[PATCH v2 01/13] drm/mediatek: add refcount for DPI power on/off

Bibby Hsieh
2018-09-05T08:31:34Z

From: chunhui dai <chunhui.dai@mediatek.com>

add refcount for DPI power on/off to protect the flow

Signed-off-by: chunhui dai <chunhui.dai@mediatek.com>
---
drivers/gpu/drm/mediatek/mtk_dpi.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
index 6c0ea39d5739..d9373e67d328 100644
--- a/drivers/gpu/drm/mediatek/mtk_dpi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
@@ -77,6 +77,7 @@ struct mtk_dpi {
enum mtk_dpi_out_bit_num bit_num;
enum mtk_dpi_out_channel_swap channel_swap;
bool power_sta;
+ int refcount;
u8 power_ctl;
};

@@ -369,6 +370,12 @@ static void mtk_dpi_config_color_format(struct mtk_dpi *dpi,

static void mtk_dpi_power_off(struct mtk_dpi *dpi, enum mtk_dpi_power_ctl pctl)
{
+ if (WARN_ON(dpi->refcount == 0))
+ return;
+
+ if (--dpi->refcount != 0)
+ return;
+
dpi->power_ctl &= ~pctl;

if ((dpi->power_ctl & DPI_POWER_START) ||
@@ -388,14 +395,17 @@ static int mtk_dpi_power_on(struct mtk_dpi *dpi, enum mtk_dpi_power_ctl pctl)
{
int ret;

+ if (++dpi->refcount != 1)
+ return 0;
+
dpi->power_ctl |= pctl;

if (!(dpi->power_ctl & DPI_POWER_START) &&
!(dpi->power_ctl & DPI_POWER_ENABLE))
- return 0;
+ goto err_refcount;

if (dpi->power_sta)
- return 0;
+ goto err_refcount;

ret = clk_prepare_enable(dpi->engine_clk);
if (ret) {
@@ -417,6 +427,8 @@ static int mtk_dpi_power_on(struct mtk_dpi *dpi, enum mtk_dpi_power_ctl pctl)
clk_disable_unprepare(dpi->engine_clk);
err_eng:
dpi->power_ctl &= ~pctl;
+err_refcount:
+ dpi->refcount--;
return ret;
}

--
2.12.5.2.gbdf23ab