[PATCH] phy: mediatek: Avoid floating point constants

[Guillaume Ranquet]

On Wed, 19 Apr 2023 14:21, Thierry Reding <thierry.reding at gmail.com> wrote:
>From: Thierry Reding <treding at nvidia.com>
>
>When building with old versions of GCC (6.3 in this case), the compiler
>stumbles over the floating point constants in this driver:
>
>	drivers/phy/mediatek/phy-mtk-hdmi-mt8195.c: In function ‘mtk_hdmi_pll_prepare’:
>	drivers/phy/mediatek/phy-mtk-hdmi-mt8195.c:331:23: error: ‘-mgeneral-regs-only’ is incompatible with floating-point code
>	  } else if (pixel_clk >= 74.175 * MEGA && pixel_clk <= 300 * MEGA) {
>
>	drivers/phy/mediatek/phy-mtk-hdmi-mt8195.c:361:12: error: ‘-mgeneral-regs-only’ is incompatible with floating-point code
>	 static int mtk_hdmi_pll_prepare(struct clk_hw *hw)
>		    ^~~~~~~~~~~~~~~~~~~~
>	drivers/phy/mediatek/phy-mtk-hdmi-mt8195.c:361:12: error: ‘-mgeneral-regs-only’ is incompatible with floating-point code
>
>Fix this by switching to the KILO macro instead and multiplying the
>constants by 1000 to get rid of the floating point.
>
>Fixes: 45810d486bb4 ("phy: mediatek: add support for phy-mtk-hdmi-mt8195")
>Reported-by: Jonathan Hunter <jonathanh at nvidia.com>
>Signed-off-by: Thierry Reding <treding at nvidia.com>
>---
> drivers/phy/mediatek/phy-mtk-hdmi-mt8195.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
>diff --git a/drivers/phy/mediatek/phy-mtk-hdmi-mt8195.c b/drivers/phy/mediatek/phy-mtk-hdmi-mt8195.c
>index abfc077fb0a8..b10af26cad2f 100644
>--- a/drivers/phy/mediatek/phy-mtk-hdmi-mt8195.c
>+++ b/drivers/phy/mediatek/phy-mtk-hdmi-mt8195.c
>@@ -239,9 +239,9 @@ static int mtk_hdmi_pll_calc(struct mtk_hdmi_phy *hdmi_phy, struct clk_hw *hw,
> 		txposdiv = 8;
> 	else if (tmds_clk >= 54 * MEGA && tmds_clk < 148.35 * MEGA)
> 		txposdiv = 4;
>-	else if (tmds_clk >= 148.35 * MEGA && tmds_clk < 296.7 * MEGA)
>+	else if (tmds_clk >= 148350 * KILO && tmds_clk < 296700 * KILO)
> 		txposdiv = 2;
>-	else if (tmds_clk >= 296.7 * MEGA && tmds_clk <= 594 * MEGA)
>+	else if (tmds_clk >= 296700 * KILO && tmds_clk <= 594 * MEGA)
> 		txposdiv = 1;
> 	else
> 		return -EINVAL;
>@@ -328,12 +328,12 @@ static int mtk_hdmi_pll_drv_setting(struct clk_hw *hw)
> 		clk_channel_bias = 0x34; /* 20mA */
> 		impedance_en = 0xf;
> 		impedance = 0x36; /* 100ohm */
>-	} else if (pixel_clk >= 74.175 * MEGA && pixel_clk <= 300 * MEGA) {
>+	} else if (pixel_clk >= 74175 * KILO && pixel_clk <= 300 * MEGA) {
> 		data_channel_bias = 0x34; /* 20mA */
> 		clk_channel_bias = 0x2c; /* 16mA */
> 		impedance_en = 0xf;
> 		impedance = 0x36; /* 100ohm */
>-	} else if (pixel_clk >= 27 * MEGA && pixel_clk < 74.175 * MEGA) {
>+	} else if (pixel_clk >= 27 * MEGA && pixel_clk < 74175 * KILO) {
> 		data_channel_bias = 0x14; /* 10mA */
> 		clk_channel_bias = 0x14; /* 10mA */
> 		impedance_en = 0x0;
>--
>2.40.0
>

Thx for the fix!

Reviewed-by: Guillaume Ranquet <granquet at baylibre.com>