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 #include <linux/pinctrl/consumer.h> 23 24 /* Serialize access to ssc_list and user count */ 25 static DEFINE_SPINLOCK(user_lock); 26 static LIST_HEAD(ssc_list); 27 28 struct ssc_device *ssc_request(unsigned int ssc_num) 29 { 30 int ssc_valid = 0; 31 struct ssc_device *ssc; 32 33 spin_lock(&user_lock); 34 list_for_each_entry(ssc, &ssc_list, list) { 35 if (ssc->pdev->dev.of_node) { 36 if (of_alias_get_id(ssc->pdev->dev.of_node, "ssc") 37 == 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_enable(ssc->clk); 62 63 return ssc; 64 } 65 EXPORT_SYMBOL(ssc_request); 66 67 void ssc_free(struct ssc_device *ssc) 68 { 69 spin_lock(&user_lock); 70 if (ssc->user) { 71 ssc->user--; 72 clk_disable(ssc->clk); 73 } else { 74 dev_dbg(&ssc->pdev->dev, "device already free\n"); 75 } 76 spin_unlock(&user_lock); 77 } 78 EXPORT_SYMBOL(ssc_free); 79 80 static struct atmel_ssc_platform_data at91rm9200_config = { 81 .use_dma = 0, 82 }; 83 84 static struct atmel_ssc_platform_data at91sam9g45_config = { 85 .use_dma = 1, 86 }; 87 88 static const struct platform_device_id atmel_ssc_devtypes[] = { 89 { 90 .name = "at91rm9200_ssc", 91 .driver_data = (unsigned long) &at91rm9200_config, 92 }, { 93 .name = "at91sam9g45_ssc", 94 .driver_data = (unsigned long) &at91sam9g45_config, 95 }, { 96 /* sentinel */ 97 } 98 }; 99 100 #ifdef CONFIG_OF 101 static const struct of_device_id atmel_ssc_dt_ids[] = { 102 { 103 .compatible = "atmel,at91rm9200-ssc", 104 .data = &at91rm9200_config, 105 }, { 106 .compatible = "atmel,at91sam9g45-ssc", 107 .data = &at91sam9g45_config, 108 }, { 109 /* sentinel */ 110 } 111 }; 112 MODULE_DEVICE_TABLE(of, atmel_ssc_dt_ids); 113 #endif 114 115 static inline const struct atmel_ssc_platform_data * __init 116 atmel_ssc_get_driver_data(struct platform_device *pdev) 117 { 118 if (pdev->dev.of_node) { 119 const struct of_device_id *match; 120 match = of_match_node(atmel_ssc_dt_ids, pdev->dev.of_node); 121 if (match == NULL) 122 return NULL; 123 return match->data; 124 } 125 126 return (struct atmel_ssc_platform_data *) 127 platform_get_device_id(pdev)->driver_data; 128 } 129 130 static int ssc_probe(struct platform_device *pdev) 131 { 132 struct resource *regs; 133 struct ssc_device *ssc; 134 const struct atmel_ssc_platform_data *plat_dat; 135 struct pinctrl *pinctrl; 136 137 pinctrl = devm_pinctrl_get_select_default(&pdev->dev); 138 if (IS_ERR(pinctrl)) { 139 dev_err(&pdev->dev, "Failed to request pinctrl\n"); 140 return PTR_ERR(pinctrl); 141 } 142 143 ssc = devm_kzalloc(&pdev->dev, sizeof(struct ssc_device), GFP_KERNEL); 144 if (!ssc) { 145 dev_dbg(&pdev->dev, "out of memory\n"); 146 return -ENOMEM; 147 } 148 149 ssc->pdev = pdev; 150 151 plat_dat = atmel_ssc_get_driver_data(pdev); 152 if (!plat_dat) 153 return -ENODEV; 154 ssc->pdata = (struct atmel_ssc_platform_data *)plat_dat; 155 156 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 157 if (!regs) { 158 dev_dbg(&pdev->dev, "no mmio resource defined\n"); 159 return -ENXIO; 160 } 161 162 ssc->regs = devm_request_and_ioremap(&pdev->dev, regs); 163 if (!ssc->regs) { 164 dev_dbg(&pdev->dev, "ioremap failed\n"); 165 return -EINVAL; 166 } 167 168 ssc->phybase = regs->start; 169 170 ssc->clk = devm_clk_get(&pdev->dev, "pclk"); 171 if (IS_ERR(ssc->clk)) { 172 dev_dbg(&pdev->dev, "no pclk clock defined\n"); 173 return -ENXIO; 174 } 175 176 /* disable all interrupts */ 177 clk_enable(ssc->clk); 178 ssc_writel(ssc->regs, IDR, ~0UL); 179 ssc_readl(ssc->regs, SR); 180 clk_disable(ssc->clk); 181 182 ssc->irq = platform_get_irq(pdev, 0); 183 if (!ssc->irq) { 184 dev_dbg(&pdev->dev, "could not get irq\n"); 185 return -ENXIO; 186 } 187 188 spin_lock(&user_lock); 189 list_add_tail(&ssc->list, &ssc_list); 190 spin_unlock(&user_lock); 191 192 platform_set_drvdata(pdev, ssc); 193 194 dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n", 195 ssc->regs, ssc->irq); 196 197 return 0; 198 } 199 200 static int ssc_remove(struct platform_device *pdev) 201 { 202 struct ssc_device *ssc = platform_get_drvdata(pdev); 203 204 spin_lock(&user_lock); 205 list_del(&ssc->list); 206 spin_unlock(&user_lock); 207 208 return 0; 209 } 210 211 static struct platform_driver ssc_driver = { 212 .driver = { 213 .name = "ssc", 214 .owner = THIS_MODULE, 215 .of_match_table = of_match_ptr(atmel_ssc_dt_ids), 216 }, 217 .id_table = atmel_ssc_devtypes, 218 .probe = ssc_probe, 219 .remove = ssc_remove, 220 }; 221 module_platform_driver(ssc_driver); 222 223 MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>"); 224 MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91"); 225 MODULE_LICENSE("GPL"); 226 MODULE_ALIAS("platform:ssc"); 227