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