linux-kernel - [PATCH v3 2/3] drm/bridge: analogix_dp: use jiffies to simulate timeout loop

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Date:   Fri,  9 Sep 2016 17:44:50 +0800
From:   Yakir Yang <ykk@...k-chips.com>
To:     Sean Paul <seanpaul@...omium.org>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        Inki Dae <inki.dae@...sung.com>,
        David Airlie <airlied@...ux.ie>
Cc:     Tomeu Vizoso <tomeu.vizoso@...labora.com>,
        Mika Kahola <mika.kahola@...el.com>,
        Stéphane Marchesin <marcheu@...omium.org>,
        Tomasz Figa <tfiga@...omium.org>, dianders@...omium.org,
        Thierry Reding <treding@...dia.com>,
        Krzysztof Kozlowski <k.kozlowski@...sung.com>,
        Heiko Stuebner <heiko@...ech.de>,
        Jingoo Han <jingoohan1@...il.com>,
        Javier Martinez Canillas <javier@....samsung.com>,
        Yakir Yang <ykk@...k-chips.com>, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, linux-samsung-soc@...r.kernel.org,
        linux-rockchip@...ts.infradead.org
Subject: [PATCH v3 2/3] drm/bridge: analogix_dp: use jiffies to simulate timeout loop

Signed-off-by: Yakir Yang <ykk@...k-chips.com>
---
Changes in v3:
- Suggested by Sean

Changes in v2: None

 drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |  3 ++-
 drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c  | 18 +++++++++---------
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
index a15f076..d564e90 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
@@ -16,10 +16,11 @@
 #include <drm/drm_crtc.h>
 #include <drm/drm_dp_helper.h>
 
-#define DP_TIMEOUT_LOOP_COUNT 100
 #define MAX_CR_LOOP 5
 #define MAX_EQ_LOOP 5
 
+#define DP_TIMEOUT_LOOP_MS			msecs_to_jiffies(1)
+
 /* DP_MAX_LANE_COUNT */
 #define DPCD_ENHANCED_FRAME_CAP(x)		(((x) >> 7) & 0x1)
 #define DPCD_MAX_LANE_COUNT(x)			((x) & 0x1f)
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index a4d17b8..15a4cf0 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -335,7 +335,7 @@ void analogix_dp_set_analog_power_down(struct analogix_dp_device *dp,
 void analogix_dp_init_analog_func(struct analogix_dp_device *dp)
 {
 	u32 reg;
-	int timeout_loop = 0;
+	unsigned long timeout;
 
 	analogix_dp_set_analog_power_down(dp, POWER_ALL, 0);
 
@@ -350,9 +350,9 @@ void analogix_dp_init_analog_func(struct analogix_dp_device *dp)
 	if (analogix_dp_get_pll_lock_status(dp) == PLL_UNLOCKED) {
 		analogix_dp_set_pll_power_down(dp, 0);
 
+		timeout = jiffies + DP_TIMEOUT_LOOP_MS;
 		while (analogix_dp_get_pll_lock_status(dp) == PLL_UNLOCKED) {
-			timeout_loop++;
-			if (DP_TIMEOUT_LOOP_COUNT < timeout_loop) {
+			if (time_after(jiffies, timeout)) {
 				dev_err(dp->dev, "failed to get pll lock status\n");
 				return;
 			}
@@ -501,7 +501,7 @@ int analogix_dp_start_aux_transaction(struct analogix_dp_device *dp)
 {
 	int reg;
 	int retval = 0;
-	int timeout_loop = 0;
+	unsigned long timeout;
 
 	/* Enable AUX CH operation */
 	reg = readl(dp->reg_base + ANALOGIX_DP_AUX_CH_CTL_2);
@@ -509,10 +509,10 @@ int analogix_dp_start_aux_transaction(struct analogix_dp_device *dp)
 	writel(reg, dp->reg_base + ANALOGIX_DP_AUX_CH_CTL_2);
 
 	/* Is AUX CH command reply received? */
+	timeout = jiffies + DP_TIMEOUT_LOOP_MS;
 	reg = readl(dp->reg_base + ANALOGIX_DP_INT_STA);
 	while (!(reg & RPLY_RECEIV)) {
-		timeout_loop++;
-		if (DP_TIMEOUT_LOOP_COUNT < timeout_loop) {
+		if (time_after(jiffies, timeout)) {
 			dev_err(dp->dev, "AUX CH command reply failed!\n");
 			return -ETIMEDOUT;
 		}
@@ -1055,7 +1055,7 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
 {
 	u32 reg;
 	u8 *buffer = msg->buffer;
-	int timeout_loop = 0;
+	unsigned long timeout;
 	unsigned int i;
 	int num_transferred = 0;
 
@@ -1123,10 +1123,10 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
 
 	/* Is AUX CH command reply received? */
 	/* TODO: Wait for an interrupt instead of looping? */
+	timeout = jiffies + DP_TIMEOUT_LOOP_MS;
 	reg = readl(dp->reg_base + ANALOGIX_DP_INT_STA);
 	while (!(reg & RPLY_RECEIV)) {
-		timeout_loop++;
-		if (timeout_loop > DP_TIMEOUT_LOOP_COUNT) {
+		if (time_after(jiffies, timeout)) {
 			dev_err(dp->dev, "AUX CH command reply failed!\n");
 			return -ETIMEDOUT;
 		}
-- 
1.9.1