clk: bcm281xx: add initial clock framework support

Add code for device tree support of clocks in the BCM281xx family of
SoCs.  Machines in this family use peripheral clocks implemented by
"Kona" clock control units (CCUs).  (Other Broadcom SoC families use
Kona style CCUs as well, but support for them is not yet upstream.)

A BCM281xx SoC has multiple CCUs, each of which manages a set of
clocks on the SoC.  A Kona peripheral clock is composite clock that
may include a gate, a parent clock multiplexor, and zero, one
or two dividers.  There is a variety of gate types, and many gates
implement hardware-managed gating (often called "auto-gating").
Most dividers divide their input clock signal by an integer value
(one or more).  There are also "fractional" dividers which allow
division by non-integer values.  To accomodate such dividers,
clock rates and dividers are generally maintained by the code in
"scaled" form, which allows integer and fractional dividers to
be handled in a uniform way.

If present, the gate for a Kona peripheral clock must be enabled
when a change is made to its multiplexor or one of its dividers.
Additionally, dividers and multiplexors have trigger registers which
must be used whenever the divider value or selected parent clock is
changed.  The same trigger is often used for a divider and
multiplexor, and a BCM281xx peripheral clock occasionally has two
triggers.

The gate, dividers, and parent clock selector are treated in this
code as "components" of a peripheral clock.  Their functionality is
implemented directly--e.g. the common clock framework gate
implementation is not used for a Kona peripheral clock gate.  (This
has being considered though, and the intention is to evolve this
code to leverage common code as much as possible.)

The source code is divided into three general portions:

    drivers/clk/bcm/clk-kona.h
    drivers/clk/bcm/clk-kona.c
        These implement the basic Kona clock functionality,
        including the clk_ops methods and various routines to
        manipulate registers and interpret their values.  This
        includes some functions used to set clocks to a desired
        initial state (though this feature is only partially
        implemented here).

    drivers/clk/bcm/clk-kona-setup.c
        This contains generic run-time initialization code for
        data structures representing Kona CCUs and clocks.  This
        encapsulates the clock structure initialization that can't
        be done statically.  Note that there is a great deal of
        validity-checking code here, making explicit certain
        assumptions in the code.   This is mostly useful for adding
        new clock definitions and could possibly be disabled for
        production use.

    drivers/clk/bcm/clk-bcm281xx.c
        This file defines the specific CCUs used by BCM281XX family
        SoCs, as well as the specific clocks implemented by each.
        It declares a device tree clock match entry for each CCU
        defined.

    include/dt-bindings/clock/bcm281xx.h
        This file defines the selector (index) values used to
        identify a particular clock provided by a CCU.  It consists
        entirely of C preprocessor constants, to be used by both the
        C source and device tree source files.

Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Tim Kryger <tim.kryger@linaro.org>
Reviewed-by: Matt Porter <mporter@linaro.org>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Matt Porter <mporter@linaro.org>

1 files changed, 416 insertions, 0 deletions

diff --git a/drivers/clk/bcm/clk-bcm281xx.c b/drivers/clk/bcm/clk-bcm281xx.c
new file mode 100644
index 000000000000..3c66de696aeb
--- /dev/null
+++ b/drivers/clk/bcm/clk-bcm281xx.c
@@ -0,0 +1,416 @@
+/*
+ * Copyright (C) 2013 Broadcom Corporation
+ * Copyright 2013 Linaro Limited
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "clk-kona.h"
+#include "dt-bindings/clock/bcm281xx.h"
+
+/* bcm11351 CCU device tree "compatible" strings */
+#define BCM11351_DT_ROOT_CCU_COMPAT	"brcm,bcm11351-root-ccu"
+#define BCM11351_DT_AON_CCU_COMPAT	"brcm,bcm11351-aon-ccu"
+#define BCM11351_DT_HUB_CCU_COMPAT	"brcm,bcm11351-hub-ccu"
+#define BCM11351_DT_MASTER_CCU_COMPAT	"brcm,bcm11351-master-ccu"
+#define BCM11351_DT_SLAVE_CCU_COMPAT	"brcm,bcm11351-slave-ccu"
+
+/* Root CCU clocks */
+
+static struct peri_clk_data frac_1m_data = {
+	.gate		= HW_SW_GATE(0x214, 16, 0, 1),
+	.trig		= TRIGGER(0x0e04, 0),
+	.div		= FRAC_DIVIDER(0x0e00, 0, 22, 16),
+	.clocks		= CLOCKS("ref_crystal"),
+};
+
+/* AON CCU clocks */
+
+static struct peri_clk_data hub_timer_data = {
+	.gate		= HW_SW_GATE(0x0414, 16, 0, 1),
+	.clocks		= CLOCKS("bbl_32k",
+				 "frac_1m",
+				 "dft_19_5m"),
+	.sel		= SELECTOR(0x0a10, 0, 2),
+	.trig		= TRIGGER(0x0a40, 4),
+};
+
+static struct peri_clk_data pmu_bsc_data = {
+	.gate		= HW_SW_GATE(0x0418, 16, 0, 1),
+	.clocks		= CLOCKS("ref_crystal",
+				 "pmu_bsc_var",
+				 "bbl_32k"),
+	.sel		= SELECTOR(0x0a04, 0, 2),
+	.div		= DIVIDER(0x0a04, 3, 4),
+	.trig		= TRIGGER(0x0a40, 0),
+};
+
+static struct peri_clk_data pmu_bsc_var_data = {
+	.clocks		= CLOCKS("var_312m",
+				 "ref_312m"),
+	.sel		= SELECTOR(0x0a00, 0, 2),
+	.div		= DIVIDER(0x0a00, 4, 5),
+	.trig		= TRIGGER(0x0a40, 2),
+};
+
+/* Hub CCU clocks */
+
+static struct peri_clk_data tmon_1m_data = {
+	.gate		= HW_SW_GATE(0x04a4, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "frac_1m"),
+	.sel		= SELECTOR(0x0e74, 0, 2),
+	.trig		= TRIGGER(0x0e84, 1),
+};
+
+/* Master CCU clocks */
+
+static struct peri_clk_data sdio1_data = {
+	.gate		= HW_SW_GATE(0x0358, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_52m",
+				 "ref_52m",
+				 "var_96m",
+				 "ref_96m"),
+	.sel		= SELECTOR(0x0a28, 0, 3),
+	.div		= DIVIDER(0x0a28, 4, 14),
+	.trig		= TRIGGER(0x0afc, 9),
+};
+
+static struct peri_clk_data sdio2_data = {
+	.gate		= HW_SW_GATE(0x035c, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_52m",
+				 "ref_52m",
+				 "var_96m",
+				 "ref_96m"),
+	.sel		= SELECTOR(0x0a2c, 0, 3),
+	.div		= DIVIDER(0x0a2c, 4, 14),
+	.trig		= TRIGGER(0x0afc, 10),
+};
+
+static struct peri_clk_data sdio3_data = {
+	.gate		= HW_SW_GATE(0x0364, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_52m",
+				 "ref_52m",
+				 "var_96m",
+				 "ref_96m"),
+	.sel		= SELECTOR(0x0a34, 0, 3),
+	.div		= DIVIDER(0x0a34, 4, 14),
+	.trig		= TRIGGER(0x0afc, 12),
+};
+
+static struct peri_clk_data sdio4_data = {
+	.gate		= HW_SW_GATE(0x0360, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_52m",
+				 "ref_52m",
+				 "var_96m",
+				 "ref_96m"),
+	.sel		= SELECTOR(0x0a30, 0, 3),
+	.div		= DIVIDER(0x0a30, 4, 14),
+	.trig		= TRIGGER(0x0afc, 11),
+};
+
+static struct peri_clk_data usb_ic_data = {
+	.gate		= HW_SW_GATE(0x0354, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_96m",
+				 "ref_96m"),
+	.div		= FIXED_DIVIDER(2),
+	.sel		= SELECTOR(0x0a24, 0, 2),
+	.trig		= TRIGGER(0x0afc, 7),
+};
+
+/* also called usbh_48m */
+static struct peri_clk_data hsic2_48m_data = {
+	.gate		= HW_SW_GATE(0x0370, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_96m",
+				 "ref_96m"),
+	.sel		= SELECTOR(0x0a38, 0, 2),
+	.div		= FIXED_DIVIDER(2),
+	.trig		= TRIGGER(0x0afc, 5),
+};
+
+/* also called usbh_12m */
+static struct peri_clk_data hsic2_12m_data = {
+	.gate		= HW_SW_GATE(0x0370, 20, 4, 5),
+	.div		= DIVIDER(0x0a38, 12, 2),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_96m",
+				 "ref_96m"),
+	.pre_div	= FIXED_DIVIDER(2),
+	.sel		= SELECTOR(0x0a38, 0, 2),
+	.trig		= TRIGGER(0x0afc, 5),
+};
+
+/* Slave CCU clocks */
+
+static struct peri_clk_data uartb_data = {
+	.gate		= HW_SW_GATE(0x0400, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_156m",
+				 "ref_156m"),
+	.sel		= SELECTOR(0x0a10, 0, 2),
+	.div		= FRAC_DIVIDER(0x0a10, 4, 12, 8),
+	.trig		= TRIGGER(0x0afc, 2),
+};
+
+static struct peri_clk_data uartb2_data = {
+	.gate		= HW_SW_GATE(0x0404, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_156m",
+				 "ref_156m"),
+	.sel		= SELECTOR(0x0a14, 0, 2),
+	.div		= FRAC_DIVIDER(0x0a14, 4, 12, 8),
+	.trig		= TRIGGER(0x0afc, 3),
+};
+
+static struct peri_clk_data uartb3_data = {
+	.gate		= HW_SW_GATE(0x0408, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_156m",
+				 "ref_156m"),
+	.sel		= SELECTOR(0x0a18, 0, 2),
+	.div		= FRAC_DIVIDER(0x0a18, 4, 12, 8),
+	.trig		= TRIGGER(0x0afc, 4),
+};
+
+static struct peri_clk_data uartb4_data = {
+	.gate		= HW_SW_GATE(0x0408, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_156m",
+				 "ref_156m"),
+	.sel		= SELECTOR(0x0a1c, 0, 2),
+	.div		= FRAC_DIVIDER(0x0a1c, 4, 12, 8),
+	.trig		= TRIGGER(0x0afc, 5),
+};
+
+static struct peri_clk_data ssp0_data = {
+	.gate		= HW_SW_GATE(0x0410, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_104m",
+				 "ref_104m",
+				 "var_96m",
+				 "ref_96m"),
+	.sel		= SELECTOR(0x0a20, 0, 3),
+	.div		= DIVIDER(0x0a20, 4, 14),
+	.trig		= TRIGGER(0x0afc, 6),
+};
+
+static struct peri_clk_data ssp2_data = {
+	.gate		= HW_SW_GATE(0x0418, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_104m",
+				 "ref_104m",
+				 "var_96m",
+				 "ref_96m"),
+	.sel		= SELECTOR(0x0a28, 0, 3),
+	.div		= DIVIDER(0x0a28, 4, 14),
+	.trig		= TRIGGER(0x0afc, 8),
+};
+
+static struct peri_clk_data bsc1_data = {
+	.gate		= HW_SW_GATE(0x0458, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_104m",
+				 "ref_104m",
+				 "var_13m",
+				 "ref_13m"),
+	.sel		= SELECTOR(0x0a64, 0, 3),
+	.trig		= TRIGGER(0x0afc, 23),
+};
+
+static struct peri_clk_data bsc2_data = {
+	.gate		= HW_SW_GATE(0x045c, 18, 2, 3),
+	.clocks	= CLOCKS("ref_crystal",
+				 "var_104m",
+				 "ref_104m",
+				 "var_13m",
+				 "ref_13m"),
+	.sel		= SELECTOR(0x0a68, 0, 3),
+	.trig		= TRIGGER(0x0afc, 24),
+};
+
+static struct peri_clk_data bsc3_data = {
+	.gate		= HW_SW_GATE(0x0484, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_104m",
+				 "ref_104m",
+				 "var_13m",
+				 "ref_13m"),
+	.sel		= SELECTOR(0x0a84, 0, 3),
+	.trig		= TRIGGER(0x0b00, 2),
+};
+
+static struct peri_clk_data pwm_data = {
+	.gate		= HW_SW_GATE(0x0468, 18, 2, 3),
+	.clocks		= CLOCKS("ref_crystal",
+				 "var_104m"),
+	.sel		= SELECTOR(0x0a70, 0, 2),
+	.div		= DIVIDER(0x0a70, 4, 3),
+	.trig		= TRIGGER(0x0afc, 15),
+};
+
+/*
+ * CCU setup routines
+ *
+ * These are called from kona_dt_ccu_setup() to initialize the array
+ * of clocks provided by the CCU.  Once allocated, the entries in
+ * the array are initialized by calling kona_clk_setup() with the
+ * initialization data for each clock.  They return 0 if successful
+ * or an error code otherwise.
+ */
+static int __init bcm281xx_root_ccu_clks_setup(struct ccu_data *ccu)
+{
+	struct clk **clks;
+	size_t count = BCM281XX_ROOT_CCU_CLOCK_COUNT;
+
+	clks = kzalloc(count * sizeof(*clks), GFP_KERNEL);
+	if (!clks) {
+		pr_err("%s: failed to allocate root clocks\n", __func__);
+		return -ENOMEM;
+	}
+	ccu->data.clks = clks;
+	ccu->data.clk_num = count;
+
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_ROOT_CCU_FRAC_1M, frac_1m);
+
+	return 0;
+}
+
+static int __init bcm281xx_aon_ccu_clks_setup(struct ccu_data *ccu)
+{
+	struct clk **clks;
+	size_t count = BCM281XX_AON_CCU_CLOCK_COUNT;
+
+	clks = kzalloc(count * sizeof(*clks), GFP_KERNEL);
+	if (!clks) {
+		pr_err("%s: failed to allocate aon clocks\n", __func__);
+		return -ENOMEM;
+	}
+	ccu->data.clks = clks;
+	ccu->data.clk_num = count;
+
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_AON_CCU_HUB_TIMER, hub_timer);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_AON_CCU_PMU_BSC, pmu_bsc);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_AON_CCU_PMU_BSC_VAR, pmu_bsc_var);
+
+	return 0;
+}
+
+static int __init bcm281xx_hub_ccu_clks_setup(struct ccu_data *ccu)
+{
+	struct clk **clks;
+	size_t count = BCM281XX_HUB_CCU_CLOCK_COUNT;
+
+	clks = kzalloc(count * sizeof(*clks), GFP_KERNEL);
+	if (!clks) {
+		pr_err("%s: failed to allocate hub clocks\n", __func__);
+		return -ENOMEM;
+	}
+	ccu->data.clks = clks;
+	ccu->data.clk_num = count;
+
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_HUB_CCU_TMON_1M, tmon_1m);
+
+	return 0;
+}
+
+static int __init bcm281xx_master_ccu_clks_setup(struct ccu_data *ccu)
+{
+	struct clk **clks;
+	size_t count = BCM281XX_MASTER_CCU_CLOCK_COUNT;
+
+	clks = kzalloc(count * sizeof(*clks), GFP_KERNEL);
+	if (!clks) {
+		pr_err("%s: failed to allocate master clocks\n", __func__);
+		return -ENOMEM;
+	}
+	ccu->data.clks = clks;
+	ccu->data.clk_num = count;
+
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_MASTER_CCU_SDIO1, sdio1);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_MASTER_CCU_SDIO2, sdio2);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_MASTER_CCU_SDIO3, sdio3);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_MASTER_CCU_SDIO4, sdio4);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_MASTER_CCU_USB_IC, usb_ic);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_MASTER_CCU_HSIC2_48M, hsic2_48m);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_MASTER_CCU_HSIC2_12M, hsic2_12m);
+
+	return 0;
+}
+
+static int __init bcm281xx_slave_ccu_clks_setup(struct ccu_data *ccu)
+{
+	struct clk **clks;
+	size_t count = BCM281XX_SLAVE_CCU_CLOCK_COUNT;
+
+	clks = kzalloc(count * sizeof(*clks), GFP_KERNEL);
+	if (!clks) {
+		pr_err("%s: failed to allocate slave clocks\n", __func__);
+		return -ENOMEM;
+	}
+	ccu->data.clks = clks;
+	ccu->data.clk_num = count;
+
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_SLAVE_CCU_UARTB, uartb);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_SLAVE_CCU_UARTB2, uartb2);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_SLAVE_CCU_UARTB3, uartb3);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_SLAVE_CCU_UARTB4, uartb4);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_SLAVE_CCU_SSP0, ssp0);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_SLAVE_CCU_SSP2, ssp2);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_SLAVE_CCU_BSC1, bsc1);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_SLAVE_CCU_BSC2, bsc2);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_SLAVE_CCU_BSC3, bsc3);
+	PERI_CLK_SETUP(clks, ccu, BCM281XX_SLAVE_CCU_PWM, pwm);
+
+	return 0;
+}
+
+/* Device tree match table callback functions */
+
+static void __init kona_dt_root_ccu_setup(struct device_node *node)
+{
+	kona_dt_ccu_setup(node, bcm281xx_root_ccu_clks_setup);
+}
+
+static void __init kona_dt_aon_ccu_setup(struct device_node *node)
+{
+	kona_dt_ccu_setup(node, bcm281xx_aon_ccu_clks_setup);
+}
+
+static void __init kona_dt_hub_ccu_setup(struct device_node *node)
+{
+	kona_dt_ccu_setup(node, bcm281xx_hub_ccu_clks_setup);
+}
+
+static void __init kona_dt_master_ccu_setup(struct device_node *node)
+{
+	kona_dt_ccu_setup(node, bcm281xx_master_ccu_clks_setup);
+}
+
+static void __init kona_dt_slave_ccu_setup(struct device_node *node)
+{
+	kona_dt_ccu_setup(node, bcm281xx_slave_ccu_clks_setup);
+}
+
+CLK_OF_DECLARE(bcm11351_root_ccu, BCM11351_DT_ROOT_CCU_COMPAT,
+			kona_dt_root_ccu_setup);
+CLK_OF_DECLARE(bcm11351_aon_ccu, BCM11351_DT_AON_CCU_COMPAT,
+			kona_dt_aon_ccu_setup);
+CLK_OF_DECLARE(bcm11351_hub_ccu, BCM11351_DT_HUB_CCU_COMPAT,
+			kona_dt_hub_ccu_setup);
+CLK_OF_DECLARE(bcm11351_master_ccu, BCM11351_DT_MASTER_CCU_COMPAT,
+			kona_dt_master_ccu_setup);
+CLK_OF_DECLARE(bcm11351_slave_ccu, BCM11351_DT_SLAVE_CCU_COMPAT,
+			kona_dt_slave_ccu_setup);