The BayTrail and CherryTrail platforms provide platform clocks
through their Power Management Controller (PMC).
The SoC supports up to 6 clocks (PMC_PLT_CLK[5:0]) with a
frequency of either 19.2 MHz (PLL) or 25 MHz (XTAL) for BayTrail
and a frequency of 19.2 MHz (XTAL) for CherryTrail. These clocks
are available for general system use, where appropriate, and each
have Control & Frequency register fields associated with them.
Signed-off-by: Irina Tirdea <irina.tirdea@xxxxxxxxx>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
---
drivers/clk/x86/Makefile | 3 +
drivers/clk/x86/clk-byt-plt.c | 380 ++++++++++++++++++++++++++
include/linux/platform_data/x86/clk-byt-plt.h | 31 +++
3 files changed, 414 insertions(+)
create mode 100644 drivers/clk/x86/clk-byt-plt.c
create mode 100644 include/linux/platform_data/x86/clk-byt-plt.h
diff --git a/drivers/clk/x86/Makefile b/drivers/clk/x86/Makefile
index 0478138..bf7c132 100644
--- a/drivers/clk/x86/Makefile
+++ b/drivers/clk/x86/Makefile
@@ -1,2 +1,5 @@
clk-x86-lpss-objs := clk-lpt.o
obj-$(CONFIG_X86_INTEL_LPSS) += clk-x86-lpss.o
+ifeq ($(CONFIG_COMMON_CLK), y)
+obj-$(CONFIG_PMC_ATOM) += clk-byt-plt.o
+endif
diff --git a/drivers/clk/x86/clk-byt-plt.c b/drivers/clk/x86/clk-byt-plt.c
new file mode 100644
index 0000000..2303e0d
--- /dev/null
+++ b/drivers/clk/x86/clk-byt-plt.c
@@ -0,0 +1,380 @@
+/*
+ * Intel Atom platform clocks driver for BayTrail and CherryTrail SoC.
+ *
+ * Copyright (C) 2016, Intel Corporation
+ * Author: Irina Tirdea <irina.tirdea@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/clkdev.h>
+#include <linux/platform_data/x86/clk-byt-plt.h>
+
+#define PLT_CLK_NAME_BASE "pmc_plt_clk_"
+#define PLT_CLK_DRIVER_NAME "clk-byt-plt"
+
+#define PMC_CLK_CTL_SIZE 4
+#define PMC_CLK_NUM 6
+#define PMC_MASK_CLK_CTL GENMASK(1, 0)
+#define PMC_MASK_CLK_FREQ BIT(2)
+#define PMC_CLK_CTL_GATED_ON_D3 0x0
+#define PMC_CLK_CTL_FORCE_ON 0x1
+#define PMC_CLK_CTL_FORCE_OFF 0x2
+#define PMC_CLK_CTL_RESERVED 0x3
+#define PMC_CLK_FREQ_XTAL 0x0 /* 25 MHz */
+#define PMC_CLK_FREQ_PLL 0x4 /* 19.2 MHz */
+
+struct clk_plt_fixed {
+ struct clk_hw *clk;
+ struct clk_lookup *lookup;
+};
+
+struct clk_plt {
+ struct clk_hw hw;
+ void __iomem *reg;
+ struct clk_lookup *lookup;
+ spinlock_t lock;
+};
+
+#define to_clk_plt(_hw) container_of(_hw, struct clk_plt, hw)
+
+struct clk_plt_data {
+ struct clk_plt_fixed **parents;
+ u8 nparents;
+ struct clk_plt *clks[PMC_CLK_NUM];
+};
+
+static inline int plt_reg_to_parent(int reg)
+{
+ switch (reg & PMC_MASK_CLK_FREQ) {
+ case PMC_CLK_FREQ_XTAL:
+ return 0; /* index 0 in parents[] */
+ case PMC_CLK_FREQ_PLL:
+ return 1; /* index 1 in parents[] */
+ }
+
+ return 0;
+}
+
+static inline int plt_parent_to_reg(int index)
+{
+ switch (index) {
+ case 0: /* index 0 in parents[] */
+ return PMC_CLK_FREQ_XTAL;
+ case 1: /* index 0 in parents[] */
+ return PMC_CLK_FREQ_PLL;
+ }
+
+ return PMC_CLK_FREQ_XTAL;
+}
+
+static inline int plt_reg_to_enabled(int reg)
+{
+ switch (reg & PMC_MASK_CLK_CTL) {
+ case PMC_CLK_CTL_GATED_ON_D3:
+ case PMC_CLK_CTL_FORCE_ON:
+ return 1; /* enabled */
+ case PMC_CLK_CTL_FORCE_OFF:
+ case PMC_CLK_CTL_RESERVED:
+ default:
+ return 0; /* disabled */
+ }
+}
+
+static void plt_clk_reg_update(struct clk_plt *clk, u32 mask, u32 val)
+{
+ u32 orig, tmp;
+ unsigned long flags = 0;
+
+ spin_lock_irqsave(&clk->lock, flags);
+
+ orig = readl(clk->reg);
+
+ tmp = orig & ~mask;
+ tmp |= val & mask;
+
+ if (tmp != orig)
+ writel(tmp, clk->reg);
+
+ spin_unlock_irqrestore(&clk->lock, flags);
+}
+
+static int plt_clk_set_parent(struct clk_hw *hw, u8 index)
+{
+ struct clk_plt *clk = to_clk_plt(hw);
+
+ plt_clk_reg_update(clk, PMC_MASK_CLK_FREQ, plt_parent_to_reg(index));
+
+ return 0;
+}
+
+static u8 plt_clk_get_parent(struct clk_hw *hw)
+{
+ struct clk_plt *clk = to_clk_plt(hw);
+ u32 value;
+
+ value = readl(clk->reg);
+
+ return plt_reg_to_parent(value);
+}
+
+static int plt_clk_enable(struct clk_hw *hw)
+{
+ struct clk_plt *clk = to_clk_plt(hw);
+
+ plt_clk_reg_update(clk, PMC_MASK_CLK_CTL, PMC_CLK_CTL_FORCE_ON);
+
+ return 0;
+}
+
+static void plt_clk_disable(struct clk_hw *hw)
+{
+ struct clk_plt *clk = to_clk_plt(hw);
+
+ plt_clk_reg_update(clk, PMC_MASK_CLK_CTL, PMC_CLK_CTL_FORCE_OFF);
+}
+
+static int plt_clk_is_enabled(struct clk_hw *hw)
+{
+ struct clk_plt *clk = to_clk_plt(hw);
+ u32 value;
+
+ value = readl(clk->reg);
+
+ return plt_reg_to_enabled(value);
+}
+
+static const struct clk_ops plt_clk_ops = {
+ .enable = plt_clk_enable,
+ .disable = plt_clk_disable,
+ .is_enabled = plt_clk_is_enabled,
+ .get_parent = plt_clk_get_parent,
+ .set_parent = plt_clk_set_parent,
+ .determine_rate = __clk_mux_determine_rate,
+};
+
+static struct clk_plt *plt_clk_register(struct platform_device *pdev, int id,
+ void __iomem *base,
+ const char **parent_names,
+ int num_parents)
+{
+ struct clk_plt *pclk;
+ struct clk_init_data init;
+ int ret;
+
+ pclk = devm_kzalloc(&pdev->dev, sizeof(*pclk), GFP_KERNEL);
+ if (!pclk)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = kasprintf(GFP_KERNEL, "%s%d", PLT_CLK_NAME_BASE, id);
+ init.ops = &plt_clk_ops;
+ init.flags = 0;
+ init.parent_names = parent_names;
+ init.num_parents = num_parents;
+
+ pclk->hw.init = &init;
+ pclk->reg = base + id * PMC_CLK_CTL_SIZE;
+ spin_lock_init(&pclk->lock);
+
+ ret = devm_clk_hw_register(&pdev->dev, &pclk->hw);
+ if (ret)
+ goto err_free_init;
+
+ pclk->lookup = clkdev_hw_create(&pclk->hw, init.name, NULL);
+ if (!pclk->lookup) {
+ ret = -ENOMEM;
+ goto err_free_init;
+ }
+
+ kfree(init.name);
+
+ return pclk;
+
+err_free_init:
+ kfree(init.name);
+ return ERR_PTR(ret);
+}
+
+static void plt_clk_unregister(struct clk_plt *pclk)
+{
+ clkdev_drop(pclk->lookup);
+}
+
+static struct clk_plt_fixed *plt_clk_register_fixed_rate(struct platform_device *pdev,
+ const char *name,
+ const char *parent_name,
+ unsigned long fixed_rate)
+{
+ struct clk_plt_fixed *pclk;
+ int ret = 0;
+
+ pclk = devm_kzalloc(&pdev->dev, sizeof(*pclk), GFP_KERNEL);
+ if (!pclk)
+ return ERR_PTR(-ENOMEM);
+
+ pclk->clk = clk_hw_register_fixed_rate(&pdev->dev, name, parent_name,
+ 0, fixed_rate);
+ if (IS_ERR(pclk->clk))
+ return ERR_CAST(pclk->clk);
+
+ pclk->lookup = clkdev_hw_create(pclk->clk, name, NULL);
+ if (!pclk->lookup) {
+ ret = -ENOMEM;
+ goto err_clk_unregister;
+ }
+
+ return pclk;
+
+err_clk_unregister:
+ clk_hw_unregister_fixed_rate(pclk->clk);
+ return ERR_PTR(ret);
+}
+
+static void plt_clk_unregister_fixed_rate(struct clk_plt_fixed *pclk)
+{
+ clkdev_drop(pclk->lookup);
+ clk_hw_unregister_fixed_rate(pclk->clk);
+}
+
+static const char **plt_clk_register_parents(struct platform_device *pdev,
+ struct clk_plt_data *data,
+ const struct pmc_clk *clks)
+{
+ const char **parent_names;
+ int i, err;
+
+ data->nparents = 0;
+ while (clks[data->nparents].name)
+ data->nparents++;
+
+ data->parents = devm_kcalloc(&pdev->dev, data->nparents,
+ sizeof(*data->parents), GFP_KERNEL);
+ if (!data->parents) {
+ err = -ENOMEM;
+ goto err_out;
+ }
+
+ parent_names = kcalloc(data->nparents, sizeof(*parent_names),
+ GFP_KERNEL);
+ if (!parent_names) {
+ err = -ENOMEM;
+ goto err_out;
+ }
+
+ for (i = 0; i < data->nparents; i++) {
+ data->parents[i] =
+ plt_clk_register_fixed_rate(pdev, clks[i].name,
+ clks[i].parent_name,
+ clks[i].freq);
+ if (IS_ERR(data->parents[i])) {
+ err = PTR_ERR(data->parents[i]);
+ goto err_unreg;
+ }
+ parent_names[i] = kstrdup_const(clks[i].name, GFP_KERNEL);
+ }
+
+ return parent_names;
+
+err_unreg:
+ for (i--; i >= 0; i--) {
+ plt_clk_unregister_fixed_rate(data->parents[i]);
+ kfree_const(parent_names[i]);
+ }
+ kfree(parent_names);
+err_out:
+ data->nparents = 0;
+ return ERR_PTR(err);
+}
+
+static void plt_clk_unregister_parents(struct clk_plt_data *data)
+{
+ int i;
+
+ for (i = 0; i < data->nparents; i++)
+ plt_clk_unregister_fixed_rate(data->parents[i]);
+}
+
+static int plt_clk_probe(struct platform_device *pdev)
+{
+ struct clk_plt_data *data;
+ int i, err;
+ const char **parent_names;
+ const struct pmc_clk_data *pmc_data;
+
+ pmc_data = dev_get_platdata(&pdev->dev);
+ if (!pmc_data || !pmc_data->clks)
+ return -EINVAL;
+
+ data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ parent_names = plt_clk_register_parents(pdev, data, pmc_data->clks);
+ if (IS_ERR(parent_names))
+ return PTR_ERR(parent_names);
+
+ for (i = 0; i < PMC_CLK_NUM; i++) {
+ data->clks[i] = plt_clk_register(pdev, i, pmc_data->base,
+ parent_names, data->nparents);
+ if (IS_ERR(data->clks[i])) {
+ err = PTR_ERR(data->clks[i]);
+ goto err_unreg_clk_plt;
+ }
+ }
+
+ for (i = 0; i < data->nparents; i++)
+ kfree_const(parent_names[i]);
+ kfree(parent_names);
+
+ dev_set_drvdata(&pdev->dev, data);
+ return 0;
+
+err_unreg_clk_plt:
+ for (i--; i >= 0; i--)
+ plt_clk_unregister(data->clks[i]);
+ plt_clk_unregister_parents(data);
+ for (i = 0; i < data->nparents; i++)
+ kfree_const(parent_names[i]);
+ kfree(parent_names);
+ return err;
+}
+
+static int plt_clk_remove(struct platform_device *pdev)
+{
+ struct clk_plt_data *data;
+ int i;
+
+ data = dev_get_drvdata(&pdev->dev);
+ if (!data)
+ return 0;
+
+ for (i = 0; i < PMC_CLK_NUM; i++)
+ plt_clk_unregister(data->clks[i]);
+ plt_clk_unregister_parents(data);
+ return 0;
+}
+
+static struct platform_driver plt_clk_driver = {
+ .driver = {
+ .name = PLT_CLK_DRIVER_NAME,
+ },
+ .probe = plt_clk_probe,
+ .remove = plt_clk_remove,
+};
+module_platform_driver(plt_clk_driver);
+
+MODULE_DESCRIPTION("Intel Atom platform clocks driver");
+MODULE_AUTHOR("Irina Tirdea <irina.tirdea@xxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/platform_data/x86/clk-byt-plt.h b/include/linux/platform_data/x86/clk-byt-plt.h
new file mode 100644
index 0000000..e6bca9c
--- /dev/null
+++ b/include/linux/platform_data/x86/clk-byt-plt.h
@@ -0,0 +1,31 @@
+/*
+ * Intel Atom platform clocks for BayTrail and CherryTrail SoC.
+ *
+ * Copyright (C) 2016, Intel Corporation
+ * Author: Irina Tirdea <irina.tirdea@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#ifndef __CLK_BYT_PLT_H
+#define __CLK_BYT_PLT_H
+
+struct pmc_clk {
+ const char *name;
+ unsigned long freq;
+ const char *parent_name;
+};
+
+struct pmc_clk_data {
+ void __iomem *base;
+ const struct pmc_clk *clks;
+};
+
+#endif /* __CLK_BYT_PLT_H */
--
1.9.1
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