644 > --- a/drivers/bluetooth/btmtkuart.c > +++ b/drivers/bluetooth/btmtkuart.c > @@ -383,8 +383,8 @@ static void btmtkuart_recv(struct hci_dev *hdev, const u8 *data, size_t count) > } > } > > -static ssize_t btmtkuart_receive_buf(struct serdev_device *serdev, > - const u8 *data, size_t count) > +static size_t btmtkuart_receive_buf(struct serdev_device *serdev, > + const u8 *data, size_t count) > { > struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev); > > diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c > index 1d592ac413d1..056bef5b2919 100644 > --- a/drivers/bluetooth/btnxpuart.c > +++ b/drivers/bluetooth/btnxpuart.c > @@ -1264,8 +1264,8 @@ static const struct h4_recv_pkt nxp_recv_pkts[] = { > { NXP_RECV_FW_REQ_V3, .recv = nxp_recv_fw_req_v3 }, > }; > > -static ssize_t btnxpuart_receive_buf(struct serdev_device *serdev, > - const u8 *data, size_t count) > +static size_t btnxpuart_receive_buf(struct serdev_device *serdev, > + const u8 *data, size_t count) > { > struct btnxpuart_dev *nxpdev = serdev_device_get_drvdata(serdev); > > diff --git a/drivers/bluetooth/hci_serdev.c b/drivers/bluetooth/hci_serdev.c > index 39c8b567da3c..a3c3beb2806d 100644 > --- a/drivers/bluetooth/hci_serdev.c > +++ b/drivers/bluetooth/hci_serdev.c > @@ -271,8 +271,8 @@ static void hci_uart_write_wakeup(struct serdev_device *serdev) > * > * Return: number of processed bytes > */ > -static ssize_t hci_uart_receive_buf(struct serdev_device *serdev, > - const u8 *data, size_t count) > +static size_t hci_uart_receive_buf(struct serdev_device *serdev, > + const u8 *data, size_t count) > { > struct hci_uart *hu = serdev_device_get_drvdata(serdev); > > diff --git a/drivers/gnss/serial.c b/drivers/gnss/serial.c > index baa956494e79..0e43bf6294f8 100644 > --- a/drivers/gnss/serial.c > +++ b/drivers/gnss/serial.c > @@ -80,7 +80,7 @@ static const struct gnss_operations gnss_serial_gnss_ops = { > .write_raw = gnss_serial_write_raw, > }; > > -static ssize_t gnss_serial_receive_buf(struct serdev_device *serdev, > +static size_t gnss_serial_receive_buf(struct serdev_device *serdev, > const u8 *buf, size_t count) > { > struct gnss_serial *gserial = serdev_device_get_drvdata(serdev); > diff --git a/drivers/gnss/sirf.c b/drivers/gnss/sirf.c > index 6801a8fb2040..79375d14bbb6 100644 > --- a/drivers/gnss/sirf.c > +++ b/drivers/gnss/sirf.c > @@ -160,7 +160,7 @@ static const struct gnss_operations sirf_gnss_ops = { > .write_raw = sirf_write_raw, > }; > > -static ssize_t sirf_receive_buf(struct serdev_device *serdev, > +static size_t sirf_receive_buf(struct serdev_device *serdev, > const u8 *buf, size_t count) > { > struct sirf_data *data = serdev_device_get_drvdata(serdev); > diff --git a/drivers/greybus/gb-beagleplay.c b/drivers/greybus/gb-beagleplay.c > index c3e90025064b..33f8fad70260 100644 > --- a/drivers/greybus/gb-beagleplay.c > +++ b/drivers/greybus/gb-beagleplay.c > @@ -271,7 +271,7 @@ static void hdlc_rx_frame(struct gb_beagleplay *bg) > } > } > > -static ssize_t hdlc_rx(struct gb_beagleplay *bg, const u8 *data, size_t count) > +static size_t hdlc_rx(struct gb_beagleplay *bg, const u8 *data, size_t count) > { > size_t i; > u8 c; > @@ -331,8 +331,8 @@ static void hdlc_deinit(struct gb_beagleplay *bg) > flush_work(&bg->tx_work); > } > > -static ssize_t gb_tty_receive(struct serdev_device *sd, const u8 *data, > - size_t count) > +static size_t gb_tty_receive(struct serdev_device *sd, const u8 *data, > + size_t count) > { > struct gb_beagleplay *bg = serdev_device_get_drvdata(sd); > > diff --git a/drivers/iio/chemical/pms7003.c b/drivers/iio/chemical/pms7003.c > index b5cf15a515d2..43025866d5b7 100644 > --- a/drivers/iio/chemical/pms7003.c > +++ b/drivers/iio/chemical/pms7003.c > @@ -211,8 +211,8 @@ static bool pms7003_frame_is_okay(struct pms7003_frame *frame) > return checksum == pms7003_calc_checksum(frame); > } > > -static ssize_t pms7003_receive_buf(struct serdev_device *serdev, const u8 *buf, > - size_t size) > +static size_t pms7003_receive_buf(struct serdev_device *serdev, const u8 *buf, > + size_t size) > { > struct iio_dev *indio_dev = serdev_device_get_drvdata(serdev); > struct pms7003_state *state = iio_priv(indio_dev); > diff --git a/drivers/iio/chemical/scd30_serial.c b/drivers/iio/chemical/scd30_serial.c > index a47654591e55..2adb76dbb020 100644 > --- a/drivers/iio/chemical/scd30_serial.c > +++ b/drivers/iio/chemical/scd30_serial.c > @@ -174,8 +174,8 @@ static int scd30_serdev_command(struct scd30_state *state, enum scd30_cmd cmd, u > return 0; > } > > -static ssize_t scd30_serdev_receive_buf(struct serdev_device *serdev, > - const u8 *buf, size_t size) > +static size_t scd30_serdev_receive_buf(struct serdev_device *serdev, > + const u8 *buf, size_t size) > { > struct iio_dev *indio_dev = serdev_device_get_drvdata(serdev); > struct scd30_serdev_priv *priv; > diff --git a/drivers/iio/chemical/sps30_serial.c b/drivers/iio/chemical/sps30_serial.c > index 3afa89f8acc3..a6dfbe28c914 100644 > --- a/drivers/iio/chemical/sps30_serial.c > +++ b/drivers/iio/chemical/sps30_serial.c > @@ -210,8 +210,8 @@ static int sps30_serial_command(struct sps30_state *state, unsigned char cmd, > return rsp_size; > } > > -static ssize_t sps30_serial_receive_buf(struct serdev_device *serdev, > - const u8 *buf, size_t size) > +static size_t sps30_serial_receive_buf(struct serdev_device *serdev, > + const u8 *buf, size_t size) > { > struct iio_dev *indio_dev = dev_get_drvdata(&serdev->dev); > struct sps30_serial_priv *priv; > diff --git a/drivers/iio/imu/bno055/bno055_ser_core.c b/drivers/iio/imu/bno055/bno055_ser_core.c > index 5677bdf4f846..694ff14a3aa2 100644 > --- a/drivers/iio/imu/bno055/bno055_ser_core.c > +++ b/drivers/iio/imu/bno055/bno055_ser_core.c > @@ -378,8 +378,8 @@ static void bno055_ser_handle_rx(struct bno055_ser_priv *priv, int status) > * Also, we assume to RX one pkt per time (i.e. the HW doesn't send anything > * unless we require to AND we don't queue more than one request per time). > */ > -static ssize_t bno055_ser_receive_buf(struct serdev_device *serdev, > - const u8 *buf, size_t size) > +static size_t bno055_ser_receive_buf(struct serdev_device *serdev, > + const u8 *buf, size_t size) > { > int status; > struct bno055_ser_priv *priv = serdev_device_get_drvdata(serdev); > diff --git a/drivers/mfd/rave-sp.c b/drivers/mfd/rave-sp.c > index 6ff84b2600c5..62a6613fb070 100644 > --- a/drivers/mfd/rave-sp.c > +++ b/drivers/mfd/rave-sp.c > @@ -471,8 +471,8 @@ static void rave_sp_receive_frame(struct rave_sp *sp, > rave_sp_receive_reply(sp, data, length); > } > > -static ssize_t rave_sp_receive_buf(struct serdev_device *serdev, > - const u8 *buf, size_t size) > +static size_t rave_sp_receive_buf(struct serdev_device *serdev, > + const u8 *buf, size_t size) > { > struct device *dev = &serdev->dev; > struct rave_sp *sp = dev_get_drvdata(dev); > diff --git a/drivers/net/ethernet/qualcomm/qca_uart.c b/drivers/net/ethernet/qualcomm/qca_uart.c > index 223321897b96..20f50bde82ac 100644 > --- a/drivers/net/ethernet/qualcomm/qca_uart.c > +++ b/drivers/net/ethernet/qualcomm/qca_uart.c > @@ -58,7 +58,7 @@ struct qcauart { > unsigned char *tx_buffer; > }; > > -static ssize_t > +static size_t > qca_tty_receive(struct serdev_device *serdev, const u8 *data, size_t count) > { > struct qcauart *qca = serdev_device_get_drvdata(serdev); > diff --git a/drivers/nfc/pn533/uart.c b/drivers/nfc/pn533/uart.c > index 2eb5978bd79e..cfbbe0713317 100644 > --- a/drivers/nfc/pn533/uart.c > +++ b/drivers/nfc/pn533/uart.c > @@ -203,8 +203,8 @@ static int pn532_uart_rx_is_frame(struct sk_buff *skb) > return 0; > } > > -static ssize_t pn532_receive_buf(struct serdev_device *serdev, > - const u8 *data, size_t count) > +static size_t pn532_receive_buf(struct serdev_device *serdev, > + const u8 *data, size_t count) > { > struct pn532_uart_phy *dev = serdev_device_get_drvdata(serdev); > size_t i; > diff --git a/drivers/nfc/s3fwrn5/uart.c b/drivers/nfc/s3fwrn5/uart.c > index 456d3947116c..9c09c10c2a46 100644 > --- a/drivers/nfc/s3fwrn5/uart.c > +++ b/drivers/nfc/s3fwrn5/uart.c > @@ -51,8 +51,8 @@ static const struct s3fwrn5_phy_ops uart_phy_ops = { > .write = s3fwrn82_uart_write, > }; > > -static ssize_t s3fwrn82_uart_read(struct serdev_device *serdev, > - const u8 *data, size_t count) > +static size_t s3fwrn82_uart_read(struct serdev_device *serdev, > + const u8 *data, size_t count) > { > struct s3fwrn82_uart_phy *phy = serdev_device_get_drvdata(serdev); > size_t i; > diff --git a/drivers/platform/chrome/cros_ec_uart.c b/drivers/platform/chrome/cros_ec_uart.c > index 68d80559fddc..8ea867c2a01a 100644 > --- a/drivers/platform/chrome/cros_ec_uart.c > +++ b/drivers/platform/chrome/cros_ec_uart.c > @@ -81,8 +81,8 @@ struct cros_ec_uart { > struct response_info response; > }; > > -static ssize_t cros_ec_uart_rx_bytes(struct serdev_device *serdev, > - const u8 *data, size_t count) > +static size_t cros_ec_uart_rx_bytes(struct serdev_device *serdev, > + const u8 *data, size_t count) > { > struct ec_host_response *host_response; > struct cros_ec_device *ec_dev = serdev_device_get_drvdata(serdev); > diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c > index 9591a28bc38a..ba550eaa06fc 100644 > --- a/drivers/platform/surface/aggregator/core.c > +++ b/drivers/platform/surface/aggregator/core.c > @@ -227,8 +227,8 @@ EXPORT_SYMBOL_GPL(ssam_client_bind); > > /* -- Glue layer (serdev_device -> ssam_controller). ------------------------ */ > > -static ssize_t ssam_receive_buf(struct serdev_device *dev, const u8 *buf, > - size_t n) > +static size_t ssam_receive_buf(struct serdev_device *dev, const u8 *buf, > + size_t n) > { > struct ssam_controller *ctrl; > int ret; > diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c > index e94e090cf0a1..3d7ae7fa5018 100644 > --- a/drivers/tty/serdev/serdev-ttyport.c > +++ b/drivers/tty/serdev/serdev-ttyport.c > @@ -27,19 +27,17 @@ static size_t ttyport_receive_buf(struct tty_port *port, const u8 *cp, > { > struct serdev_controller *ctrl = port->client_data; > struct serport *serport = serdev_controller_get_drvdata(ctrl); > - int ret; > + size_t ret; > > if (!test_bit(SERPORT_ACTIVE, &serport->flags)) > return 0; > > ret = serdev_controller_receive_buf(ctrl, cp, count); > > - dev_WARN_ONCE(&ctrl->dev, ret < 0 || ret > count, > - "receive_buf returns %d (count = %zu)\n", > + dev_WARN_ONCE(&ctrl->dev, ret > count, > + "receive_buf returns %zu (count = %zu)\n", > ret, count); > - if (ret < 0) > - return 0; > - else if (ret > count) > + if (ret > count) > return count; > > return ret; > diff --git a/include/linux/serdev.h b/include/linux/serdev.h > index 3fab88ba265e..ff78efc1f60d 100644 > --- a/include/linux/serdev.h > +++ b/include/linux/serdev.h > @@ -27,7 +27,7 @@ struct serdev_device; > * not sleep. > */ > struct serdev_device_ops { > - ssize_t (*receive_buf)(struct serdev_device *, const u8 *, size_t); > + size_t (*receive_buf)(struct serdev_device *, const u8 *, size_t); > void (*write_wakeup)(struct serdev_device *); > }; > > @@ -185,9 +185,9 @@ static inline void serdev_controller_write_wakeup(struct serdev_controller *ctrl > serdev->ops->write_wakeup(serdev); > } > > -static inline ssize_t serdev_controller_receive_buf(struct serdev_controller *ctrl, > - const u8 *data, > - size_t count) > +static inline size_t serdev_controller_receive_buf(struct serdev_controller *ctrl, > + const u8 *data, > + size_t count) > { > struct serdev_device *serdev = ctrl->serdev; > > diff --git a/sound/drivers/serial-generic.c b/sound/drivers/serial-generic.c > index d6e5aafd697c..36409a56c675 100644 > --- a/sound/drivers/serial-generic.c > +++ b/sound/drivers/serial-generic.c > @@ -100,8 +100,8 @@ static void snd_serial_generic_write_wakeup(struct serdev_device *serdev) > snd_serial_generic_tx_wakeup(drvdata); > } > > -static ssize_t snd_serial_generic_receive_buf(struct serdev_device *serdev, > - const u8 *buf, size_t count) > +static size_t snd_serial_generic_receive_buf(struct serdev_device *serdev, > + const u8 *buf, size_t count) > { > int ret; > struct snd_serial_generic *drvdata = serdev_device_get_drvdata(serdev);
On 1/22/24 12:05 PM, Francesco Dolcini wrote: > From: Francesco Dolcini <francesco.dolcini@toradex.com> > > receive_buf() is called from ttyport_receive_buf() that expects values > ">= 0" from serdev_controller_receive_buf(), change its return type from > ssize_t to size_t. > > The need for this clean-up was noticed while fixing a warning, see > commit 94d053942544 ("Bluetooth: btnxpuart: fix recv_buf() return value"). > Changing the callback prototype to return an unsigned seems the best way > to document the API and ensure that is properly used. > > GNSS drivers implementation of serdev receive_buf() callback return > directly the return value of gnss_insert_raw(). gnss_insert_raw() > returns a signed int, however this is not an issue since the value > returned is always positive, because of the kfifo_in() implementation. Agreed. > gnss_insert_raw() could be changed to return also an unsigned, however > this is not implemented here as request by the GNSS maintainer Johan > Hovold. I was going to suggest this, and suggest changing the "ret" in gnss_insert_raw() to return size_t. But to really do that right it would include some other changes as well. Leaving it as an int as Johan suggests preserves correct behavior. One minor point below, plus a couple comments affirming that an int return value is OK because it's always non-negative. Reviewed-by: Alex Elder <elder@linaro.org> > Suggested-by: Jiri Slaby <jirislaby@kernel.org> > Link: https://lore.kernel.org/all/087be419-ec6b-47ad-851a-5e1e3ea5cfcc@kernel.org/ > Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com> > Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> #for-iio > --- > v1: > - https://lore.kernel.org/all/20231214170146.641783-1-francesco@dolcini.it/ > v2: > - rebased on 6.8-rc1 > - add acked-by Jonathan > - do not change gnss_insert_raw() > - do not change the code style of the gnss code > - commit message improvements, explain the reasons for doing only minimal > changes on the GNSS part > --- > drivers/bluetooth/btmtkuart.c | 4 ++-- > drivers/bluetooth/btnxpuart.c | 4 ++-- > drivers/bluetooth/hci_serdev.c | 4 ++-- > drivers/gnss/serial.c | 2 +- > drivers/gnss/sirf.c | 2 +- > drivers/greybus/gb-beagleplay.c | 6 +++--- > drivers/iio/chemical/pms7003.c | 4 ++-- > drivers/iio/chemical/scd30_serial.c | 4 ++-- > drivers/iio/chemical/sps30_serial.c | 4 ++-- > drivers/iio/imu/bno055/bno055_ser_core.c | 4 ++-- > drivers/mfd/rave-sp.c | 4 ++-- > drivers/net/ethernet/qualcomm/qca_uart.c | 2 +- > drivers/nfc/pn533/uart.c | 4 ++-- > drivers/nfc/s3fwrn5/uart.c | 4 ++-- > drivers/platform/chrome/cros_ec_uart.c | 4 ++-- > drivers/platform/surface/aggregator/core.c | 4 ++-- > drivers/tty/serdev/serdev-ttyport.c | 10 ++++------ > include/linux/serdev.h | 8 ++++---- > sound/drivers/serial-generic.c | 4 ++-- > 19 files changed, 40 insertions(+), 42 deletions(-) > . . . > diff --git a/drivers/mfd/rave-sp.c b/drivers/mfd/rave-sp.c > index 6ff84b2600c5..62a6613fb070 100644 > --- a/drivers/mfd/rave-sp.c > +++ b/drivers/mfd/rave-sp.c > @@ -471,8 +471,8 @@ static void rave_sp_receive_frame(struct rave_sp *sp, > rave_sp_receive_reply(sp, data, length); > } > > -static ssize_t rave_sp_receive_buf(struct serdev_device *serdev, > - const u8 *buf, size_t size) > +static size_t rave_sp_receive_buf(struct serdev_device *serdev, > + const u8 *buf, size_t size) > { > struct device *dev = &serdev->dev; > struct rave_sp *sp = dev_get_drvdata(dev); One return path in this function returns (src - buf), which is *almost* guaranteed to be positive. The one case it wouldn't be is if the assignment of end wraps around, and that's not checked. I think it's fine, but... That seems theoretically possible. > diff --git a/drivers/net/ethernet/qualcomm/qca_uart.c b/drivers/net/ethernet/qualcomm/qca_uart.c > index 223321897b96..20f50bde82ac 100644 . . . > diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c > index 9591a28bc38a..ba550eaa06fc 100644 > --- a/drivers/platform/surface/aggregator/core.c > +++ b/drivers/platform/surface/aggregator/core.c > @@ -227,8 +227,8 @@ EXPORT_SYMBOL_GPL(ssam_client_bind); > > /* -- Glue layer (serdev_device -> ssam_controller). ------------------------ */ > > -static ssize_t ssam_receive_buf(struct serdev_device *dev, const u8 *buf, > - size_t n) > +static size_t ssam_receive_buf(struct serdev_device *dev, const u8 *buf, > + size_t n) > { > struct ssam_controller *ctrl; > int ret; Here you the return value will be positive despite ret being a signed int. So like the GNSS case, this is OK. > diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c > index e94e090cf0a1..3d7ae7fa5018 100644 . . . > diff --git a/sound/drivers/serial-generic.c b/sound/drivers/serial-generic.c > index d6e5aafd697c..36409a56c675 100644 > --- a/sound/drivers/serial-generic.c > +++ b/sound/drivers/serial-generic.c > @@ -100,8 +100,8 @@ static void snd_serial_generic_write_wakeup(struct serdev_device *serdev) > snd_serial_generic_tx_wakeup(drvdata); > } > > -static ssize_t snd_serial_generic_receive_buf(struct serdev_device *serdev, > - const u8 *buf, size_t count) > +static size_t snd_serial_generic_receive_buf(struct serdev_device *serdev, > + const u8 *buf, size_t count) > { > int ret; > struct snd_serial_generic *drvdata = serdev_device_get_drvdata(serdev); Same thing here.
On Mon, Jan 22, 2024 at 07:05:51PM +0100, Francesco Dolcini wrote: > From: Francesco Dolcini <francesco.dolcini@toradex.com> > > receive_buf() is called from ttyport_receive_buf() that expects values > ">= 0" from serdev_controller_receive_buf(), change its return type from > ssize_t to size_t. > > The need for this clean-up was noticed while fixing a warning, see > commit 94d053942544 ("Bluetooth: btnxpuart: fix recv_buf() return value"). > Changing the callback prototype to return an unsigned seems the best way > to document the API and ensure that is properly used. > > GNSS drivers implementation of serdev receive_buf() callback return > directly the return value of gnss_insert_raw(). gnss_insert_raw() > returns a signed int, however this is not an issue since the value > returned is always positive, because of the kfifo_in() implementation. > gnss_insert_raw() could be changed to return also an unsigned, however > this is not implemented here as request by the GNSS maintainer Johan > Hovold. > > Suggested-by: Jiri Slaby <jirislaby@kernel.org> > Link: https://lore.kernel.org/all/087be419-ec6b-47ad-851a-5e1e3ea5cfcc@kernel.org/ > Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com> > Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> #for-iio > --- > v1: > - https://lore.kernel.org/all/20231214170146.641783-1-francesco@dolcini.it/ > v2: > - rebased on 6.8-rc1 > - add acked-by Jonathan > - do not change gnss_insert_raw() > - do not change the code style of the gnss code > - commit message improvements, explain the reasons for doing only minimal > changes on the GNSS part Looks good to me now: Reviewed-by: Johan Hovold <johan@kernel.org>
On Mon, 22 Jan 2024, Francesco Dolcini wrote: > From: Francesco Dolcini <francesco.dolcini@toradex.com> > > receive_buf() is called from ttyport_receive_buf() that expects values > ">= 0" from serdev_controller_receive_buf(), change its return type from > ssize_t to size_t. > > The need for this clean-up was noticed while fixing a warning, see > commit 94d053942544 ("Bluetooth: btnxpuart: fix recv_buf() return value"). > Changing the callback prototype to return an unsigned seems the best way > to document the API and ensure that is properly used. > > GNSS drivers implementation of serdev receive_buf() callback return > directly the return value of gnss_insert_raw(). gnss_insert_raw() > returns a signed int, however this is not an issue since the value > returned is always positive, because of the kfifo_in() implementation. > gnss_insert_raw() could be changed to return also an unsigned, however > this is not implemented here as request by the GNSS maintainer Johan > Hovold. > > Suggested-by: Jiri Slaby <jirislaby@kernel.org> > Link: https://lore.kernel.org/all/087be419-ec6b-47ad-851a-5e1e3ea5cfcc@kernel.org/ > Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com> > Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> #for-iio > --- > v1: > - https://lore.kernel.org/all/20231214170146.641783-1-francesco@dolcini.it/ > v2: > - rebased on 6.8-rc1 > - add acked-by Jonathan > - do not change gnss_insert_raw() > - do not change the code style of the gnss code > - commit message improvements, explain the reasons for doing only minimal > changes on the GNSS part > --- > drivers/bluetooth/btmtkuart.c | 4 ++-- > drivers/bluetooth/btnxpuart.c | 4 ++-- > drivers/bluetooth/hci_serdev.c | 4 ++-- > drivers/gnss/serial.c | 2 +- > drivers/gnss/sirf.c | 2 +- > drivers/greybus/gb-beagleplay.c | 6 +++--- > drivers/iio/chemical/pms7003.c | 4 ++-- > drivers/iio/chemical/scd30_serial.c | 4 ++-- > drivers/iio/chemical/sps30_serial.c | 4 ++-- > drivers/iio/imu/bno055/bno055_ser_core.c | 4 ++-- > drivers/mfd/rave-sp.c | 4 ++-- Acked-by: Lee Jones <lee@kernel.org> > drivers/net/ethernet/qualcomm/qca_uart.c | 2 +- > drivers/nfc/pn533/uart.c | 4 ++-- > drivers/nfc/s3fwrn5/uart.c | 4 ++-- > drivers/platform/chrome/cros_ec_uart.c | 4 ++-- > drivers/platform/surface/aggregator/core.c | 4 ++-- > drivers/tty/serdev/serdev-ttyport.c | 10 ++++------ > include/linux/serdev.h | 8 ++++---- > sound/drivers/serial-generic.c | 4 ++-- > 19 files changed, 40 insertions(+), 42 deletions(-)
Hello: This patch was applied to chrome-platform/linux.git (for-kernelci) by Greg Kroah-Hartman <gregkh@linuxfoundation.org>: On Mon, 22 Jan 2024 19:05:51 +0100 you wrote: > From: Francesco Dolcini <francesco.dolcini@toradex.com> > > receive_buf() is called from ttyport_receive_buf() that expects values > ">= 0" from serdev_controller_receive_buf(), change its return type from > ssize_t to size_t. > > The need for this clean-up was noticed while fixing a warning, see > commit 94d053942544 ("Bluetooth: btnxpuart: fix recv_buf() return value"). > Changing the callback prototype to return an unsigned seems the best way > to document the API and ensure that is properly used. > > [...] Here is the summary with links: - [v2] treewide, serdev: change receive_buf() return type to size_t https://git.kernel.org/chrome-platform/c/fed99212acae You are awesome, thank you!
Hello: This patch was applied to chrome-platform/linux.git (for-next) by Greg Kroah-Hartman <gregkh@linuxfoundation.org>: On Mon, 22 Jan 2024 19:05:51 +0100 you wrote: > From: Francesco Dolcini <francesco.dolcini@toradex.com> > > receive_buf() is called from ttyport_receive_buf() that expects values > ">= 0" from serdev_controller_receive_buf(), change its return type from > ssize_t to size_t. > > The need for this clean-up was noticed while fixing a warning, see > commit 94d053942544 ("Bluetooth: btnxpuart: fix recv_buf() return value"). > Changing the callback prototype to return an unsigned seems the best way > to document the API and ensure that is properly used. > > [...] Here is the summary with links: - [v2] treewide, serdev: change receive_buf() return type to size_t https://git.kernel.org/chrome-platform/c/fed99212acae You are awesome, thank you!
diff --git a/drivers/bluetooth/btmtkuart.c b/drivers/bluetooth/btmtkuart.c index 3c84fcbda01a..e6bc4a73c9fc 100644 --- a/drivers/bluetooth/btmtkuart.c +++ b/drivers/bluetooth/btmtkuart.c @@ -383,8 +383,8 @@ static void btmtkuart_recv(struct hci_dev *hdev, const u8 *data, size_t count) } } -static ssize_t btmtkuart_receive_buf(struct serdev_device *serdev, - const u8 *data, size_t count) +static size_t btmtkuart_receive_buf(struct serdev_device *serdev, + const u8 *data, size_t count) { struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev); diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c index 1d592ac413d1..056bef5b2919 100644 --- a/drivers/bluetooth/btnxpuart.c +++ b/drivers/bluetooth/btnxpuart.c @@ -1264,8 +1264,8 @@ static const struct h4_recv_pkt nxp_recv_pkts[] = { { NXP_RECV_FW_REQ_V3, .recv = nxp_recv_fw_req_v3 }, }; -static ssize_t btnxpuart_receive_buf(struct serdev_device *serdev, - const u8 *data, size_t count) +static size_t btnxpuart_receive_buf(struct serdev_device *serdev, + const u8 *data, size_t count) { struct btnxpuart_dev *nxpdev = serdev_device_get_drvdata(serdev); diff --git a/drivers/bluetooth/hci_serdev.c b/drivers/bluetooth/hci_serdev.c index 39c8b567da3c..a3c3beb2806d 100644 --- a/drivers/bluetooth/hci_serdev.c +++ b/drivers/bluetooth/hci_serdev.c @@ -271,8 +271,8 @@ static void hci_uart_write_wakeup(struct serdev_device *serdev) * * Return: number of processed bytes */ -static ssize_t hci_uart_receive_buf(struct serdev_device *serdev, - const u8 *data, size_t count) +static size_t hci_uart_receive_buf(struct serdev_device *serdev, + const u8 *data, size_t count) { struct hci_uart *hu = serdev_device_get_drvdata(serdev); diff --git a/drivers/gnss/serial.c b/drivers/gnss/serial.c index baa956494e79..0e43bf6294f8 100644 --- a/drivers/gnss/serial.c +++ b/drivers/gnss/serial.c @@ -80,7 +80,7 @@ static const struct gnss_operations gnss_serial_gnss_ops = { .write_raw = gnss_serial_write_raw, }; -static ssize_t gnss_serial_receive_buf(struct serdev_device *serdev, +static size_t gnss_serial_receive_buf(struct serdev_device *serdev, const u8 *buf, size_t count) { struct gnss_serial *gserial = serdev_device_get_drvdata(serdev); diff --git a/drivers/gnss/sirf.c b/drivers/gnss/sirf.c index 6801a8fb2040..79375d14bbb6 100644 --- a/drivers/gnss/sirf.c +++ b/drivers/gnss/sirf.c @@ -160,7 +160,7 @@ static const struct gnss_operations sirf_gnss_ops = { .write_raw = sirf_write_raw, }; -static ssize_t sirf_receive_buf(struct serdev_device *serdev, +static size_t sirf_receive_buf(struct serdev_device *serdev, const u8 *buf, size_t count) { struct sirf_data *data = serdev_device_get_drvdata(serdev); diff --git a/drivers/greybus/gb-beagleplay.c b/drivers/greybus/gb-beagleplay.c index c3e90025064b..33f8fad70260 100644 --- a/drivers/greybus/gb-beagleplay.c +++ b/drivers/greybus/gb-beagleplay.c @@ -271,7 +271,7 @@ static void hdlc_rx_frame(struct gb_beagleplay *bg) } } -static ssize_t hdlc_rx(struct gb_beagleplay *bg, const u8 *data, size_t count) +static size_t hdlc_rx(struct gb_beagleplay *bg, const u8 *data, size_t count) { size_t i; u8 c; @@ -331,8 +331,8 @@ static void hdlc_deinit(struct gb_beagleplay *bg) flush_work(&bg->tx_work); } -static ssize_t gb_tty_receive(struct serdev_device *sd, const u8 *data, - size_t count) +static size_t gb_tty_receive(struct serdev_device *sd, const u8 *data, + size_t count) { struct gb_beagleplay *bg = serdev_device_get_drvdata(sd); diff --git a/drivers/iio/chemical/pms7003.c b/drivers/iio/chemical/pms7003.c index b5cf15a515d2..43025866d5b7 100644 --- a/drivers/iio/chemical/pms7003.c +++ b/drivers/iio/chemical/pms7003.c @@ -211,8 +211,8 @@ static bool pms7003_frame_is_okay(struct pms7003_frame *frame) return checksum == pms7003_calc_checksum(frame); } -static ssize_t pms7003_receive_buf(struct serdev_device *serdev, const u8 *buf, - size_t size) +static size_t pms7003_receive_buf(struct serdev_device *serdev, const u8 *buf, + size_t size) { struct iio_dev *indio_dev = serdev_device_get_drvdata(serdev); struct pms7003_state *state = iio_priv(indio_dev); diff --git a/drivers/iio/chemical/scd30_serial.c b/drivers/iio/chemical/scd30_serial.c index a47654591e55..2adb76dbb020 100644 --- a/drivers/iio/chemical/scd30_serial.c +++ b/drivers/iio/chemical/scd30_serial.c @@ -174,8 +174,8 @@ static int scd30_serdev_command(struct scd30_state *state, enum scd30_cmd cmd, u return 0; } -static ssize_t scd30_serdev_receive_buf(struct serdev_device *serdev, - const u8 *buf, size_t size) +static size_t scd30_serdev_receive_buf(struct serdev_device *serdev, + const u8 *buf, size_t size) { struct iio_dev *indio_dev = serdev_device_get_drvdata(serdev); struct scd30_serdev_priv *priv; diff --git a/drivers/iio/chemical/sps30_serial.c b/drivers/iio/chemical/sps30_serial.c index 3afa89f8acc3..a6dfbe28c914 100644 --- a/drivers/iio/chemical/sps30_serial.c +++ b/drivers/iio/chemical/sps30_serial.c @@ -210,8 +210,8 @@ static int sps30_serial_command(struct sps30_state *state, unsigned char cmd, return rsp_size; } -static ssize_t sps30_serial_receive_buf(struct serdev_device *serdev, - const u8 *buf, size_t size) +static size_t sps30_serial_receive_buf(struct serdev_device *serdev, + const u8 *buf, size_t size) { struct iio_dev *indio_dev = dev_get_drvdata(&serdev->dev); struct sps30_serial_priv *priv; diff --git a/drivers/iio/imu/bno055/bno055_ser_core.c b/drivers/iio/imu/bno055/bno055_ser_core.c index 5677bdf4f846..694ff14a3aa2 100644 --- a/drivers/iio/imu/bno055/bno055_ser_core.c +++ b/drivers/iio/imu/bno055/bno055_ser_core.c @@ -378,8 +378,8 @@ static void bno055_ser_handle_rx(struct bno055_ser_priv *priv, int status) * Also, we assume to RX one pkt per time (i.e. the HW doesn't send anything * unless we require to AND we don't queue more than one request per time). */ -static ssize_t bno055_ser_receive_buf(struct serdev_device *serdev, - const u8 *buf, size_t size) +static size_t bno055_ser_receive_buf(struct serdev_device *serdev, + const u8 *buf, size_t size) { int status; struct bno055_ser_priv *priv = serdev_device_get_drvdata(serdev); diff --git a/drivers/mfd/rave-sp.c b/drivers/mfd/rave-sp.c index 6ff84b2600c5..62a6613fb070 100644 --- a/drivers/mfd/rave-sp.c +++ b/drivers/mfd/rave-sp.c @@ -471,8 +471,8 @@ static void rave_sp_receive_frame(struct rave_sp *sp, rave_sp_receive_reply(sp, data, length); } -static ssize_t rave_sp_receive_buf(struct serdev_device *serdev, - const u8 *buf, size_t size) +static size_t rave_sp_receive_buf(struct serdev_device *serdev, + const u8 *buf, size_t size) { struct device *dev = &serdev->dev; struct rave_sp *sp = dev_get_drvdata(dev); diff --git a/drivers/net/ethernet/qualcomm/qca_uart.c b/drivers/net/ethernet/qualcomm/qca_uart.c index 223321897b96..20f50bde82ac 100644 --- a/drivers/net/ethernet/qualcomm/qca_uart.c +++ b/drivers/net/ethernet/qualcomm/qca_uart.c @@ -58,7 +58,7 @@ struct qcauart { unsigned char *tx_buffer; }; -static ssize_t +static size_t qca_tty_receive(struct serdev_device *serdev, const u8 *data, size_t count) { struct qcauart *qca = serdev_device_get_drvdata(serdev); diff --git a/drivers/nfc/pn533/uart.c b/drivers/nfc/pn533/uart.c index 2eb5978bd79e..cfbbe0713317 100644 --- a/drivers/nfc/pn533/uart.c +++ b/drivers/nfc/pn533/uart.c @@ -203,8 +203,8 @@ static int pn532_uart_rx_is_frame(struct sk_buff *skb) return 0; } -static ssize_t pn532_receive_buf(struct serdev_device *serdev, - const u8 *data, size_t count) +static size_t pn532_receive_buf(struct serdev_device *serdev, + const u8 *data, size_t count) { struct pn532_uart_phy *dev = serdev_device_get_drvdata(serdev); size_t i; diff --git a/drivers/nfc/s3fwrn5/uart.c b/drivers/nfc/s3fwrn5/uart.c index 456d3947116c..9c09c10c2a46 100644 --- a/drivers/nfc/s3fwrn5/uart.c +++ b/drivers/nfc/s3fwrn5/uart.c @@ -51,8 +51,8 @@ static const struct s3fwrn5_phy_ops uart_phy_ops = { .write = s3fwrn82_uart_write, }; -static ssize_t s3fwrn82_uart_read(struct serdev_device *serdev, - const u8 *data, size_t count) +static size_t s3fwrn82_uart_read(struct serdev_device *serdev, + const u8 *data, size_t count) { struct s3fwrn82_uart_phy *phy = serdev_device_get_drvdata(serdev); size_t i; diff --git a/drivers/platform/chrome/cros_ec_uart.c b/drivers/platform/chrome/cros_ec_uart.c index 68d80559fddc..8ea867c2a01a 100644 --- a/drivers/platform/chrome/cros_ec_uart.c +++ b/drivers/platform/chrome/cros_ec_uart.c @@ -81,8 +81,8 @@ struct cros_ec_uart { struct response_info response; }; -static ssize_t cros_ec_uart_rx_bytes(struct serdev_device *serdev, - const u8 *data, size_t count) +static size_t cros_ec_uart_rx_bytes(struct serdev_device *serdev, + const u8 *data, size_t count) { struct ec_host_response *host_response; struct cros_ec_device *ec_dev = serdev_device_get_drvdata(serdev); diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c index 9591a28bc38a..ba550eaa06fc 100644 --- a/drivers/platform/surface/aggregator/core.c +++ b/drivers/platform/surface/aggregator/core.c @@ -227,8 +227,8 @@ EXPORT_SYMBOL_GPL(ssam_client_bind); /* -- Glue layer (serdev_device -> ssam_controller). ------------------------ */ -static ssize_t ssam_receive_buf(struct serdev_device *dev, const u8 *buf, - size_t n) +static size_t ssam_receive_buf(struct serdev_device *dev, const u8 *buf, + size_t n) { struct ssam_controller *ctrl; int ret; diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c index e94e090cf0a1..3d7ae7fa5018 100644 --- a/drivers/tty/serdev/serdev-ttyport.c +++ b/drivers/tty/serdev/serdev-ttyport.c @@ -27,19 +27,17 @@ static size_t ttyport_receive_buf(struct tty_port *port, const u8 *cp, { struct serdev_controller *ctrl = port->client_data; struct serport *serport = serdev_controller_get_drvdata(ctrl); - int ret; + size_t ret; if (!test_bit(SERPORT_ACTIVE, &serport->flags)) return 0; ret = serdev_controller_receive_buf(ctrl, cp, count); - dev_WARN_ONCE(&ctrl->dev, ret < 0 || ret > count, - "receive_buf returns %d (count = %zu)\n", + dev_WARN_ONCE(&ctrl->dev, ret > count, + "receive_buf returns %zu (count = %zu)\n", ret, count); - if (ret < 0) - return 0; - else if (ret > count) + if (ret > count) return count; return ret; diff --git a/include/linux/serdev.h b/include/linux/serdev.h index 3fab88ba265e..ff78efc1f60d 100644 --- a/include/linux/serdev.h +++ b/include/linux/serdev.h @@ -27,7 +27,7 @@ struct serdev_device; * not sleep. */ struct serdev_device_ops { - ssize_t (*receive_buf)(struct serdev_device *, const u8 *, size_t); + size_t (*receive_buf)(struct serdev_device *, const u8 *, size_t); void (*write_wakeup)(struct serdev_device *); }; @@ -185,9 +185,9 @@ static inline void serdev_controller_write_wakeup(struct serdev_controller *ctrl serdev->ops->write_wakeup(serdev); } -static inline ssize_t serdev_controller_receive_buf(struct serdev_controller *ctrl, - const u8 *data, - size_t count) +static inline size_t serdev_controller_receive_buf(struct serdev_controller *ctrl, + const u8 *data, + size_t count) { struct serdev_device *serdev = ctrl->serdev; diff --git a/sound/drivers/serial-generic.c b/sound/drivers/serial-generic.c index d6e5aafd697c..36409a56c675 100644 --- a/sound/drivers/serial-generic.c +++ b/sound/drivers/serial-generic.c @@ -100,8 +100,8 @@ static void snd_serial_generic_write_wakeup(struct serdev_device *serdev) snd_serial_generic_tx_wakeup(drvdata); } -static ssize_t snd_serial_generic_receive_buf(struct serdev_device *serdev, - const u8 *buf, size_t count) +static size_t snd_serial_generic_receive_buf(struct serdev_device *serdev, + const u8 *buf, size_t count) { int ret; struct snd_serial_generic *drvdata = serdev_device_get_drvdata(serdev);