leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

clk: sunxi-ng: sun8i: r40: Use sigma delta modulation for audio PLL

Browse Source 
Audio cores need specific clock rates which can't be simply obtained by
adjusting integer multipliers and dividers. HW for such cases supports
delta-sigma modulation which enables fractional multipliers.

Port H3 delta-sigma table to R40. They have identical audio PLLs.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20200825131049.1277596-1-jernej.skrabec@siol.net
This commit is contained in:
Jernej Skrabec 2020-08-25 15:10:49 +02:00 committed by Maxime Ripard
parent fb038ce4db
commit a3ba99a24b
No known key found for this signature in database
GPG Key ID: E3EF0D6F671851C5
1 changed files with 24 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
drivers/clk/sunxi-ng/ccu-sun8i-r40.c
View File

@ -45,15 +45,26 @@ static struct ccu_nkmp pll_cpu_clk = {
* the base (2x, 4x and 8x), and one variable divider (the one true
* pll audio).
*
* We don't have any need for the variable divider for now, so we just
* hardcode it to match with the clock names
* With sigma-delta modulation for fractional-N on the audio PLL,
* we have to use specific dividers. This means the variable divider
* can no longer be used, as the audio codec requests the exact clock
* rates we support through this mechanism. So we now hard code the
* variable divider to 1. This means the clock rates will no longer
* match the clock names.
*/
#define SUN8I_R40_PLL_AUDIO_REG 0x008
static SUNXI_CCU_NM_WITH_GATE_LOCK(pll_audio_base_clk, "pll-audio-base",
static struct ccu_sdm_setting pll_audio_sdm_table[] = {
{ .rate = 22579200, .pattern = 0xc0010d84, .m = 8, .n = 7 },
{ .rate = 24576000, .pattern = 0xc000ac02, .m = 14, .n = 14 },
};
static SUNXI_CCU_NM_WITH_SDM_GATE_LOCK(pll_audio_base_clk, "pll-audio-base",
"osc24M", 0x008,
8, 7, /* N */
0, 5, /* M */
pll_audio_sdm_table, BIT(24),
0x284, BIT(31),
BIT(31), /* gate */
BIT(28), /* lock */
CLK_SET_RATE_UNGATE);
@ -952,10 +963,10 @@ static const struct clk_hw *clk_parent_pll_audio[] = {
&pll_audio_base_clk.common.hw
};
/* We hardcode the divider to 4 for now */
/* We hardcode the divider to 1 for now */
static CLK_FIXED_FACTOR_HWS(pll_audio_clk, "pll-audio",
clk_parent_pll_audio,
4, 1, CLK_SET_RATE_PARENT);
1, 1, CLK_SET_RATE_PARENT);
static CLK_FIXED_FACTOR_HWS(pll_audio_2x_clk, "pll-audio-2x",
clk_parent_pll_audio,
2, 1, CLK_SET_RATE_PARENT);
@ -1307,10 +1318,10 @@ static int sun8i_r40_ccu_probe(struct platform_device *pdev)
if (IS_ERR(reg))
return PTR_ERR(reg);
/* Force the PLL-Audio-1x divider to 4 */
/* Force the PLL-Audio-1x divider to 1 */
val = readl(reg + SUN8I_R40_PLL_AUDIO_REG);
val &= ~GENMASK(19, 16);
writel(val | (3 << 16), reg + SUN8I_R40_PLL_AUDIO_REG);
writel(val | (0 << 16), reg + SUN8I_R40_PLL_AUDIO_REG);
/* Force PLL-MIPI to MIPI mode */
val = readl(reg + SUN8I_R40_PLL_MIPI_REG);