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authorKen Chang <kenc@nvidia.com>2014-04-18 13:52:48 +0800
committerMarc Jones <marc.jones@se-eng.com>2014-12-17 01:07:53 +0100
commitcbae0de7b91e723d11926cf24acef6b7389257ea (patch)
tree370cc40a1664b0b94ede875deb0afe632f665b3b /src
parent43e925252ab0df6539c993557cb1526ae2337cd1 (diff)
tegra124: change PLLD VCO calculation algorithm
The current algo sets dc shift clock divider to 5 and PLLD DIVP to 0, this is causing VCO out of the characterized range for some panels. This CL changes the dc shift clock divider to 1 and calculates a proper DIVP to have the VCO inside the characterized range, i.e., 500MHz ~ 1000MHz. BRANCH=none BUG=none TEST=Verify on below panels the pixel clock frequencies are correct. 1. AUO B133XTN01.3 (69.5 MHz) pixelclk(MHz), pll_d(MHz), m/n/p without: 69.5 695 12/695/0 with: 69.5 139 3/139/2 2. AUO B140HTT01.0 (141 MHz) pixelclk(MHz), pll_d(MHz), m/n/p without: VCO (1410000000) out of range. Cannot support. with: 141 282 2/94/1 3. LG LP140WH8 (76.32 MHz) pixelclk(MHz), pll_d(MHz), m/n/p without: 76.32 763.2 5/381/0 with: 76.3125 152.625 8/407/2 4. N116BGE-EA2 (76.42 MHz) pixelclk(MHz), pll_d(MHz), m/n/p without: 76.40 764 3/191/0 with: 76.375 152.75 12/611/2 Original-Change-Id: Id4b3a4865acde37a97d7346ec88406f5237304eb Original-Signed-off-by: Ken Chang <kenc@nvidia.com> Original-Reviewed-on: https://chromium-review.googlesource.com/195534 Original-Reviewed-by: Hung-Te Lin <hungte@chromium.org> (cherry picked from commit 1b56566786aa86c14f691fa3858b878f27b6b4de) Signed-off-by: Marc Jones <marc.jones@se-eng.com> Change-Id: Ia9de93420e60323f143a42db842febdd3706fe44 Reviewed-on: http://review.coreboot.org/7773 Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org> Tested-by: build bot (Jenkins)
Diffstat (limited to 'src')
-rw-r--r--src/soc/nvidia/tegra124/clock.c23
-rw-r--r--src/soc/nvidia/tegra124/display.c4
2 files changed, 17 insertions, 10 deletions
diff --git a/src/soc/nvidia/tegra124/clock.c b/src/soc/nvidia/tegra124/clock.c
index eed5116c32..c5b06f4557 100644
--- a/src/soc/nvidia/tegra124/clock.c
+++ b/src/soc/nvidia/tegra124/clock.c
@@ -304,7 +304,8 @@ clock_display(u32 frequency)
* = (cf * n) >> p, where 1MHz < cf < 6MHz
* = ((ref / m) * n) >> p
*
- * Assume p = 0, find best (m, n). since m has only 5 bits, we can
+ * Iterate the possible values of p (3 bits, 2^7) to find out a minimum
+ * safe vco, then find best (m, n). since m has only 5 bits, we can
* iterate all possible values. Note Tegra 124 supports 11 bits for n,
* but our pll_fields has only 10 bits for n.
*
@@ -312,19 +313,25 @@ clock_display(u32 frequency)
* work if the values are not in "safe" range by panel specification.
*/
struct pllpad_dividers plld = { 0 };
- u32 ref = clock_get_pll_input_khz() * 1000, m, n;
- u32 cf, vco = frequency;
- u32 diff, best_diff = vco;
- const u32 max_m = 1 << 5, max_n = 1 << 10, mhz = 1000 * 1000,
- min_vco = 500 * mhz, max_vco = 1000 * mhz,
+ u32 ref = clock_get_pll_input_khz() * 1000, m, n, p = 0;
+ u32 cf, vco;
+ u32 diff, best_diff;
+ const u32 max_m = 1 << 5, max_n = 1 << 10, max_p = 1 << 3,
+ mhz = 1000 * 1000, min_vco = 500 * mhz, max_vco = 1000 * mhz,
min_cf = 1 * mhz, max_cf = 6 * mhz;
+ for (vco = frequency; vco < min_vco && p < max_p; p++)
+ vco <<= 1;
+
if (vco < min_vco || vco > max_vco) {
- printk(BIOS_ERR, "%s: VCO (%d) out of range. Cannot support.\n",
- __func__, vco);
+ printk(BIOS_ERR, "%s: Cannot find out a supported VCO"
+ " for Frequency (%u).\n", __func__, frequency);
return -1;
}
+ plld.p = p;
+ best_diff = vco;
+
for (m = 1; m < max_m && best_diff; m++) {
cf = ref / m;
if (cf < min_cf)
diff --git a/src/soc/nvidia/tegra124/display.c b/src/soc/nvidia/tegra124/display.c
index 33769bac6d..87472efd09 100644
--- a/src/soc/nvidia/tegra124/display.c
+++ b/src/soc/nvidia/tegra124/display.c
@@ -124,12 +124,12 @@ static int update_display_mode(struct display_controller *disp_ctrl,
* Currently most panels work inside clock range 50MHz~100MHz, and PLLD
* has some requirements to have VCO in range 500MHz~1000MHz (see
* clock.c for more detail). To simplify calculation, we set
- * PixelClockDiv to 1 and ShiftClockDiv to 5. In future these values
+ * PixelClockDiv to 1 and ShiftClockDiv to 1. In future these values
* may be calculated by clock_display, to allow wider frequency range.
*
* Note ShiftClockDiv is a 7.1 format value.
*/
- const u32 shift_clock_div = 5;
+ const u32 shift_clock_div = 1;
WRITEL((PIXEL_CLK_DIVIDER_PCD1 << PIXEL_CLK_DIVIDER_SHIFT) |
((shift_clock_div - 1) * 2) << SHIFT_CLK_DIVIDER_SHIFT,
&disp_ctrl->disp.disp_clk_ctrl);