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_valid = 1; 38 break; 39 } 40 } else if (ssc->pdev->id == ssc_num) { 41 ssc_valid = 1; 42 break; 43 } 44 } 45 46 if (!ssc_valid) { 47 spin_unlock(&user_lock); 48 pr_err("ssc: ssc%d platform device is missing\n", ssc_num); 49 return ERR_PTR(-ENODEV); 50 } 51 52 if (ssc->user) { 53 spin_unlock(&user_lock); 54 dev_dbg(&ssc->pdev->dev, "module busy\n"); 55 return ERR_PTR(-EBUSY); 56 } 57 ssc->user++; 58 spin_unlock(&user_lock); 59 60 clk_enable(ssc->clk); 61 62 return ssc; 63 } 64 EXPORT_SYMBOL(ssc_request); 65 66 void ssc_free(struct ssc_device *ssc) 67 { 68 spin_lock(&user_lock); 69 if (ssc->user) { 70 ssc->user--; 71 clk_disable(ssc->clk); 72 } else { 73 dev_dbg(&ssc->pdev->dev, "device already free\n"); 74 } 75 spin_unlock(&user_lock); 76 } 77 EXPORT_SYMBOL(ssc_free); 78 79 static struct atmel_ssc_platform_data at91rm9200_config = { 80 .use_dma = 0, 81 }; 82 83 static struct atmel_ssc_platform_data at91sam9g45_config = { 84 .use_dma = 1, 85 }; 86 87 static const struct platform_device_id atmel_ssc_devtypes[] = { 88 { 89 .name = "at91rm9200_ssc", 90 .driver_data = (unsigned long) &at91rm9200_config, 91 }, { 92 .name = "at91sam9g45_ssc", 93 .driver_data = (unsigned long) &at91sam9g45_config, 94 }, { 95 /* sentinel */ 96 } 97 }; 98 99 #ifdef CONFIG_OF 100 static const struct of_device_id atmel_ssc_dt_ids[] = { 101 { 102 .compatible = "atmel,at91rm9200-ssc", 103 .data = &at91rm9200_config, 104 }, { 105 .compatible = "atmel,at91sam9g45-ssc", 106 .data = &at91sam9g45_config, 107 }, { 108 /* sentinel */ 109 } 110 }; 111 MODULE_DEVICE_TABLE(of, atmel_ssc_dt_ids); 112 #endif 113 114 static inline const struct atmel_ssc_platform_data * __init 115 atmel_ssc_get_driver_data(struct platform_device *pdev) 116 { 117 if (pdev->dev.of_node) { 118 const struct of_device_id *match; 119 match = of_match_node(atmel_ssc_dt_ids, pdev->dev.of_node); 120 if (match == NULL) 121 return NULL; 122 return match->data; 123 } 124 125 return (struct atmel_ssc_platform_data *) 126 platform_get_device_id(pdev)->driver_data; 127 } 128 129 static int ssc_probe(struct platform_device *pdev) 130 { 131 struct resource *regs; 132 struct ssc_device *ssc; 133 const struct atmel_ssc_platform_data *plat_dat; 134 135 ssc = devm_kzalloc(&pdev->dev, sizeof(struct ssc_device), GFP_KERNEL); 136 if (!ssc) { 137 dev_dbg(&pdev->dev, "out of memory\n"); 138 return -ENOMEM; 139 } 140 141 ssc->pdev = pdev; 142 143 plat_dat = atmel_ssc_get_driver_data(pdev); 144 if (!plat_dat) 145 return -ENODEV; 146 ssc->pdata = (struct atmel_ssc_platform_data *)plat_dat; 147 148 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 149 if (!regs) { 150 dev_dbg(&pdev->dev, "no mmio resource defined\n"); 151 return -ENXIO; 152 } 153 154 ssc->regs = devm_request_and_ioremap(&pdev->dev, regs); 155 if (!ssc->regs) { 156 dev_dbg(&pdev->dev, "ioremap failed\n"); 157 return -EINVAL; 158 } 159 160 ssc->phybase = regs->start; 161 162 ssc->clk = devm_clk_get(&pdev->dev, "pclk"); 163 if (IS_ERR(ssc->clk)) { 164 dev_dbg(&pdev->dev, "no pclk clock defined\n"); 165 return -ENXIO; 166 } 167 168 /* disable all interrupts */ 169 clk_enable(ssc->clk); 170 ssc_writel(ssc->regs, IDR, ~0UL); 171 ssc_readl(ssc->regs, SR); 172 clk_disable(ssc->clk); 173 174 ssc->irq = platform_get_irq(pdev, 0); 175 if (!ssc->irq) { 176 dev_dbg(&pdev->dev, "could not get irq\n"); 177 return -ENXIO; 178 } 179 180 spin_lock(&user_lock); 181 list_add_tail(&ssc->list, &ssc_list); 182 spin_unlock(&user_lock); 183 184 platform_set_drvdata(pdev, ssc); 185 186 dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n", 187 ssc->regs, ssc->irq); 188 189 return 0; 190 } 191 192 static int ssc_remove(struct platform_device *pdev) 193 { 194 struct ssc_device *ssc = platform_get_drvdata(pdev); 195 196 spin_lock(&user_lock); 197 list_del(&ssc->list); 198 spin_unlock(&user_lock); 199 200 return 0; 201 } 202 203 static struct platform_driver ssc_driver = { 204 .driver = { 205 .name = "ssc", 206 .owner = THIS_MODULE, 207 .of_match_table = of_match_ptr(atmel_ssc_dt_ids), 208 }, 209 .id_table = atmel_ssc_devtypes, 210 .probe = ssc_probe, 211 .remove = ssc_remove, 212 }; 213 module_platform_driver(ssc_driver); 214 215 MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>"); 216 MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91"); 217 MODULE_LICENSE("GPL"); 218 MODULE_ALIAS("platform:ssc"); 219