[PATCH v2 2/4] media: sunxi-cir: Remove unnecessary spinlock

From: Samuel Holland
Date: Mon Jan 18 2021 - 01:05:50 EST


Only one register, SUNXI_IR_CIR_REG, is accessed from outside the
interrupt handler, and that register is not accessed from inside it.
As there is no overlap between different contexts, no lock is needed.

Signed-off-by: Samuel Holland <samuel@xxxxxxxxxxxx>
---
drivers/media/rc/sunxi-cir.c | 10 ----------
1 file changed, 10 deletions(-)

diff --git a/drivers/media/rc/sunxi-cir.c b/drivers/media/rc/sunxi-cir.c
index 0a7f7eab3cc3..48be400421cd 100644
--- a/drivers/media/rc/sunxi-cir.c
+++ b/drivers/media/rc/sunxi-cir.c
@@ -86,7 +86,6 @@ struct sunxi_ir_quirks {
};

struct sunxi_ir {
- spinlock_t ir_lock;
struct rc_dev *rc;
void __iomem *base;
int irq;
@@ -105,8 +104,6 @@ static irqreturn_t sunxi_ir_irq(int irqno, void *dev_id)
struct sunxi_ir *ir = dev_id;
struct ir_raw_event rawir = {};

- spin_lock(&ir->ir_lock);
-
status = readl(ir->base + SUNXI_IR_RXSTA_REG);

/* clean all pending statuses */
@@ -137,8 +134,6 @@ static irqreturn_t sunxi_ir_irq(int irqno, void *dev_id)
ir_raw_event_handle(ir->rc);
}

- spin_unlock(&ir->ir_lock);
-
return IRQ_HANDLED;
}

@@ -160,17 +155,14 @@ static int sunxi_ir_set_timeout(struct rc_dev *rc_dev, unsigned int timeout)
{
struct sunxi_ir *ir = rc_dev->priv;
unsigned int base_clk = clk_get_rate(ir->clk);
- unsigned long flags;

unsigned int ithr = sunxi_usec_to_ithr(base_clk, timeout);

dev_dbg(rc_dev->dev.parent, "setting idle threshold to %u\n", ithr);

- spin_lock_irqsave(&ir->ir_lock, flags);
/* Set noise threshold and idle threshold */
writel(REG_CIR_NTHR(SUNXI_IR_RXNOISE) | REG_CIR_ITHR(ithr),
ir->base + SUNXI_IR_CIR_REG);
- spin_unlock_irqrestore(&ir->ir_lock, flags);

rc_dev->timeout = sunxi_ithr_to_usec(base_clk, ithr);

@@ -199,8 +191,6 @@ static int sunxi_ir_probe(struct platform_device *pdev)
return -ENODEV;
}

- spin_lock_init(&ir->ir_lock);
-
ir->fifo_size = quirks->fifo_size;

/* Clock */
--
2.26.2