[ARM] omap: add support for bypassing DPLLs

This roughly corresponds with OMAP commits: 7d06c48, 3241b19,
88b5d9b, 18a5500, 9c909ac, 5c6497b, 8b1f0bd, 2ac1da8.

For both OMAP2 and OMAP3, we note the reference and bypass clocks in
the DPLL data structure.  Whenever we modify the DPLL rate, we first
ensure that both the reference and bypass clocks are enabled.  Then,
we decide whether to use the reference and DPLL, or the bypass clock
if the desired rate is identical to the bypass rate, and program the
DPLL appropriately.  Finally, we update the clock's parent, and then
disable the unused clocks.

This keeps the parents correctly balanced, and more importantly ensures
that the bypass clock is running whenever we reprogram the DPLL.  This
is especially important because the procedure for reprogramming the DPLL
involves switching to the bypass clock.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 28 insertions, 149 deletions

diff --git a/arch/arm/mach-omap2/clock34xx.h b/arch/arm/mach-omap2/clock34xx.h
index 764c7cd9fd84..70ec10deb654 100644
--- a/arch/arm/mach-omap2/clock34xx.h
+++ b/arch/arm/mach-omap2/clock34xx.h
@@ -48,6 +48,10 @@ static int omap3_core_dpll_m2_set_rate(struct clk *clk, unsigned long rate);
  * DPLL5 supplies other peripheral clocks (USBHOST, USIM).
  */
 
+/* Forward declarations for DPLL bypass clocks */
+static struct clk dpll1_fck;
+static struct clk dpll2_fck;
+
 /* CM_CLKEN_PLL*.EN* bit values - not all are available for every DPLL */
 #define DPLL_LOW_POWER_STOP             0x1
 #define DPLL_LOW_POWER_BYPASS           0x5
@@ -217,16 +221,6 @@ static struct clk sys_clkout1 = {
 
 /* CM CLOCKS */
 
-static const struct clksel_rate dpll_bypass_rates[] = {
-        { .div = 1, .val = 0, .flags = RATE_IN_343X | DEFAULT_RATE },
-        { .div = 0 }
-};
-
-static const struct clksel_rate dpll_locked_rates[] = {
-        { .div = 1, .val = 1, .flags = RATE_IN_343X | DEFAULT_RATE },
-        { .div = 0 }
-};
-
 static const struct clksel_rate div16_dpll_rates[] = {
         { .div = 1, .val = 1, .flags = RATE_IN_343X | DEFAULT_RATE },
         { .div = 2, .val = 2, .flags = RATE_IN_343X },
@@ -254,6 +248,8 @@ static struct dpll_data dpll1_dd = {
         .mult_div1_reg  = OMAP_CM_REGADDR(MPU_MOD, OMAP3430_CM_CLKSEL1_PLL),
         .mult_mask      = OMAP3430_MPU_DPLL_MULT_MASK,
         .div1_mask      = OMAP3430_MPU_DPLL_DIV_MASK,
+        .clk_bypass     = &dpll1_fck,
+        .clk_ref        = &sys_ck,
         .freqsel_mask   = OMAP3430_MPU_DPLL_FREQSEL_MASK,
         .control_reg    = OMAP_CM_REGADDR(MPU_MOD, OMAP3430_CM_CLKEN_PLL),
         .enable_mask    = OMAP3430_EN_MPU_DPLL_MASK,
@@ -324,6 +320,8 @@ static struct dpll_data dpll2_dd = {
         .mult_div1_reg  = OMAP_CM_REGADDR(OMAP3430_IVA2_MOD, OMAP3430_CM_CLKSEL1_PLL),
         .mult_mask      = OMAP3430_IVA2_DPLL_MULT_MASK,
         .div1_mask      = OMAP3430_IVA2_DPLL_DIV_MASK,
+        .clk_bypass     = &dpll2_fck,
+        .clk_ref        = &sys_ck,
         .freqsel_mask   = OMAP3430_IVA2_DPLL_FREQSEL_MASK,
         .control_reg    = OMAP_CM_REGADDR(OMAP3430_IVA2_MOD, OMAP3430_CM_CLKEN_PLL),
         .enable_mask    = OMAP3430_EN_IVA2_DPLL_MASK,
@@ -384,6 +382,8 @@ static struct dpll_data dpll3_dd = {
         .mult_div1_reg  = OMAP_CM_REGADDR(PLL_MOD, CM_CLKSEL1),
         .mult_mask      = OMAP3430_CORE_DPLL_MULT_MASK,
         .div1_mask      = OMAP3430_CORE_DPLL_DIV_MASK,
+        .clk_bypass     = &sys_ck,
+        .clk_ref        = &sys_ck,
         .freqsel_mask   = OMAP3430_CORE_DPLL_FREQSEL_MASK,
         .control_reg    = OMAP_CM_REGADDR(PLL_MOD, CM_CLKEN),
         .enable_mask    = OMAP3430_EN_CORE_DPLL_MASK,
@@ -477,37 +477,19 @@ static struct clk dpll3_m2_ck = {
         .recalc         = &omap2_clksel_recalc,
 };
 
-static const struct clksel core_ck_clksel[] = {
-        { .parent = &sys_ck,      .rates = dpll_bypass_rates },
-        { .parent = &dpll3_m2_ck, .rates = dpll_locked_rates },
-        { .parent = NULL }
-};
-
 static struct clk core_ck = {
         .name           = "core_ck",
         .ops            = &clkops_null,
-        .init           = &omap2_init_clksel_parent,
-        .clksel_reg     = OMAP_CM_REGADDR(PLL_MOD, CM_IDLEST),
-        .clksel_mask    = OMAP3430_ST_CORE_CLK_MASK,
-        .clksel         = core_ck_clksel,
-        .recalc         = &omap2_clksel_recalc,
-};
-
-static const struct clksel dpll3_m2x2_ck_clksel[] = {
-        { .parent = &sys_ck,      .rates = dpll_bypass_rates },
-        { .parent = &dpll3_x2_ck, .rates = dpll_locked_rates },
-        { .parent = NULL }
+        .parent         = &dpll3_m2_ck,
+        .recalc         = &followparent_recalc,
 };
 
 static struct clk dpll3_m2x2_ck = {
         .name           = "dpll3_m2x2_ck",
         .ops            = &clkops_null,
-        .init           = &omap2_init_clksel_parent,
-        .clksel_reg     = OMAP_CM_REGADDR(PLL_MOD, CM_IDLEST),
-        .clksel_mask    = OMAP3430_ST_CORE_CLK_MASK,
-        .clksel         = dpll3_m2x2_ck_clksel,
+        .parent         = &dpll3_x2_ck,
         .clkdm_name     = "dpll3_clkdm",
-        .recalc         = &omap2_clksel_recalc,
+        .recalc         = &followparent_recalc,
 };
 
 /* The PWRDN bit is apparently only available on 3430ES2 and above */
@@ -541,22 +523,12 @@ static struct clk dpll3_m3x2_ck = {
         .recalc         = &omap3_clkoutx2_recalc,
 };
 
-static const struct clksel emu_core_alwon_ck_clksel[] = {
-        { .parent = &sys_ck,        .rates = dpll_bypass_rates },
-        { .parent = &dpll3_m3x2_ck, .rates = dpll_locked_rates },
-        { .parent = NULL }
-};
-
 static struct clk emu_core_alwon_ck = {
         .name           = "emu_core_alwon_ck",
         .ops            = &clkops_null,
         .parent         = &dpll3_m3x2_ck,
-        .init           = &omap2_init_clksel_parent,
-        .clksel_reg     = OMAP_CM_REGADDR(PLL_MOD, CM_IDLEST),
-        .clksel_mask    = OMAP3430_ST_CORE_CLK_MASK,
-        .clksel         = emu_core_alwon_ck_clksel,
         .clkdm_name     = "dpll3_clkdm",
-        .recalc         = &omap2_clksel_recalc,
+        .recalc         = &followparent_recalc,
 };
 
 /* DPLL4 */
@@ -566,6 +538,8 @@ static struct dpll_data dpll4_dd = {
         .mult_div1_reg  = OMAP_CM_REGADDR(PLL_MOD, CM_CLKSEL2),
         .mult_mask      = OMAP3430_PERIPH_DPLL_MULT_MASK,
         .div1_mask      = OMAP3430_PERIPH_DPLL_DIV_MASK,
+        .clk_bypass     = &sys_ck,
+        .clk_ref        = &sys_ck,
         .freqsel_mask   = OMAP3430_PERIPH_DPLL_FREQSEL_MASK,
         .control_reg    = OMAP_CM_REGADDR(PLL_MOD, CM_CLKEN),
         .enable_mask    = OMAP3430_EN_PERIPH_DPLL_MASK,
@@ -637,12 +611,6 @@ static struct clk dpll4_m2x2_ck = {
         .recalc         = &omap3_clkoutx2_recalc,
 };
 
-static const struct clksel omap_96m_alwon_fck_clksel[] = {
-        { .parent = &sys_ck,        .rates = dpll_bypass_rates },
-        { .parent = &dpll4_m2x2_ck, .rates = dpll_locked_rates },
-        { .parent = NULL }
-};
-
 /*
  * DPLL4 generates DPLL4_M2X2_CLK which is then routed into the PRM as
  * PRM_96M_ALWON_(F)CLK.  Two clocks then emerge from the PRM:
@@ -653,11 +621,7 @@ static struct clk omap_96m_alwon_fck = {
         .name           = "omap_96m_alwon_fck",
         .ops            = &clkops_null,
         .parent         = &dpll4_m2x2_ck,
-        .init           = &omap2_init_clksel_parent,
-        .clksel_reg     = OMAP_CM_REGADDR(PLL_MOD, CM_IDLEST),
-        .clksel_mask    = OMAP3430_ST_PERIPH_CLK_MASK,
-        .clksel         = omap_96m_alwon_fck_clksel,
-        .recalc         = &omap2_clksel_recalc,
+        .recalc         = &followparent_recalc,
 };
 
 static struct clk cm_96m_fck = {
@@ -720,23 +684,6 @@ static struct clk dpll4_m3x2_ck = {
         .recalc         = &omap3_clkoutx2_recalc,
 };
 
-static const struct clksel virt_omap_54m_fck_clksel[] = {
-        { .parent = &sys_ck,        .rates = dpll_bypass_rates },
-        { .parent = &dpll4_m3x2_ck, .rates = dpll_locked_rates },
-        { .parent = NULL }
-};
-
-static struct clk virt_omap_54m_fck = {
-        .name           = "virt_omap_54m_fck",
-        .ops            = &clkops_null,
-        .parent         = &dpll4_m3x2_ck,
-        .init           = &omap2_init_clksel_parent,
-        .clksel_reg     = OMAP_CM_REGADDR(PLL_MOD, CM_IDLEST),
-        .clksel_mask    = OMAP3430_ST_PERIPH_CLK_MASK,
-        .clksel         = virt_omap_54m_fck_clksel,
-        .recalc         = &omap2_clksel_recalc,
-};
-
 static const struct clksel_rate omap_54m_d4m3x2_rates[] = {
         { .div = 1, .val = 0, .flags = RATE_IN_343X | DEFAULT_RATE },
         { .div = 0 }
@@ -748,7 +695,7 @@ static const struct clksel_rate omap_54m_alt_rates[] = {
 };
 
 static const struct clksel omap_54m_clksel[] = {
-        { .parent = &virt_omap_54m_fck, .rates = omap_54m_d4m3x2_rates },
+        { .parent = &dpll4_m3x2_ck, .rates = omap_54m_d4m3x2_rates },
         { .parent = &sys_altclk,    .rates = omap_54m_alt_rates },
         { .parent = NULL }
 };
@@ -891,6 +838,8 @@ static struct dpll_data dpll5_dd = {
         .mult_div1_reg  = OMAP_CM_REGADDR(PLL_MOD, OMAP3430ES2_CM_CLKSEL4),
         .mult_mask      = OMAP3430ES2_PERIPH2_DPLL_MULT_MASK,
         .div1_mask      = OMAP3430ES2_PERIPH2_DPLL_DIV_MASK,
+        .clk_bypass     = &sys_ck,
+        .clk_ref        = &sys_ck,
         .freqsel_mask   = OMAP3430ES2_PERIPH2_DPLL_FREQSEL_MASK,
         .control_reg    = OMAP_CM_REGADDR(PLL_MOD, OMAP3430ES2_CM_CLKEN2),
         .enable_mask    = OMAP3430ES2_EN_PERIPH2_DPLL_MASK,
@@ -936,23 +885,6 @@ static struct clk dpll5_m2_ck = {
         .recalc         = &omap2_clksel_recalc,
 };
 
-static const struct clksel omap_120m_fck_clksel[] = {
-        { .parent = &sys_ck,      .rates = dpll_bypass_rates },
-        { .parent = &dpll5_m2_ck, .rates = dpll_locked_rates },
-        { .parent = NULL }
-};
-
-static struct clk omap_120m_fck = {
-        .name           = "omap_120m_fck",
-        .ops            = &clkops_null,
-        .parent         = &dpll5_m2_ck,
-        .init           = &omap2_init_clksel_parent,
-        .clksel_reg     = OMAP_CM_REGADDR(PLL_MOD, CM_IDLEST2),
-        .clksel_mask    = OMAP3430ES2_ST_PERIPH2_CLK_MASK,
-        .clksel         = omap_120m_fck_clksel,
-        .recalc         = &omap2_clksel_recalc,
-};
-
 /* CM EXTERNAL CLOCK OUTPUTS */
 
 static const struct clksel_rate clkout2_src_core_rates[] = {
@@ -1058,28 +990,12 @@ static struct clk dpll1_fck = {
         .recalc         = &omap2_clksel_recalc,
 };
 
-/*
- * MPU clksel:
- * If DPLL1 is locked, mpu_ck derives from DPLL1; otherwise, mpu_ck
- * derives from the high-frequency bypass clock originating from DPLL3,
- * called 'dpll1_fck'
- */
-static const struct clksel mpu_clksel[] = {
-        { .parent = &dpll1_fck,     .rates = dpll_bypass_rates },
-        { .parent = &dpll1_x2m2_ck, .rates = dpll_locked_rates },
-        { .parent = NULL }
-};
-
 static struct clk mpu_ck = {
         .name           = "mpu_ck",
         .ops            = &clkops_null,
         .parent         = &dpll1_x2m2_ck,
-        .init           = &omap2_init_clksel_parent,
-        .clksel_reg     = OMAP_CM_REGADDR(MPU_MOD, OMAP3430_CM_IDLEST_PLL),
-        .clksel_mask    = OMAP3430_ST_MPU_CLK_MASK,
-        .clksel         = mpu_clksel,
         .clkdm_name     = "mpu_clkdm",
-        .recalc         = &omap2_clksel_recalc,
+        .recalc         = &followparent_recalc,
 };
 
 /* arm_fck is divided by two when DPLL1 locked; otherwise, passthrough mpu_ck */
@@ -1129,19 +1045,6 @@ static struct clk dpll2_fck = {
         .recalc         = &omap2_clksel_recalc,
 };
 
-/*
- * IVA2 clksel:
- * If DPLL2 is locked, iva2_ck derives from DPLL2; otherwise, iva2_ck
- * derives from the high-frequency bypass clock originating from DPLL3,
- * called 'dpll2_fck'
- */
-
-static const struct clksel iva2_clksel[] = {
-        { .parent = &dpll2_fck,   .rates = dpll_bypass_rates },
-        { .parent = &dpll2_m2_ck, .rates = dpll_locked_rates },
-        { .parent = NULL }
-};
-
 static struct clk iva2_ck = {
         .name           = "iva2_ck",
         .ops            = &clkops_omap2_dflt_wait,
@@ -1149,12 +1052,8 @@ static struct clk iva2_ck = {
         .init           = &omap2_init_clksel_parent,
         .enable_reg     = OMAP_CM_REGADDR(OMAP3430_IVA2_MOD, CM_FCLKEN),
         .enable_bit     = OMAP3430_CM_FCLKEN_IVA2_EN_IVA2_SHIFT,
-        .clksel_reg     = OMAP_CM_REGADDR(OMAP3430_IVA2_MOD,
-                                          OMAP3430_CM_IDLEST_PLL),
-        .clksel_mask    = OMAP3430_ST_IVA2_CLK_MASK,
-        .clksel         = iva2_clksel,
         .clkdm_name     = "iva2_clkdm",
-        .recalc         = &omap2_clksel_recalc,
+        .recalc         = &followparent_recalc,
 };
 
 /* Common interface clocks */
@@ -1384,7 +1283,7 @@ static struct clk ts_fck = {
 static struct clk usbtll_fck = {
         .name           = "usbtll_fck",
         .ops            = &clkops_omap2_dflt,
-        .parent         = &omap_120m_fck,
+        .parent         = &dpll5_m2_ck,
         .enable_reg     = OMAP_CM_REGADDR(CORE_MOD, OMAP3430ES2_CM_FCLKEN3),
         .enable_bit     = OMAP3430ES2_EN_USBTLL_SHIFT,
         .recalc         = &followparent_recalc,
@@ -2094,24 +1993,14 @@ static struct clk des1_ick = {
 };
 
 /* DSS */
-static const struct clksel dss1_alwon_fck_clksel[] = {
-        { .parent = &sys_ck,        .rates = dpll_bypass_rates },
-        { .parent = &dpll4_m4x2_ck, .rates = dpll_locked_rates },
-        { .parent = NULL }
-};
-
 static struct clk dss1_alwon_fck = {
         .name           = "dss1_alwon_fck",
         .ops            = &clkops_omap2_dflt,
         .parent         = &dpll4_m4x2_ck,
-        .init           = &omap2_init_clksel_parent,
         .enable_reg     = OMAP_CM_REGADDR(OMAP3430_DSS_MOD, CM_FCLKEN),
         .enable_bit     = OMAP3430_EN_DSS1_SHIFT,
-        .clksel_reg     = OMAP_CM_REGADDR(PLL_MOD, CM_IDLEST),
-        .clksel_mask    = OMAP3430_ST_PERIPH_CLK_MASK,
-        .clksel         = dss1_alwon_fck_clksel,
         .clkdm_name     = "dss_clkdm",
-        .recalc         = &omap2_clksel_recalc,
+        .recalc         = &followparent_recalc,
 };
 
 static struct clk dss_tv_fck = {
@@ -2161,24 +2050,14 @@ static struct clk dss_ick = {
 
 /* CAM */
 
-static const struct clksel cam_mclk_clksel[] = {
-        { .parent = &sys_ck,        .rates = dpll_bypass_rates },
-        { .parent = &dpll4_m5x2_ck, .rates = dpll_locked_rates },
-        { .parent = NULL }
-};
-
 static struct clk cam_mclk = {
         .name           = "cam_mclk",
         .ops            = &clkops_omap2_dflt_wait,
         .parent         = &dpll4_m5x2_ck,
-        .init           = &omap2_init_clksel_parent,
-        .clksel_reg     = OMAP_CM_REGADDR(PLL_MOD, CM_IDLEST),
-        .clksel_mask    = OMAP3430_ST_PERIPH_CLK_MASK,
-        .clksel         = cam_mclk_clksel,
         .enable_reg     = OMAP_CM_REGADDR(OMAP3430_CAM_MOD, CM_FCLKEN),
         .enable_bit     = OMAP3430_EN_CAM_SHIFT,
         .clkdm_name     = "cam_clkdm",
-        .recalc         = &omap2_clksel_recalc,
+        .recalc         = &followparent_recalc,
 };
 
 static struct clk cam_ick = {
@@ -2209,7 +2088,7 @@ static struct clk csi2_96m_fck = {
 static struct clk usbhost_120m_fck = {
         .name           = "usbhost_120m_fck",
         .ops            = &clkops_omap2_dflt_wait,
-        .parent         = &omap_120m_fck,
+        .parent         = &dpll5_m2_ck,
         .init           = &omap2_init_clk_clkdm,
         .enable_reg     = OMAP_CM_REGADDR(OMAP3430ES2_USBHOST_MOD, CM_FCLKEN),
         .enable_bit     = OMAP3430ES2_EN_USBHOST2_SHIFT,
@@ -2260,7 +2139,7 @@ static const struct clksel_rate usim_120m_rates[] = {
 
 static const struct clksel usim_clksel[] = {
         { .parent = &omap_96m_fck,      .rates = usim_96m_rates },
-        { .parent = &omap_120m_fck,     .rates = usim_120m_rates },
+        { .parent = &dpll5_m2_ck,       .rates = usim_120m_rates },
         { .parent = &sys_ck,            .rates = div2_rates },
         { .parent = NULL },
 };