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>

3 files changed, 218 insertions, 0 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 26a36f88735..2aea25ba7ba 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -329,6 +329,16 @@ config MFD_88PM8607
 	  individual components like voltage regulators, RTC and
 	  battery-charger under the corresponding menus.
 
+config AB4500_CORE
+	tristate "ST-Ericsson's AB4500 Mixed Signal Power management chip"
+	depends on SPI
+	default y
+	help
+	  Select this option to enable access to AB4500 power management
+	  chip. This connects to U8500 on the SSP/SPI bus and exports
+	  read/write functions for the devices to get access to this chip.
+	  This chip embeds various other multimedia funtionalities as well.
+
 endmenu
 
 menu "Multimedia Capabilities Port drivers"
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 2596add427a..1792b1ff8ff 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -52,4 +52,5 @@ obj-$(CONFIG_PCF50633_ADC)	+= pcf50633-adc.o
 obj-$(CONFIG_PCF50633_GPIO)	+= pcf50633-gpio.o
 obj-$(CONFIG_AB3100_CORE)	+= ab3100-core.o
 obj-$(CONFIG_AB3100_OTP)	+= ab3100-otp.o
+obj-$(CONFIG_AB4500_CORE)	+= ab4500-core.o
 obj-$(CONFIG_MFD_88PM8607)	+= 88pm8607.o
diff --git a/drivers/mfd/ab4500-core.c b/drivers/mfd/ab4500-core.c
new file mode 100644
index 00000000000..3ad91f7ee22
--- /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");