mfd: New AB8500 driver

Add a new driver to support the AB8500 Power Management chip, replacing
the current AB4500.  The new driver replaces the old one, instead of an
incremental modification, because this is a substantial overhaul
including:

 - Split of the driver into -core and -spi portions, to allow another
   interface layer to be added

 - Addition of interrupt support

 - Switch to MFD core API for handling subdevices

 - Simplification of the APIs to remove a redundant block parameter

 - Rename of the APIs and macros from ab4500_* to ab8500_*

 - Rename of the files from ab4500* to ab8500*

 - Change of the driver name from ab4500 to ab8500

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 133 insertions, 0 deletions

diff --git a/drivers/mfd/ab8500-spi.c b/drivers/mfd/ab8500-spi.c
new file mode 100644
index 000000000000..b81d4f768ef6
--- /dev/null
+++ b/drivers/mfd/ab8500-spi.c
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2010
+ *
+ * License Terms: GNU General Public License v2
+ * Author: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/mfd/ab8500.h>
+
+/*
+ * This funtion writes to any AB8500 registers using
+ * SPI protocol &  before it writes it packs the data
+ * in the below 24 bit frame format
+ *
+ *       *|------------------------------------|
+ *       *| 23|22...18|17.......10|9|8|7......0|
+ *       *| r/w  bank       adr          data  |
+ *       * ------------------------------------
+ *
+ * This function shouldn't be called from interrupt
+ * context
+ */
+static int ab8500_spi_write(struct ab8500 *ab8500, u16 addr, u8 data)
+{
+        struct spi_device *spi = container_of(ab8500->dev, struct spi_device,
+                                              dev);
+        unsigned long spi_data = addr << 10 | data;
+        struct spi_transfer xfer;
+        struct spi_message msg;
+
+        ab8500->tx_buf[0] = spi_data;
+        ab8500->rx_buf[0] = 0;
+
+        xfer.tx_buf     = ab8500->tx_buf;
+        xfer.rx_buf     = NULL;
+        xfer.len        = sizeof(unsigned long);
+
+        spi_message_init(&msg);
+        spi_message_add_tail(&xfer, &msg);
+
+        return spi_sync(spi, &msg);
+}
+
+static int ab8500_spi_read(struct ab8500 *ab8500, u16 addr)
+{
+        struct spi_device *spi = container_of(ab8500->dev, struct spi_device,
+                                              dev);
+        unsigned long spi_data = 1 << 23 | addr << 10;
+        struct spi_transfer xfer;
+        struct spi_message msg;
+        int ret;
+
+        ab8500->tx_buf[0] = spi_data;
+        ab8500->rx_buf[0] = 0;
+
+        xfer.tx_buf     = ab8500->tx_buf;
+        xfer.rx_buf     = ab8500->rx_buf;
+        xfer.len        = sizeof(unsigned long);
+
+        spi_message_init(&msg);
+        spi_message_add_tail(&xfer, &msg);
+
+        ret = spi_sync(spi, &msg);
+        if (!ret)
+                ret = ab8500->rx_buf[0];
+
+        return ret;
+}
+
+static int __devinit ab8500_spi_probe(struct spi_device *spi)
+{
+        struct ab8500 *ab8500;
+        int ret;
+
+        ab8500 = kzalloc(sizeof *ab8500, GFP_KERNEL);
+        if (!ab8500)
+                return -ENOMEM;
+
+        ab8500->dev = &spi->dev;
+        ab8500->irq = spi->irq;
+
+        ab8500->read = ab8500_spi_read;
+        ab8500->write = ab8500_spi_write;
+
+        spi_set_drvdata(spi, ab8500);
+
+        ret = ab8500_init(ab8500);
+        if (ret)
+                kfree(ab8500);
+
+        return ret;
+}
+
+static int __devexit ab8500_spi_remove(struct spi_device *spi)
+{
+        struct ab8500 *ab8500 = spi_get_drvdata(spi);
+
+        ab8500_exit(ab8500);
+        kfree(ab8500);
+
+        return 0;
+}
+
+static struct spi_driver ab8500_spi_driver = {
+        .driver = {
+                .name = "ab8500",
+                .owner = THIS_MODULE,
+        },
+        .probe  = ab8500_spi_probe,
+        .remove = __devexit_p(ab8500_spi_remove)
+};
+
+static int __init ab8500_spi_init(void)
+{
+        return spi_register_driver(&ab8500_spi_driver);
+}
+subsys_initcall(ab8500_spi_init);
+
+static void __exit ab8500_spi_exit(void)
+{
+        spi_unregister_driver(&ab8500_spi_driver);
+}
+module_exit(ab8500_spi_exit);
+
+MODULE_AUTHOR("Srinidhi KASAGAR <srinidhi.kasagar@stericsson.com");
+MODULE_DESCRIPTION("AB8500 SPI");
+MODULE_LICENSE("GPL v2");