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firwmare: turn i2c errors into &str

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Astro 2019-08-16 01:07:59 +02:00 committed by Sébastien Bourdeauducq
parent 8fc5ce902f
commit a8aabd3815
2 changed files with 31 additions and 32 deletions
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33
artiq/firmware/libboard_artiq/i2c.rs
View File

@ -2,6 +2,8 @@
mod imp {
use board_misoc::{csr, clock};
const INVALID_BUS: &'static str = "Invalid I2C bus";
fn half_period() { clock::spin_us(100) }
fn sda_bit(busno: u8) -> u8 { 1 << (2 * busno + 1) }
fn scl_bit(busno: u8) -> u8 { 1 << (2 * busno) }
@ -76,9 +78,9 @@ mod imp {
}
}
pub fn start(busno: u8) -> Result<(), ()> {
pub fn start(busno: u8) -> Result<(), &'static str> {
if busno as u32 >= csr::CONFIG_I2C_BUS_COUNT {
return Err(())
return Err(INVALID_BUS)
}
// Set SCL high then SDA low
scl_o(busno, true);
@ -88,9 +90,9 @@ mod imp {
Ok(())
}
pub fn restart(busno: u8) -> Result<(), ()> {
pub fn restart(busno: u8) -> Result<(), &'static str> {
if busno as u32 >= csr::CONFIG_I2C_BUS_COUNT {
return Err(())
return Err(INVALID_BUS)
}
// Set SCL low then SDA high */
scl_o(busno, false);
@ -102,9 +104,9 @@ mod imp {
Ok(())
}
pub fn stop(busno: u8) -> Result<(), ()> {
pub fn stop(busno: u8) -> Result<(), &'static str> {
if busno as u32 >= csr::CONFIG_I2C_BUS_COUNT {
return Err(())
return Err(INVALID_BUS)
}
// First, make sure SCL is low, so that the target releases the SDA line
scl_o(busno, false);
@ -118,9 +120,9 @@ mod imp {
Ok(())
}
pub fn write(busno: u8, data: u8) -> Result<bool, ()> {
pub fn write(busno: u8, data: u8) -> Result<bool, &'static str> {
if busno as u32 >= csr::CONFIG_I2C_BUS_COUNT {
return Err(())
return Err(INVALID_BUS)
}
// MSB first
for bit in (0..8).rev() {
@ -144,9 +146,9 @@ mod imp {
Ok(!sda_i(busno))
}
pub fn read(busno: u8, ack: bool) -> Result<u8, ()> {
pub fn read(busno: u8, ack: bool) -> Result<u8, &'static str> {
if busno as u32 >= csr::CONFIG_I2C_BUS_COUNT {
return Err(())
return Err(INVALID_BUS)
}
// Set SCL low first, otherwise setting SDA as input may cause a transition
// on SDA with SCL high which will be interpreted as START/STOP condition.
@ -180,12 +182,13 @@ mod imp {
#[cfg(not(has_i2c))]
mod imp {
const NO_I2C: &'static str = "No I2C support on this platform";
pub fn init() {}
pub fn start(_busno: u8) -> Result<(), ()> { Err(()) }
pub fn restart(_busno: u8) -> Result<(), ()> { Err(()) }
pub fn stop(_busno: u8) -> Result<(), ()> { Err(()) }
pub fn write(_busno: u8, _data: u8) -> Result<bool, ()> { Err(()) }
pub fn read(_busno: u8, _ack: bool) -> Result<u8, ()> { Err(()) }
pub fn start(_busno: u8) -> Result<(), &'static str> { Err(NO_I2C) }
pub fn restart(_busno: u8) -> Result<(), &'static str> { Err(NO_I2C) }
pub fn stop(_busno: u8) -> Result<(), &'static str> { Err(NO_I2C) }
pub fn write(_busno: u8, _data: u8) -> Result<bool, &'static str> { Err(NO_I2C) }
pub fn read(_busno: u8, _ack: bool) -> Result<u8, &'static str> { Err(NO_I2C) }
}
pub use self::imp::*;

30
artiq/firmware/libboard_artiq/i2c_eeprom.rs
View File

@ -26,30 +26,26 @@ impl EEPROM {
fn select(&self) -> Result<(), &'static str> {
let mask: u16 = 1 << self.port;
pca9548::select(self.busno, I2C_SWITCH0, mask as u8)?;
pca9548::select(self.busno, I2C_SWITCH1, (mask >> 8) as u8)
pca9548::select(self.busno, I2C_SWITCH1, (mask >> 8) as u8)?;
Ok(())
}
pub fn read<'a>(&self, addr: u8, buf: &'a mut [u8]) -> Result<(), &'static str> {
self.select()?;
Ok(()).and_then(|()| {
i2c::start(self.busno)?;
i2c::write(self.busno, self.address)?;
i2c::write(self.busno, addr)?;
Ok(())
}).map_err(|()| "I2C address write error")?;
i2c::start(self.busno)?;
i2c::write(self.busno, self.address)?;
i2c::write(self.busno, addr)?;
Ok(()).and_then(|()| {
i2c::restart(self.busno)?;
i2c::write(self.busno, self.address | 1)?;
let buf_len = buf.len();
for (i, byte) in buf.iter_mut().enumerate() {
*byte = i2c::read(self.busno, i < buf_len - 1)?;
}
i2c::restart(self.busno)?;
i2c::write(self.busno, self.address | 1)?;
let buf_len = buf.len();
for (i, byte) in buf.iter_mut().enumerate() {
*byte = i2c::read(self.busno, i < buf_len - 1)?;
}
i2c::stop(self.busno)?;
Ok(())
}).map_err(|()| "I2C read error")?;
i2c::stop(self.busno)?;
Ok(())
}