mfd: add AB4500 driver

This adds core driver support for AB4500 mixed signal
multimedia & power management chip. This connects to U8500
on the SSP (pl022) and exports read/write functions for
the device to get access to this chip. This also registers
the client devices and sets the parent.

Signed-off-by: srinidhi kasagar <srinidhi.kasagar@stericsson.com>
Acked-by: Andrea Gallo <andrea.gallo@stericsson.com>
Reviewed-by: Mark Brown <broonie@sirena.org.uk>
Reviewed-by: Jean-Christophe <plagnioj@jcrosoft.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 207 insertions, 0 deletions

diff --git a/drivers/mfd/ab4500-core.c b/drivers/mfd/ab4500-core.c
new file mode 100644
index 000000000000..3ad91f7ee22b
--- /dev/null
+++ b/drivers/mfd/ab4500-core.c
@@ -0,0 +1,207 @@
+/*
+ * Copyright (C) 2009 ST-Ericsson
+ *
+ * Author: Srinidhi KASAGAR <srinidhi.kasagar@stericsson.com>
+ *
+ * This program is free software; you can redistribute it
+ * and/or modify it under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation.
+ *
+ * AB4500 is a companion power management chip used with U8500.
+ * On this platform, this is interfaced with SSP0 controller
+ * which is a ARM primecell pl022.
+ *
+ * At the moment the module just exports read/write features.
+ * Interrupt management to be added - TODO.
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/mfd/ab4500.h>
+
+/* just required if probe fails, we need to
+ * unregister the device
+ */
+static struct spi_driver ab4500_driver;
+
+/*
+ * This funtion writes to any AB4500 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
+ */
+int ab4500_write(struct ab4500 *ab4500, unsigned char block,
+                unsigned long addr, unsigned char data)
+{
+        struct spi_transfer xfer;
+        struct spi_message      msg;
+        int err;
+        unsigned long spi_data =
+                block << 18 | addr << 10 | data;
+
+        mutex_lock(&ab4500->lock);
+        ab4500->tx_buf[0] = spi_data;
+        ab4500->rx_buf[0] = 0;
+
+        xfer.tx_buf     = ab4500->tx_buf;
+        xfer.rx_buf     = NULL;
+        xfer.len        = sizeof(unsigned long);
+
+        spi_message_init(&msg);
+        spi_message_add_tail(&xfer, &msg);
+
+        err = spi_sync(ab4500->spi, &msg);
+        mutex_unlock(&ab4500->lock);
+
+        return err;
+}
+EXPORT_SYMBOL(ab4500_write);
+
+int ab4500_read(struct ab4500 *ab4500, unsigned char block,
+                unsigned long addr)
+{
+        struct spi_transfer xfer;
+        struct spi_message      msg;
+        unsigned long spi_data =
+                1 << 23 | block << 18 | addr << 10;
+
+        mutex_lock(&ab4500->lock);
+        ab4500->tx_buf[0] = spi_data;
+        ab4500->rx_buf[0] = 0;
+
+        xfer.tx_buf     = ab4500->tx_buf;
+        xfer.rx_buf     = ab4500->rx_buf;
+        xfer.len        = sizeof(unsigned long);
+
+        spi_message_init(&msg);
+        spi_message_add_tail(&xfer, &msg);
+
+        spi_sync(ab4500->spi, &msg);
+        mutex_unlock(&ab4500->lock);
+
+        return  ab4500->rx_buf[0];
+}
+EXPORT_SYMBOL(ab4500_read);
+
+/* ref: ab3100 core */
+#define AB4500_DEVICE(devname, devid)                           \
+static struct platform_device ab4500_##devname##_device = {     \
+        .name   = devid,                                        \
+        .id     = -1,                                           \
+}
+
+/* list of childern devices of ab4500 - all are
+ * not populated here - TODO
+ */
+AB4500_DEVICE(charger, "ab4500-charger");
+AB4500_DEVICE(audio, "ab4500-audio");
+AB4500_DEVICE(usb, "ab4500-usb");
+AB4500_DEVICE(tvout, "ab4500-tvout");
+AB4500_DEVICE(sim, "ab4500-sim");
+AB4500_DEVICE(gpadc, "ab4500-gpadc");
+AB4500_DEVICE(clkmgt, "ab4500-clkmgt");
+AB4500_DEVICE(misc, "ab4500-misc");
+
+static struct platform_device *ab4500_platform_devs[] = {
+        &ab4500_charger_device,
+        &ab4500_audio_device,
+        &ab4500_usb_device,
+        &ab4500_tvout_device,
+        &ab4500_sim_device,
+        &ab4500_gpadc_device,
+        &ab4500_clkmgt_device,
+        &ab4500_misc_device,
+};
+
+static int __init ab4500_probe(struct spi_device *spi)
+{
+        struct ab4500   *ab4500;
+        unsigned char revision;
+        int err = 0;
+        int i;
+
+        ab4500 = kzalloc(sizeof *ab4500, GFP_KERNEL);
+        if (!ab4500) {
+                dev_err(&spi->dev, "could not allocate AB4500\n");
+                err = -ENOMEM;
+                goto not_detect;
+        }
+
+        ab4500->spi = spi;
+        spi_set_drvdata(spi, ab4500);
+
+        mutex_init(&ab4500->lock);
+
+        /* read the revision register */
+        revision = ab4500_read(ab4500, AB4500_MISC, AB4500_REV_REG);
+
+        /* revision id 0x0 is for early drop, 0x10 is for cut1.0 */
+        if (revision == 0x0 || revision == 0x10)
+                dev_info(&spi->dev, "Detected chip: %s, revision = %x\n",
+                        ab4500_driver.driver.name, revision);
+        else    {
+                dev_err(&spi->dev, "unknown chip: 0x%x\n", revision);
+                goto not_detect;
+        }
+
+        for (i = 0; i < ARRAY_SIZE(ab4500_platform_devs); i++)  {
+                ab4500_platform_devs[i]->dev.parent =
+                        &spi->dev;
+                platform_set_drvdata(ab4500_platform_devs[i], ab4500);
+        }
+
+        /* register the ab4500 platform devices */
+        platform_add_devices(ab4500_platform_devs,
+                        ARRAY_SIZE(ab4500_platform_devs));
+
+        return err;
+
+ not_detect:
+        spi_unregister_driver(&ab4500_driver);
+        kfree(ab4500);
+        return err;
+}
+
+static int __devexit ab4500_remove(struct spi_device *spi)
+{
+        struct ab4500 *ab4500 =
+                spi_get_drvdata(spi);
+
+        kfree(ab4500);
+
+        return 0;
+}
+
+static struct spi_driver ab4500_driver = {
+        .driver = {
+                .name = "ab4500",
+                .owner = THIS_MODULE,
+        },
+        .probe = ab4500_probe,
+        .remove = __devexit_p(ab4500_remove)
+};
+
+static int __devinit ab4500_init(void)
+{
+        return spi_register_driver(&ab4500_driver);
+}
+
+static void __exit ab4500_exit(void)
+{
+        spi_unregister_driver(&ab4500_driver);
+}
+
+subsys_initcall_sync(ab4500_init);
+
+MODULE_AUTHOR("Srinidhi KASAGAR <srinidhi.kasagar@stericsson.com");
+MODULE_DESCRIPTION("AB4500 core driver");
+MODULE_LICENSE("GPL");