mfd: dm355evm msp430 driver

Basic MFD framework for the MSP430 microcontroller firmware used
on the dm355evm board:

 - Provides an interface for other drivers: register read/write
   utilities, and register declarations.

 - Directly exports:
     * Many signals through the GPIO framework
         + LEDs
         + SW6 through gpio sysfs
	 + NTSC/nPAL jumper through gpio sysfs
	 + ... more could be added later, e.g. MMC signals
     * Child devices:
	+ LEDs, via leds-gpio child (and default triggers)
	+ RTC, via rtc-dm355evm child device
	+ Buttons and IR control, via dm355evm_keys

 - Supports power-off system call.  Use the reset button to power
   the board back up; the power supply LED will be on, but the
   MSP430 waits to re-activate the regulators.

 - On probe() this:
     * Announces firmware revision
     * Turns off the banked LEDs
     * Exports the resources noted above
     * Hooks the power-off support
     * Muxes tvp5146 -or- imager for video input

Unless the new tvp514x driver (tracked for mainline) is configured,
this assumes that some custom imager driver handles video-in.

This completely ignores the registers reporting the output voltages
on the various power supplies.  Someone could add a hwmon interface
if that seems useful.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Samuel Ortiz <sameo@openedhand.com>

3 files changed, 430 insertions, 0 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 781a27955ff..02e9146ca44 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -34,6 +34,14 @@ config MFD_ASIC3
           This driver supports the ASIC3 multifunction chip found on many
           PDAs (mainly iPAQ and HTC based ones)
 
+config MFD_DM355EVM_MSP
+        bool "DaVinci DM355 EVM microcontroller"
+        depends on I2C && MACH_DAVINCI_DM355_EVM
+        help
+          This driver supports the MSP430 microcontroller used on these
+          boards.  MSP430 firmware manages resets and power sequencing,
+          inputs from buttons and the IR remote, LEDs, an RTC, and more.
+
 config HTC_EGPIO
         bool "HTC EGPIO support"
         depends on GENERIC_HARDIRQS && GPIOLIB && ARM
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 9a5ad8af911..8f6cd5c4893 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -8,6 +8,8 @@ obj-$(CONFIG_MFD_ASIC3)		+= asic3.o
 obj-$(CONFIG_HTC_EGPIO)         += htc-egpio.o
 obj-$(CONFIG_HTC_PASIC3)        += htc-pasic3.o
 
+obj-$(CONFIG_MFD_DM355EVM_MSP)  += dm355evm_msp.o
+
 obj-$(CONFIG_MFD_T7L66XB)       += t7l66xb.o
 obj-$(CONFIG_MFD_TC6387XB)      += tc6387xb.o
 obj-$(CONFIG_MFD_TC6393XB)      += tc6393xb.o
diff --git a/drivers/mfd/dm355evm_msp.c b/drivers/mfd/dm355evm_msp.c
new file mode 100644
index 00000000000..4214b3f7242
--- /dev/null
+++ b/drivers/mfd/dm355evm_msp.c
@@ -0,0 +1,420 @@
+/*
+ * dm355evm_msp.c - driver for MSP430 firmware on DM355EVM board
+ *
+ * Copyright (C) 2008 David Brownell
+ *
+ * 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/init.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/leds.h>
+#include <linux/i2c.h>
+#include <linux/i2c/dm355evm_msp.h>
+
+
+/*
+ * The DM355 is a DaVinci chip with video support but no C64+ DSP.  Its
+ * EVM board has an MSP430 programmed with firmware for various board
+ * support functions.  This driver exposes some of them directly, and
+ * supports other drivers (e.g. RTC, input) for more complex access.
+ *
+ * Because this firmware is entirely board-specific, this file embeds
+ * knowledge that would be passed as platform_data in a generic driver.
+ *
+ * This driver was tested with firmware revision A4.
+ */
+
+#if defined(CONFIG_KEYBOARD_DM355EVM) \
+                || defined(CONFIG_KEYBOARD_DM355EVM_MODULE)
+#define msp_has_keyboard()      true
+#else
+#define msp_has_keyboard()      false
+#endif
+
+#if defined(CONFIG_LEDS_GPIO) || defined(CONFIG_LEDS_GPIO_MODULE)
+#define msp_has_leds()          true
+#else
+#define msp_has_leds()          false
+#endif
+
+#if defined(CONFIG_RTC_DRV_DM355EVM) || defined(CONFIG_RTC_DRV_DM355EVM_MODULE)
+#define msp_has_rtc()           true
+#else
+#define msp_has_rtc()           false
+#endif
+
+#if defined(CONFIG_VIDEO_TVP514X) || defined(CONFIG_VIDEO_TVP514X_MODULE)
+#define msp_has_tvp()           true
+#else
+#define msp_has_tvp()           false
+#endif
+
+
+/*----------------------------------------------------------------------*/
+
+/* REVISIT for paranoia's sake, retry reads/writes on error */
+
+static struct i2c_client *msp430;
+
+/**
+ * dm355evm_msp_write - Writes a register in dm355evm_msp
+ * @value: the value to be written
+ * @reg: register address
+ *
+ * Returns result of operation - 0 is success, else negative errno
+ */
+int dm355evm_msp_write(u8 value, u8 reg)
+{
+        return i2c_smbus_write_byte_data(msp430, reg, value);
+}
+EXPORT_SYMBOL(dm355evm_msp_write);
+
+/**
+ * dm355evm_msp_read - Reads a register from dm355evm_msp
+ * @reg: register address
+ *
+ * Returns result of operation - value, or negative errno
+ */
+int dm355evm_msp_read(u8 reg)
+{
+        return i2c_smbus_read_byte_data(msp430, reg);
+}
+EXPORT_SYMBOL(dm355evm_msp_read);
+
+/*----------------------------------------------------------------------*/
+
+/*
+ * Many of the msp430 pins are just used as fixed-direction GPIOs.
+ * We could export a few more of them this way, if we wanted.
+ */
+#define MSP_GPIO(bit,reg)       ((DM355EVM_MSP_ ## reg) << 3 | (bit))
+
+static const u8 msp_gpios[] = {
+        /* eight leds */
+        MSP_GPIO(0, LED), MSP_GPIO(1, LED),
+        MSP_GPIO(2, LED), MSP_GPIO(3, LED),
+        MSP_GPIO(4, LED), MSP_GPIO(5, LED),
+        MSP_GPIO(6, LED), MSP_GPIO(7, LED),
+        /* SW6 and the NTSC/nPAL jumper */
+        MSP_GPIO(0, SWITCH1), MSP_GPIO(1, SWITCH1),
+        MSP_GPIO(2, SWITCH1), MSP_GPIO(3, SWITCH1),
+        MSP_GPIO(4, SWITCH1),
+};
+
+#define MSP_GPIO_REG(offset)    (msp_gpios[(offset)] >> 3)
+#define MSP_GPIO_MASK(offset)   BIT(msp_gpios[(offset)] & 0x07)
+
+static int msp_gpio_in(struct gpio_chip *chip, unsigned offset)
+{
+        switch (MSP_GPIO_REG(offset)) {
+        case DM355EVM_MSP_SWITCH1:
+        case DM355EVM_MSP_SWITCH2:
+        case DM355EVM_MSP_SDMMC:
+                return 0;
+        default:
+                return -EINVAL;
+        }
+}
+
+static u8 msp_led_cache;
+
+static int msp_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+        int reg, status;
+
+        reg = MSP_GPIO_REG(offset);
+        status = dm355evm_msp_read(reg);
+        if (status < 0)
+                return status;
+        if (reg == DM355EVM_MSP_LED)
+                msp_led_cache = status;
+        return status & MSP_GPIO_MASK(offset);
+}
+
+static int msp_gpio_out(struct gpio_chip *chip, unsigned offset, int value)
+{
+        int mask, bits;
+
+        /* NOTE:  there are some other signals that could be
+         * packaged as output GPIOs, but they aren't as useful
+         * as the LEDs ... so for now we don't.
+         */
+        if (MSP_GPIO_REG(offset) != DM355EVM_MSP_LED)
+                return -EINVAL;
+
+        mask = MSP_GPIO_MASK(offset);
+        bits = msp_led_cache;
+
+        bits &= ~mask;
+        if (value)
+                bits |= mask;
+        msp_led_cache = bits;
+
+        return dm355evm_msp_write(bits, DM355EVM_MSP_LED);
+}
+
+static void msp_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+        msp_gpio_out(chip, offset, value);
+}
+
+static struct gpio_chip dm355evm_msp_gpio = {
+        .label                  = "dm355evm_msp",
+        .owner                  = THIS_MODULE,
+        .direction_input        = msp_gpio_in,
+        .get                    = msp_gpio_get,
+        .direction_output       = msp_gpio_out,
+        .set                    = msp_gpio_set,
+        .base                   = -EINVAL,              /* dynamic assignment */
+        .ngpio                  = ARRAY_SIZE(msp_gpios),
+        .can_sleep              = true,
+};
+
+/*----------------------------------------------------------------------*/
+
+static struct device *add_child(struct i2c_client *client, const char *name,
+                void *pdata, unsigned pdata_len,
+                bool can_wakeup, int irq)
+{
+        struct platform_device  *pdev;
+        int                     status;
+
+        pdev = platform_device_alloc(name, -1);
+        if (!pdev) {
+                dev_dbg(&client->dev, "can't alloc dev\n");
+                status = -ENOMEM;
+                goto err;
+        }
+
+        device_init_wakeup(&pdev->dev, can_wakeup);
+        pdev->dev.parent = &client->dev;
+
+        if (pdata) {
+                status = platform_device_add_data(pdev, pdata, pdata_len);
+                if (status < 0) {
+                        dev_dbg(&pdev->dev, "can't add platform_data\n");
+                        goto err;
+                }
+        }
+
+        if (irq) {
+                struct resource r = {
+                        .start = irq,
+                        .flags = IORESOURCE_IRQ,
+                };
+
+                status = platform_device_add_resources(pdev, &r, 1);
+                if (status < 0) {
+                        dev_dbg(&pdev->dev, "can't add irq\n");
+                        goto err;
+                }
+        }
+
+        status = platform_device_add(pdev);
+
+err:
+        if (status < 0) {
+                platform_device_put(pdev);
+                dev_err(&client->dev, "can't add %s dev\n", name);
+                return ERR_PTR(status);
+        }
+        return &pdev->dev;
+}
+
+static int add_children(struct i2c_client *client)
+{
+        static const struct {
+                int offset;
+                char *label;
+        } config_inputs[] = {
+                /* 8 == right after the LEDs */
+                { 8 + 0, "sw6_1", },
+                { 8 + 1, "sw6_2", },
+                { 8 + 2, "sw6_3", },
+                { 8 + 3, "sw6_4", },
+                { 8 + 4, "NTSC/nPAL", },
+        };
+
+        struct device   *child;
+        int             status;
+        int             i;
+
+        /* GPIO-ish stuff */
+        dm355evm_msp_gpio.dev = &client->dev;
+        status = gpiochip_add(&dm355evm_msp_gpio);
+        if (status < 0)
+                return status;
+
+        /* LED output */
+        if (msp_has_leds()) {
+#define GPIO_LED(l)     .name = l, .active_low = true
+                static struct gpio_led evm_leds[] = {
+                        { GPIO_LED("dm355evm::ds14"),
+                                .default_trigger = "heartbeat", },
+                        { GPIO_LED("dm355evm::ds15"),
+                                .default_trigger = "mmc0", },
+                        { GPIO_LED("dm355evm::ds16"),
+                                /* could also be a CE-ATA drive */
+                                .default_trigger = "mmc1", },
+                        { GPIO_LED("dm355evm::ds17"),
+                                .default_trigger = "nand-disk", },
+                        { GPIO_LED("dm355evm::ds18"), },
+                        { GPIO_LED("dm355evm::ds19"), },
+                        { GPIO_LED("dm355evm::ds20"), },
+                        { GPIO_LED("dm355evm::ds21"), },
+                };
+#undef GPIO_LED
+
+                struct gpio_led_platform_data evm_led_data = {
+                        .num_leds       = ARRAY_SIZE(evm_leds),
+                        .leds           = evm_leds,
+                };
+
+                for (i = 0; i < ARRAY_SIZE(evm_leds); i++)
+                        evm_leds[i].gpio = i + dm355evm_msp_gpio.base;
+
+                /* NOTE:  these are the only fully programmable LEDs
+                 * on the board, since GPIO-61/ds22 (and many signals
+                 * going to DC7) must be used for AEMIF address lines
+                 * unless the top 1 GB of NAND is unused...
+                 */
+                child = add_child(client, "leds-gpio",
+                                &evm_led_data, sizeof(evm_led_data),
+                                false, 0);
+                if (IS_ERR(child))
+                        return PTR_ERR(child);
+        }
+
+        /* configuration inputs */
+        for (i = 0; i < ARRAY_SIZE(config_inputs); i++) {
+                int gpio = dm355evm_msp_gpio.base + config_inputs[i].offset;
+
+                gpio_request(gpio, config_inputs[i].label);
+                gpio_direction_input(gpio);
+
+                /* make it easy for userspace to see these */
+                gpio_export(gpio, false);
+        }
+
+        /* RTC is a 32 bit counter, no alarm */
+        if (msp_has_rtc()) {
+                child = add_child(client, "rtc-dm355evm",
+                                NULL, 0, false, 0);
+                if (IS_ERR(child))
+                        return PTR_ERR(child);
+        }
+
+        /* input from buttons and IR remote (uses the IRQ) */
+        if (msp_has_keyboard()) {
+                child = add_child(client, "dm355evm_keys",
+                                NULL, 0, true, client->irq);
+                if (IS_ERR(child))
+                        return PTR_ERR(child);
+        }
+
+        return 0;
+}
+
+/*----------------------------------------------------------------------*/
+
+static void dm355evm_command(unsigned command)
+{
+        int status;
+
+        status = dm355evm_msp_write(command, DM355EVM_MSP_COMMAND);
+        if (status < 0)
+                dev_err(&msp430->dev, "command %d failure %d\n",
+                                command, status);
+}
+
+static void dm355evm_power_off(void)
+{
+        dm355evm_command(MSP_COMMAND_POWEROFF);
+}
+
+static int dm355evm_msp_remove(struct i2c_client *client)
+{
+        pm_power_off = NULL;
+        msp430 = NULL;
+        return 0;
+}
+
+static int
+dm355evm_msp_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+        int             status;
+        const char      *video = msp_has_tvp() ? "TVP5146" : "imager";
+
+        if (msp430)
+                return -EBUSY;
+        msp430 = client;
+
+        /* display revision status; doubles as sanity check */
+        status = dm355evm_msp_read(DM355EVM_MSP_FIRMREV);
+        if (status < 0)
+                goto fail;
+        dev_info(&client->dev, "firmware v.%02X, %s as video-in\n",
+                        status, video);
+
+        /* mux video input:  either tvp5146 or some external imager */
+        status = dm355evm_msp_write(msp_has_tvp() ? 0 : MSP_VIDEO_IMAGER,
+                        DM355EVM_MSP_VIDEO_IN);
+        if (status < 0)
+                dev_warn(&client->dev, "error %d muxing %s as video-in\n",
+                        status, video);
+
+        /* init LED cache, and turn off the LEDs */
+        msp_led_cache = 0xff;
+        dm355evm_msp_write(msp_led_cache, DM355EVM_MSP_LED);
+
+        /* export capabilities we support */
+        status = add_children(client);
+        if (status < 0)
+                goto fail;
+
+        /* PM hookup */
+        pm_power_off = dm355evm_power_off;
+
+        return 0;
+
+fail:
+        /* FIXME remove children ... */
+        dm355evm_msp_remove(client);
+        return status;
+}
+
+static const struct i2c_device_id dm355evm_msp_ids[] = {
+        { "dm355evm_msp", 0 },
+        { /* end of list */ },
+};
+MODULE_DEVICE_TABLE(i2c, dm355evm_msp_ids);
+
+static struct i2c_driver dm355evm_msp_driver = {
+        .driver.name    = "dm355evm_msp",
+        .id_table       = dm355evm_msp_ids,
+        .probe          = dm355evm_msp_probe,
+        .remove         = dm355evm_msp_remove,
+};
+
+static int __init dm355evm_msp_init(void)
+{
+        return i2c_add_driver(&dm355evm_msp_driver);
+}
+subsys_initcall(dm355evm_msp_init);
+
+static void __exit dm355evm_msp_exit(void)
+{
+        i2c_del_driver(&dm355evm_msp_driver);
+}
+module_exit(dm355evm_msp_exit);
+
+MODULE_DESCRIPTION("Interface to MSP430 firmware on DM355EVM");
+MODULE_LICENSE("GPL");