clk: mvebu: add clock gating control provider for DT

This driver allows to provide DT clocks for clock gates found on
Marvell Dove and Kirkwood SoCs. The clock gates are referenced by
the phandle index of the corresponding bit in the clock gating control
register to ease lookup in the datasheet.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>

6 files changed, 280 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/clock/mvebu-gated-clock.txt b/Documentation/devicetree/bindings/clock/mvebu-gated-clock.txt
new file mode 100644
index 000000000000..4ad8ccd15e67
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/mvebu-gated-clock.txt
@@ -0,0 +1,76 @@
+* Gated Clock bindings for Marvell Orion SoCs
+
+Marvell Dove and Kirkwood allow some peripheral clocks to be gated to save
+some power. The clock consumer should specify the desired clock by having
+the clock ID in its "clocks" phandle cell. The clock ID is directly mapped to
+the corresponding clock gating control bit in HW to ease manual clock lookup
+in datasheet.
+
+The following is a list of provided IDs for Dove:
+ID      Clock   Peripheral
+-----------------------------------
+0       usb0    USB Host 0
+1       usb1    USB Host 1
+2       ge      Gigabit Ethernet
+3       sata    SATA Host
+4       pex0    PCIe Cntrl 0
+5       pex1    PCIe Cntrl 1
+8       sdio0   SDHCI Host 0
+9       sdio1   SDHCI Host 1
+10      nand    NAND Cntrl
+11      camera  Camera Cntrl
+12      i2s0    I2S Cntrl 0
+13      i2s1    I2S Cntrl 1
+15      crypto  CESA engine
+21      ac97    AC97 Cntrl
+22      pdma    Peripheral DMA
+23      xor0    XOR DMA 0
+24      xor1    XOR DMA 1
+30      gephy   Gigabit Ethernel PHY
+Note: gephy(30) is implemented as a parent clock of ge(2)
+
+The following is a list of provided IDs for Kirkwood:
+ID      Clock   Peripheral
+-----------------------------------
+0       ge0     Gigabit Ethernet 0
+2       pex0    PCIe Cntrl 0
+3       usb0    USB Host 0
+4       sdio    SDIO Cntrl
+5       tsu     Transp. Stream Unit
+6       dunit   SDRAM Cntrl
+7       runit   Runit
+8       xor0    XOR DMA 0
+9       audio   I2S Cntrl 0
+14      sata0   SATA Host 0
+15      sata1   SATA Host 1
+16      xor1    XOR DMA 1
+17      crypto  CESA engine
+18      pex1    PCIe Cntrl 1
+19      ge1     Gigabit Ethernet 0
+20      tdm     Time Division Mplx
+
+Required properties:
+- compatible : shall be one of the following:
+        "marvell,dove-gating-clock" - for Dove SoC clock gating
+        "marvell,kirkwood-gating-clock" - for Kirkwood SoC clock gating
+- reg : shall be the register address of the Clock Gating Control register
+- #clock-cells : from common clock binding; shall be set to 1
+
+Optional properties:
+- clocks : default parent clock phandle (e.g. tclk)
+
+Example:
+
+gate_clk: clock-gating-control@d0038 {
+        compatible = "marvell,dove-gating-clock";
+        reg = <0xd0038 0x4>;
+        /* default parent clock is tclk */
+        clocks = <&core_clk 0>;
+        #clock-cells = <1>;
+};
+
+sdio0: sdio@92000 {
+        compatible = "marvell,dove-sdhci";
+        /* get clk gate bit 8 (sdio0) */
+        clocks = <&gate_clk 8>;
+};
diff --git a/drivers/clk/mvebu/Kconfig b/drivers/clk/mvebu/Kconfig
index 1dd93ada9cb3..57323fd15ec9 100644
--- a/drivers/clk/mvebu/Kconfig
+++ b/drivers/clk/mvebu/Kconfig
@@ -4,3 +4,5 @@ config MVEBU_CLK_CORE
 config MVEBU_CLK_CPU
        bool
 
+config MVEBU_CLK_GATING
+       bool
diff --git a/drivers/clk/mvebu/Makefile b/drivers/clk/mvebu/Makefile
index 93da083b77e3..58df3dc49363 100644
--- a/drivers/clk/mvebu/Makefile
+++ b/drivers/clk/mvebu/Makefile
@@ -1,2 +1,3 @@
 obj-$(CONFIG_MVEBU_CLK_CORE)    += clk.o clk-core.o
 obj-$(CONFIG_MVEBU_CLK_CPU)     += clk-cpu.o
+obj-$(CONFIG_MVEBU_CLK_GATING)  += clk-gating-ctrl.o
diff --git a/drivers/clk/mvebu/clk-gating-ctrl.c b/drivers/clk/mvebu/clk-gating-ctrl.c
new file mode 100644
index 000000000000..fa69f87c5797
--- /dev/null
+++ b/drivers/clk/mvebu/clk-gating-ctrl.c
@@ -0,0 +1,177 @@
+/*
+ * Marvell MVEBU clock gating control.
+ *
+ * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
+ * Andrew Lunn <andrew@lunn.ch>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/clk/mvebu.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+struct mvebu_gating_ctrl {
+        spinlock_t lock;
+        struct clk **gates;
+        int num_gates;
+};
+
+struct mvebu_soc_descr {
+        const char *name;
+        const char *parent;
+        int bit_idx;
+};
+
+#define to_clk_gate(_hw) container_of(_hw, struct clk_gate, hw)
+
+static struct clk __init *mvebu_clk_gating_get_src(
+        struct of_phandle_args *clkspec, void *data)
+{
+        struct mvebu_gating_ctrl *ctrl = (struct mvebu_gating_ctrl *)data;
+        int n;
+
+        if (clkspec->args_count < 1)
+                return ERR_PTR(-EINVAL);
+
+        for (n = 0; n < ctrl->num_gates; n++) {
+                struct clk_gate *gate =
+                        to_clk_gate(__clk_get_hw(ctrl->gates[n]));
+                if (clkspec->args[0] == gate->bit_idx)
+                        return ctrl->gates[n];
+        }
+        return ERR_PTR(-ENODEV);
+}
+
+static void __init mvebu_clk_gating_setup(
+        struct device_node *np, const struct mvebu_soc_descr *descr)
+{
+        struct mvebu_gating_ctrl *ctrl;
+        struct clk *clk;
+        void __iomem *base;
+        const char *default_parent = NULL;
+        int n;
+
+        base = of_iomap(np, 0);
+
+        clk = of_clk_get(np, 0);
+        if (!IS_ERR(clk)) {
+                default_parent = __clk_get_name(clk);
+                clk_put(clk);
+        }
+
+        ctrl = kzalloc(sizeof(struct mvebu_gating_ctrl), GFP_KERNEL);
+        if (WARN_ON(!ctrl))
+                return;
+
+        spin_lock_init(&ctrl->lock);
+
+        /*
+         * Count, allocate, and register clock gates
+         */
+        for (n = 0; descr[n].name;)
+                n++;
+
+        ctrl->num_gates = n;
+        ctrl->gates = kzalloc(ctrl->num_gates * sizeof(struct clk *),
+                              GFP_KERNEL);
+        if (WARN_ON(!ctrl->gates)) {
+                kfree(ctrl);
+                return;
+        }
+
+        for (n = 0; n < ctrl->num_gates; n++) {
+                const char *parent =
+                        (descr[n].parent) ? descr[n].parent : default_parent;
+                ctrl->gates[n] = clk_register_gate(NULL, descr[n].name, parent,
+                                   0, base, descr[n].bit_idx, 0, &ctrl->lock);
+                WARN_ON(IS_ERR(ctrl->gates[n]));
+        }
+        of_clk_add_provider(np, mvebu_clk_gating_get_src, ctrl);
+}
+
+/*
+ * SoC specific clock gating control
+ */
+
+#ifdef CONFIG_ARCH_DOVE
+static const struct mvebu_soc_descr __initconst dove_gating_descr[] = {
+        { "usb0", NULL, 0 },
+        { "usb1", NULL, 1 },
+        { "ge", "gephy", 2 },
+        { "sata", NULL, 3 },
+        { "pex0", NULL, 4 },
+        { "pex1", NULL, 5 },
+        { "sdio0", NULL, 8 },
+        { "sdio1", NULL, 9 },
+        { "nand", NULL, 10 },
+        { "camera", NULL, 11 },
+        { "i2s0", NULL, 12 },
+        { "i2s1", NULL, 13 },
+        { "crypto", NULL, 15 },
+        { "ac97", NULL, 21 },
+        { "pdma", NULL, 22 },
+        { "xor0", NULL, 23 },
+        { "xor1", NULL, 24 },
+        { "gephy", NULL, 30 },
+        { }
+};
+#endif
+
+#ifdef CONFIG_ARCH_KIRKWOOD
+static const struct mvebu_soc_descr __initconst kirkwood_gating_descr[] = {
+        { "ge0", NULL, 0 },
+        { "pex0", NULL, 2 },
+        { "usb0", NULL, 3 },
+        { "sdio", NULL, 4 },
+        { "tsu", NULL, 5 },
+        { "runit", NULL, 7 },
+        { "xor0", NULL, 8 },
+        { "audio", NULL, 9 },
+        { "sata0", NULL, 14 },
+        { "sata1", NULL, 15 },
+        { "xor1", NULL, 16 },
+        { "crypto", NULL, 17 },
+        { "pex1", NULL, 18 },
+        { "ge1", NULL, 19 },
+        { "tdm", NULL, 20 },
+        { }
+};
+#endif
+
+static const __initdata struct of_device_id clk_gating_match[] = {
+#ifdef CONFIG_ARCH_DOVE
+        {
+                .compatible = "marvell,dove-gating-clock",
+                .data = dove_gating_descr,
+        },
+#endif
+
+#ifdef CONFIG_ARCH_KIRKWOOD
+        {
+                .compatible = "marvell,kirkwood-gating-clock",
+                .data = kirkwood_gating_descr,
+        },
+#endif
+
+        { }
+};
+
+void __init mvebu_gating_clk_init(void)
+{
+        struct device_node *np;
+
+        for_each_matching_node(np, clk_gating_match) {
+                const struct of_device_id *match =
+                        of_match_node(clk_gating_match, np);
+                mvebu_clk_gating_setup(np,
+                       (const struct mvebu_soc_descr *)match->data);
+        }
+}
diff --git a/drivers/clk/mvebu/clk-gating-ctrl.h b/drivers/clk/mvebu/clk-gating-ctrl.h
new file mode 100644
index 000000000000..9275d1e51f1b
--- /dev/null
+++ b/drivers/clk/mvebu/clk-gating-ctrl.h
@@ -0,0 +1,22 @@
+/*
+ * Marvell EBU gating clock handling
+ *
+ * Copyright (C) 2012 Marvell
+ *
+ * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#ifndef __MVEBU_CLK_GATING_H
+#define __MVEBU_CLK_GATING_H
+
+#ifdef CONFIG_MVEBU_CLK_GATING
+void __init mvebu_gating_clk_init(void);
+#else
+void mvebu_gating_clk_init(void) {}
+#endif
+
+#endif
diff --git a/drivers/clk/mvebu/clk.c b/drivers/clk/mvebu/clk.c
index e3d4d7a9de6a..855681b8a9dc 100644
--- a/drivers/clk/mvebu/clk.c
+++ b/drivers/clk/mvebu/clk.c
@@ -17,9 +17,11 @@
 #include <linux/of.h>
 #include "clk-core.h"
 #include "clk-cpu.h"
+#include "clk-gating-ctrl.h"
 
 void __init mvebu_clocks_init(void)
 {
         mvebu_core_clk_init();
+        mvebu_gating_clk_init();
         mvebu_cpu_clk_init();
 }