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pca954x: improve code, fix I2C_SW_RESET behavior

This commit is contained in:
mwojcik 2022-02-11 11:22:53 +08:00
parent fbc783d7ad
commit dacc816eb4
1 changed files with 20 additions and 18 deletions
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38
libboard_zynq/src/i2c/mod.rs
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@ -7,7 +7,7 @@ use super::time::Microseconds;
use embedded_hal::timer::CountDown; use embedded_hal::timer::CountDown;
use libregister::{RegisterR, RegisterRW, RegisterW}; use libregister::{RegisterR, RegisterRW, RegisterW};
enum PCA954X { pub enum I2cMultiplexer {
PCA9548 = 0, PCA9548 = 0,
#[cfg(feature = "target_kasli_soc")] #[cfg(feature = "target_kasli_soc")]
PCA9547 = 1, PCA9547 = 1,
@ -16,7 +16,7 @@ enum PCA954X {
pub struct I2c { pub struct I2c {
regs: regs::RegisterBlock, regs: regs::RegisterBlock,
count_down: super::timer::global::CountDown<Microseconds>, count_down: super::timer::global::CountDown<Microseconds>,
pca_type: PCA954X pca_type: I2cMultiplexer
} }
impl I2c { impl I2c {
@ -63,7 +63,7 @@ impl I2c {
let self_ = Self { let self_ = Self {
regs: regs::RegisterBlock::i2c(), regs: regs::RegisterBlock::i2c(),
count_down: unsafe { super::timer::GlobalTimer::get() }.countdown(), count_down: unsafe { super::timer::GlobalTimer::get() }.countdown(),
pca_type: PCA954X::PCA9548 pca_type: I2cMultiplexer::PCA9548 //default for zc706
}; };
// Setup GPIO output mask // Setup GPIO output mask
@ -75,7 +75,7 @@ impl I2c {
w.scl(true).sda(true) w.scl(true).sda(true)
}); });
//Kasli-SoC exclusive: I2C_SW_RESET configuration //Kasli-SoC only: I2C_SW_RESET configuration
#[cfg(feature = "target_kasli_soc")] #[cfg(feature = "target_kasli_soc")]
{ {
self_.regs.gpio_output_mask_lower.modify(|_, w| { self_.regs.gpio_output_mask_lower.modify(|_, w| {
@ -144,13 +144,15 @@ impl I2c {
} }
#[cfg(feature = "target_kasli_soc")] #[cfg(feature = "target_kasli_soc")]
pub fn pca_autodetect(&mut self) -> Result<PCA954X, &'static str> { fn pca_autodetect(&mut self) -> Result<I2cMultiplexer, &'static str> {
// start with resetting the PCA954X // start with resetting the PCA954X
// SDA must be clear (before start)
/*self.i2cswr_oe(false); // reset time is 500ns, unit_delay (100us) to account for propagation
self.unit_delay(); self.i2cswr_o(true);
self.i2cswr_oe(true);*/ self.unit_delay();
self.i2cswr_o(false);
self.unit_delay();
let pca954x_read_addr = (0x71 << 1) | 0x01; let pca954x_read_addr = (0x71 << 1) | 0x01;
self.start()?; self.start()?;
@ -161,8 +163,8 @@ impl I2c {
let config = self.read(false)?; let config = self.read(false)?;
let pca = match config { let pca = match config {
0x00 => PCA954X::PCA9548, 0x00 => I2cMultiplexer::PCA9548,
0x08 => PCA954X::PCA9547, 0x08 => I2cMultiplexer::PCA9547,
_ => { return Err("Unknown response for PCA954X autodetect")}, _ => { return Err("Unknown response for PCA954X autodetect")},
}; };
self.stop()?; self.stop()?;
@ -198,7 +200,7 @@ impl I2c {
#[cfg(feature = "target_kasli_soc")] #[cfg(feature = "target_kasli_soc")]
{ {
self.unit_delay(); self.i2cswr_oe(true);
self.pca_type = self.pca_autodetect()?; self.pca_type = self.pca_autodetect()?;
} }
@ -300,18 +302,18 @@ impl I2c {
pub fn pca954x_select(&mut self, address: u8, channel: u8) -> Result<(), &'static str> { pub fn pca954x_select(&mut self, address: u8, channel: u8) -> Result<(), &'static str> {
self.start()?; self.start()?;
// PCA9547 supports only one channel at a time // PCA9547 supports only one channel at a time
// for compatibility, PCA9548 is treated as such // for compatibility, PCA9548 is treated as such too
let setting = match self.pca_type { let setting = match self.pca_type {
PCA954X::PCA9548 => 1 << channel, I2cMultiplexer::PCA9548 => 1 << channel,
#[cfg(feature = "target_kasli_soc")] #[cfg(feature = "target_kasli_soc")]
PCA954X::PCA9547 => channel | 0x08, I2cMultiplexer::PCA9547 => channel | 0x08,
}; };
if !self.write(address << 1)? { if !self.write(address << 1)? {
return Err("PCA9548 failed to ack write address") return Err("PCA954X failed to ack write address")
} }
if !self.write(setting)? { if !self.write(setting)? {
return Err("PCA9548 failed to ack control word") return Err("PCA954X failed to ack control word")
} }
self.stop()?; self.stop()?;
Ok(()) Ok(())