2 * hda_i915.c - routines for Haswell HDA controller power well support
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License as published by the Free
6 * Software Foundation; either version 2 of the License, or (at your option)
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
11 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software Foundation,
16 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 #include <linux/init.h>
20 #include <linux/module.h>
21 #include <sound/core.h>
22 #include <drm/i915_powerwell.h>
26 /* Intel HSW/BDW display HDA controller Extended Mode registers.
27 * EM4 (M value) and EM5 (N Value) are used to convert CDClk (Core Display
28 * Clock) to 24MHz BCLK: BCLK = CDCLK * M / N
29 * The values will be lost when the display power well is disabled.
31 #define ICH6_REG_EM4 0x100c
32 #define ICH6_REG_EM5 0x1010
34 static int (*get_power)(void);
35 static int (*put_power)(void);
36 static int (*get_cdclk)(void);
38 int hda_display_power(bool enable)
40 if (!get_power || !put_power)
43 pr_debug("HDA display power %s \n",
44 enable ? "Enable" : "Disable");
51 void haswell_set_bclk(struct azx *chip)
54 unsigned int bclk_m, bclk_n;
59 cdclk_freq = get_cdclk();
67 default: /* default CDCLK 450MHz */
83 azx_writew(chip, EM4, bclk_m);
84 azx_writew(chip, EM5, bclk_n);
88 int hda_i915_init(void)
92 get_power = symbol_request(i915_request_power_well);
94 pr_warn("hda-i915: get_power symbol get fail\n");
98 put_power = symbol_request(i915_release_power_well);
100 symbol_put(i915_request_power_well);
105 get_cdclk = symbol_request(i915_get_cdclk_freq);
106 if (!get_cdclk) /* may have abnormal BCLK and audio playback rate */
107 pr_warn("hda-i915: get_cdclk symbol get fail\n");
109 pr_debug("HDA driver get symbol successfully from i915 module\n");
114 int hda_i915_exit(void)
117 symbol_put(i915_request_power_well);
121 symbol_put(i915_release_power_well);
125 symbol_put(i915_get_cdclk_freq);