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Roger Peppe
8cb226938b
Also change the `tester` package slightly to use an exposed `Registers` array rather adding yet another accessor method to retrieve a register value. This seems to me more transparent and "obvious" - we aren't trying to hide the fact that there's just a simple memory store there. Also unexport the `assertRegisterRange` method which was never intended to be part of the public API.
62 lines
1.6 KiB
Go
62 lines
1.6 KiB
Go
package tester
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// MaxRegisters is the maximum number of registers supported for a Device.
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const MaxRegisters = 200
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// I2CDevice represents a mock I2C device on a mock I2C bus.
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type I2CDevice struct {
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c Failer
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// addr is the i2c device address.
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addr uint8
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// Registers holds the device registers. It can be inspected
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// or changed as desired for testing.
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Registers [MaxRegisters]uint8
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// If Err is non-nil, it will be returned as the error from the
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// I2C methods.
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Err error
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}
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// NewI2CDevice returns a new mock I2C device.
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func NewI2CDevice(c Failer, addr uint8) *I2CDevice {
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return &I2CDevice{
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c: c,
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addr: addr,
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}
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}
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// Addr returns the Device address.
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func (d *I2CDevice) Addr() uint8 {
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return d.addr
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}
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// ReadRegister implements I2C.ReadRegister.
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func (d *I2CDevice) ReadRegister(r uint8, buf []byte) error {
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if d.Err != nil {
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return d.Err
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}
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d.assertRegisterRange(r, buf)
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copy(buf, d.Registers[r:])
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return nil
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}
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// WriteRegister implements I2C.WriteRegister.
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func (d *I2CDevice) WriteRegister(r uint8, buf []byte) error {
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if d.Err != nil {
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return d.Err
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}
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d.assertRegisterRange(r, buf)
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copy(d.Registers[r:], buf)
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return nil
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}
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// assertRegisterRange asserts that reading or writing the given
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// register and subsequent registers is in range of the available registers.
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func (d *I2CDevice) assertRegisterRange(r uint8, buf []byte) {
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if int(r) >= len(d.Registers) {
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d.c.Fatalf("register read/write [%#x, %#x] start out of range", r, int(r)+len(buf))
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}
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if int(r)+len(buf) > len(d.Registers) {
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d.c.Fatalf("register read/write [%#x, %#x] end out of range", r, int(r)+len(buf))
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}
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}
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