142099322SDeepak Sikri /* 242099322SDeepak Sikri * drivers/cpufreq/spear-cpufreq.c 342099322SDeepak Sikri * 442099322SDeepak Sikri * CPU Frequency Scaling for SPEAr platform 542099322SDeepak Sikri * 642099322SDeepak Sikri * Copyright (C) 2012 ST Microelectronics 742099322SDeepak Sikri * Deepak Sikri <deepak.sikri@st.com> 842099322SDeepak Sikri * 942099322SDeepak Sikri * This file is licensed under the terms of the GNU General Public 1042099322SDeepak Sikri * License version 2. This program is licensed "as is" without any 1142099322SDeepak Sikri * warranty of any kind, whether express or implied. 1242099322SDeepak Sikri */ 1342099322SDeepak Sikri 1442099322SDeepak Sikri #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 1542099322SDeepak Sikri 1642099322SDeepak Sikri #include <linux/clk.h> 1742099322SDeepak Sikri #include <linux/cpufreq.h> 1842099322SDeepak Sikri #include <linux/err.h> 1942099322SDeepak Sikri #include <linux/init.h> 2042099322SDeepak Sikri #include <linux/module.h> 21c0e46948SSudeep KarkadaNagesha #include <linux/of_device.h> 222449d33aSViresh Kumar #include <linux/platform_device.h> 2342099322SDeepak Sikri #include <linux/slab.h> 2442099322SDeepak Sikri #include <linux/types.h> 2542099322SDeepak Sikri 2642099322SDeepak Sikri /* SPEAr CPUFreq driver data structure */ 2742099322SDeepak Sikri static struct { 2842099322SDeepak Sikri struct clk *clk; 2942099322SDeepak Sikri unsigned int transition_latency; 3042099322SDeepak Sikri struct cpufreq_frequency_table *freq_tbl; 3142099322SDeepak Sikri u32 cnt; 3242099322SDeepak Sikri } spear_cpufreq; 3342099322SDeepak Sikri 3442099322SDeepak Sikri static struct clk *spear1340_cpu_get_possible_parent(unsigned long newfreq) 3542099322SDeepak Sikri { 3642099322SDeepak Sikri struct clk *sys_pclk; 3742099322SDeepak Sikri int pclk; 3842099322SDeepak Sikri /* 3942099322SDeepak Sikri * In SPEAr1340, cpu clk's parent sys clk can take input from 4042099322SDeepak Sikri * following sources 4142099322SDeepak Sikri */ 4242099322SDeepak Sikri const char *sys_clk_src[] = { 4342099322SDeepak Sikri "sys_syn_clk", 4442099322SDeepak Sikri "pll1_clk", 4542099322SDeepak Sikri "pll2_clk", 4642099322SDeepak Sikri "pll3_clk", 4742099322SDeepak Sikri }; 4842099322SDeepak Sikri 4942099322SDeepak Sikri /* 5042099322SDeepak Sikri * As sys clk can have multiple source with their own range 5142099322SDeepak Sikri * limitation so we choose possible sources accordingly 5242099322SDeepak Sikri */ 5342099322SDeepak Sikri if (newfreq <= 300000000) 5442099322SDeepak Sikri pclk = 0; /* src is sys_syn_clk */ 5542099322SDeepak Sikri else if (newfreq > 300000000 && newfreq <= 500000000) 5642099322SDeepak Sikri pclk = 3; /* src is pll3_clk */ 5742099322SDeepak Sikri else if (newfreq == 600000000) 5842099322SDeepak Sikri pclk = 1; /* src is pll1_clk */ 5942099322SDeepak Sikri else 6042099322SDeepak Sikri return ERR_PTR(-EINVAL); 6142099322SDeepak Sikri 6242099322SDeepak Sikri /* Get parent to sys clock */ 6342099322SDeepak Sikri sys_pclk = clk_get(NULL, sys_clk_src[pclk]); 6442099322SDeepak Sikri if (IS_ERR(sys_pclk)) 6542099322SDeepak Sikri pr_err("Failed to get %s clock\n", sys_clk_src[pclk]); 6642099322SDeepak Sikri 6742099322SDeepak Sikri return sys_pclk; 6842099322SDeepak Sikri } 6942099322SDeepak Sikri 7042099322SDeepak Sikri /* 7142099322SDeepak Sikri * In SPEAr1340, we cannot use newfreq directly because we need to actually 7242099322SDeepak Sikri * access a source clock (clk) which might not be ancestor of cpu at present. 7342099322SDeepak Sikri * Hence in SPEAr1340 we would operate on source clock directly before switching 7442099322SDeepak Sikri * cpu clock to it. 7542099322SDeepak Sikri */ 7642099322SDeepak Sikri static int spear1340_set_cpu_rate(struct clk *sys_pclk, unsigned long newfreq) 7742099322SDeepak Sikri { 7842099322SDeepak Sikri struct clk *sys_clk; 7942099322SDeepak Sikri int ret = 0; 8042099322SDeepak Sikri 8142099322SDeepak Sikri sys_clk = clk_get_parent(spear_cpufreq.clk); 8242099322SDeepak Sikri if (IS_ERR(sys_clk)) { 8342099322SDeepak Sikri pr_err("failed to get cpu's parent (sys) clock\n"); 8442099322SDeepak Sikri return PTR_ERR(sys_clk); 8542099322SDeepak Sikri } 8642099322SDeepak Sikri 8742099322SDeepak Sikri /* Set the rate of the source clock before changing the parent */ 8842099322SDeepak Sikri ret = clk_set_rate(sys_pclk, newfreq); 8942099322SDeepak Sikri if (ret) { 9042099322SDeepak Sikri pr_err("Failed to set sys clk rate to %lu\n", newfreq); 9142099322SDeepak Sikri return ret; 9242099322SDeepak Sikri } 9342099322SDeepak Sikri 9442099322SDeepak Sikri ret = clk_set_parent(sys_clk, sys_pclk); 9542099322SDeepak Sikri if (ret) { 9642099322SDeepak Sikri pr_err("Failed to set sys clk parent\n"); 9742099322SDeepak Sikri return ret; 9842099322SDeepak Sikri } 9942099322SDeepak Sikri 10042099322SDeepak Sikri return 0; 10142099322SDeepak Sikri } 10242099322SDeepak Sikri 10342099322SDeepak Sikri static int spear_cpufreq_target(struct cpufreq_policy *policy, 1049c0ebcf7SViresh Kumar unsigned int index) 10542099322SDeepak Sikri { 106bb25f13aSSachin Kamat long newfreq; 10742099322SDeepak Sikri struct clk *srcclk; 1089c0ebcf7SViresh Kumar int ret, mult = 1; 10942099322SDeepak Sikri 11042099322SDeepak Sikri newfreq = spear_cpufreq.freq_tbl[index].frequency * 1000; 1119c0ebcf7SViresh Kumar 11242099322SDeepak Sikri if (of_machine_is_compatible("st,spear1340")) { 11342099322SDeepak Sikri /* 11442099322SDeepak Sikri * SPEAr1340 is special in the sense that due to the possibility 11542099322SDeepak Sikri * of multiple clock sources for cpu clk's parent we can have 11642099322SDeepak Sikri * different clock source for different frequency of cpu clk. 11742099322SDeepak Sikri * Hence we need to choose one from amongst these possible clock 11842099322SDeepak Sikri * sources. 11942099322SDeepak Sikri */ 12042099322SDeepak Sikri srcclk = spear1340_cpu_get_possible_parent(newfreq); 12142099322SDeepak Sikri if (IS_ERR(srcclk)) { 12242099322SDeepak Sikri pr_err("Failed to get src clk\n"); 12342099322SDeepak Sikri return PTR_ERR(srcclk); 12442099322SDeepak Sikri } 12542099322SDeepak Sikri 12642099322SDeepak Sikri /* SPEAr1340: src clk is always 2 * intended cpu clk */ 12742099322SDeepak Sikri mult = 2; 12842099322SDeepak Sikri } else { 12942099322SDeepak Sikri /* 13042099322SDeepak Sikri * src clock to be altered is ancestor of cpu clock. Hence we 13142099322SDeepak Sikri * can directly work on cpu clk 13242099322SDeepak Sikri */ 13342099322SDeepak Sikri srcclk = spear_cpufreq.clk; 13442099322SDeepak Sikri } 13542099322SDeepak Sikri 13642099322SDeepak Sikri newfreq = clk_round_rate(srcclk, newfreq * mult); 137189c9b8dSPaul Walmsley if (newfreq <= 0) { 13842099322SDeepak Sikri pr_err("clk_round_rate failed for cpu src clock\n"); 13942099322SDeepak Sikri return newfreq; 14042099322SDeepak Sikri } 14142099322SDeepak Sikri 14242099322SDeepak Sikri if (mult == 2) 14342099322SDeepak Sikri ret = spear1340_set_cpu_rate(srcclk, newfreq); 14442099322SDeepak Sikri else 14542099322SDeepak Sikri ret = clk_set_rate(spear_cpufreq.clk, newfreq); 14642099322SDeepak Sikri 147d4019f0aSViresh Kumar if (ret) 14842099322SDeepak Sikri pr_err("CPU Freq: cpu clk_set_rate failed: %d\n", ret); 14942099322SDeepak Sikri 15042099322SDeepak Sikri return ret; 15142099322SDeepak Sikri } 15242099322SDeepak Sikri 15342099322SDeepak Sikri static int spear_cpufreq_init(struct cpufreq_policy *policy) 15442099322SDeepak Sikri { 155652ed95dSViresh Kumar policy->clk = spear_cpufreq.clk; 1567a936bd0SViresh Kumar return cpufreq_generic_init(policy, spear_cpufreq.freq_tbl, 1577a936bd0SViresh Kumar spear_cpufreq.transition_latency); 15842099322SDeepak Sikri } 15942099322SDeepak Sikri 16042099322SDeepak Sikri static struct cpufreq_driver spear_cpufreq_driver = { 16142099322SDeepak Sikri .name = "cpufreq-spear", 162ae6b4271SViresh Kumar .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK, 163e2132fa6SViresh Kumar .verify = cpufreq_generic_frequency_table_verify, 1649c0ebcf7SViresh Kumar .target_index = spear_cpufreq_target, 165652ed95dSViresh Kumar .get = cpufreq_generic_get, 16642099322SDeepak Sikri .init = spear_cpufreq_init, 167e2132fa6SViresh Kumar .attr = cpufreq_generic_attr, 16842099322SDeepak Sikri }; 16942099322SDeepak Sikri 1702449d33aSViresh Kumar static int spear_cpufreq_probe(struct platform_device *pdev) 17142099322SDeepak Sikri { 17242099322SDeepak Sikri struct device_node *np; 17342099322SDeepak Sikri const struct property *prop; 17442099322SDeepak Sikri struct cpufreq_frequency_table *freq_tbl; 17542099322SDeepak Sikri const __be32 *val; 17642099322SDeepak Sikri int cnt, i, ret; 17742099322SDeepak Sikri 178c0e46948SSudeep KarkadaNagesha np = of_cpu_device_node_get(0); 17942099322SDeepak Sikri if (!np) { 18042099322SDeepak Sikri pr_err("No cpu node found"); 18142099322SDeepak Sikri return -ENODEV; 18242099322SDeepak Sikri } 18342099322SDeepak Sikri 18442099322SDeepak Sikri if (of_property_read_u32(np, "clock-latency", 18542099322SDeepak Sikri &spear_cpufreq.transition_latency)) 18642099322SDeepak Sikri spear_cpufreq.transition_latency = CPUFREQ_ETERNAL; 18742099322SDeepak Sikri 18842099322SDeepak Sikri prop = of_find_property(np, "cpufreq_tbl", NULL); 18942099322SDeepak Sikri if (!prop || !prop->value) { 19042099322SDeepak Sikri pr_err("Invalid cpufreq_tbl"); 19142099322SDeepak Sikri ret = -ENODEV; 19242099322SDeepak Sikri goto out_put_node; 19342099322SDeepak Sikri } 19442099322SDeepak Sikri 19542099322SDeepak Sikri cnt = prop->length / sizeof(u32); 19642099322SDeepak Sikri val = prop->value; 19742099322SDeepak Sikri 19871508a1fSViresh Kumar freq_tbl = kzalloc(sizeof(*freq_tbl) * (cnt + 1), GFP_KERNEL); 19942099322SDeepak Sikri if (!freq_tbl) { 20042099322SDeepak Sikri ret = -ENOMEM; 20142099322SDeepak Sikri goto out_put_node; 20242099322SDeepak Sikri } 20342099322SDeepak Sikri 20471508a1fSViresh Kumar for (i = 0; i < cnt; i++) 20542099322SDeepak Sikri freq_tbl[i].frequency = be32_to_cpup(val++); 20642099322SDeepak Sikri 20742099322SDeepak Sikri freq_tbl[i].frequency = CPUFREQ_TABLE_END; 20842099322SDeepak Sikri 20942099322SDeepak Sikri spear_cpufreq.freq_tbl = freq_tbl; 21042099322SDeepak Sikri 21142099322SDeepak Sikri of_node_put(np); 21242099322SDeepak Sikri 21342099322SDeepak Sikri spear_cpufreq.clk = clk_get(NULL, "cpu_clk"); 21442099322SDeepak Sikri if (IS_ERR(spear_cpufreq.clk)) { 21542099322SDeepak Sikri pr_err("Unable to get CPU clock\n"); 21642099322SDeepak Sikri ret = PTR_ERR(spear_cpufreq.clk); 21742099322SDeepak Sikri goto out_put_mem; 21842099322SDeepak Sikri } 21942099322SDeepak Sikri 22042099322SDeepak Sikri ret = cpufreq_register_driver(&spear_cpufreq_driver); 22142099322SDeepak Sikri if (!ret) 22242099322SDeepak Sikri return 0; 22342099322SDeepak Sikri 22442099322SDeepak Sikri pr_err("failed register driver: %d\n", ret); 22542099322SDeepak Sikri clk_put(spear_cpufreq.clk); 22642099322SDeepak Sikri 22742099322SDeepak Sikri out_put_mem: 22842099322SDeepak Sikri kfree(freq_tbl); 22942099322SDeepak Sikri return ret; 23042099322SDeepak Sikri 23142099322SDeepak Sikri out_put_node: 23242099322SDeepak Sikri of_node_put(np); 23342099322SDeepak Sikri return ret; 23442099322SDeepak Sikri } 2352449d33aSViresh Kumar 2362449d33aSViresh Kumar static struct platform_driver spear_cpufreq_platdrv = { 2372449d33aSViresh Kumar .driver = { 2382449d33aSViresh Kumar .name = "spear-cpufreq", 2392449d33aSViresh Kumar .owner = THIS_MODULE, 2402449d33aSViresh Kumar }, 2412449d33aSViresh Kumar .probe = spear_cpufreq_probe, 2422449d33aSViresh Kumar }; 2432449d33aSViresh Kumar module_platform_driver(spear_cpufreq_platdrv); 24442099322SDeepak Sikri 24542099322SDeepak Sikri MODULE_AUTHOR("Deepak Sikri <deepak.sikri@st.com>"); 24642099322SDeepak Sikri MODULE_DESCRIPTION("SPEAr CPUFreq driver"); 24742099322SDeepak Sikri MODULE_LICENSE("GPL"); 248