| 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"); |