[PATCH v3 2/3] clk: keystone: Add gate control clock driver
Santosh Shilimkar
santosh.shilimkar at ti.com
Wed Sep 25 21:18:14 EDT 2013
Add the driver for the clock gate control which uses PSC (Power Sleep
Controller) IP on Keystone 2 based SOCs. It is responsible for enabling and
disabling of the clocks for different IPs present in the SoC.
Cc: Mike Turquette <mturquette at linaro.org>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar at ti.com>
---
.../devicetree/bindings/clock/keystone-gate.txt | 29 +++
drivers/clk/keystone/gate.c | 264 ++++++++++++++++++++
2 files changed, 293 insertions(+)
create mode 100644 Documentation/devicetree/bindings/clock/keystone-gate.txt
create mode 100644 drivers/clk/keystone/gate.c
diff --git a/Documentation/devicetree/bindings/clock/keystone-gate.txt b/Documentation/devicetree/bindings/clock/keystone-gate.txt
new file mode 100644
index 0000000..c5aa187
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/keystone-gate.txt
@@ -0,0 +1,29 @@
+Status: Unstable - ABI compatibility may be broken in the future
+
+Binding for Keystone gate control driver which uses PSC controller IP.
+
+This binding uses the common clock binding[1].
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+Required properties:
+- compatible : shall be "ti,keystone,psc-clock".
+- #clock-cells : from common clock binding; shall be set to 0.
+- clocks : parent clock phandle
+- reg : psc control and domain address address space
+- reg-names : psc control and domain registers
+- domain-id : psc domain id needed to check the transition state register
+
+Optional properties:
+- clock-output-names : From common clock binding to override the
+ default output clock name
+Example:
+ clkusb: clkusb {
+ #clock-cells = <0>;
+ compatible = "ti,keystone,psc-clock";
+ clocks = <&chipclk16>;
+ clock-output-names = "usb";
+ reg = <0x02350008 0xb00>, <0x02350000 0x400>;
+ reg-names = "control", "domain";
+ domain-id = <0>;
+ };
diff --git a/drivers/clk/keystone/gate.c b/drivers/clk/keystone/gate.c
new file mode 100644
index 0000000..1f333bc
--- /dev/null
+++ b/drivers/clk/keystone/gate.c
@@ -0,0 +1,264 @@
+/*
+ * Clock driver for Keystone 2 based devices
+ *
+ * Copyright (C) 2013 Texas Instruments.
+ * Murali Karicheri <m-karicheri2 at ti.com>
+ * Santosh Shilimkar <santosh.shilimkar at ti.com>
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/of_address.h>
+#include <linux/of.h>
+#include <linux/module.h>
+
+/* PSC register offsets */
+#define PTCMD 0x120
+#define PTSTAT 0x128
+#define PDSTAT 0x200
+#define PDCTL 0x300
+#define MDSTAT 0x800
+#define MDCTL 0xa00
+
+/* PSC module states */
+#define PSC_STATE_SWRSTDISABLE 0
+#define PSC_STATE_SYNCRST 1
+#define PSC_STATE_DISABLE 2
+#define PSC_STATE_ENABLE 3
+
+#define MDSTAT_STATE_MASK 0x3f
+#define MDSTAT_MCKOUT BIT(12)
+#define PDSTAT_STATE_MASK 0x1f
+#define MDCTL_FORCE BIT(31)
+#define MDCTL_LRESET BIT(8)
+#define PDCTL_NEXT BIT(0)
+
+/* Maximum timeout to bail out state transition for module */
+#define STATE_TRANS_MAX_COUNT 0xffff
+
+static void __iomem *domain_transition_base;
+
+/**
+ * struct clk_psc_data - PSC data
+ * @control_base: Base address for a PSC control
+ * @domain_base: Base address for a PSC domain
+ * @domain_id: PSC domain id number
+ */
+struct clk_psc_data {
+ void __iomem *control_base;
+ void __iomem *domain_base;
+ u32 domain_id;
+};
+
+/**
+ * struct clk_psc - PSC clock structure
+ * @hw: clk_hw for the psc
+ * @psc_data: PSC driver specific data
+ * @lock: Spinlock used by the driver
+ */
+struct clk_psc {
+ struct clk_hw hw;
+ struct clk_psc_data *psc_data;
+ spinlock_t *lock;
+};
+
+static DEFINE_SPINLOCK(psc_lock);
+
+#define to_clk_psc(_hw) container_of(_hw, struct clk_psc, hw)
+
+static void psc_config(void __iomem *control_base, void __iomem *domain_base,
+ u32 next_state, u32 domain_id)
+{
+ u32 ptcmd, pdstat, pdctl, mdstat, mdctl, ptstat;
+ u32 count = STATE_TRANS_MAX_COUNT;
+
+ mdctl = readl(control_base + MDCTL);
+ mdctl &= ~MDSTAT_STATE_MASK;
+ mdctl |= next_state;
+ /* For disable, we always put the module in local reset */
+ if (next_state == PSC_STATE_DISABLE)
+ mdctl &= ~MDCTL_LRESET;
+ writel(mdctl, control_base + MDCTL);
+
+ pdstat = readl(domain_base + PDSTAT);
+ if (!(pdstat & PDSTAT_STATE_MASK)) {
+ pdctl = readl(domain_base + PDCTL);
+ pdctl |= PDCTL_NEXT;
+ writel(pdctl, domain_base + PDCTL);
+ }
+
+ ptcmd = 1 << domain_id;
+ writel(ptcmd, domain_transition_base + PTCMD);
+ do {
+ ptstat = readl(domain_transition_base + PTSTAT);
+ } while (((ptstat >> domain_id) & 1) && count--);
+
+ count = STATE_TRANS_MAX_COUNT;
+ do {
+ mdstat = readl(control_base + MDSTAT);
+ } while (!((mdstat & MDSTAT_STATE_MASK) == next_state) && count--);
+}
+
+static int keystone_clk_is_enabled(struct clk_hw *hw)
+{
+ struct clk_psc *psc = to_clk_psc(hw);
+ struct clk_psc_data *data = psc->psc_data;
+ u32 mdstat = readl(data->control_base + MDSTAT);
+
+ return (mdstat & MDSTAT_MCKOUT) ? 1 : 0;
+}
+
+static int keystone_clk_enable(struct clk_hw *hw)
+{
+ struct clk_psc *psc = to_clk_psc(hw);
+ struct clk_psc_data *data = psc->psc_data;
+ unsigned long flags = 0;
+
+ if (psc->lock)
+ spin_lock_irqsave(psc->lock, flags);
+
+ psc_config(data->control_base, data->domain_base,
+ PSC_STATE_ENABLE, data->domain_id);
+
+ if (psc->lock)
+ spin_unlock_irqrestore(psc->lock, flags);
+
+ return 0;
+}
+
+static void keystone_clk_disable(struct clk_hw *hw)
+{
+ struct clk_psc *psc = to_clk_psc(hw);
+ struct clk_psc_data *data = psc->psc_data;
+ unsigned long flags = 0;
+
+ if (psc->lock)
+ spin_lock_irqsave(psc->lock, flags);
+
+ psc_config(data->control_base, data->domain_base,
+ PSC_STATE_DISABLE, data->domain_id);
+
+ if (psc->lock)
+ spin_unlock_irqrestore(psc->lock, flags);
+}
+
+static const struct clk_ops clk_psc_ops = {
+ .enable = keystone_clk_enable,
+ .disable = keystone_clk_disable,
+ .is_enabled = keystone_clk_is_enabled,
+};
+
+/**
+ * clk_register_psc - register psc clock
+ * @dev: device that is registering this clock
+ * @name: name of this clock
+ * @parent_name: name of clock's parent
+ * @psc_data: platform data to configure this clock
+ * @lock: spinlock used by this clock
+ */
+static struct clk *clk_register_psc(struct device *dev,
+ const char *name,
+ const char *parent_name,
+ struct clk_psc_data *psc_data,
+ spinlock_t *lock)
+{
+ struct clk_init_data init;
+ struct clk_psc *psc;
+ struct clk *clk;
+
+ psc = kzalloc(sizeof(*psc), GFP_KERNEL);
+ if (!psc)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &clk_psc_ops;
+ init.parent_names = (parent_name ? &parent_name : NULL);
+ init.num_parents = (parent_name ? 1 : 0);
+
+ psc->psc_data = psc_data;
+ psc->lock = lock;
+ psc->hw.init = &init;
+
+ clk = clk_register(NULL, &psc->hw);
+ if (IS_ERR(clk))
+ kfree(psc);
+
+ return clk;
+}
+
+/**
+ * of_psc_clk_init - initialize psc clock through DT
+ * @node: device tree node for this clock
+ * @lock: spinlock used by this clock
+ */
+static void __init of_psc_clk_init(struct device_node *node, spinlock_t *lock)
+{
+ const char *clk_name = node->name;
+ const char *parent_name;
+ struct clk_psc_data *data;
+ struct clk *clk;
+ int i;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data) {
+ pr_err("%s: Out of memory\n", __func__);
+ return;
+ }
+
+ i = of_property_match_string(node, "reg-names", "control");
+ data->control_base = of_iomap(node, i);
+ if (!data->control_base) {
+ pr_err("%s: control ioremap failed\n", __func__);
+ goto out;
+ }
+
+ i = of_property_match_string(node, "reg-names", "domain");
+ data->domain_base = of_iomap(node, i);
+ if (!data->domain_base) {
+ pr_err("%s: domain ioremap failed\n", __func__);
+ iounmap(data->control_base);
+ goto out;
+ }
+
+ of_property_read_u32(node, "domain-id", &data->domain_id);
+
+ /* Domain transition registers at fixed address space of domain_id 0 */
+ if (!domain_transition_base && !data->domain_id)
+ domain_transition_base = data->domain_base;
+
+ of_property_read_string(node, "clock-output-names", &clk_name);
+ parent_name = of_clk_get_parent_name(node, 0);
+ if (!parent_name) {
+ pr_err("%s: Parent clock not found\n", __func__);
+ goto out;
+ }
+
+ clk = clk_register_psc(NULL, clk_name, parent_name, data, lock);
+ if (clk) {
+ of_clk_add_provider(node, of_clk_src_simple_get, clk);
+ return;
+ }
+
+ pr_err("%s: error registering clk %s\n", __func__, node->name);
+out:
+ kfree(data);
+ return;
+}
+
+/**
+ * of_keystone_psc_clk_init - initialize psc clock through DT
+ * @node: device tree node for this clock
+ */
+static void __init of_keystone_psc_clk_init(struct device_node *node)
+{
+ of_psc_clk_init(node, &psc_lock);
+}
+CLK_OF_DECLARE(keystone_gate_clk, "ti,keystone,psc-clock",
+ of_keystone_psc_clk_init);
--
1.7.9.5
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