[src/trunk]: src/sys/arch/arm/nvidia Fix I2C clock calculations. Previously ...

[jakllsch <jakllsch%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/8ca8a463949c
branches:  trunk
changeset: 817327:8ca8a463949c
user:      jakllsch <jakllsch%NetBSD.org@localhost>
date:      Wed Aug 17 00:09:19 2016 +0000

description:
Fix I2C clock calculations.  Previously I2C clocks were half what was
requested.  The I2C clock registers have a LSB of one-half rather than
one-whole like the rest of them.

diffstat:

 sys/arch/arm/nvidia/tegra124_car.c |  45 +++++++++++++++++++++++++++----------
 1 files changed, 32 insertions(+), 13 deletions(-)

diffs (110 lines):

diff -r 708c2c1662b5 -r 8ca8a463949c sys/arch/arm/nvidia/tegra124_car.c
--- a/sys/arch/arm/nvidia/tegra124_car.c        Tue Aug 16 23:47:45 2016 +0000
+++ b/sys/arch/arm/nvidia/tegra124_car.c        Wed Aug 17 00:09:19 2016 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: tegra124_car.c,v 1.2 2015/12/23 12:43:25 jmcneill Exp $ */
+/* $NetBSD: tegra124_car.c,v 1.3 2016/08/17 00:09:19 jakllsch Exp $ */
 
 /*-
  * Copyright (c) 2015 Jared D. McNeill <jmcneill%invisible.ca@localhost>
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: tegra124_car.c,v 1.2 2015/12/23 12:43:25 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: tegra124_car.c,v 1.3 2016/08/17 00:09:19 jakllsch Exp $");
 
 #include <sys/param.h>
 #include <sys/bus.h>
@@ -1076,7 +1076,7 @@
        bus_space_tag_t bst = sc->sc_bst;
        bus_space_handle_t bsh = sc->sc_bsh;
        struct clk *clk_parent;
-       u_int div;
+       u_int rate;
 
        KASSERT(tclk->type == TEGRA_CLK_DIV);
 
@@ -1087,22 +1087,30 @@
        const u_int raw_div = __SHIFTOUT(v, tdiv->bits);
 
        switch (tdiv->reg) {
+       case CAR_CLKSRC_I2C1_REG:
+       case CAR_CLKSRC_I2C2_REG:
+       case CAR_CLKSRC_I2C3_REG:
+       case CAR_CLKSRC_I2C4_REG:
+       case CAR_CLKSRC_I2C5_REG:
+       case CAR_CLKSRC_I2C6_REG:
+               rate = parent_rate * 1 / (raw_div + 1);
+               break;
        case CAR_CLKSRC_UARTA_REG:
        case CAR_CLKSRC_UARTB_REG:
        case CAR_CLKSRC_UARTC_REG:
        case CAR_CLKSRC_UARTD_REG:
                if (v & CAR_CLKSRC_UART_DIV_ENB) {
-                       div = raw_div * 2;
+                       rate = parent_rate * 2 / (raw_div + 2);
                } else {
-                       div = 2;
+                       rate = parent_rate;
                }
                break;
        default:
-               div = raw_div * 2;
+               rate = parent_rate * 2 / (raw_div + 2);
                break;
        }
 
-       return (parent_rate * 2) / div;
+       return rate;
 }
 
 static int
@@ -1125,6 +1133,8 @@
 
        v = bus_space_read_4(bst, bsh, tdiv->reg);
 
+       raw_div = __SHIFTOUT(tdiv->bits, tdiv->bits);
+
        switch (tdiv->reg) {
        case CAR_CLKSRC_UARTA_REG:
        case CAR_CLKSRC_UARTB_REG:
@@ -1134,6 +1144,7 @@
                        v &= ~CAR_CLKSRC_UART_DIV_ENB;
                } else {
                        v |= CAR_CLKSRC_UART_DIV_ENB;
+                       raw_div = (parent_rate * 2) / rate - 2;
                }
                break;
        case CAR_CLKSRC_SATA_REG:
@@ -1141,16 +1152,24 @@
                        tegra_reg_set_clear(bst, bsh, CAR_SATA_PLL_CFG0_REG,
                            0, CAR_SATA_PLL_CFG0_PADPLL_RESET_SWCTL);
                        v |= CAR_CLKSRC_SATA_AUX_CLK_ENB;
+                       raw_div = (parent_rate * 2) / rate - 2;
                } else {
                        v &= ~CAR_CLKSRC_SATA_AUX_CLK_ENB;
                }
                break;
-       }
-
-       if (rate) {
-               raw_div = (parent_rate * 2) / rate - 2;
-       } else {
-               raw_div = __SHIFTOUT(tdiv->bits, tdiv->bits);
+       case CAR_CLKSRC_I2C1_REG:
+       case CAR_CLKSRC_I2C2_REG:
+       case CAR_CLKSRC_I2C3_REG:
+       case CAR_CLKSRC_I2C4_REG:
+       case CAR_CLKSRC_I2C5_REG:
+       case CAR_CLKSRC_I2C6_REG:
+               if (rate)
+                       raw_div = parent_rate / rate - 1;
+               break;
+       default:
+               if (rate)
+                       raw_div = (parent_rate * 2) / rate - 2;
+               break;
        }
 
        v &= ~tdiv->bits;