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Linux/drivers/misc/atmel_tclib.c

  1 #include <linux/atmel_tc.h>
  2 #include <linux/clk.h>
  3 #include <linux/err.h>
  4 #include <linux/init.h>
  5 #include <linux/io.h>
  6 #include <linux/ioport.h>
  7 #include <linux/kernel.h>
  8 #include <linux/platform_device.h>
  9 #include <linux/module.h>
 10 #include <linux/slab.h>
 11 #include <linux/export.h>
 12 #include <linux/of.h>
 13 
 14 /*
 15  * This is a thin library to solve the problem of how to portably allocate
 16  * one of the TC blocks.  For simplicity, it doesn't currently expect to
 17  * share individual timers between different drivers.
 18  */
 19 
 20 #if defined(CONFIG_AVR32)
 21 /* AVR32 has these divide PBB */
 22 const u8 atmel_tc_divisors[5] = { 0, 4, 8, 16, 32, };
 23 EXPORT_SYMBOL(atmel_tc_divisors);
 24 
 25 #elif defined(CONFIG_ARCH_AT91)
 26 /* AT91 has these divide MCK */
 27 const u8 atmel_tc_divisors[5] = { 2, 8, 32, 128, 0, };
 28 EXPORT_SYMBOL(atmel_tc_divisors);
 29 
 30 #endif
 31 
 32 static DEFINE_SPINLOCK(tc_list_lock);
 33 static LIST_HEAD(tc_list);
 34 
 35 /**
 36  * atmel_tc_alloc - allocate a specified TC block
 37  * @block: which block to allocate
 38  *
 39  * Caller allocates a block.  If it is available, a pointer to a
 40  * pre-initialized struct atmel_tc is returned. The caller can access
 41  * the registers directly through the "regs" field.
 42  */
 43 struct atmel_tc *atmel_tc_alloc(unsigned block)
 44 {
 45         struct atmel_tc         *tc;
 46         struct platform_device  *pdev = NULL;
 47 
 48         spin_lock(&tc_list_lock);
 49         list_for_each_entry(tc, &tc_list, node) {
 50                 if (tc->allocated)
 51                         continue;
 52 
 53                 if ((tc->pdev->dev.of_node && tc->id == block) ||
 54                     (tc->pdev->id == block)) {
 55                         pdev = tc->pdev;
 56                         tc->allocated = true;
 57                         break;
 58                 }
 59         }
 60         spin_unlock(&tc_list_lock);
 61 
 62         return pdev ? tc : NULL;
 63 }
 64 EXPORT_SYMBOL_GPL(atmel_tc_alloc);
 65 
 66 /**
 67  * atmel_tc_free - release a specified TC block
 68  * @tc: Timer/counter block that was returned by atmel_tc_alloc()
 69  *
 70  * This reverses the effect of atmel_tc_alloc(), invalidating the resource
 71  * returned by that routine and making the TC available to other drivers.
 72  */
 73 void atmel_tc_free(struct atmel_tc *tc)
 74 {
 75         spin_lock(&tc_list_lock);
 76         if (tc->allocated)
 77                 tc->allocated = false;
 78         spin_unlock(&tc_list_lock);
 79 }
 80 EXPORT_SYMBOL_GPL(atmel_tc_free);
 81 
 82 #if defined(CONFIG_OF)
 83 static struct atmel_tcb_config tcb_rm9200_config = {
 84         .counter_width = 16,
 85 };
 86 
 87 static struct atmel_tcb_config tcb_sam9x5_config = {
 88         .counter_width = 32,
 89 };
 90 
 91 static const struct of_device_id atmel_tcb_dt_ids[] = {
 92         {
 93                 .compatible = "atmel,at91rm9200-tcb",
 94                 .data = &tcb_rm9200_config,
 95         }, {
 96                 .compatible = "atmel,at91sam9x5-tcb",
 97                 .data = &tcb_sam9x5_config,
 98         }, {
 99                 /* sentinel */
100         }
101 };
102 
103 MODULE_DEVICE_TABLE(of, atmel_tcb_dt_ids);
104 #endif
105 
106 static int __init tc_probe(struct platform_device *pdev)
107 {
108         struct atmel_tc *tc;
109         struct clk      *clk;
110         int             irq;
111         struct resource *r;
112         unsigned int    i;
113 
114         irq = platform_get_irq(pdev, 0);
115         if (irq < 0)
116                 return -EINVAL;
117 
118         tc = devm_kzalloc(&pdev->dev, sizeof(struct atmel_tc), GFP_KERNEL);
119         if (!tc)
120                 return -ENOMEM;
121 
122         tc->pdev = pdev;
123 
124         clk = devm_clk_get(&pdev->dev, "t0_clk");
125         if (IS_ERR(clk))
126                 return PTR_ERR(clk);
127 
128         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
129         tc->regs = devm_ioremap_resource(&pdev->dev, r);
130         if (IS_ERR(tc->regs))
131                 return PTR_ERR(tc->regs);
132 
133         /* Now take SoC information if available */
134         if (pdev->dev.of_node) {
135                 const struct of_device_id *match;
136                 match = of_match_node(atmel_tcb_dt_ids, pdev->dev.of_node);
137                 if (match)
138                         tc->tcb_config = match->data;
139 
140                 tc->id = of_alias_get_id(tc->pdev->dev.of_node, "tcb");
141         } else {
142                 tc->id = pdev->id;
143         }
144 
145         tc->clk[0] = clk;
146         tc->clk[1] = devm_clk_get(&pdev->dev, "t1_clk");
147         if (IS_ERR(tc->clk[1]))
148                 tc->clk[1] = clk;
149         tc->clk[2] = devm_clk_get(&pdev->dev, "t2_clk");
150         if (IS_ERR(tc->clk[2]))
151                 tc->clk[2] = clk;
152 
153         tc->irq[0] = irq;
154         tc->irq[1] = platform_get_irq(pdev, 1);
155         if (tc->irq[1] < 0)
156                 tc->irq[1] = irq;
157         tc->irq[2] = platform_get_irq(pdev, 2);
158         if (tc->irq[2] < 0)
159                 tc->irq[2] = irq;
160 
161         for (i = 0; i < 3; i++)
162                 writel(ATMEL_TC_ALL_IRQ, tc->regs + ATMEL_TC_REG(i, IDR));
163 
164         spin_lock(&tc_list_lock);
165         list_add_tail(&tc->node, &tc_list);
166         spin_unlock(&tc_list_lock);
167 
168         platform_set_drvdata(pdev, tc);
169 
170         return 0;
171 }
172 
173 static void tc_shutdown(struct platform_device *pdev)
174 {
175         int i;
176         struct atmel_tc *tc = platform_get_drvdata(pdev);
177 
178         for (i = 0; i < 3; i++)
179                 writel(ATMEL_TC_ALL_IRQ, tc->regs + ATMEL_TC_REG(i, IDR));
180 }
181 
182 static struct platform_driver tc_driver = {
183         .driver = {
184                 .name   = "atmel_tcb",
185                 .of_match_table = of_match_ptr(atmel_tcb_dt_ids),
186         },
187         .shutdown = tc_shutdown,
188 };
189 
190 static int __init tc_init(void)
191 {
192         return platform_driver_probe(&tc_driver, tc_probe);
193 }
194 arch_initcall(tc_init);
195 

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