svn commit: r264119 - head/sys/arm/ti

[Ian Lepore]

Author: ian
Date: Fri Apr  4 15:03:03 2014
New Revision: 264119
URL: http://svnweb.freebsd.org/changeset/base/264119

Log:
  Adjust the comments about translating clock divisor bits to match recent
  code changes.

Modified:
  head/sys/arm/ti/ti_sdhci.c

Modified: head/sys/arm/ti/ti_sdhci.c
==============================================================================
--- head/sys/arm/ti/ti_sdhci.c	Fri Apr  4 14:54:54 2014	(r264118)
+++ head/sys/arm/ti/ti_sdhci.c	Fri Apr  4 15:03:03 2014	(r264119)
@@ -167,13 +167,12 @@ ti_sdhci_read_2(device_t dev, struct sdh
 	 * but doesn't split them into low:high fields.  Instead they're a
 	 * single number in the range 0..1023 and the number is exactly the
 	 * clock divisor (with 0 and 1 both meaning divide by 1).  The SDHCI
-	 * driver code expects a v2.0 divisor (value N is power of two in the
-	 * range 0..128 and clock is divided by 2N).  The shifting and masking
+	 * driver code expects a v2.0 or v3.0 divisor.  The shifting and masking
 	 * here extracts the MMCHS representation from the hardware word, cleans
-	 * those bits out, applies the 2N adjustment, and plugs that into the
-	 * bit positions for the 2.0 divisor in the returned register value. The
-	 * ti_sdhci_write_2() routine performs the opposite transformation when
-	 * the SDHCI driver writes to the register.
+	 * those bits out, applies the 2N adjustment, and plugs the result into
+	 * the bit positions for the 2.0 or 3.0 divisor in the returned register
+	 * value. The ti_sdhci_write_2() routine performs the opposite
+	 * transformation when the SDHCI driver writes to the register.
 	 */
 	if (off == SDHCI_CLOCK_CONTROL) {
 		val32 = RD4(sc, SDHCI_CLOCK_CONTROL);
@@ -254,8 +253,9 @@ ti_sdhci_write_2(device_t dev, struct sd
 	uint32_t clkdiv, val32;
 
 	/*
-	 * Translate between the hardware and SDHCI 2.0 representations of the
-	 * clock divisor.  See the comments in ti_sdhci_read_2() for details.
+	 * Translate between the hardware and SDHCI 2.0 or 3.0 representations
+	 * of the clock divisor.  See the comments in ti_sdhci_read_2() for
+	 * details.
 	 */
 	if (off == SDHCI_CLOCK_CONTROL) {
 		clkdiv = (val >> SDHCI_DIVIDER_SHIFT) & SDHCI_DIVIDER_MASK;