clk: x86: Add ST oscout platform clock

Stoney SoC provides oscout clock. This clock can support 25Mhz and
48Mhz of frequency.
The clock is available for general system use.

Signed-off-by: Akshu Agrawal <akshu.agrawal@amd.com>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

3 files changed, 96 insertions, 1 deletions

diff --git a/drivers/clk/x86/Makefile b/drivers/clk/x86/Makefile
index 1367afb03858..00303bc05415 100644
--- a/drivers/clk/x86/Makefile
+++ b/drivers/clk/x86/Makefile
@@ -1,3 +1,4 @@
+obj-$(CONFIG_PMC_ATOM)          += clk-pmc-atom.o
+obj-$(CONFIG_X86_AMD_PLATFORM_DEVICE)   += clk-st.o
 clk-x86-lpss-objs               := clk-lpt.o
 obj-$(CONFIG_X86_INTEL_LPSS)    += clk-x86-lpss.o
-obj-$(CONFIG_PMC_ATOM)          += clk-pmc-atom.o
diff --git a/drivers/clk/x86/clk-st.c b/drivers/clk/x86/clk-st.c
new file mode 100644
index 000000000000..fb62f3938008
--- /dev/null
+++ b/drivers/clk/x86/clk-st.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: MIT
+/*
+ * clock framework for AMD Stoney based clocks
+ *
+ * Copyright 2018 Advanced Micro Devices, Inc.
+ */
+
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/platform_data/clk-st.h>
+#include <linux/platform_device.h>
+
+/* Clock Driving Strength 2 register */
+#define CLKDRVSTR2      0x28
+/* Clock Control 1 register */
+#define MISCCLKCNTL1    0x40
+/* Auxiliary clock1 enable bit */
+#define OSCCLKENB       2
+/* 25Mhz auxiliary output clock freq bit */
+#define OSCOUT1CLK25MHZ 16
+
+#define ST_CLK_48M      0
+#define ST_CLK_25M      1
+#define ST_CLK_MUX      2
+#define ST_CLK_GATE     3
+#define ST_MAX_CLKS     4
+
+static const char * const clk_oscout1_parents[] = { "clk48MHz", "clk25MHz" };
+static struct clk_hw *hws[ST_MAX_CLKS];
+
+static int st_clk_probe(struct platform_device *pdev)
+{
+        struct st_clk_data *st_data;
+
+        st_data = dev_get_platdata(&pdev->dev);
+        if (!st_data || !st_data->base)
+                return -EINVAL;
+
+        hws[ST_CLK_48M] = clk_hw_register_fixed_rate(NULL, "clk48MHz", NULL, 0,
+                                                     48000000);
+        hws[ST_CLK_25M] = clk_hw_register_fixed_rate(NULL, "clk25MHz", NULL, 0,
+                                                     25000000);
+
+        hws[ST_CLK_MUX] = clk_hw_register_mux(NULL, "oscout1_mux",
+                clk_oscout1_parents, ARRAY_SIZE(clk_oscout1_parents),
+                0, st_data->base + CLKDRVSTR2, OSCOUT1CLK25MHZ, 3, 0, NULL);
+
+        clk_set_parent(hws[ST_CLK_MUX]->clk, hws[ST_CLK_25M]->clk);
+
+        hws[ST_CLK_GATE] = clk_hw_register_gate(NULL, "oscout1", "oscout1_mux",
+                0, st_data->base + MISCCLKCNTL1, OSCCLKENB,
+                CLK_GATE_SET_TO_DISABLE, NULL);
+
+        clk_hw_register_clkdev(hws[ST_CLK_GATE], "oscout1", NULL);
+
+        return 0;
+}
+
+static int st_clk_remove(struct platform_device *pdev)
+{
+        int i;
+
+        for (i = 0; i < ST_MAX_CLKS; i++)
+                clk_hw_unregister(hws[i]);
+        return 0;
+}
+
+static struct platform_driver st_clk_driver = {
+        .driver = {
+                .name = "clk-st",
+                .suppress_bind_attrs = true,
+        },
+        .probe = st_clk_probe,
+        .remove = st_clk_remove,
+};
+builtin_platform_driver(st_clk_driver);
diff --git a/include/linux/platform_data/clk-st.h b/include/linux/platform_data/clk-st.h
new file mode 100644
index 000000000000..7cdb6a402b35
--- /dev/null
+++ b/include/linux/platform_data/clk-st.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * clock framework for AMD Stoney based clock
+ *
+ * Copyright 2018 Advanced Micro Devices, Inc.
+ */
+
+#ifndef __CLK_ST_H
+#define __CLK_ST_H
+
+#include <linux/compiler.h>
+
+struct st_clk_data {
+        void __iomem *base;
+};
+
+#endif /* __CLK_ST_H */