Re: [PATCH 1/2] drm/rockchip: lvds: move pclk preparation in with clk_get

From: Quentin Schulz
Date: Fri Feb 28 2025 - 12:20:08 EST


Hi Heiko,

On 2/28/25 5:57 PM, Heiko Stuebner wrote:
From: Heiko Stuebner <heiko.stuebner@xxxxxxxxx>

The LVDS block needs a separate pclk only on some socs, so currently
requests and prepares it in the soc-specific probe function, but common
code is required to unprepare it in the error path or on driver remove.

While this works because clk_unprepare just does nothing if clk is NULL,
this mismatch of who is responsible still is not very nice.
The clock-framework already has a helper for clk-get-and-prepare even
with devres support in devm_clk_get_prepared().

This will get and prepare the clock and also unprepare it on driver
removal, saving the driver from having to handle it "manually".

Signed-off-by: Heiko Stuebner <heiko.stuebner@xxxxxxxxx>

Reviewed-by: Quentin Schulz <quentin.schulz@xxxxxxxxx>

Small nitpick below.

---
drivers/gpu/drm/rockchip/rockchip_lvds.c | 17 ++---------------
1 file changed, 2 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_lvds.c b/drivers/gpu/drm/rockchip/rockchip_lvds.c
index 385cf6881504..c19b7b1f6cb5 100644
--- a/drivers/gpu/drm/rockchip/rockchip_lvds.c
+++ b/drivers/gpu/drm/rockchip/rockchip_lvds.c
@@ -448,13 +448,11 @@ struct drm_encoder_helper_funcs px30_lvds_encoder_helper_funcs = {
static int rk3288_lvds_probe(struct platform_device *pdev,
struct rockchip_lvds *lvds)
{
- int ret;
-
lvds->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(lvds->regs))
return PTR_ERR(lvds->regs);
- lvds->pclk = devm_clk_get(lvds->dev, "pclk_lvds");
+ lvds->pclk = devm_clk_get_prepared(lvds->dev, "pclk_lvds");
if (IS_ERR(lvds->pclk)) {
DRM_DEV_ERROR(lvds->dev, "could not get pclk_lvds\n");

Should we say

Could not get or prepare pclk_lvds\n

instead?

Thanks!
Quentin