mfd: Add syscon driver based on regmap
Add regmap based syscon driver.
This is usually used for access misc bits in registers which does not belong
to a specific module, for example, IMX IOMUXC GPR and ANATOP.
With this driver, client can use generic regmap API to access registers
which are registered into syscon.
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Dong Aisheng <dong.aisheng@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
new file mode 100644
index 0000000..65fe609
--- /dev/null
+++ b/drivers/mfd/syscon.c
@@ -0,0 +1,176 @@
+/*
+ * System Control Driver
+ *
+ * Copyright (C) 2012 Freescale Semiconductor, Inc.
+ * Copyright (C) 2012 Linaro Ltd.
+ *
+ * Author: Dong Aisheng <dong.aisheng@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+static struct platform_driver syscon_driver;
+
+struct syscon {
+ struct device *dev;
+ void __iomem *base;
+ struct regmap *regmap;
+};
+
+static int syscon_match(struct device *dev, void *data)
+{
+ struct syscon *syscon = dev_get_drvdata(dev);
+ struct device_node *dn = data;
+
+ return (syscon->dev->of_node == dn) ? 1 : 0;
+}
+
+struct regmap *syscon_node_to_regmap(struct device_node *np)
+{
+ struct syscon *syscon;
+ struct device *dev;
+
+ dev = driver_find_device(&syscon_driver.driver, NULL, np,
+ syscon_match);
+ if (!dev)
+ return ERR_PTR(-EPROBE_DEFER);
+
+ syscon = dev_get_drvdata(dev);
+
+ return syscon->regmap;
+}
+EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
+
+struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
+{
+ struct device_node *syscon_np;
+ struct regmap *regmap;
+
+ syscon_np = of_find_compatible_node(NULL, NULL, s);
+ if (!syscon_np)
+ return ERR_PTR(-ENODEV);
+
+ regmap = syscon_node_to_regmap(syscon_np);
+ of_node_put(syscon_np);
+
+ return regmap;
+}
+EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
+
+struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
+ const char *property)
+{
+ struct device_node *syscon_np;
+ struct regmap *regmap;
+
+ syscon_np = of_parse_phandle(np, property, 0);
+ if (!syscon_np)
+ return ERR_PTR(-ENODEV);
+
+ regmap = syscon_node_to_regmap(syscon_np);
+ of_node_put(syscon_np);
+
+ return regmap;
+}
+EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
+
+static const struct of_device_id of_syscon_match[] = {
+ { .compatible = "syscon", },
+ { },
+};
+
+static struct regmap_config syscon_regmap_config = {
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+};
+
+static int __devinit syscon_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct syscon *syscon;
+ struct resource res;
+ int ret;
+
+ if (!np)
+ return -ENOENT;
+
+ syscon = devm_kzalloc(dev, sizeof(struct syscon),
+ GFP_KERNEL);
+ if (!syscon)
+ return -ENOMEM;
+
+ syscon->base = of_iomap(np, 0);
+ if (!syscon->base)
+ return -EADDRNOTAVAIL;
+
+ ret = of_address_to_resource(np, 0, &res);
+ if (ret)
+ return ret;
+
+ syscon_regmap_config.max_register = res.end - res.start - 3;
+ syscon->regmap = devm_regmap_init_mmio(dev, syscon->base,
+ &syscon_regmap_config);
+ if (IS_ERR(syscon->regmap)) {
+ dev_err(dev, "regmap init failed\n");
+ return PTR_ERR(syscon->regmap);
+ }
+
+ syscon->dev = dev;
+ platform_set_drvdata(pdev, syscon);
+
+ dev_info(dev, "syscon regmap start 0x%x end 0x%x registered\n",
+ res.start, res.end);
+
+ return 0;
+}
+
+static int __devexit syscon_remove(struct platform_device *pdev)
+{
+ struct syscon *syscon;
+
+ syscon = platform_get_drvdata(pdev);
+ iounmap(syscon->base);
+ platform_set_drvdata(pdev, NULL);
+
+ return 0;
+}
+
+static struct platform_driver syscon_driver = {
+ .driver = {
+ .name = "syscon",
+ .owner = THIS_MODULE,
+ .of_match_table = of_syscon_match,
+ },
+ .probe = syscon_probe,
+ .remove = __devexit_p(syscon_remove),
+};
+
+static int __init syscon_init(void)
+{
+ return platform_driver_register(&syscon_driver);
+}
+postcore_initcall(syscon_init);
+
+static void __exit syscon_exit(void)
+{
+ platform_driver_unregister(&syscon_driver);
+}
+module_exit(syscon_exit);
+
+MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
+MODULE_DESCRIPTION("System Control driver");
+MODULE_LICENSE("GPL v2");