ARM: tegra: clock: Refcount periph clock enables

Some peripheral clocks share enable bits.  Refcount the enables so
that calling clk_disable on one clock will not turn off another
clock.

Signed-off-by: Colin Cross <ccross@android.com>
Acked-by: Olof Johansson <olof@lixom.net>

1 files changed, 31 insertions, 6 deletions

diff --git a/arch/arm/mach-tegra/tegra2_clocks.c b/arch/arm/mach-tegra/tegra2_clocks.c
index 59e77ba9580..2ca8b74ec07 100644
--- a/arch/arm/mach-tegra/tegra2_clocks.c
+++ b/arch/arm/mach-tegra/tegra2_clocks.c
@@ -159,6 +159,12 @@ static void __iomem *reg_pmc_base = IO_ADDRESS(TEGRA_PMC_BASE);
  */
 static DEFINE_SPINLOCK(clock_register_lock);
 
+/*
+ * Some peripheral clocks share an enable bit, so refcount the enable bits
+ * in registers CLK_ENABLE_L, CLK_ENABLE_H, and CLK_ENABLE_U
+ */
+static int tegra_periph_clk_enable_refcount[3 * 32];
+
 #define clk_writel(value, reg) \
         __raw_writel(value, (u32)reg_clk_base + (reg))
 #define clk_readl(reg) \
@@ -952,8 +958,17 @@ static void tegra2_periph_clk_init(struct clk *c)
 static int tegra2_periph_clk_enable(struct clk *c)
 {
         u32 val;
+        unsigned long flags;
+        int refcount;
         pr_debug("%s on clock %s\n", __func__, c->name);
 
+        spin_lock_irqsave(&clock_register_lock, flags);
+
+        refcount = tegra_periph_clk_enable_refcount[c->u.periph.clk_num]++;
+
+        if (refcount > 1)
+                goto out;
+
         clk_writel(PERIPH_CLK_TO_ENB_BIT(c),
                 CLK_OUT_ENB_SET + PERIPH_CLK_TO_ENB_SET_REG(c));
         if (!(c->flags & PERIPH_NO_RESET) && !(c->flags & PERIPH_MANUAL_RESET))
@@ -966,15 +981,29 @@ static int tegra2_periph_clk_enable(struct clk *c)
                 val |= 0x3 << 24;
                 clk_writel(val, c->reg);
         }
+
+out:
+        spin_unlock_irqrestore(&clock_register_lock, flags);
+
         return 0;
 }
 
 static void tegra2_periph_clk_disable(struct clk *c)
 {
+        unsigned long flags;
+
         pr_debug("%s on clock %s\n", __func__, c->name);
 
-        clk_writel(PERIPH_CLK_TO_ENB_BIT(c),
-                CLK_OUT_ENB_CLR + PERIPH_CLK_TO_ENB_SET_REG(c));
+        spin_lock_irqsave(&clock_register_lock, flags);
+
+        if (c->refcnt)
+                tegra_periph_clk_enable_refcount[c->u.periph.clk_num]--;
+
+        if (tegra_periph_clk_enable_refcount[c->u.periph.clk_num] == 0)
+                clk_writel(PERIPH_CLK_TO_ENB_BIT(c),
+                        CLK_OUT_ENB_CLR + PERIPH_CLK_TO_ENB_SET_REG(c));
+
+        spin_unlock_irqrestore(&clock_register_lock, flags);
 }
 
 static void tegra2_periph_clk_reset(struct clk *c, bool assert)
@@ -2076,7 +2105,6 @@ struct clk tegra_list_clks[] = {
         PERIPH_CLK("timer",     "timer",                NULL,   5,      0,      26000000,  mux_clk_m,                   0),
         PERIPH_CLK("i2s1",      "i2s.0",                NULL,   11,     0x100,  26000000,  mux_pllaout0_audio2x_pllp_clkm,      MUX | DIV_U71),
         PERIPH_CLK("i2s2",      "i2s.1",                NULL,   18,     0x104,  26000000,  mux_pllaout0_audio2x_pllp_clkm,      MUX | DIV_U71),
-        /* FIXME: spdif has 2 clocks but 1 enable */
         PERIPH_CLK("spdif_out", "spdif_out",            NULL,   10,     0x108,  100000000, mux_pllaout0_audio2x_pllp_clkm,      MUX | DIV_U71),
         PERIPH_CLK("spdif_in",  "spdif_in",             NULL,   10,     0x10c,  100000000, mux_pllp_pllc_pllm,          MUX | DIV_U71),
         PERIPH_CLK("pwm",       "pwm",                  NULL,   17,     0x110,  432000000, mux_pllp_pllc_audio_clkm_clk32,      MUX | DIV_U71),
@@ -2089,7 +2117,6 @@ struct clk tegra_list_clks[] = {
         PERIPH_CLK("sbc4",      "spi_tegra.3",          NULL,   68,     0x1b4,  160000000, mux_pllp_pllc_pllm_clkm,     MUX | DIV_U71),
         PERIPH_CLK("ide",       "ide",                  NULL,   25,     0x144,  100000000, mux_pllp_pllc_pllm_clkm,     MUX | DIV_U71), /* requires min voltage */
         PERIPH_CLK("ndflash",   "tegra_nand",           NULL,   13,     0x160,  164000000, mux_pllp_pllc_pllm_clkm,     MUX | DIV_U71), /* scales with voltage */
-        /* FIXME: vfir shares an enable with uartb */
         PERIPH_CLK("vfir",      "vfir",                 NULL,   7,      0x168,  72000000,  mux_pllp_pllc_pllm_clkm,     MUX | DIV_U71),
         PERIPH_CLK("sdmmc1",    "sdhci-tegra.0",        NULL,   14,     0x150,  52000000,  mux_pllp_pllc_pllm_clkm,     MUX | DIV_U71), /* scales with voltage */
         PERIPH_CLK("sdmmc2",    "sdhci-tegra.1",        NULL,   9,      0x154,  52000000,  mux_pllp_pllc_pllm_clkm,     MUX | DIV_U71), /* scales with voltage */
@@ -2120,13 +2147,11 @@ struct clk tegra_list_clks[] = {
         PERIPH_CLK("uarte",     "uart.4",               NULL,   66,     0x1c4,  600000000, mux_pllp_pllc_pllm_clkm,     MUX),
         PERIPH_CLK("3d",        "3d",                   NULL,   24,     0x158,  300000000, mux_pllm_pllc_pllp_plla,     MUX | DIV_U71 | PERIPH_MANUAL_RESET), /* scales with voltage and process_id */
         PERIPH_CLK("2d",        "2d",                   NULL,   21,     0x15c,  300000000, mux_pllm_pllc_pllp_plla,     MUX | DIV_U71), /* scales with voltage and process_id */
-        /* FIXME: vi and vi_sensor share an enable */
         PERIPH_CLK("vi",        "tegra_camera",         "vi",   20,     0x148,  150000000, mux_pllm_pllc_pllp_plla,     MUX | DIV_U71), /* scales with voltage and process_id */
         PERIPH_CLK("vi_sensor", "tegra_camera",         "vi_sensor",    20,     0x1a8,  150000000, mux_pllm_pllc_pllp_plla,     MUX | DIV_U71 | PERIPH_NO_RESET), /* scales with voltage and process_id */
         PERIPH_CLK("epp",       "epp",                  NULL,   19,     0x16c,  300000000, mux_pllm_pllc_pllp_plla,     MUX | DIV_U71), /* scales with voltage and process_id */
         PERIPH_CLK("mpe",       "mpe",                  NULL,   60,     0x170,  250000000, mux_pllm_pllc_pllp_plla,     MUX | DIV_U71), /* scales with voltage and process_id */
         PERIPH_CLK("host1x",    "host1x",               NULL,   28,     0x180,  166000000, mux_pllm_pllc_pllp_plla,     MUX | DIV_U71), /* scales with voltage and process_id */
-        /* FIXME: cve and tvo share an enable   */
         PERIPH_CLK("cve",       "cve",                  NULL,   49,     0x140,  250000000, mux_pllp_plld_pllc_clkm,     MUX | DIV_U71), /* requires min voltage */
         PERIPH_CLK("tvo",       "tvo",                  NULL,   49,     0x188,  250000000, mux_pllp_plld_pllc_clkm,     MUX | DIV_U71), /* requires min voltage */
         PERIPH_CLK("hdmi",      "hdmi",                 NULL,   51,     0x18c,  600000000, mux_pllp_plld_pllc_clkm,     MUX | DIV_U71), /* requires min voltage */