linux-kernel - [PATCH v1] applesmc: Cleanups on top of re-work comms

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Date:   Wed, 11 Nov 2020 15:55:31 +1100
From:   Brad Campbell <brad@...rfbargle.com>
To:     linux-hwmon@...r.kernel.org
Cc:     Arnd Bergmann <arnd@...db.de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        hns@...delico.com, Guenter Roeck <linux@...ck-us.net>,
        Andreas Kemnade <andreas@...nade.info>,
        Jean Delvare <jdelvare@...e.com>,
        Henrik Rydberg <rydberg@...math.org>
Subject: [PATCH v1] applesmc: Cleanups on top of re-work comms

A few small cleanups on top of the comms changes for applesmc.c :

send_byte() is always called with APPLESMC_CMD_PORT, so simplify.
Remove redundant check from smc_sane().
Consolidate writing length with other setup parameters.
Consolidate read and write error messages to a single statement each.

Length and error consolidation suggested by Henrik Rydberg <rydberg@...math.org>

Signed-off-by: Brad Campbell <brad@...rfbargle.com>

Index: linux-stable/drivers/hwmon/applesmc.c
===================================================================
--- linux-stable.orig/drivers/hwmon/applesmc.c
+++ linux-stable/drivers/hwmon/applesmc.c
@@ -176,7 +176,7 @@ static int wait_status(u8 val, u8 mask)
 
 /* send_byte - Write to SMC data port. Callers must hold applesmc_lock. */
 
-static int send_byte(u8 cmd, u16 port)
+static int send_byte(u8 cmd)
 {
 	int status;
 
@@ -186,7 +186,7 @@ static int send_byte(u8 cmd, u16 port)
 	status = wait_status(SMC_STATUS_BUSY, SMC_STATUS_BUSY);
 	if (status)
 		return status;
-	outb(cmd, port);
+	outb(cmd, APPLESMC_DATA_PORT);
 	return 0;
 }
 
@@ -219,10 +219,7 @@ static int smc_sane(void)
 	ret = send_command(APPLESMC_READ_CMD);
 	if (ret)
 		return ret;
-	ret = wait_status(0, SMC_STATUS_BUSY);
-	if (!ret)
-		return ret;
-	return -EIO;
+	return wait_status(0, SMC_STATUS_BUSY);
 }
 
 static int send_argument(const char *key)
@@ -230,7 +227,7 @@ static int send_argument(const char *key
 	int i;
 
 	for (i = 0; i < 4; i++)
-		if (send_byte(key[i], APPLESMC_DATA_PORT))
+		if (send_byte(key[i]))
 			return -EIO;
 	return 0;
 }
@@ -245,23 +242,14 @@ static int read_smc(u8 cmd, const char *
 	if (ret)
 		return ret;
 
-	if (send_command(cmd) || send_argument(key)) {
-		pr_warn("%.4s: read arg fail\n", key);
-		return -EIO;
-	}
-
-	/* This has no effect on newer (2012) SMCs */
-	if (send_byte(len, APPLESMC_DATA_PORT)) {
-		pr_warn("%.4s: read len fail\n", key);
-		return -EIO;
-	}
+	if (send_command(cmd) || send_argument(key) || send_byte(len))
+		goto err;
 
 	for (i = 0; i < len; i++) {
 		if (wait_status(SMC_STATUS_AWAITING_DATA | SMC_STATUS_BUSY,
-				SMC_STATUS_AWAITING_DATA | SMC_STATUS_BUSY) < 0) {
-			pr_warn("%.4s: read data[%d] fail\n", key, i);
-			return -EIO;
-		}
+				SMC_STATUS_AWAITING_DATA | SMC_STATUS_BUSY))
+			goto err;
+
 		buffer[i] = inb(APPLESMC_DATA_PORT);
 	}
 
@@ -277,6 +265,9 @@ static int read_smc(u8 cmd, const char *
 		pr_warn("flushed %d bytes, last value is: %d\n", i, data);
 
 	return wait_status(0, SMC_STATUS_BUSY);
+err:
+	pr_warn("read cmd fail: %x %.4s %d\n", cmd, key, len);
+	return -EIO;
 }
 
 static int write_smc(u8 cmd, const char *key, const u8 *buffer, u8 len)
@@ -288,24 +279,17 @@ static int write_smc(u8 cmd, const char
 	if (ret)
 		return ret;
 
-	if (send_command(cmd) || send_argument(key)) {
-		pr_warn("%s: write arg fail\n", key);
-		return -EIO;
-	}
+	if (send_command(cmd) || send_argument(key) || send_byte(len))
+		goto err;
 
-	if (send_byte(len, APPLESMC_DATA_PORT)) {
-		pr_warn("%.4s: write len fail\n", key);
-		return -EIO;
-	}
-
-	for (i = 0; i < len; i++) {
-		if (send_byte(buffer[i], APPLESMC_DATA_PORT)) {
-			pr_warn("%s: write data fail\n", key);
-			return -EIO;
-		}
-	}
+	for (i = 0; i < len; i++)
+		if (send_byte(buffer[i]))
+			goto err;
 
 	return wait_status(0, SMC_STATUS_BUSY);
+err:
+	pr_warn("write cmd fail: %x %.4s %d\n", cmd, key, len);
+	return -EIO;
 }
 
 static int read_register_count(unsigned int *count)