defmodule PCA9641 do
@derive [Wafer.Chip]
defstruct ~w[conn int_pin state]a
@behaviour Wafer.Conn
alias PCA9641.Registers
alias Wafer.Conn
import Wafer.Twiddles
require Logger
@moduledoc """
PCA9641 Driver for Elixir using Wafer.
The PCA9641 I2C bus arbiter allows two I2C masters (eg Raspberry Pis) to be
connected to the same downstream I2C bus. The chip decides which master has
access to the bus based on it's own internal state machine.
The device also contains an interrupt input pin which can be used for
downstream devices to signal interrupts and be passed to the two interrupt
outputs connected to the two masters.
## Examples
Connecting to the device using Elixir Circuits.
iex> {:ok, i2c_conn} = Wafer.Driver.Circuits.I2C.acquire(bus_name: "i2c-1", address: 0x70)
...> {:ok, int_conn} = Wafer.Driver.Circuits.GPIO.acquire(pin: 7, direction: :in)
...> {:ok, conn} = PCA9641.acquire(conn: i2c_conn, int_pin: int_conn)
"""
@interrupts_fwd %{
bus_hung: 6,
mbox_full: 5,
mbox_empty: 4,
test_int: 3,
lock_grant: 2,
bus_lost: 1,
int_in: 0
}
@interrupts_bkwd @interrupts_fwd |> Enum.map(fn {k, v} -> {v, k} end) |> Enum.into(%{})
@type interrupt_name ::
:bus_hung | :mbox_full | :mbox_empty | :test_int | :lock_grant | :bus_lost | :int_in
@type t :: %PCA9641{conn: Conn.t(), int_pin: Conn.t()}
@type mailbox_data :: <<_::16>>
@type acquire_options :: [acquire_option]
@type acquire_option :: {:conn, Conn.t(), int_pin: Conn.t()}
# The magic number that means this is really a PCA9641 device.
@pca9641_id 0x38
@doc """
Acquire a connection to the PCA9641 device using the passed in I2C connection.
## Options:
- `conn` (required) an I2C connection, probably from `ElixirALE.I2C` or
`Circuits.I2C`.
- `int_pin` a (optional) GPIO connection for the interrupt pin This should
be already set to direction `:in`.
"""
@spec acquire(acquire_options) :: {:ok, t} | {:error, reason :: any}
@impl Wafer.Conn
def acquire(options) do
with {:ok, conn} <- Keyword.fetch(options, :conn),
int_pin <- Keyword.get(options, :int_pin) do
{:ok, %PCA9641{conn: conn, int_pin: int_pin, state: :unknown}}
else
:error -> {:error, "`PCA9641.acquire/1` requires the `conn` option."}
{:error, reason} -> {:error, reason}
end
end
@doc """
Enable interrupts on the `int_pin`.
Enables interrupts on the GPIO pin which is connected to the PCA9641 interrupt
pin. The Wafer interrupt message metadata field will contain this PCA9641
conn.
"""
@spec interrupt_pin_enable(t) :: {:ok, t} | {:error, reason :: any}
def interrupt_pin_enable(%PCA9641{int_pin: nil}), do: {:error, "No interrupt pin specified."}
def interrupt_pin_enable(%PCA9641{int_pin: conn} = dev) do
with {:ok, conn} <- Wafer.GPIO.enable_interrupt(conn, :falling, dev),
do: {:ok, %{dev | int_pin: conn}}
end
@doc """
Enable interrupts on the `int_pin`.
Enables interrupts on the GPIO pin which is connected to the PCA9641 interrupt
pin. The Wafer interrupt message metadata field will contain a two-tuple of
this PCA9641 conn and `metadata`.
"""
@spec interrupt_pin_enable(t, metadata :: any) :: {:ok, t} | {:error, reason :: any}
def interrupt_pin_enable(%PCA9641{int_pin: nil}, _metadata),
do: {:error, "No interrupt pin specified."}
def interrupt_pin_enable(%PCA9641{int_pin: conn} = dev, metadata) do
with {:ok, conn} <- Wafer.GPIO.enable_interrupt(conn, :falling, {dev, metadata}),
do: {:ok, %{dev | int_pin: conn}}
end
@doc """
Disable interrupts on the `int_pin`.
Disables interrupts on the GPIO pin which is connected to the PCA9641
interrupt pin.
"""
@spec interrupt_pin_disable(t) :: {:ok, t} | {:error, reason :: any}
def interrupt_pin_disable(%PCA9641{int_pin: nil}), do: {:error, "No interrupt pin specified."}
def interrupt_pin_disable(%PCA9641{int_pin: conn} = dev) do
with {:ok, conn} <- Wafer.GPIO.disable_interrupt(conn, :both),
do: {:ok, %{dev | int_pin: conn}}
end
@doc """
Verify the contents of the identity register.
It should match the expected value of `#{@pca9641_id}`.
"""
@spec verify_identity(t) :: {:ok, t} | {:error, reason :: any}
def verify_identity(%PCA9641{conn: conn} = dev) do
case Registers.read_id(conn) do
{:ok, <<@pca9641_id>>} -> {:ok, %{dev | conn: conn}}
{:ok, <<id>>} -> {:error, "Found incorrect ID #{inspect(id)}"}
{:error, reason} -> {:error, reason}
end
end
@doc """
Attempt to acquire the downstream I2C bus.
"""
@spec request_downstream_bus(t) :: {:ok, t} | {:error, reason :: any}
def request_downstream_bus(%PCA9641{} = dev) do
case lock_request(dev, true) do
{:ok, dev} -> wait_for_bus_init(dev)
{:error, reason} -> {:error, reason}
end
end
@doc """
PRIORITY
Master can set this register bit for setting priority of the winner when two
masters request the downstream bus at the same time.
"""
@spec priority?(t) :: boolean
def priority?(conn) do
with {:ok, data} <- Registers.read_control(conn),
true <- get_bool(data, 7),
do: true,
else: (_ -> false)
end
@doc """
PRIORITY
Master can set this register bit for setting priority of the winner when two
masters request the downstream bus at the same time.
"""
@spec priority(t, boolean) :: {:ok, t} | {:error, reason :: any}
def priority(%PCA9641{conn: conn} = dev, true) do
with {:ok, conn} <- Registers.update_control(conn, &set_bit(&1, 7)),
do: {:ok, %{dev | conn: conn}}
end
def priority(%PCA9641{conn: conn} = dev, false) do
with {:ok, conn} <- Registers.update_control(conn, &clear_bit(&1, 7)),
do: {:ok, %{dev | conn: conn}}
end
@doc """
SMBUS_DIS
When PCA9641 detects an SMBus time-out, if this bit is set, PCA9641 will
disconnect I2C-bus from master to downstream bus.
- `false` -> Normal operation.
- `true` -> Connectivity between master and downstream bus will be
disconnected upon detecting an SMBus time-out condition.
"""
@spec downstream_disconnect_on_timeout?(t) :: boolean
def downstream_disconnect_on_timeout?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_control(conn),
true <- get_bool(data, 6),
do: true,
else: (_ -> false)
end
@doc """
SMBUS_DIS
When PCA9641 detects an SMBus time-out, if this bit is set, PCA9641 will
disconnect I2C-bus from master to downstream bus.
- `false` -> Normal operation.
- `true` -> Connectivity between master and downstream bus will be
disconnected upon detecting an SMBus time-out condition.
"""
@spec downstream_disconnect_on_timeout(t, boolean) :: {:ok, t} | {:error, term}
def downstream_disconnect_on_timeout(%PCA9641{conn: conn} = dev, true) do
with {:ok, conn} <- Registers.update_control(conn, &set_bit(&1, 6)),
do: {:ok, %{dev | conn: conn}}
end
def downstream_disconnect_on_timeout(%PCA9641{conn: conn} = dev, false) do
with {:ok, conn} <- Registers.update_control(conn, &clear_bit(&1, 6)),
do: {:ok, %{dev | conn: conn}}
end
@doc """
IDLE_TIMER_DIS
After RES_TIME is expired, I2C-bus idle for more than 100 ms, PCA9641 will
disconnect master from downstream bus and takes away its grant if this
register bit is enabled. This IDLE_TIMER_DIS function also applies when there
is a grant of a request with zero value on RES_TIME.
- `false` -> Normal operation.
- `true` -> Enable 100 ms idle timer. After reserve timer expires or if
reserve timer is disabled, if the downstream bus is idle for more than 100
ms, the connection between master and downstream bus will be disconnected.
"""
@spec idle_timer_disconnect?(t) :: boolean
def idle_timer_disconnect?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_control(conn),
true <- get_bool(data, 5),
do: true,
else: (_ -> false)
end
@doc """
IDLE_TIMER_DIS
After RES_TIME is expired, I2C-bus idle for more than 100 ms, PCA9641 will
disconnect master from downstream bus and takes away its grant if this
register bit is enabled. This IDLE_TIMER_DIS function also applies when there
is a grant of a request with zero value on RES_TIME.
- `false` -> Normal operation.
- `true` -> Enable 100 ms idle timer. After reserve timer expires or if
reserve timer is disabled, if the downstream bus is idle for more than 100
ms, the connection between master and downstream bus will be disconnected.
"""
@spec idle_timer_disconnect(t, boolean) :: {:ok, t} | {:error, term}
def idle_timer_disconnect(%{conn: conn} = dev, true) do
with {:ok, conn} <- Registers.update_control(conn, &set_bit(&1, 5)),
do: {:ok, %{dev | conn: conn}}
end
def idle_timer_disconnect(%{conn: conn} = dev, false) do
with {:ok, conn} <- Registers.update_control(conn, &clear_bit(&1, 5)),
do: {:ok, %{dev | conn: conn}}
end
@doc """
SMBUS_SWRST
Non-granted or granted master sends a soft reset, if this bit is set, PCA9641
sets clock LOW for 35 ms following reset of all register values to defaults.
- `false` -> Normal operation.
- `true` -> Enable sending SMBus time-out to downstream bus, after receiving a
general call soft reset from master.
"""
@spec smbus_software_reset?(t) :: boolean
def smbus_software_reset?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_control(conn),
true <- get_bool(data, 4),
do: true,
else: (_ -> false)
end
@doc """
SMBUS_SWRST
Non-granted or granted master sends a soft reset, if this bit is set, PCA9641
sets clock LOW for 35 ms following reset of all register values to defaults.
- `false` -> Normal operation.
- `true` -> Enable sending SMBus time-out to downstream bus, after receiving a
general call soft reset from master.
"""
@spec smbus_software_reset(t, boolean) :: {:ok, t} | {:error, term}
def smbus_software_reset(%PCA9641{conn: conn} = dev, true) do
with {:ok, conn} <- Registers.update_control(conn, &set_bit(&1, 4)),
do: {:ok, %{dev | conn: conn}}
end
def smbus_software_reset(%PCA9641{conn: conn} = dev, false) do
with {:ok, conn} <- Registers.update_control(conn, &clear_bit(&1, 4)),
do: {:ok, %{dev | conn: conn}}
end
@doc """
BUS_INIT
Bus initialization for PCA9641 sends one clock out and checks SDA signal. If
SDA is HIGH, PCA9641 sends a ‘not acknowledge’ and a STOP condition. The
BUS_INIT function is completed. If SDA is LOW, PCA9641 sends other clock out
and checks SDA again. The PCA9641 will send out 9 clocks (maximum), and if SDA
is still LOW, PCA9641 determines the bus initialization has failed.
- `false` -> Normal operation.
- `true` -> Start initialization on next bus connect function to downstream
bus.
"""
@spec bus_init?(t) :: boolean
def bus_init?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_control(conn),
true <- get_bool(data, 3),
do: true,
else: (_ -> false)
end
@doc """
BUS_INIT
Bus initialization for PCA9641 sends one clock out and checks SDA signal. If
SDA is HIGH, PCA9641 sends a ‘not acknowledge’ and a STOP condition. The
BUS_INIT function is completed. If SDA is LOW, PCA9641 sends other clock out
and checks SDA again. The PCA9641 will send out 9 clocks (maximum), and if SDA
is still LOW, PCA9641 determines the bus initialization has failed.
- `false` -> Normal operation.
- `true` -> Start initialization on next bus connect function to downstream
bus.
"""
@spec bus_init(t, boolean) :: {:ok, t} | {:error, term}
def bus_init(%PCA9641{conn: conn} = dev, true) do
with {:ok, conn} <- Registers.update_control(conn, &set_bit(&1, 3)),
do: {:ok, %{dev | conn: conn}}
end
def bus_init(%PCA9641{conn: conn} = dev, false) do
with {:ok, conn} <- Registers.update_control(conn, &clear_bit(&1, 3)),
do: {:ok, %{dev | conn: conn}}
end
@doc """
BUS_CONNECT
Connectivity between master and downstream bus; the internal switch connects
I2C-bus from master to downstream bus only if LOCK_GRANT = 1.
- `false` -> Do not connect I2C-bus from master to downstream bus.
- `true` -> Connect downstream bus; the internal switch is closed only if LOCK_GRANT = 1.
"""
@spec bus_connect?(t) :: boolean
def bus_connect?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_control(conn),
true <- get_bool(data, 2),
do: true,
else: (_ -> false)
end
@doc """
BUS_CONNECT
Connectivity between master and downstream bus; the internal switch connects
I2C-bus from master to downstream bus only if LOCK_GRANT = 1.
- `false` -> Do not connect I2C-bus from master to downstream bus.
- `true` -> Connect downstream bus; the internal switch is closed only if LOCK_GRANT = 1.
"""
@spec bus_connect(t, boolean) :: {:ok, t} | {:error, term}
def bus_connect(%PCA9641{conn: conn} = dev, true) do
with {:ok, conn} <- Registers.update_control(conn, &set_bit(&1, 2)),
do: {:ok, %{dev | conn: conn}}
end
def bus_connect(%PCA9641{conn: conn} = dev, false) do
with {:ok, conn} <- Registers.update_control(conn, &clear_bit(&1, 2)),
do: {:ok, %{dev | conn: conn}}
end
@doc """
LOCK_GRANT
This is a status read only register bit. Lock grant status register bit
indicates the ownership between reading master and the downstream bus. If this
register bit is 1, the reading master has owned the downstream bus. If this
register bit is zero, the reading master has not owned the downstream bus.
- `false` -> This master does not have a lock on the downstream bus.
- `true` -> This master has a lock on the downstream bus.
"""
@spec lock_grant?(t) :: boolean
def lock_grant?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_control(conn),
true <- get_bool(data, 1),
do: true,
else: (_ -> false)
end
@doc """
LOCK_REQ
Lock request register bit is for a master requesting the downstream bus when
it does not have a lock on downstream bus. When a master has a lock on
downstream bus, it can give up the ownership by writing zero to LOCK_REQ
register bit. When LOCK_REQ becomes zero, LOCK_GRANT bit becomes zero and the
internal switch will be open.
- `false` -> Master is not requesting a lock on the downstream bus or giving
up the lock if master had a lock on the downstream bus.
- `true` -> Master is requesting a lock on the downstream bus.
"""
@spec lock_request?(t) :: boolean
def lock_request?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_control(conn),
true <- get_bool(data, 0),
do: true,
else: (_ -> false)
end
@doc """
LOCK_REQ
Lock request register bit is for a master requesting the downstream bus when
it does not have a lock on downstream bus. When a master has a lock on
downstream bus, it can give up the ownership by writing zero to LOCK_REQ
register bit. When LOCK_REQ becomes zero, LOCK_GRANT bit becomes zero and the
internal switch will be open.
- `false` -> Master is not requesting a lock on the downstream bus or giving
up the lock if master had a lock on the downstream bus.
- `true` -> Master is requesting a lock on the downstream bus.
"""
@spec lock_request(t, boolean) :: {:ok, t} | {:error, term}
def lock_request(%PCA9641{conn: conn} = dev, true) do
with {:ok, conn} <- Registers.update_control(conn, &set_bit(&1, 0)),
do: {:ok, %{dev | conn: conn}}
end
def lock_request(%PCA9641{conn: conn} = dev, false) do
with {:ok, conn} <- Registers.update_control(conn, &clear_bit(&1, 0)),
do: {:ok, %{dev | conn: conn}}
end
@doc """
SDA_IO
SDA becomes I/O pin; master can read or write to this register bit. If master
reads this bit, the value is the state of the downstream SDA pin. Zero value
means SDA is LOW, and one means SDA pin is HIGH. When master writes ‘0’ to
this register bit, the downstream SDA pin will assert LOW. If master writes‘1’
to this register bit, the downstream SDA pin will be pulled HIGH. Remark: SDA
becomes I/O pin only when BUS_CONNECT = 0 and LOCK_GRANT = 1.
- `false` -> When read, indicates the SDA pin of the downstream bus is LOW.
When written, PCA9641 drives SDA pin of downstream bus LOW.
- `true` -> When read, indicates the SDA pin of the downstream bus is HIGH.
When written, PCA9641 drives SDA pin of the downstream bus HIGH.
"""
@spec sda_becomes_io?(t) :: boolean
def sda_becomes_io?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_status(conn),
true <- get_bool(data, 7),
do: true,
else: (_ -> false)
end
@doc """
SDA_IO
SDA becomes I/O pin; master can read or write to this register bit. If master
reads this bit, the value is the state of the downstream SDA pin. Zero value
means SDA is LOW, and one means SDA pin is HIGH. When master writes ‘0’ to
this register bit, the downstream SDA pin will assert LOW. If master writes‘1’
to this register bit, the downstream SDA pin will be pulled HIGH. Remark: SDA
becomes I/O pin only when BUS_CONNECT = 0 and LOCK_GRANT = 1.
- `false` -> When read, indicates the SDA pin of the downstream bus is LOW.
When written, PCA9641 drives SDA pin of downstream bus LOW.
- `true` -> When read, indicates the SDA pin of the downstream bus is HIGH.
When written, PCA9641 drives SDA pin of the downstream bus HIGH.
"""
@spec sda_becomes_io(t, boolean) :: {:ok, t} | {:error, term}
def sda_becomes_io(%PCA9641{conn: conn} = dev, true) do
with {:ok, conn} <- Registers.update_status(conn, &set_bit(&1, 7)),
do: {:ok, %{dev | conn: conn}}
end
def sda_becomes_io(%PCA9641{conn: conn} = dev, false) do
with {:ok, conn} <- Registers.update_status(conn, &clear_bit(&1, 7)),
do: {:ok, %{dev | conn: conn}}
end
@doc """
SCL_IO
SCL becomes I/O pin; master can read or write to this register bit. If master
reads this bit, the value is the state of the downstream SCL pin. Zero value
means SCL is LOW, and one means SCL pin is HIGH. When master writes ‘0’ to
this register bit, the downstream SCL pin will assert LOW. If master writes‘1’
to this register bit, the downstream SCL pin will be pulled HIGH. Remark: SCL
becomes I/O pin only when BUS_CONNECT = 0 and LOCK_GRANT = 1.
- `false` -> When read, shows the SCL pin of the downstream bus is LOW. When
written, PCA9641 drives SCL pin of downstream bus LOW.
- `true` -> When read, shows the SCL pin of the downstream bus is HIGH. When
written, PCA9641 drives SCL pin of the downstream bus HIGH.
"""
@spec scl_becomes_io?(t) :: boolean
def scl_becomes_io?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_status(conn),
true <- get_bool(data, 6),
do: true,
else: (_ -> false)
end
@doc """
SCL_IO
SCL becomes I/O pin; master can read or write to this register bit. If master
reads this bit, the value is the state of the downstream SCL pin. Zero value
means SCL is LOW, and one means SCL pin is HIGH. When master writes ‘0’ to
this register bit, the downstream SCL pin will assert LOW. If master writes‘1’
to this register bit, the downstream SCL pin will be pulled HIGH. Remark: SCL
becomes I/O pin only when BUS_CONNECT = 0 and LOCK_GRANT = 1.
- `false` -> When read, shows the SCL pin of the downstream bus is LOW. When
written, PCA9641 drives SCL pin of downstream bus LOW.
- `true` -> When read, shows the SCL pin of the downstream bus is HIGH. When
written, PCA9641 drives SCL pin of the downstream bus HIGH.
"""
@spec scl_becomes_io(t, boolean) :: {:ok, t} | {:error, term}
def scl_becomes_io(%PCA9641{conn: conn} = dev, true) do
with {:ok, conn} <- Registers.update_status(conn, &set_bit(&1, 6)),
do: {:ok, %{dev | conn: conn}}
end
def scl_becomes_io(%PCA9641{conn: conn} = dev, false) do
with {:ok, conn} <- Registers.update_status(conn, &clear_bit(&1, 6)),
do: {:ok, %{dev | conn: conn}}
end
@doc """
TEST_INT
Test interrupt output pin; a master can send an interrupt to itself by writing
‘1’ to this register bit. Writing ‘0’ to this register bit has no effect. To
clear this interrupt, master must write ‘1’ to TEST_INT_INT in Interrupt
Status register.
- `false` -> Normal operation.
- `true` -> Causes PCA9641 INT pin to go LOW if not masked by TEST_INT_INT in
Interrupt Mask register. Allows this master to invoke its Interrupt Service
Routine to handle housekeeping tasks.
"""
@spec test_interrupt_pin?(t) :: boolean
def test_interrupt_pin?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_status(conn),
true <- get_bool(data, 5),
do: true,
else: (_ -> false)
end
@doc """
TEST_INT
Test interrupt output pin; a master can send an interrupt to itself by writing
‘1’ to this register bit. Writing ‘0’ to this register bit has no effect. To
clear this interrupt, master must write ‘1’ to TEST_INT_INT in Interrupt
Status register.
- `false` -> Normal operation.
- `true` -> Causes PCA9641 INT pin to go LOW if not masked by TEST_INT_INT in
Interrupt Mask register. Allows this master to invoke its Interrupt Service
Routine to handle housekeeping tasks.
"""
@spec test_interrupt_pin(t, boolean) :: {:ok, t} | {:error, term}
def test_interrupt_pin(%PCA9641{conn: conn} = dev, true) do
with {:ok, conn} <- Registers.update_status(conn, &set_bit(&1, 5)),
do: {:ok, %{dev | conn: conn}}
end
def test_interrupt_pin(%PCA9641{conn: conn} = dev, false) do
with {:ok, conn} <- Registers.update_status(conn, &clear_bit(&1, 5)),
do: {:ok, %{dev | conn: conn}}
end
@doc """
MBOX_FULL
This is a read-only status register bit. If this bit is ‘0’, it indicates no
data is available in the mail box. If it is ‘1’, it indicates new data is
available in the mail box.
- `false` -> No data is available for *this* master.
- `true` -> Mailbox contains data for *this* master from the other master.
"""
@spec mailbox_full?(t) :: boolean
def mailbox_full?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_status(conn),
true <- get_bool(data, 4),
do: true,
else: (_ -> false)
end
@doc """
MBOX_EMPTY
This is a read-only status register bit. If this bit is ‘0’, it indicates
other master mailbox is full, and this master cannot send more data to other
master mailbox. If it is ‘1’, it indicates other master is empty and this
master can send data to other master mailbox.
- `false` -> *Other* master mailbox is full; wait until *other* master reads
data.
- `true` -> *Other* master mailbox is empty. *Other* master has read previous
data and it is permitted to write new data.
"""
@spec mailbox_empty?(t) :: boolean
def mailbox_empty?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_status(conn),
true <- get_bool(data, 3),
do: true,
else: (_ -> false)
end
@doc """
BUS_HUNG
This is a read-only status register bit. If this register bit is ‘0’, it
indicates the bus is in normal condition. If this bit is ‘1’, it indicates the
bus is hung. The hung bus means SDA signal is LOW and SCL signal does not
toggle for more than 500 ms or SCL is LOW for 500 ms.
- `false` -> Normal operation.
- `true` -> Downstream bus hung; when SDA signal is LOW and SCL signal does
not toggle for more than 500 ms or SCL is LOW for 500 ms.
"""
@spec bus_hung?(t) :: boolean
def bus_hung?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_status(conn),
true <- get_bool(data, 2),
do: true,
else: (_ -> false)
end
@doc """
BUS_INIT_FAIL
This is a read-only status register bit. If this register bit is ‘0’, it
indicates the bus initialization function has passed. The downstream bus is in
idle mode (SCL and SDA are HIGH). If this register bit is ‘1’, it indicates
the bus initialization function has failed. The SDA signal could be stuck LOW.
- `false` -> Normal operation.
- `true` -> Bus initialization has failed. SDA still LOW, the downstream bus
cannot recover.
"""
@spec bus_initialisation_failed?(t) :: boolean
def bus_initialisation_failed?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_status(conn),
true <- get_bool(data, 1),
do: true,
else: (_ -> false)
end
@doc """
OTHER_LOCK
This is a status read-only register bit. Other master lock status indicates
the ownership between other master and the downstream bus. If this register
bit is ‘1’, the other master has owned the downstream bus. If this register
bit is ‘0’, the other master does not own the downstream bus.
- `false` -> The other master does not have a lock on the downstream bus.
- `true` -> The other master has a lock on the downstream bus.
"""
@spec other_lock?(t) :: boolean
def other_lock?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_status(conn),
true <- get_bool(data, 0),
do: true,
else: (_ -> false)
end
@doc """
RES_TIME
Reserve timer. Changes during LOCK_GRANT = 1 will have no effect.
Returns `{:ok, n}` where `n` is the number if milliseconds remaining in the
reservation.
"""
@spec reserve_time(t) :: {:ok, non_neg_integer, t} | {:error, term}
def reserve_time(%PCA9641{conn: conn} = dev) do
with {:ok, <<ms>>} <- Registers.read_reserve_time(conn), do: {:ok, ms, dev}
end
@doc """
RES_TIME
Reserve timer. Changes during LOCK_GRANT = 1 will have no effect.
`ms` is the number of milliseconds remaining in the reservation.
"""
@spec reserve_time(t) :: {:ok, t} | {:error, term}
def reserve_time(%PCA9641{conn: conn} = dev, ms)
when is_integer(ms) and ms >= 0 and ms <= 0xFF do
with {:ok, conn} <- Registers.write_reserve_time(conn, <<ms>>), do: {:ok, %{dev | conn: conn}}
end
def reserve_time(_conn, _ms), do: {:error, "Invalid milliseconds value"}
@doc """
Indicates the reasons for which an interrupt was generated (if any).
"""
@spec interrupt_reason(t) :: {:ok, [interrupt_name()]} | {:error, reason :: any}
def interrupt_reason(%PCA9641{conn: conn}) do
with {:ok, <<value>>} <- Registers.read_interrupt_status(conn) do
reasons =
@interrupts_fwd
|> Enum.reduce([], fn {name, idx}, interrupts ->
if get_bit(value, idx) == 1,
do: [name | interrupts],
else: interrupts
end)
{:ok, reasons}
end
end
@doc """
Clear specific interrupts from the interrupt status register
"""
@spec interrupt_clear(t, :all | [interrupt_name()]) :: {:ok, t} | {:error, term}
def interrupt_clear(%PCA9641{conn: conn} = dev, :all) do
with {:ok, conn} <- Registers.write_interrupt_status(conn, <<0x7F>>),
do: {:ok, %{dev | conn: conn}}
end
def interrupt_clear(%PCA9641{conn: conn} = dev, interrupt_names)
when is_list(interrupt_names) do
clear_mask =
interrupt_names
|> Enum.reduce(<<0>>, fn name, mask ->
case Map.fetch(@interrupts_fwd, name) do
{:ok, i} -> set_bit(mask, i)
_ -> mask
end
end)
with {:ok, conn} <- Registers.write_interrupt_status(conn, clear_mask),
do: {:ok, %{dev | conn: conn}}
end
@doc """
Enable the specified interrupts.
"""
@spec interrupt_enable(t, :all | :none | [interrupt_name()]) :: {:ok, t} | {:error, term}
def interrupt_enable(%PCA9641{conn: conn} = dev, :all) do
with {:ok, conn} <- Registers.write_interrupt_mask(conn, <<0>>),
do: {:ok, %{dev | conn: conn}}
end
def interrupt_enable(%PCA9641{conn: conn} = dev, :none) do
with {:ok, conn} <- Registers.write_interrupt_mask(conn, <<0x7F>>),
do: {:ok, %{dev | conn: conn}}
end
def interrupt_enable(%PCA9641{conn: conn} = dev, interrupts) do
with {:ok, conn} <-
Registers.update_interrupt_mask(conn, fn data ->
interrupts
|> Enum.reduce(data, fn interrupt_name, data ->
bit = Map.fetch!(@interrupts_fwd, interrupt_name)
clear_bit(data, bit)
end)
end),
do: {:ok, %{dev | conn: conn}}
end
@doc """
Returns a list of atoms containing the
"""
@spec interrupt_enabled(t) :: {:ok, [interrupt_name()]} | {:error, term}
def interrupt_enabled(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_interrupt_mask(conn) do
interrupts =
data
|> find_zeroes()
|> Enum.reduce([], fn i, interrupts ->
case Map.fetch(@interrupts_bkwd, i) do
{:ok, name} -> [name | interrupts]
_ -> interrupts
end
end)
{:ok, interrupts}
end
end
@doc """
BUS_HUNG_INT
Indicates to both masters that SDA signal is LOW and SCL signal does not
toggle for more than 500 ms or SCL is LOW for 500 ms.
- `false` -> No interrupt generated; normal operation.
- `true` -> Interrupt generated; downstream bus cannot recover; when SDA
signal is LOW and SCL signal does not toggle for more than 500 ms or SCL is
LOW for 500 ms,
"""
@spec bus_hung_interrupt?(t) :: boolean
def bus_hung_interrupt?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_interrupt_status(conn),
true <- get_bool(data, 6),
do: true,
else: (_ -> false)
end
@doc """
MBOX_FULL_INT
Indicates the mailbox has new mail.
- `false` -> No interrupt generated; mailbox is not full.
- `true` -> Interrupt generated; mailbox full.
"""
@spec mailbox_full_interrupt?(t) :: boolean
def mailbox_full_interrupt?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_interrupt_status(conn),
true <- get_bool(data, 5),
do: true,
else: (_ -> false)
end
@doc """
MBOX_EMPTY_INT
Indicates the sent mail is empty, other master has read the mail.
- `false` -> No interrupt generated; sent mail is not empty.
- `true` -> Interrupt generated; mailbox is empty.
"""
@spec mailbox_empty_interrupt?(t) :: boolean
def mailbox_empty_interrupt?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_interrupt_status(conn),
true <- get_bool(data, 4),
do: true,
else: (_ -> false)
end
@doc """
TEST_INT_INT
Indicates this master has sent an interrupt to itself.
- `false` -> No interrupt generated; master has not set the TEST_INT bit in
STATUS register.
- `true` -> Interrupt generated; master activates its interrupt pin via the
TEST_INT bit in STATUS register.
"""
@spec test_interrupt_pin_interrupt?(t) :: boolean
def test_interrupt_pin_interrupt?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_interrupt_status(conn),
true <- get_bool(data, 3),
do: true,
else: (_ -> false)
end
@doc """
LOCK_GRANT_INT
Indicates the master has a lock (ownership) on the downstream bus.
- `false` -> No interrupt generated; this master does not have a lock on the
downstream bus.
- `true` -> Interrupt generated; this master has a lock on the downstream bus.
"""
@spec lock_grant_interrupt?(t) :: boolean
def lock_grant_interrupt?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_interrupt_status(conn),
true <- get_bool(data, 2),
do: true,
else: (_ -> false)
end
@doc """
BUS_LOST_INT
Indicates the master has involuntarily lost the ownership of the downstream
bus.
- `false` -> No interrupt generated; this master is controlling the downstream
bus.
- `true` -> Interrupt generated; this master has involuntarily lost the
control of the downstream bus.
"""
@spec bus_lost_interrupt?(t) :: boolean
def bus_lost_interrupt?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_interrupt_status(conn),
true <- get_bool(data, 1),
do: true,
else: (_ -> false)
end
@doc """
INT_IN_INT
Indicates that there is an interrupt from the downstream bus to both the
granted and non-granted masters.
- `false` -> No interrupt on interrupt input pin INT_IN.
- `true` -> Interrupt on interrupt input pin INT_IN.
"""
@spec interupt_in_interrupt?(t) :: boolean
def interupt_in_interrupt?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_interrupt_status(conn),
true <- get_bool(data, 0),
do: true,
else: (_ -> false)
end
@doc """
BUS_HUNG_MSK
- `false` -> Enable output interrupt when BUS_HUNG function is set.
- `true` -> Disable output interrupt when BUS_HUNG function is set.
"""
@spec bus_hung_interrupt_enabled?(t) :: boolean
def bus_hung_interrupt_enabled?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_interrupt_mask(conn),
false <- get_bool(data, 6),
do: true,
else: (_ -> false)
end
@doc """
MBOX_FULL_MSK
- `false` -> Enable output interrupt when MBOX_FULL function is set.
- `true` -> Disable output interrupt when MBOX_FULL function is set.
"""
@spec mailbox_full_interrupt_enabled?(t) :: boolean
def mailbox_full_interrupt_enabled?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_interrupt_mask(conn),
false <- get_bool(data, 5),
do: true,
else: (_ -> false)
end
@doc """
MBOX_EMPTY_MSK
- `false` -> Enable output interrupt when MBOX_EMPTY function is set.
- `true` -> Disable output interrupt when MBOX_EMPTY function is set.
"""
@spec mailbox_empty_interrupt_enabled?(t) :: boolean
def mailbox_empty_interrupt_enabled?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_interrupt_mask(conn),
false <- get_bool(data, 4),
do: true,
else: (_ -> false)
end
@doc """
TEST_INT_MSK
- `false` -> Enable output interrupt when TEST_INT function is set.
- `true` -> Disable output interrupt when TEST_INT function is set.
"""
@spec test_interrupt_interrupt_enabled?(t) :: boolean
def test_interrupt_interrupt_enabled?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_interrupt_mask(conn),
false <- get_bool(data, 3),
do: true,
else: (_ -> false)
end
@doc """
LOCK_GRANT_MSK
- `false` -> Enable output interrupt when LOCK_GRANT function is set.
- `true` -> Disable output interrupt when LOCK_GRANT function is set.
"""
@spec lock_grant_interrupt_enabled?(t) :: boolean
def lock_grant_interrupt_enabled?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_interrupt_mask(conn),
false <- get_bool(data, 2),
do: true,
else: (_ -> false)
end
@doc """
BUS_LOST_MSK
- `false` -> Enable output interrupt when BUS_LOST function is set.
- `true` -> Disable output interrupt when BUS_LOST function is set.
"""
@spec bus_lost_interrupt_enabled?(t) :: boolean
def bus_lost_interrupt_enabled?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_interrupt_mask(conn),
false <- get_bool(data, 1),
do: true,
else: (_ -> false)
end
@doc """
INT_IN_MSK
- `false` -> Enable output interrupt when INT_IN function is set.
- `true` -> Disable output interrupt when INT_IN function is set.
"""
@spec interrupt_in_interrupt_enabled?(t) :: boolean
def interrupt_in_interrupt_enabled?(%PCA9641{conn: conn}) do
with {:ok, data} <- Registers.read_interrupt_mask(conn),
false <- get_bool(data, 0),
do: true,
else: (_ -> false)
end
@doc """
Read shared mailbox.
"""
@spec read_mailbox(t) :: {:ok, mailbox_data, t} | {:error, term}
def read_mailbox(%PCA9641{conn: conn} = dev) do
with {:ok, <<lsb>>} <- Registers.read_mailbox_lsb(conn),
{:ok, <<msb>>} <- Registers.read_mailbox_msb(conn),
do: {:ok, <<msb, lsb>>, %{dev | conn: conn}}
end
@doc """
Write shared mailbox.
"""
@spec write_mailbox(t, mailbox_data) :: {:ok, t} | {:error, term}
def write_mailbox(%PCA9641{conn: conn} = dev, <<msb, lsb>>) do
with {:ok, conn} <- Registers.write_mailbox_lsb(conn, <<lsb>>),
{:ok, conn} <- Registers.write_mailbox_msb(conn, <<msb>>),
do: {:ok, %{dev | conn: conn}}
end
@doc """
Abandon the downstream bus.
"""
@spec abandon_downstream_bus(t) :: {:ok, t} | {:error, term}
def abandon_downstream_bus(%PCA9641{conn: conn} = dev) do
with {:ok, conn} <- Registers.write_control(conn, <<0>>), do: {:ok, %{dev | conn: conn}}
end
@doc """
Waits for downstream bus initialisation to succeed.
Waits for a maximum of 1 second.
"""
@spec wait_for_bus_init(t) :: {:ok, t} | {:error, :bus_init_fail}
def wait_for_bus_init(conn), do: do_wait_for_bus_init(conn, 0)
defp do_wait_for_bus_init(_conn, 10), do: {:error, :bus_init_fail}
defp do_wait_for_bus_init(%PCA9641{} = conn, i) do
if bus_init?(conn) do
:timer.sleep(100)
do_wait_for_bus_init(conn, i + 1)
else
if bus_initialisation_failed?(conn),
do: {:error, :bus_init_fail},
else: {:ok, conn}
end
end
end
