[PATCH 5.5 212/367] drm: atmel-hlcdc: use double rate for pixel clock only if supported

Greg Kroah-Hartman
2020-02-10T13:00:46Z

From: Claudiu Beznea <claudiu.beznea@microchip.com>

commit 07acf4bafe81dd37eff3fbcfbbdbc48084bc202b upstream.

Doubled system clock should be used as pixel cock source only if this
is supported. This is emphasized by the value of
atmel_hlcdc_crtc::dc::desc::fixed_clksrc.

Fixes: a6eca2abdd42 ("drm: atmel-hlcdc: add config option for clock selection")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Boris Brezillon <bbrezillon@kernel.org>
Cc: <stable@vger.kernel.org> # v5.3+
Link: https://patchwork.freedesktop.org/patch/msgid/1576672109-22707-2-git-send-email-claudiu.beznea@microchip.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
@@ -95,14 +95,14 @@ static void atmel_hlcdc_crtc_mode_set_no
(adj->crtc_hdisplay - 1) |
((adj->crtc_vdisplay - 1) << 16));

+ prate = clk_get_rate(crtc->dc->hlcdc->sys_clk);
+ mode_rate = adj->crtc_clock * 1000;
if (!crtc->dc->desc->fixed_clksrc) {
+ prate *= 2;
cfg |= ATMEL_HLCDC_CLKSEL;
mask |= ATMEL_HLCDC_CLKSEL;
}

- prate = 2 * clk_get_rate(crtc->dc->hlcdc->sys_clk);
- mode_rate = adj->crtc_clock * 1000;
-
div = DIV_ROUND_UP(prate, mode_rate);
if (div < 2) {
div = 2;