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authorMichael Walle <michael@walle.cc>2020-09-15 00:43:29 +0300
committerLee Jones <lee.jones@linaro.org>2020-09-17 17:56:58 +0300
commit3abee4579484c554961bb0af92a77adc0ebd791d (patch)
tree036427cf7ee2eb2fe6d263df7567d5151fa974ff /drivers/mfd/simple-mfd-i2c.c
parent9123e3a74ec7b934a4a099e98af6a61c2f80bbf5 (diff)
downloadlinux-3abee4579484c554961bb0af92a77adc0ebd791d.tar.xz
mfd: Add simple regmap based I2C driver
There are I2C devices which contain several different functions but doesn't require any special access functions. For these kind of drivers an I2C regmap should be enough. Create an I2C driver which creates an I2C regmap and enumerates its children. If a device wants to use this as its MFD core driver, it has to add an individual compatible string. It may provide its own regmap configuration. Subdevices can use dev_get_regmap() on the parent to get their regmap instance. Signed-off-by: Michael Walle <michael@walle.cc> Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'drivers/mfd/simple-mfd-i2c.c')
-rw-r--r--drivers/mfd/simple-mfd-i2c.c56
1 files changed, 56 insertions, 0 deletions
diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
new file mode 100644
index 000000000000..28e96a246be1
--- /dev/null
+++ b/drivers/mfd/simple-mfd-i2c.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Simple MFD - I2C
+ *
+ * This driver creates a single register map with the intention for it to be
+ * shared by all sub-devices. Children can use their parent's device structure
+ * (dev.parent) in order to reference it.
+ *
+ * Once the register map has been successfully initialised, any sub-devices
+ * represented by child nodes in Device Tree will be subsequently registered.
+ */
+
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/regmap.h>
+
+static const struct regmap_config simple_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+};
+
+static int simple_mfd_i2c_probe(struct i2c_client *i2c)
+{
+ const struct regmap_config *config;
+ struct regmap *regmap;
+
+ config = device_get_match_data(&i2c->dev);
+ if (!config)
+ config = &simple_regmap_config;
+
+ regmap = devm_regmap_init_i2c(i2c, config);
+ if (IS_ERR(regmap))
+ return PTR_ERR(regmap);
+
+ return devm_of_platform_populate(&i2c->dev);
+}
+
+static const struct of_device_id simple_mfd_i2c_of_match[] = {
+ {}
+};
+MODULE_DEVICE_TABLE(of, simple_mfd_i2c_of_match);
+
+static struct i2c_driver simple_mfd_i2c_driver = {
+ .probe_new = simple_mfd_i2c_probe,
+ .driver = {
+ .name = "simple-mfd-i2c",
+ .of_match_table = simple_mfd_i2c_of_match,
+ },
+};
+module_i2c_driver(simple_mfd_i2c_driver);
+
+MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
+MODULE_DESCRIPTION("Simple MFD - I2C driver");
+MODULE_LICENSE("GPL v2");