1 files changed, 44 insertions, 11 deletions

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index db3204d2a3..07f7b48bad 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -237,6 +237,14 @@
 #define MAX310x_REV_MASK		(0xf8)
 #define MAX310X_WRITE_BIT		0x80
 
+/* Port startup definitions */
+#define MAX310X_PORT_STARTUP_WAIT_RETRIES	20 /* Number of retries */
+#define MAX310X_PORT_STARTUP_WAIT_DELAY_MS	10 /* Delay between retries */
+
+/* Crystal-related definitions */
+#define MAX310X_XTAL_WAIT_RETRIES	20 /* Number of retries */
+#define MAX310X_XTAL_WAIT_DELAY_MS	10 /* Delay between retries */
+
 /* MAX3107 specific */
 #define MAX3107_REV_ID			(0xa0)
 
@@ -402,7 +410,7 @@ static int max14830_detect(struct device *dev)
 	ret = s->if_cfg->extended_reg_enable(dev, true);
 	if (ret)
 		return ret;
-	
+
 	regmap_read(s->regmap, s->if_cfg->rev_id_reg, &val);
 	s->if_cfg->extended_reg_enable(dev, false);
 	if (((val & MAX310x_REV_MASK) != MAX14830_REV_ID)) {
@@ -583,7 +591,7 @@ static int max310x_update_best_err(unsigned long f, long *besterr)
 	return 1;
 }
 
-static u32 max310x_set_ref_clk(struct device *dev, struct max310x_port *s,
+static s32 max310x_set_ref_clk(struct device *dev, struct max310x_port *s,
 			       unsigned long freq, bool xtal)
 {
 	unsigned int div, clksrc, pllcfg = 0;
@@ -641,12 +649,20 @@ static u32 max310x_set_ref_clk(struct device *dev, struct max310x_port *s,
 
 	/* Wait for crystal */
 	if (xtal) {
-		unsigned int val;
-		msleep(10);
-		regmap_read(s->regmap, MAX310X_STS_IRQSTS_REG, &val);
-		if (!(val & MAX310X_STS_CLKREADY_BIT)) {
-			dev_warn(dev, "clock is not stable yet\n");
-		}
+		bool stable = false;
+		unsigned int try = 0, val = 0;
+
+		do {
+			msleep(MAX310X_XTAL_WAIT_DELAY_MS);
+			regmap_read(s->regmap, MAX310X_STS_IRQSTS_REG, &val);
+
+			if (val & MAX310X_STS_CLKREADY_BIT)
+				stable = true;
+		} while (!stable && (++try < MAX310X_XTAL_WAIT_RETRIES));
+
+		if (!stable)
+			return dev_err_probe(dev, -EAGAIN,
+					     "clock is not stable\n");
 	}
 
 	return bestfreq;
@@ -1271,7 +1287,7 @@ static int max310x_probe(struct device *dev, const struct max310x_devtype *devty
 {
 	int i, ret, fmin, fmax, freq;
 	struct max310x_port *s;
-	u32 uartclk = 0;
+	s32 uartclk = 0;
 	bool xtal;
 
 	for (i = 0; i < devtype->nr; i++)
@@ -1334,6 +1350,9 @@ static int max310x_probe(struct device *dev, const struct max310x_devtype *devty
 		goto out_clk;
 
 	for (i = 0; i < devtype->nr; i++) {
+		bool started = false;
+		unsigned int try = 0, val = 0;
+
 		/* Reset port */
 		regmap_write(regmaps[i], MAX310X_MODE2_REG,
 			     MAX310X_MODE2_RST_BIT);
@@ -1342,13 +1361,27 @@ static int max310x_probe(struct device *dev, const struct max310x_devtype *devty
 
 		/* Wait for port startup */
 		do {
-			regmap_read(regmaps[i], MAX310X_BRGDIVLSB_REG, &ret);
-		} while (ret != 0x01);
+			msleep(MAX310X_PORT_STARTUP_WAIT_DELAY_MS);
+			regmap_read(regmaps[i], MAX310X_BRGDIVLSB_REG, &val);
+
+			if (val == 0x01)
+				started = true;
+		} while (!started && (++try < MAX310X_PORT_STARTUP_WAIT_RETRIES));
+
+		if (!started) {
+			ret = dev_err_probe(dev, -EAGAIN, "port reset failed\n");
+			goto out_uart;
+		}
 
 		regmap_write(regmaps[i], MAX310X_MODE1_REG, devtype->mode1);
 	}
 
 	uartclk = max310x_set_ref_clk(dev, s, freq, xtal);
+	if (uartclk < 0) {
+		ret = uartclk;
+		goto out_uart;
+	}
+
 	dev_dbg(dev, "Reference clock set to %i Hz\n", uartclk);
 
 	for (i = 0; i < devtype->nr; i++) {