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

[Bibby Hsieh]

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

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

Signed-off-by: chunhui dai <chunhui....@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

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