1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * kirkwood_freq.c: cpufreq driver for the Marvell kirkwood
5 * Copyright (C) 2013 Andrew Lunn <andrew@lunn.ch>
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/clk.h>
11 #include <linux/cpufreq.h>
12 #include <linux/of_device.h>
13 #include <linux/platform_device.h>
15 #include <asm/proc-fns.h>
17 #define CPU_SW_INT_BLK BIT(28)
23 struct clk
*powersave_clk
;
28 #define STATE_CPU_FREQ 0x01
29 #define STATE_DDR_FREQ 0x02
32 * Kirkwood can swap the clock to the CPU between two clocks:
37 * The frequencies are set at runtime before registering this table.
39 static struct cpufreq_frequency_table kirkwood_freq_table
[] = {
40 {0, STATE_CPU_FREQ
, 0}, /* CPU uses cpuclk */
41 {0, STATE_DDR_FREQ
, 0}, /* CPU uses ddrclk */
42 {0, 0, CPUFREQ_TABLE_END
},
45 static unsigned int kirkwood_cpufreq_get_cpu_frequency(unsigned int cpu
)
47 return clk_get_rate(priv
.powersave_clk
) / 1000;
50 static int kirkwood_cpufreq_target(struct cpufreq_policy
*policy
,
53 unsigned int state
= kirkwood_freq_table
[index
].driver_data
;
58 /* Disable interrupts to the CPU */
59 reg
= readl_relaxed(priv
.base
);
60 reg
|= CPU_SW_INT_BLK
;
61 writel_relaxed(reg
, priv
.base
);
65 clk_set_parent(priv
.powersave_clk
, priv
.cpu_clk
);
68 clk_set_parent(priv
.powersave_clk
, priv
.ddr_clk
);
72 /* Wait-for-Interrupt, while the hardware changes frequency */
75 /* Enable interrupts to the CPU */
76 reg
= readl_relaxed(priv
.base
);
77 reg
&= ~CPU_SW_INT_BLK
;
78 writel_relaxed(reg
, priv
.base
);
85 /* Module init and exit code */
86 static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy
*policy
)
88 return cpufreq_generic_init(policy
, kirkwood_freq_table
, 5000);
91 static struct cpufreq_driver kirkwood_cpufreq_driver
= {
92 .flags
= CPUFREQ_NEED_INITIAL_FREQ_CHECK
,
93 .get
= kirkwood_cpufreq_get_cpu_frequency
,
94 .verify
= cpufreq_generic_frequency_table_verify
,
95 .target_index
= kirkwood_cpufreq_target
,
96 .init
= kirkwood_cpufreq_cpu_init
,
97 .name
= "kirkwood-cpufreq",
98 .attr
= cpufreq_generic_attr
,
101 static int kirkwood_cpufreq_probe(struct platform_device
*pdev
)
103 struct device_node
*np
;
104 struct resource
*res
;
107 priv
.dev
= &pdev
->dev
;
109 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
110 priv
.base
= devm_ioremap_resource(&pdev
->dev
, res
);
111 if (IS_ERR(priv
.base
))
112 return PTR_ERR(priv
.base
);
114 np
= of_cpu_device_node_get(0);
116 dev_err(&pdev
->dev
, "failed to get cpu device node\n");
120 priv
.cpu_clk
= of_clk_get_by_name(np
, "cpu_clk");
121 if (IS_ERR(priv
.cpu_clk
)) {
122 dev_err(priv
.dev
, "Unable to get cpuclk\n");
123 err
= PTR_ERR(priv
.cpu_clk
);
127 err
= clk_prepare_enable(priv
.cpu_clk
);
129 dev_err(priv
.dev
, "Unable to prepare cpuclk\n");
133 kirkwood_freq_table
[0].frequency
= clk_get_rate(priv
.cpu_clk
) / 1000;
135 priv
.ddr_clk
= of_clk_get_by_name(np
, "ddrclk");
136 if (IS_ERR(priv
.ddr_clk
)) {
137 dev_err(priv
.dev
, "Unable to get ddrclk\n");
138 err
= PTR_ERR(priv
.ddr_clk
);
142 err
= clk_prepare_enable(priv
.ddr_clk
);
144 dev_err(priv
.dev
, "Unable to prepare ddrclk\n");
147 kirkwood_freq_table
[1].frequency
= clk_get_rate(priv
.ddr_clk
) / 1000;
149 priv
.powersave_clk
= of_clk_get_by_name(np
, "powersave");
150 if (IS_ERR(priv
.powersave_clk
)) {
151 dev_err(priv
.dev
, "Unable to get powersave\n");
152 err
= PTR_ERR(priv
.powersave_clk
);
155 err
= clk_prepare_enable(priv
.powersave_clk
);
157 dev_err(priv
.dev
, "Unable to prepare powersave clk\n");
161 err
= cpufreq_register_driver(&kirkwood_cpufreq_driver
);
163 dev_err(priv
.dev
, "Failed to register cpufreq driver\n");
171 clk_disable_unprepare(priv
.powersave_clk
);
173 clk_disable_unprepare(priv
.ddr_clk
);
175 clk_disable_unprepare(priv
.cpu_clk
);
182 static int kirkwood_cpufreq_remove(struct platform_device
*pdev
)
184 cpufreq_unregister_driver(&kirkwood_cpufreq_driver
);
186 clk_disable_unprepare(priv
.powersave_clk
);
187 clk_disable_unprepare(priv
.ddr_clk
);
188 clk_disable_unprepare(priv
.cpu_clk
);
193 static struct platform_driver kirkwood_cpufreq_platform_driver
= {
194 .probe
= kirkwood_cpufreq_probe
,
195 .remove
= kirkwood_cpufreq_remove
,
197 .name
= "kirkwood-cpufreq",
201 module_platform_driver(kirkwood_cpufreq_platform_driver
);
203 MODULE_LICENSE("GPL v2");
204 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch");
205 MODULE_DESCRIPTION("cpufreq driver for Marvell's kirkwood CPU");
206 MODULE_ALIAS("platform:kirkwood-cpufreq");