[PATCH v3 2/2] pwm: th1520: Lock clock rate with clk_rate_exclusive_get

[Maurice Hieronymus]

The driver derives period and duty cycle from the clock rate read at
probe, so a later rate change would silently miscompute waveforms.
Switch to the new ExclusiveClk wrapper to hold the rate for the lifetime
of the driver data and drop the corresponding TODO.

Reviewed-by: Alice Ryhl <aliceryhl at google.com>
Reviewed-by: Michal Wilczynski <m.wilczynski at samsung.com>
Signed-off-by: Maurice Hieronymus <mhi at mailbox.org>
---
 drivers/pwm/pwm_th1520.rs | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/pwm/pwm_th1520.rs b/drivers/pwm/pwm_th1520.rs
index 343a1178c5e7..8f9d3fa39200 100644
--- a/drivers/pwm/pwm_th1520.rs
+++ b/drivers/pwm/pwm_th1520.rs
@@ -22,8 +22,16 @@
 
 use core::ops::Deref;
 use kernel::{
-    clk::{Clk, Enabled},
-    device::{Bound, Core, Device},
+    clk::{
+        Clk,
+        Enabled,
+        ExclusiveClk, //
+    },
+    device::{
+        Bound,
+        Core,
+        Device, //
+    },
     devres,
     io::{
         mem::IoMem,
@@ -93,7 +101,7 @@ struct Th1520WfHw {
 struct Th1520PwmDriverData {
     #[pin]
     iomem: devres::Devres<IoMem<TH1520_PWM_REG_SIZE>>,
-    clk: Clk<Enabled>,
+    clk: ExclusiveClk,
 }
 
 impl pwm::PwmOps for Th1520PwmDriverData {
@@ -319,10 +327,8 @@ fn probe(
         let request = pdev.io_request_by_index(0).ok_or(ENODEV)?;
 
         let clk = Clk::<Enabled>::get(dev, None)?;
+        let clk = clk.rate_exclusive_get()?;
 
-        // TODO: Get exclusive ownership of the clock to prevent rate changes.
-        // The Rust equivalent of `clk_rate_exclusive_get()` is not yet available.
-        // This should be updated once it is implemented.
         let rate_hz = clk.rate().as_hz();
         if rate_hz == 0 {
             dev_err!(dev, "Clock rate is zero\n");

-- 
2.51.2