* [scosu-sched:topic/mmap-cap-prot-wip/v6.18 340/1130] drivers/gpu/drm/bridge/tda998x_drv.c:974:12: warning: 'tda998x_derive_cts_n' defined but not used
@ 2026-05-21 5:26 kernel test robot
0 siblings, 0 replies; only message in thread
From: kernel test robot @ 2026-05-21 5:26 UTC (permalink / raw)
To: Christian Ehrhardt; +Cc: oe-kbuild-all
tree: https://github.com/scosu/linux-sched topic/mmap-cap-prot-wip/v6.18
head: f69a5a9d9fee15edde28429e23a4c749a59937bd
commit: 88aeac7d0691e6cbf6b17d417b7981bc6c7405fa [340/1130] [CHERRY-PICK] drm: i2c: Include hdmi-codec definitions only when required
config: m68k-allmodconfig (https://download.01.org/0day-ci/archive/20260521/202605211316.IMuKBDRX-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 15.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260521/202605211316.IMuKBDRX-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202605211316.IMuKBDRX-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> drivers/gpu/drm/bridge/tda998x_drv.c:974:12: warning: 'tda998x_derive_cts_n' defined but not used [-Wunused-function]
974 | static int tda998x_derive_cts_n(struct tda998x_priv *priv,
| ^~~~~~~~~~~~~~~~~~~~
>> drivers/gpu/drm/bridge/tda998x_drv.c:894:41: warning: 'tda998x_audio_route' defined but not used [-Wunused-const-variable=]
894 | static const struct tda998x_audio_route tda998x_audio_route[AUDIO_ROUTE_NUM] = {
| ^~~~~~~~~~~~~~~~~~~
vim +/tda998x_derive_cts_n +974 drivers/gpu/drm/bridge/tda998x_drv.c
ad975f9364a3e1be drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2016-10-23 893
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 @894 static const struct tda998x_audio_route tda998x_audio_route[AUDIO_ROUTE_NUM] = {
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 895 [AUDIO_ROUTE_I2S] = {
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 896 .ena_aclk = 1,
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 897 .mux_ap = MUX_AP_SELECT_I2S,
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 898 .aip_clksel = AIP_CLKSEL_AIP_I2S | AIP_CLKSEL_FS_ACLK,
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 899 },
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 900 [AUDIO_ROUTE_SPDIF] = {
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 901 .ena_aclk = 0,
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 902 .mux_ap = MUX_AP_SELECT_SPDIF,
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 903 .aip_clksel = AIP_CLKSEL_AIP_SPDIF | AIP_CLKSEL_FS_FS64SPDIF,
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 904 },
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 905 };
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 906
88aeac7d0691e6cb drivers/gpu/drm/bridge/tda998x_drv.c Christian Ehrhardt 2025-06-11 907 #ifdef CONFIG_SND_SOC_HDMI_CODEC
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 908 /* Configure the TDA998x audio data and clock routing. */
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 909 static int tda998x_derive_routing(struct tda998x_priv *priv,
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 910 struct tda998x_audio_settings *s,
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 911 unsigned int route)
c4c11dd160a8cc98 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2013-08-14 912 {
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 913 s->route = &tda998x_audio_route[route];
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 914 s->ena_ap = priv->audio_port_enable[route];
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 915 if (s->ena_ap == 0) {
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 916 dev_err(&priv->hdmi->dev, "no audio configuration found\n");
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 917 return -EINVAL;
c4c11dd160a8cc98 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2013-08-14 918 }
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 919
26f7bf1251c70baf drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-03-01 920 return 0;
c4c11dd160a8cc98 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2013-08-14 921 }
88aeac7d0691e6cb drivers/gpu/drm/bridge/tda998x_drv.c Christian Ehrhardt 2025-06-11 922 #endif
c4c11dd160a8cc98 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2013-08-14 923
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 924 /*
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 925 * The audio clock divisor register controls a divider producing Audio_Clk_Out
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 926 * from SERclk by dividing it by 2^n where 0 <= n <= 5. We don't know what
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 927 * Audio_Clk_Out or SERclk are. We guess SERclk is the same as TMDS clock.
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 928 *
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 929 * It seems that Audio_Clk_Out must be the smallest value that is greater
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 930 * than 128*fs, otherwise audio does not function. There is some suggestion
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 931 * that 126*fs is a better value.
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 932 */
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 933 static u8 tda998x_get_adiv(struct tda998x_priv *priv, unsigned int fs)
c4c11dd160a8cc98 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2013-08-14 934 {
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 935 unsigned long min_audio_clk = fs * 128;
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 936 unsigned long ser_clk = priv->tmds_clock * 1000;
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 937 u8 adiv;
c4c11dd160a8cc98 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2013-08-14 938
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 939 for (adiv = AUDIO_DIV_SERCLK_32; adiv != AUDIO_DIV_SERCLK_1; adiv--)
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 940 if (ser_clk > min_audio_clk << adiv)
c4c11dd160a8cc98 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2013-08-14 941 break;
c4c11dd160a8cc98 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2013-08-14 942
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 943 dev_dbg(&priv->hdmi->dev,
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 944 "ser_clk=%luHz fs=%uHz min_aclk=%luHz adiv=%d\n",
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 945 ser_clk, fs, min_audio_clk, adiv);
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 946
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 947 return adiv;
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 948 }
7dad3740aeb71038 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-27 949
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 950 /*
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 951 * In auto-CTS mode, the TDA998x uses a "measured time stamp" counter to
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 952 * generate the CTS value. It appears that the "measured time stamp" is
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 953 * the number of TDMS clock cycles within a number of audio input clock
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 954 * cycles defined by the k and N parameters defined below, in a similar
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 955 * way to that which is set out in the CTS generation in the HDMI spec.
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 956 *
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 957 * tmdsclk ----> mts -> /m ---> CTS
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 958 * ^
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 959 * sclk -> /k -> /N
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 960 *
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 961 * CTS = mts / m, where m is 2^M.
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 962 * /k is a divider based on the K value below, K+1 for K < 4, or 8 for K >= 4
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 963 * /N is a divider based on the HDMI specified N value.
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 964 *
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 965 * This produces the following equation:
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 966 * CTS = tmds_clock * k * N / (sclk * m)
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 967 *
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 968 * When combined with the sink-side equation, and realising that sclk is
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 969 * bclk_ratio * fs, we end up with:
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 970 * k = m * bclk_ratio / 128.
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 971 *
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 972 * Note: S/PDIF always uses a bclk_ratio of 64.
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 973 */
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 @974 static int tda998x_derive_cts_n(struct tda998x_priv *priv,
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 975 struct tda998x_audio_settings *settings,
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 976 unsigned int ratio)
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 977 {
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 978 switch (ratio) {
95db3b255fde4e83 drivers/gpu/drm/i2c/tda998x_drv.c Jyri Sarha 2016-08-09 979 case 16:
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 980 settings->cts_n = CTS_N_M(3) | CTS_N_K(0);
95db3b255fde4e83 drivers/gpu/drm/i2c/tda998x_drv.c Jyri Sarha 2016-08-09 981 break;
95db3b255fde4e83 drivers/gpu/drm/i2c/tda998x_drv.c Jyri Sarha 2016-08-09 982 case 32:
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 983 settings->cts_n = CTS_N_M(3) | CTS_N_K(1);
c4c11dd160a8cc98 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2013-08-14 984 break;
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 985 case 48:
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 986 settings->cts_n = CTS_N_M(3) | CTS_N_K(2);
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 987 break;
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 988 case 64:
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 989 settings->cts_n = CTS_N_M(3) | CTS_N_K(3);
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 990 break;
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 991 case 128:
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 992 settings->cts_n = CTS_N_M(0) | CTS_N_K(0);
95db3b255fde4e83 drivers/gpu/drm/i2c/tda998x_drv.c Jyri Sarha 2016-08-09 993 break;
3b28802e37bb1ca1 drivers/gpu/drm/i2c/tda998x_drv.c David Rheinsberg 2013-09-01 994 default:
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 995 dev_err(&priv->hdmi->dev, "unsupported bclk ratio %ufs\n",
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 996 ratio);
95db3b255fde4e83 drivers/gpu/drm/i2c/tda998x_drv.c Jyri Sarha 2016-08-09 997 return -EINVAL;
c4c11dd160a8cc98 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2013-08-14 998 }
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 999 return 0;
a03a915b8387286d drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2019-02-22 1000 }
c4c11dd160a8cc98 drivers/gpu/drm/i2c/tda998x_drv.c Russell King 2013-08-14 1001
:::::: The code at line 974 was first introduced by commit
:::::: a03a915b8387286dfd1e7500705124414802ede7 drm/i2c: tda998x: derive CTS_N value from aclk sample rate ratio
:::::: TO: Russell King <rmk+kernel@armlinux.org.uk>
:::::: CC: Russell King <rmk+kernel@armlinux.org.uk>
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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2026-05-21 5:26 [scosu-sched:topic/mmap-cap-prot-wip/v6.18 340/1130] drivers/gpu/drm/bridge/tda998x_drv.c:974:12: warning: 'tda998x_derive_cts_n' defined but not used kernel test robot
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