[v2,0/6] CAN TRANSCEIVER: Add support for CAN transceivers

Message

Aswath Govindraju April 14, 2021, 2:05 p.m. UTC

The following series of patches add support for CAN transceivers.

TCAN1042 has a standby signal that needs to be pulled high for
sending/receiving messages[1]. TCAN1043 has a enable signal along with
standby signal that needs to be pulled up for sending/receiving
messages[2], and other combinations of the two lines can be used to put the
transceiver in different states to reduce power consumption. On boards
like the AM654-idk and J721e-evm these signals are controlled using gpios.

Patch 1 rewords the comment that restricts max_link_rate attribute to have
units of Mbps.

Patch 2 adds an API for devm_of_phy_optional_get_by_index

Patch 3 models the transceiver as a phy device tree node with properties
for max bit rate supported, gpio properties for indicating gpio pin numbers
to which standby and enable signals are connected.

Patch 4 adds a generic driver to support CAN transceivers.

Patches 5 & 6 add support for implementing the transceiver as a phy of
m_can_platform driver.

changes since v1:
- Added patch 1 (in v2) that rewords the comment that restrict
  max_link_rate attribute to have units of Mbps.
- Added patch 2 (in v2) that adds an API for
  devm_of_phy_optional_get_by_index
- Patch 1 (in v1)
  - updated MAINTAINERS file
- Patch 2 (in v1)
  - replaced m_can with CAN to make the driver independent of CAN driver
  - Added prefix CAN_TRANSCEIVER for EN_PRESENT and STB_PRESENT
  - Added new line before return statements in power_on() and power_off
  - Added error handling patch for devm_kzalloc()
  - used the max_link_rate attribute directly instead of dividing it by
    1000000
  - removed the spaces before GPIOD_OUT_LOW in devm_gpiod_get()
  - Corrected requested value for standby-gpios to GPIOD_OUT_HIGH
  - Updated MAINTAINERS file
- Patch 3 (in v1)
  - replaced minItems with maxItems
  - Removed phy-names property as there is only one phy
- Patch 4 (in v1)
  - replaced dev_warn with dev_info when no transceiver is found
  - Added struct phy * field in m_can_classdev struct
  - moved phy_power_on and phy_power_off to m_can_open and m_can_close
    respectively
  - Moved the check for max_bit_rate to generice transceiver driver

[1] - https://www.ti.com/lit/ds/symlink/tcan1042h.pdf
[2] - https://www.ti.com/lit/ds/symlink/tcan1043-q1.pdf

Aswath Govindraju (4):
  phy: core: Reword the comment specifying the units of max_link_rate to
    be Mbps
  phy: Add API for devm_of_phy_optional_get_by_index
  dt-bindings: phy: Add binding for TI TCAN104x CAN transceivers
  phy: phy-can-transceiver: Add support for generic CAN transceiver
    driver

Faiz Abbas (2):
  dt-bindings: net: can: Document transceiver implementation as phy
  can: m_can: Add support for transceiver as phy

 .../bindings/net/can/bosch,m_can.yaml         |   3 +
 .../bindings/phy/ti,tcan104x-can.yaml         |  56 +++++++
 MAINTAINERS                                   |   2 +
 drivers/net/can/m_can/m_can.c                 |  18 +++
 drivers/net/can/m_can/m_can.h                 |   2 +
 drivers/net/can/m_can/m_can_platform.c        |  15 ++
 drivers/phy/Kconfig                           |   9 ++
 drivers/phy/Makefile                          |   1 +
 drivers/phy/phy-can-transceiver.c             | 146 ++++++++++++++++++
 drivers/phy/phy-core.c                        |  26 ++++
 include/linux/phy/phy.h                       |   4 +-
 11 files changed, 281 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/phy/ti,tcan104x-can.yaml
 create mode 100644 drivers/phy/phy-can-transceiver.c

Comments

Marc Kleine-Budde April 14, 2021, 3:43 p.m. UTC | #1

On 14.04.2021 19:35:15, Aswath Govindraju wrote:
> The following series of patches add support for CAN transceivers.
> 
> TCAN1042 has a standby signal that needs to be pulled high for
> sending/receiving messages[1]. TCAN1043 has a enable signal along with
> standby signal that needs to be pulled up for sending/receiving
> messages[2], and other combinations of the two lines can be used to put the
> transceiver in different states to reduce power consumption. On boards
> like the AM654-idk and J721e-evm these signals are controlled using gpios.
> 
> Patch 1 rewords the comment that restricts max_link_rate attribute to have
> units of Mbps.
> 
> Patch 2 adds an API for devm_of_phy_optional_get_by_index

You probably want to split this into 2 or even 3 separate series. The
first one would be patches 1+2 then 3+4 they can go via the phy tree.
Patches 5+6 can go via linux-can-next

> Patch 3 models the transceiver as a phy device tree node with properties
> for max bit rate supported, gpio properties for indicating gpio pin numbers
> to which standby and enable signals are connected.
> 
> Patch 4 adds a generic driver to support CAN transceivers.
> 
> Patches 5 & 6 add support for implementing the transceiver as a phy of
> m_can_platform driver.

regards,
Marc