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/*
* 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];
struct clk_lookup *mclk_lookup;
};
/* 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);
/*
* If the clock was already enabled by the firmware mark it as critical
* to avoid it being gated by the clock framework if no driver owns it.
*/
if (plt_clk_is_enabled(&pclk->hw))
init.flags |= CLK_IS_CRITICAL;
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[
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