[PATCH 1/2] mailbox: rockchip: disable pclk on probe failure and unbind

[Linmao Li]

rockchip_mbox_probe() enables the peripheral clock and then keeps going.
None of the later failure paths - platform_get_irq(),
devm_request_threaded_irq() and devm_mbox_controller_register() - disables
it again. The driver has no remove callback either, so the clock also stays
prepared and enabled once the device is unbound, and its enable count keeps
growing over bind/unbind cycles.

Use devm_clk_get_enabled() to tie disabling and unpreparing the clock to
the device lifetime. It is registered before the interrupts and the mailbox
controller, so devres releases it after both are gone.

While rewriting the error path, switch it to dev_err_probe() so that a
deferred probe is not reported as an error.

Fixes: f70ed3b5dc8b ("mailbox: rockchip: Add Rockchip mailbox driver")
Signed-off-by: Linmao Li <lilinmao@xxxxxxxxxx>
---
 drivers/mailbox/rockchip-mailbox.c | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/drivers/mailbox/rockchip-mailbox.c b/drivers/mailbox/rockchip-mailbox.c
index a1a7dee64356..d55cbf7f2cb6 100644
--- a/drivers/mailbox/rockchip-mailbox.c
+++ b/drivers/mailbox/rockchip-mailbox.c
@@ -196,19 +196,10 @@ static int rockchip_mbox_probe(struct platform_device *pdev)
 	/* Each channel has two buffers for A2B and B2A */
 	mb->buf_size = (size_t)resource_size(res) / (drv_data->num_chans * 2);
 
-	mb->pclk = devm_clk_get(&pdev->dev, "pclk_mailbox");
-	if (IS_ERR(mb->pclk)) {
-		ret = PTR_ERR(mb->pclk);
-		dev_err(&pdev->dev, "failed to get pclk_mailbox clock: %d\n",
-			ret);
-		return ret;
-	}
-
-	ret = clk_prepare_enable(mb->pclk);
-	if (ret) {
-		dev_err(&pdev->dev, "failed to enable pclk: %d\n", ret);
-		return ret;
-	}
+	mb->pclk = devm_clk_get_enabled(&pdev->dev, "pclk_mailbox");
+	if (IS_ERR(mb->pclk))
+		return dev_err_probe(&pdev->dev, PTR_ERR(mb->pclk),
+				     "failed to get and enable pclk_mailbox clock\n");
 
 	for (i = 0; i < mb->mbox.num_chans; i++) {
 		irq = platform_get_irq(pdev, i);
-- 
2.25.1