linux-sg2042/drivers/clk/socfpga/clk.c

173 lines
4.6 KiB
C

/*
* Copyright 2011-2012 Calxeda, Inc.
* Copyright (C) 2012-2013 Altera Corporation <www.altera.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.
*
* This program is distributed in the hope that 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.
*
* Based from clk-highbank.c
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/clk-provider.h>
#include <linux/io.h>
#include <linux/of.h>
/* Clock Manager offsets */
#define CLKMGR_CTRL 0x0
#define CLKMGR_BYPASS 0x4
/* Clock bypass bits */
#define MAINPLL_BYPASS (1<<0)
#define SDRAMPLL_BYPASS (1<<1)
#define SDRAMPLL_SRC_BYPASS (1<<2)
#define PERPLL_BYPASS (1<<3)
#define PERPLL_SRC_BYPASS (1<<4)
#define SOCFPGA_PLL_BG_PWRDWN 0
#define SOCFPGA_PLL_EXT_ENA 1
#define SOCFPGA_PLL_PWR_DOWN 2
#define SOCFPGA_PLL_DIVF_MASK 0x0000FFF8
#define SOCFPGA_PLL_DIVF_SHIFT 3
#define SOCFPGA_PLL_DIVQ_MASK 0x003F0000
#define SOCFPGA_PLL_DIVQ_SHIFT 16
extern void __iomem *clk_mgr_base_addr;
struct socfpga_clk {
struct clk_gate hw;
char *parent_name;
char *clk_name;
u32 fixed_div;
};
#define to_socfpga_clk(p) container_of(p, struct socfpga_clk, hw.hw)
static unsigned long clk_pll_recalc_rate(struct clk_hw *hwclk,
unsigned long parent_rate)
{
struct socfpga_clk *socfpgaclk = to_socfpga_clk(hwclk);
unsigned long divf, divq, vco_freq, reg;
unsigned long bypass;
reg = readl(socfpgaclk->hw.reg);
bypass = readl(clk_mgr_base_addr + CLKMGR_BYPASS);
if (bypass & MAINPLL_BYPASS)
return parent_rate;
divf = (reg & SOCFPGA_PLL_DIVF_MASK) >> SOCFPGA_PLL_DIVF_SHIFT;
divq = (reg & SOCFPGA_PLL_DIVQ_MASK) >> SOCFPGA_PLL_DIVQ_SHIFT;
vco_freq = parent_rate * (divf + 1);
return vco_freq / (1 + divq);
}
static struct clk_ops clk_pll_ops = {
.recalc_rate = clk_pll_recalc_rate,
};
static unsigned long clk_periclk_recalc_rate(struct clk_hw *hwclk,
unsigned long parent_rate)
{
struct socfpga_clk *socfpgaclk = to_socfpga_clk(hwclk);
u32 div;
if (socfpgaclk->fixed_div)
div = socfpgaclk->fixed_div;
else
div = ((readl(socfpgaclk->hw.reg) & 0x1ff) + 1);
return parent_rate / div;
}
static const struct clk_ops periclk_ops = {
.recalc_rate = clk_periclk_recalc_rate,
};
static __init struct clk *socfpga_clk_init(struct device_node *node,
const struct clk_ops *ops)
{
u32 reg;
struct clk *clk;
struct socfpga_clk *socfpga_clk;
const char *clk_name = node->name;
const char *parent_name;
struct clk_init_data init;
int rc;
u32 fixed_div;
rc = of_property_read_u32(node, "reg", &reg);
if (WARN_ON(rc))
return NULL;
socfpga_clk = kzalloc(sizeof(*socfpga_clk), GFP_KERNEL);
if (WARN_ON(!socfpga_clk))
return NULL;
socfpga_clk->hw.reg = clk_mgr_base_addr + reg;
rc = of_property_read_u32(node, "fixed-divider", &fixed_div);
if (rc)
socfpga_clk->fixed_div = 0;
else
socfpga_clk->fixed_div = fixed_div;
of_property_read_string(node, "clock-output-names", &clk_name);
init.name = clk_name;
init.ops = ops;
init.flags = 0;
parent_name = of_clk_get_parent_name(node, 0);
init.parent_names = &parent_name;
init.num_parents = 1;
socfpga_clk->hw.hw.init = &init;
if (strcmp(clk_name, "main_pll") || strcmp(clk_name, "periph_pll") ||
strcmp(clk_name, "sdram_pll")) {
socfpga_clk->hw.bit_idx = SOCFPGA_PLL_EXT_ENA;
clk_pll_ops.enable = clk_gate_ops.enable;
clk_pll_ops.disable = clk_gate_ops.disable;
}
clk = clk_register(NULL, &socfpga_clk->hw.hw);
if (WARN_ON(IS_ERR(clk))) {
kfree(socfpga_clk);
return NULL;
}
rc = of_clk_add_provider(node, of_clk_src_simple_get, clk);
return clk;
}
static void __init socfpga_pll_init(struct device_node *node)
{
socfpga_clk_init(node, &clk_pll_ops);
}
CLK_OF_DECLARE(socfpga_pll, "altr,socfpga-pll-clock", socfpga_pll_init);
static void __init socfpga_periph_init(struct device_node *node)
{
socfpga_clk_init(node, &periclk_ops);
}
CLK_OF_DECLARE(socfpga_periph, "altr,socfpga-perip-clk", socfpga_periph_init);
void __init socfpga_init_clocks(void)
{
struct clk *clk;
int ret;
clk = clk_register_fixed_factor(NULL, "smp_twd", "mpuclk", 0, 1, 4);
ret = clk_register_clkdev(clk, NULL, "smp_twd");
if (ret)
pr_err("smp_twd alias not registered\n");
}