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