On Wed, 22 Oct 2025, Manikandan Muralidharan wrote:
> The XLCDC IP supports parallel RGB, MIPI DSI and LVDS Display.
> The LCD Generic clock (sys_clk) is used for Parallel RGB and MIPI
> displays, while the LVDS PLL clock (lvds_pll_clk) is used for LVDS
> displays.Since both the clocks cannot co-exist together in the DT
> for a given display, this patch first attempts to retrieve sys_clk
> If that fails,it then tries to acquire lvds_pll_clk.
>
> Signed-off-by: Manikandan Muralidharan <[email protected]>
> Signed-off-by: Dharma Balasubiramani <[email protected]>
> ---
> changes in v2:
> - Rephrase the comments, commit message and err logs
> - Replace dev_err wwith dev_warn
> - Remove Initializing sys_clk and lvds_pll_clk to NULL post
> devm_kzalloc() call
>
> ---
> drivers/mfd/atmel-hlcdc.c | 16 ++++++++++++++--
> include/linux/mfd/atmel-hlcdc.h | 1 +
> 2 files changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mfd/atmel-hlcdc.c b/drivers/mfd/atmel-hlcdc.c
> index 4c4e35d404f3..f680392b01ba 100644
> --- a/drivers/mfd/atmel-hlcdc.c
> +++ b/drivers/mfd/atmel-hlcdc.c
> @@ -108,10 +108,22 @@ static int atmel_hlcdc_probe(struct platform_device
> *pdev)
> return PTR_ERR(hlcdc->periph_clk);
> }
>
> + /*
> + * Retrieve any one of the Main clk required by the LCD to operate:
> + *
> + * LCDC Generic Clock (sys_clk) - Parallel RGB and MIPI displays,
> + * LVDS PLL (lvds_pll_clk) - LVDS display
> + */
> hlcdc->sys_clk = devm_clk_get(dev, "sys_clk");
> if (IS_ERR(hlcdc->sys_clk)) {
> - dev_err(dev, "failed to get system clock\n");
> - return PTR_ERR(hlcdc->sys_clk);
> + dev_warn(dev,
> + "failed to get LCDC generic clock, trying for LVDS PLL
> clock instead\n");
Does the user really care which clock they use?
Can this just happen silently instead?
> + hlcdc->lvds_pll_clk = devm_clk_get(dev, "lvds_pll_clk");
> + if (IS_ERR(hlcdc->lvds_pll_clk)) {
> + dev_err(dev, "failed to get LVDS PLL clock\n");
Failed to obtain both the LCDC (generic) and LVDS PLL clocks
> + return PTR_ERR(hlcdc->lvds_pll_clk);
> + }
> }
>
> hlcdc->slow_clk = devm_clk_get(dev, "slow_clk");
> diff --git a/include/linux/mfd/atmel-hlcdc.h b/include/linux/mfd/atmel-hlcdc.h
> index 80d675a03b39..07c2081867fd 100644
> --- a/include/linux/mfd/atmel-hlcdc.h
> +++ b/include/linux/mfd/atmel-hlcdc.h
> @@ -75,6 +75,7 @@
> */
> struct atmel_hlcdc {
> struct regmap *regmap;
> + struct clk *lvds_pll_clk;
> struct clk *periph_clk;
> struct clk *sys_clk;
> struct clk *slow_clk;
> --
> 2.25.1
>
--
Lee Jones [李琼斯]
