From: Irina Tirdea irina.tirdea@intel.com
The BayTrail and CherryTrail platforms provide platform clocks through their Power Management Controller (PMC).
The SoC supports up to 6 clocks (PMC_PLT_CLK[0..5]) 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.
Port from legacy by Pierre Bossart, integration in clock framework by Irina Tirdea
Signed-off-by: Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com Signed-off-by: Irina Tirdea irina.tirdea@intel.com --- drivers/clk/x86/Makefile | 1 + drivers/clk/x86/clk-pmc-atom.c | 371 +++++++++++++++++++++++++ include/linux/platform_data/x86/clk-pmc-atom.h | 44 +++ 3 files changed, 416 insertions(+) create mode 100644 drivers/clk/x86/clk-pmc-atom.c create mode 100644 include/linux/platform_data/x86/clk-pmc-atom.h
diff --git a/drivers/clk/x86/Makefile b/drivers/clk/x86/Makefile index 0478138..1367afb 100644 --- a/drivers/clk/x86/Makefile +++ b/drivers/clk/x86/Makefile @@ -1,2 +1,3 @@ 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-pmc-atom.c b/drivers/clk/x86/clk-pmc-atom.c new file mode 100644 index 0000000..2b60577 --- /dev/null +++ b/drivers/clk/x86/clk-pmc-atom.c @@ -0,0 +1,371 @@ +/* + * Intel Atom platform clocks driver for BayTrail and CherryTrail SoCs + * + * Copyright (C) 2016, Intel Corporation + * Author: Irina Tirdea irina.tirdea@intel.com + * + * 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/clkdev.h> +#include <linux/err.h> +#include <linux/platform_data/x86/clk-pmc-atom.h> +#include <linux/platform_device.h> +#include <linux/slab.h> + +#define PLT_CLK_NAME_BASE "pmc_plt_clk" + +#define PMC_CLK_CTL_OFFSET 0x60 +#define PMC_CLK_CTL_SIZE 4 +#define PMC_CLK_NUM 6 +#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_MASK_CLK_CTL GENMASK(1, 0) +#define PMC_MASK_CLK_FREQ BIT(2) +#define PMC_CLK_FREQ_XTAL (0 << 2) /* 25 MHz */ +#define PMC_CLK_FREQ_PLL (1 << 2) /* 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; + /* protect access to PMC registers */ + 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]; +}; + +/* Return an index in parent table */ +static inline int plt_reg_to_parent(int reg) +{ + switch (reg & PMC_MASK_CLK_FREQ) { + default: + case PMC_CLK_FREQ_XTAL: + return 0; + case PMC_CLK_FREQ_PLL: + return 1; + } +} + +/* Return clk index of parent */ +static inline int plt_parent_to_reg(int index) +{ + switch (index) { + default: + case 0: + return PMC_CLK_FREQ_XTAL; + case 1: + return PMC_CLK_FREQ_PLL; + } +} + +/* Abstract status in simpler enabled/disabled value */ +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 tmp; + unsigned long flags; + + spin_lock_irqsave(&clk->lock, flags); + + tmp = readl(clk->reg); + tmp = (tmp & ~mask) | (val & mask); + 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 + PMC_CLK_CTL_OFFSET + id * PMC_CLK_CTL_SIZE; + spin_lock_init(&pclk->lock); + + ret = devm_clk_hw_register(&pdev->dev, &pclk->hw); + if (ret) { + pclk = ERR_PTR(ret); + goto err_free_init; + } + + pclk->lookup = clkdev_hw_create(&pclk->hw, init.name, NULL); + if (!pclk->lookup) { + pclk = ERR_PTR(-ENOMEM); + goto err_free_init; + } + +err_free_init: + kfree(init.name); + return pclk; +} + +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; + + 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) { + clk_hw_unregister_fixed_rate(pclk->clk); + return ERR_PTR(-ENOMEM); + } + + return pclk; +} + +static void plt_clk_unregister_fixed_rate(struct clk_plt_fixed *pclk) +{ + clkdev_drop(pclk->lookup); + clk_hw_unregister_fixed_rate(pclk->clk); +} + +static void plt_clk_unregister_fixed_rate_loop(struct clk_plt_data *data, + unsigned int i) +{ + while (i--) + plt_clk_unregister_fixed_rate(data->parents[i]); +} + +static void plt_clk_free_parent_names_loop(const char **parent_names, + unsigned int i) +{ + while (i--) + kfree_const(parent_names[i]); + kfree(parent_names); +} + +static void plt_clk_unregister_loop(struct clk_plt_data *data, + unsigned int i) +{ + while (i--) + plt_clk_unregister(data->clks[i]); +} + +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; + unsigned int i; + int err; + int nparents = 0; + + data->nparents = 0; + while (clks[nparents].name) + nparents++; + + data->parents = devm_kcalloc(&pdev->dev, nparents, + sizeof(*data->parents), GFP_KERNEL); + if (!data->parents) + return ERR_PTR(-ENOMEM); + + parent_names = kcalloc(nparents, sizeof(*parent_names), + GFP_KERNEL); + if (!parent_names) + return ERR_PTR(-ENOMEM); + + for (i = 0; i < 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); + } + + data->nparents = nparents; + return parent_names; + +err_unreg: + plt_clk_unregister_fixed_rate_loop(data, i); + plt_clk_free_parent_names_loop(parent_names, i); + return ERR_PTR(err); +} + +static void plt_clk_unregister_parents(struct clk_plt_data *data) +{ + plt_clk_unregister_fixed_rate_loop(data, data->nparents); +} + +static int plt_clk_probe(struct platform_device *pdev) +{ + const struct pmc_clk_data *pmc_data; + const char **parent_names; + struct clk_plt_data *data; + unsigned int i; + int err; + + 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; + } + } + + plt_clk_free_parent_names_loop(parent_names, data->nparents); + + platform_set_drvdata(pdev, data); + return 0; + +err_unreg_clk_plt: + plt_clk_unregister_loop(data, i); + plt_clk_unregister_parents(data); + plt_clk_free_parent_names_loop(parent_names, data->nparents); + return err; +} + +static int plt_clk_remove(struct platform_device *pdev) +{ + struct clk_plt_data *data; + + data = platform_get_drvdata(pdev); + + plt_clk_unregister_loop(data, PMC_CLK_NUM); + plt_clk_unregister_parents(data); + return 0; +} + +static struct platform_driver plt_clk_driver = { + .driver = { + .name = "clk-pmc-atom", + }, + .probe = plt_clk_probe, + .remove = plt_clk_remove, +}; +builtin_platform_driver(plt_clk_driver); diff --git a/include/linux/platform_data/x86/clk-pmc-atom.h b/include/linux/platform_data/x86/clk-pmc-atom.h new file mode 100644 index 0000000..3ab8922 --- /dev/null +++ b/include/linux/platform_data/x86/clk-pmc-atom.h @@ -0,0 +1,44 @@ +/* + * Intel Atom platform clocks for BayTrail and CherryTrail SoC. + * + * Copyright (C) 2016, Intel Corporation + * Author: Irina Tirdea irina.tirdea@intel.com + * + * 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 __PLATFORM_DATA_X86_CLK_PMC_ATOM_H +#define __PLATFORM_DATA_X86_CLK_PMC_ATOM_H + +/** + * struct pmc_clk - PMC platform clock configuration + * + * @name: identified, typically pmc_plt_clk_<x>, x=[0..5] + * @freq: in Hz, 19.2MHz and 25MHz (Baytrail only) supported + * @parent_name: one of 'xtal' or 'osc' + */ +struct pmc_clk { + const char *name; + unsigned long freq; + const char *parent_name; +}; + +/** + * struct pmc_clk_data - common PMC clock configuration + * + * @base: PMC clock register base offset + * @clks: pointer to set of registered clocks, typically 0..5 + */ +struct pmc_clk_data { + void __iomem *base; + const struct pmc_clk *clks; +}; + +#endif /* __PLATFORM_DATA_X86_CLK_PMC_ATOM_H */