1 /* 2 * Atmel SSC driver 3 * 4 * Copyright (C) 2007 Atmel Corporation 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 */ 10 11 #include <linux/platform_device.h> 12 #include <linux/list.h> 13 #include <linux/clk.h> 14 #include <linux/err.h> 15 #include <linux/io.h> 16 #include <linux/spinlock.h> 17 #include <linux/atmel-ssc.h> 18 #include <linux/slab.h> 19 #include <linux/module.h> 20 21 #include <linux/of.h> 22 23 /* Serialize access to ssc_list and user count */ 24 static DEFINE_SPINLOCK(user_lock); 25 static LIST_HEAD(ssc_list); 26 27 struct ssc_device *ssc_request(unsigned int ssc_num) 28 { 29 int ssc_valid = 0; 30 struct ssc_device *ssc; 31 32 spin_lock(&user_lock); 33 list_for_each_entry(ssc, &ssc_list, list) { 34 if (ssc->pdev->dev.of_node) { 35 if (of_alias_get_id(ssc->pdev->dev.of_node, "ssc") 36 == ssc_num) { 37 ssc->pdev->id = ssc_num; 38 ssc_valid = 1; 39 break; 40 } 41 } else if (ssc->pdev->id == ssc_num) { 42 ssc_valid = 1; 43 break; 44 } 45 } 46 47 if (!ssc_valid) { 48 spin_unlock(&user_lock); 49 pr_err("ssc: ssc%d platform device is missing\n", ssc_num); 50 return ERR_PTR(-ENODEV); 51 } 52 53 if (ssc->user) { 54 spin_unlock(&user_lock); 55 dev_dbg(&ssc->pdev->dev, "module busy\n"); 56 return ERR_PTR(-EBUSY); 57 } 58 ssc->user++; 59 spin_unlock(&user_lock); 60 61 clk_prepare(ssc->clk); 62 63 return ssc; 64 } 65 EXPORT_SYMBOL(ssc_request); 66 67 void ssc_free(struct ssc_device *ssc) 68 { 69 bool disable_clk = true; 70 71 spin_lock(&user_lock); 72 if (ssc->user) 73 ssc->user--; 74 else { 75 disable_clk = false; 76 dev_dbg(&ssc->pdev->dev, "device already free\n"); 77 } 78 spin_unlock(&user_lock); 79 80 if (disable_clk) 81 clk_unprepare(ssc->clk); 82 } 83 EXPORT_SYMBOL(ssc_free); 84 85 static struct atmel_ssc_platform_data at91rm9200_config = { 86 .use_dma = 0, 87 .has_fslen_ext = 0, 88 }; 89 90 static struct atmel_ssc_platform_data at91sam9rl_config = { 91 .use_dma = 0, 92 .has_fslen_ext = 1, 93 }; 94 95 static struct atmel_ssc_platform_data at91sam9g45_config = { 96 .use_dma = 1, 97 .has_fslen_ext = 1, 98 }; 99 100 static const struct platform_device_id atmel_ssc_devtypes[] = { 101 { 102 .name = "at91rm9200_ssc", 103 .driver_data = (unsigned long) &at91rm9200_config, 104 }, { 105 .name = "at91sam9rl_ssc", 106 .driver_data = (unsigned long) &at91sam9rl_config, 107 }, { 108 .name = "at91sam9g45_ssc", 109 .driver_data = (unsigned long) &at91sam9g45_config, 110 }, { 111 /* sentinel */ 112 } 113 }; 114 115 #ifdef CONFIG_OF 116 static const struct of_device_id atmel_ssc_dt_ids[] = { 117 { 118 .compatible = "atmel,at91rm9200-ssc", 119 .data = &at91rm9200_config, 120 }, { 121 .compatible = "atmel,at91sam9rl-ssc", 122 .data = &at91sam9rl_config, 123 }, { 124 .compatible = "atmel,at91sam9g45-ssc", 125 .data = &at91sam9g45_config, 126 }, { 127 /* sentinel */ 128 } 129 }; 130 MODULE_DEVICE_TABLE(of, atmel_ssc_dt_ids); 131 #endif 132 133 static inline const struct atmel_ssc_platform_data * __init 134 atmel_ssc_get_driver_data(struct platform_device *pdev) 135 { 136 if (pdev->dev.of_node) { 137 const struct of_device_id *match; 138 match = of_match_node(atmel_ssc_dt_ids, pdev->dev.of_node); 139 if (match == NULL) 140 return NULL; 141 return match->data; 142 } 143 144 return (struct atmel_ssc_platform_data *) 145 platform_get_device_id(pdev)->driver_data; 146 } 147 148 static int ssc_probe(struct platform_device *pdev) 149 { 150 struct resource *regs; 151 struct ssc_device *ssc; 152 const struct atmel_ssc_platform_data *plat_dat; 153 154 ssc = devm_kzalloc(&pdev->dev, sizeof(struct ssc_device), GFP_KERNEL); 155 if (!ssc) { 156 dev_dbg(&pdev->dev, "out of memory\n"); 157 return -ENOMEM; 158 } 159 160 ssc->pdev = pdev; 161 162 plat_dat = atmel_ssc_get_driver_data(pdev); 163 if (!plat_dat) 164 return -ENODEV; 165 ssc->pdata = (struct atmel_ssc_platform_data *)plat_dat; 166 167 if (pdev->dev.of_node) { 168 struct device_node *np = pdev->dev.of_node; 169 ssc->clk_from_rk_pin = 170 of_property_read_bool(np, "atmel,clk-from-rk-pin"); 171 } 172 173 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 174 ssc->regs = devm_ioremap_resource(&pdev->dev, regs); 175 if (IS_ERR(ssc->regs)) 176 return PTR_ERR(ssc->regs); 177 178 ssc->phybase = regs->start; 179 180 ssc->clk = devm_clk_get(&pdev->dev, "pclk"); 181 if (IS_ERR(ssc->clk)) { 182 dev_dbg(&pdev->dev, "no pclk clock defined\n"); 183 return -ENXIO; 184 } 185 186 /* disable all interrupts */ 187 clk_prepare_enable(ssc->clk); 188 ssc_writel(ssc->regs, IDR, -1); 189 ssc_readl(ssc->regs, SR); 190 clk_disable_unprepare(ssc->clk); 191 192 ssc->irq = platform_get_irq(pdev, 0); 193 if (!ssc->irq) { 194 dev_dbg(&pdev->dev, "could not get irq\n"); 195 return -ENXIO; 196 } 197 198 spin_lock(&user_lock); 199 list_add_tail(&ssc->list, &ssc_list); 200 spin_unlock(&user_lock); 201 202 platform_set_drvdata(pdev, ssc); 203 204 dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n", 205 ssc->regs, ssc->irq); 206 207 return 0; 208 } 209 210 static int ssc_remove(struct platform_device *pdev) 211 { 212 struct ssc_device *ssc = platform_get_drvdata(pdev); 213 214 spin_lock(&user_lock); 215 list_del(&ssc->list); 216 spin_unlock(&user_lock); 217 218 return 0; 219 } 220 221 static struct platform_driver ssc_driver = { 222 .driver = { 223 .name = "ssc", 224 .of_match_table = of_match_ptr(atmel_ssc_dt_ids), 225 }, 226 .id_table = atmel_ssc_devtypes, 227 .probe = ssc_probe, 228 .remove = ssc_remove, 229 }; 230 module_platform_driver(ssc_driver); 231 232 MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>"); 233 MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91"); 234 MODULE_LICENSE("GPL"); 235 MODULE_ALIAS("platform:ssc"); 236