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 <[e-mail]>
Signed-off-by: Samuel Ortiz <[e-mail]>

drivers/mfd/Kconfig

···
 	  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

drivers/mfd/Makefile

···
 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

drivers/mfd/dm355evm_msp.c

···
+/*
+ * 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");

include/linux/i2c/dm355evm_msp.h

···
+/*
+ * dm355evm_msp.h - support MSP430 microcontroller on DM355EVM board
+ */
+#ifndef __LINUX_I2C_DM355EVM_MSP
+#define __LINUX_I2C_DM355EVM_MSP
+
+/*
+ * Written against Spectrum's writeup for the A4 firmware revision,
+ * and tweaked to match source and rev D2 schematics by removing CPLD
+ * and NOR flash hooks (which were last appropriate in rev B boards).
+ *
+ * Note that the firmware supports a flavor of write posting ... to be
+ * sure a write completes, issue another read or write.
+ */
+
+/* utilities to access "registers" emulated by msp430 firmware */
+extern int dm355evm_msp_write(u8 value, u8 reg);
+extern int dm355evm_msp_read(u8 reg);
+
+
+/* command/control registers */
+#define DM355EVM_MSP_COMMAND		0x00
+#	define MSP_COMMAND_NULL		0
+#	define MSP_COMMAND_RESET_COLD	1
+#	define MSP_COMMAND_RESET_WARM	2
+#	define MSP_COMMAND_RESET_WARM_I	3
+#	define MSP_COMMAND_POWEROFF	4
+#	define MSP_COMMAND_IR_REINIT	5
+#define DM355EVM_MSP_STATUS		0x01
+#	define MSP_STATUS_BAD_OFFSET	BIT(0)
+#	define MSP_STATUS_BAD_COMMAND	BIT(1)
+#	define MSP_STATUS_POWER_ERROR	BIT(2)
+#	define MSP_STATUS_RXBUF_OVERRUN	BIT(3)
+#define DM355EVM_MSP_RESET		0x02	/* 0 bits == in reset */
+#	define MSP_RESET_DC5		BIT(0)
+#	define MSP_RESET_TVP5154	BIT(2)
+#	define MSP_RESET_IMAGER		BIT(3)
+#	define MSP_RESET_ETHERNET	BIT(4)
+#	define MSP_RESET_SYS		BIT(5)
+#	define MSP_RESET_AIC33		BIT(7)
+
+/* GPIO registers ... bit patterns mostly match the source MSP ports */
+#define DM355EVM_MSP_LED		0x03	/* active low (MSP P4) */
+#define DM355EVM_MSP_SWITCH1		0x04	/* (MSP P5, masked) */
+#	define MSP_SWITCH1_SW6_1	BIT(0)
+#	define MSP_SWITCH1_SW6_2	BIT(1)
+#	define MSP_SWITCH1_SW6_3	BIT(2)
+#	define MSP_SWITCH1_SW6_4	BIT(3)
+#	define MSP_SWITCH1_J1		BIT(4)	/* NTSC/PAL */
+#	define MSP_SWITCH1_MSP_INT	BIT(5)	/* active low */
+#define DM355EVM_MSP_SWITCH2		0x05	/* (MSP P6, masked) */
+#	define MSP_SWITCH2_SW10		BIT(3)
+#	define MSP_SWITCH2_SW11		BIT(4)
+#	define MSP_SWITCH2_SW12		BIT(5)
+#	define MSP_SWITCH2_SW13		BIT(6)
+#	define MSP_SWITCH2_SW14		BIT(7)
+#define DM355EVM_MSP_SDMMC		0x06	/* (MSP P2, masked) */
+#	define MSP_SDMMC_0_WP		BIT(1)
+#	define MSP_SDMMC_0_CD		BIT(2)	/* active low */
+#	define MSP_SDMMC_1_WP		BIT(3)
+#	define MSP_SDMMC_1_CD		BIT(4)	/* active low */
+#define DM355EVM_MSP_FIRMREV		0x07	/* not a GPIO (out of order) */
+#define DM355EVM_MSP_VIDEO_IN		0x08	/* (MSP P3, masked) */
+#	define MSP_VIDEO_IMAGER		BIT(7)	/* low == tvp5146 */
+
+/* power supply registers are currently omitted */
+
+/* RTC registers */
+#define DM355EVM_MSP_RTC_0		0x12	/* LSB */
+#define DM355EVM_MSP_RTC_1		0x13
+#define DM355EVM_MSP_RTC_2		0x14
+#define DM355EVM_MSP_RTC_3		0x15	/* MSB */
+
+/* input event queue registers; code == ((HIGH << 8) | LOW) */
+#define DM355EVM_MSP_INPUT_COUNT	0x16	/* decrement by reading LOW */
+#define DM355EVM_MSP_INPUT_HIGH		0x17
+#define DM355EVM_MSP_INPUT_LOW		0x18
+
+#endif /* __LINUX_I2C_DM355EVM_MSP */