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authorDavid Brownell <david-b@pacbell.net>2008-02-22 17:23:23 -0800
committerHaavard Skinnemoen <hskinnemoen@atmel.com>2008-03-04 13:41:23 +0100
commit2a341f5cf57dce9d89b41484a69e88adc6422f6c (patch)
tree3534a1f251749b64e7b53f5834800f182a6b4786 /drivers/misc/atmel_tclib.c
parent976dde010e513a9c7c3117a32b7b015f84b37430 (diff)
atmel_tc library
Create <linux/atmel_tc.h> based on <asm-arm/arch-at91/at91-tc.h> and the at91sam9263 and at32ap7000 datasheets. Most AT91 and AT32 SOCs have one or two of these TC blocks, which include three 16-bit timers that can be interconnected in various ways. These TC blocks can be used for external interfacing (such as PWM and measurement), or used as somewhat quirky sixteen-bit timers. Changes relative to the original version: * Drop unneeded inclusion of <linux/mutex.h> * Support an arbitrary number of TC blocks * Return a struct with information about a TC block from atmel_tc_alloc() instead of using a combination of return values and "out" parameters. * ioremap() the I/O registers on allocation * Look up clocks and irqs for all channels * Add "name" parameter to atmel_tc_alloc() and use this when requesting the iomem resource. * Check if the platform provided the necessary resources at probe() time instead of when the TCB is allocated. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Diffstat (limited to 'drivers/misc/atmel_tclib.c')
-rw-r--r--drivers/misc/atmel_tclib.c161
1 files changed, 161 insertions, 0 deletions
diff --git a/drivers/misc/atmel_tclib.c b/drivers/misc/atmel_tclib.c
new file mode 100644
index 00000000000..05dc8a31f28
--- /dev/null
+++ b/drivers/misc/atmel_tclib.c
@@ -0,0 +1,161 @@
+#include <linux/atmel_tc.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+
+/* Number of bytes to reserve for the iomem resource */
+#define ATMEL_TC_IOMEM_SIZE 256
+
+
+/*
+ * This is a thin library to solve the problem of how to portably allocate
+ * one of the TC blocks. For simplicity, it doesn't currently expect to
+ * share individual timers between different drivers.
+ */
+
+#if defined(CONFIG_AVR32)
+/* AVR32 has these divide PBB */
+const u8 atmel_tc_divisors[5] = { 0, 4, 8, 16, 32, };
+EXPORT_SYMBOL(atmel_tc_divisors);
+
+#elif defined(CONFIG_ARCH_AT91)
+/* AT91 has these divide MCK */
+const u8 atmel_tc_divisors[5] = { 2, 8, 32, 128, 0, };
+EXPORT_SYMBOL(atmel_tc_divisors);
+
+#endif
+
+static DEFINE_SPINLOCK(tc_list_lock);
+static LIST_HEAD(tc_list);
+
+/**
+ * atmel_tc_alloc - allocate a specified TC block
+ * @block: which block to allocate
+ * @name: name to be associated with the iomem resource
+ *
+ * Caller allocates a block. If it is available, a pointer to a
+ * pre-initialized struct atmel_tc is returned. The caller can access
+ * the registers directly through the "regs" field.
+ */
+struct atmel_tc *atmel_tc_alloc(unsigned block, const char *name)
+{
+ struct atmel_tc *tc;
+ struct platform_device *pdev = NULL;
+ struct resource *r;
+
+ spin_lock(&tc_list_lock);
+ list_for_each_entry(tc, &tc_list, node) {
+ if (tc->pdev->id == block) {
+ pdev = tc->pdev;
+ break;
+ }
+ }
+
+ if (!pdev || tc->iomem)
+ goto fail;
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ r = request_mem_region(r->start, ATMEL_TC_IOMEM_SIZE, name);
+ if (!r)
+ goto fail;
+
+ tc->regs = ioremap(r->start, ATMEL_TC_IOMEM_SIZE);
+ if (!tc->regs)
+ goto fail_ioremap;
+
+ tc->iomem = r;
+
+out:
+ spin_unlock(&tc_list_lock);
+ return tc;
+
+fail_ioremap:
+ release_resource(r);
+fail:
+ tc = NULL;
+ goto out;
+}
+EXPORT_SYMBOL_GPL(atmel_tc_alloc);
+
+/**
+ * atmel_tc_free - release a specified TC block
+ * @tc: Timer/counter block that was returned by atmel_tc_alloc()
+ *
+ * This reverses the effect of atmel_tc_alloc(), unmapping the I/O
+ * registers, invalidating the resource returned by that routine and
+ * making the TC available to other drivers.
+ */
+void atmel_tc_free(struct atmel_tc *tc)
+{
+ spin_lock(&tc_list_lock);
+ if (tc->regs) {
+ iounmap(tc->regs);
+ release_resource(tc->iomem);
+ tc->regs = NULL;
+ tc->iomem = NULL;
+ }
+ spin_unlock(&tc_list_lock);
+}
+EXPORT_SYMBOL_GPL(atmel_tc_free);
+
+static int __init tc_probe(struct platform_device *pdev)
+{
+ struct atmel_tc *tc;
+ struct clk *clk;
+ int irq;
+
+ if (!platform_get_resource(pdev, IORESOURCE_MEM, 0))
+ return -EINVAL;
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return -EINVAL;
+
+ tc = kzalloc(sizeof(struct atmel_tc), GFP_KERNEL);
+ if (!tc)
+ return -ENOMEM;
+
+ tc->pdev = pdev;
+
+ clk = clk_get(&pdev->dev, "t0_clk");
+ if (IS_ERR(clk)) {
+ kfree(tc);
+ return -EINVAL;
+ }
+
+ tc->clk[0] = clk;
+ tc->clk[1] = clk_get(&pdev->dev, "t1_clk");
+ if (IS_ERR(tc->clk[1]))
+ tc->clk[1] = clk;
+ tc->clk[2] = clk_get(&pdev->dev, "t2_clk");
+ if (IS_ERR(tc->clk[2]))
+ tc->clk[2] = clk;
+
+ tc->irq[0] = irq;
+ tc->irq[1] = platform_get_irq(pdev, 1);
+ if (tc->irq[1] < 0)
+ tc->irq[1] = irq;
+ tc->irq[2] = platform_get_irq(pdev, 2);
+ if (tc->irq[2] < 0)
+ tc->irq[2] = irq;
+
+ spin_lock(&tc_list_lock);
+ list_add_tail(&tc->node, &tc_list);
+ spin_unlock(&tc_list_lock);
+
+ return 0;
+}
+
+static struct platform_driver tc_driver = {
+ .driver.name = "atmel_tcb",
+};
+
+static int __init tc_init(void)
+{
+ return platform_driver_probe(&tc_driver, tc_probe);
+}
+arch_initcall(tc_init);