From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Date: Sun, 11 Feb 2018 15:07:47 +0200
Subject: drm: omapdrm: dsi: Make wait_for_bit_change() return a status
Git-commit: bafa89fcac4fa4950ffde0b4f565482290176450
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

The wait_for_bit_change() function returns the value of the bit it
polls. This requires the caller to compare the return value to the
expected bit value. As all the existing callers need is to check whether
the bit has reached the expected value, it's easier to return a boolean
status from the function.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/omapdrm/dss/dsi.c |   31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

--- a/drivers/gpu/drm/omapdrm/dss/dsi.c
+++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
@@ -524,7 +524,7 @@ static void dsi_completion_handler(void
 	complete((struct completion *)data);
 }
 
-static inline int wait_for_bit_change(struct platform_device *dsidev,
+static inline bool wait_for_bit_change(struct platform_device *dsidev,
 		const struct dsi_reg idx, int bitnum, int value)
 {
 	unsigned long timeout;
@@ -535,21 +535,21 @@ static inline int wait_for_bit_change(st
 	t = 100;
 	while (t-- > 0) {
 		if (REG_GET(dsidev, idx, bitnum, bitnum) == value)
-			return value;
+			return true;
 	}
 
 	/* then loop for 500ms, sleeping for 1ms in between */
 	timeout = jiffies + msecs_to_jiffies(500);
 	while (time_before(jiffies, timeout)) {
 		if (REG_GET(dsidev, idx, bitnum, bitnum) == value)
-			return value;
+			return true;
 
 		wait = ns_to_ktime(1000 * 1000);
 		set_current_state(TASK_UNINTERRUPTIBLE);
 		schedule_hrtimeout(&wait, HRTIMER_MODE_REL);
 	}
 
-	return !value;
+	return false;
 }
 
 static u8 dsi_get_pixel_size(enum omap_dss_dsi_pixel_format fmt)
@@ -1252,9 +1252,9 @@ static inline int dsi_if_enable(struct p
 	enable = enable ? 1 : 0;
 	REG_FLD_MOD(dsidev, DSI_CTRL, enable, 0, 0); /* IF_EN */
 
-	if (wait_for_bit_change(dsidev, DSI_CTRL, 0, enable) != enable) {
-			DSSERR("Failed to set dsi_if_enable to %d\n", enable);
-			return -EIO;
+	if (!wait_for_bit_change(dsidev, DSI_CTRL, 0, enable)) {
+		DSSERR("Failed to set dsi_if_enable to %d\n", enable);
+		return -EIO;
 	}
 
 	return 0;
@@ -1441,7 +1441,7 @@ static int dsi_pll_enable(struct dss_pll
 	/* XXX PLL does not come out of reset without this... */
 	dispc_pck_free_enable(1);
 
-	if (wait_for_bit_change(dsidev, DSI_PLL_STATUS, 0, 1) != 1) {
+	if (!wait_for_bit_change(dsidev, DSI_PLL_STATUS, 0, 1)) {
 		DSSERR("PLL not coming out of reset.\n");
 		r = -ENODEV;
 		dispc_pck_free_enable(0);
@@ -2187,7 +2187,7 @@ static int dsi_cio_init(struct platform_
 	 * I/O. */
 	dsi_read_reg(dsidev, DSI_DSIPHY_CFG5);
 
-	if (wait_for_bit_change(dsidev, DSI_DSIPHY_CFG5, 30, 1) != 1) {
+	if (!wait_for_bit_change(dsidev, DSI_DSIPHY_CFG5, 30, 1)) {
 		DSSERR("CIO SCP Clock domain not coming out of reset.\n");
 		r = -EIO;
 		goto err_scp_clk_dom;
@@ -2235,7 +2235,7 @@ static int dsi_cio_init(struct platform_
 	if (r)
 		goto err_cio_pwr;
 
-	if (wait_for_bit_change(dsidev, DSI_COMPLEXIO_CFG1, 29, 1) != 1) {
+	if (!wait_for_bit_change(dsidev, DSI_COMPLEXIO_CFG1, 29, 1)) {
 		DSSERR("CIO PWR clock domain not coming out of reset.\n");
 		r = -ENODEV;
 		goto err_cio_pwr_dom;
@@ -2376,7 +2376,7 @@ static int dsi_force_tx_stop_mode_io(str
 	r = FLD_MOD(r, 1, 15, 15);	/* FORCE_TX_STOP_MODE_IO */
 	dsi_write_reg(dsidev, DSI_TIMING1, r);
 
-	if (wait_for_bit_change(dsidev, DSI_TIMING1, 15, 0) != 0) {
+	if (!wait_for_bit_change(dsidev, DSI_TIMING1, 15, 0)) {
 		DSSERR("TX_STOP bit not going down\n");
 		return -EIO;
 	}
@@ -2518,10 +2518,9 @@ static int dsi_vc_enable(struct platform
 
 	REG_FLD_MOD(dsidev, DSI_VC_CTRL(channel), enable, 0, 0);
 
-	if (wait_for_bit_change(dsidev, DSI_VC_CTRL(channel),
-		0, enable) != enable) {
-			DSSERR("Failed to set dsi_vc_enable to %d\n", enable);
-			return -EIO;
+	if (!wait_for_bit_change(dsidev, DSI_VC_CTRL(channel), 0, enable)) {
+		DSSERR("Failed to set dsi_vc_enable to %d\n", enable);
+		return -EIO;
 	}
 
 	return 0;
@@ -2573,7 +2572,7 @@ static int dsi_vc_config_source(struct p
 	dsi_vc_enable(dsidev, channel, 0);
 
 	/* VC_BUSY */
-	if (wait_for_bit_change(dsidev, DSI_VC_CTRL(channel), 15, 0) != 0) {
+	if (!wait_for_bit_change(dsidev, DSI_VC_CTRL(channel), 15, 0)) {
 		DSSERR("vc(%d) busy when trying to config for VP\n", channel);
 		return -EIO;
 	}