ARM: AT91: Add platform data for the AT91 ADCs

The AT91 SoCs often embeds an ADC. This patch adds the needed
platform data to specify the informations required by the driver
to work properly.

For now, we only need the reference voltage and which channels
are available on the board.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/platform_data/at91_adc.h

+/*
+ * Copyright (C) 2011 Free Electrons
+ *
+ * Licensed under the GPLv2 or later.
+ */
+
+#ifndef _AT91_ADC_H_
+#define _AT91_ADC_H_
+
+/**
+ * struct at91_adc_reg_desc - Various informations relative to registers
+ * @channel_base:	Base offset for the channel data registers
+ * @drdy_mask:		Mask of the DRDY field in the relevant registers
+			(Interruptions registers mostly)
+ * @status_register:	Offset of the Interrupt Status Register
+ * @trigger_register:	Offset of the Trigger setup register
+ */
+struct at91_adc_reg_desc {
+	u8	channel_base;
+	u32	drdy_mask;
+	u8	status_register;
+	u8	trigger_register;
+};
+
+/**
+ * struct at91_adc_trigger - description of triggers
+ * @name:		name of the trigger advertised to the user
+ * @value:		value to set in the ADC's trigger setup register
+			to enable the trigger
+ * @is_external:	Does the trigger rely on an external pin?
+ */
+struct at91_adc_trigger {
+	const char	*name;
+	u8		value;
+	bool		is_external;
+};
+
+/**
+ * struct at91_adc_data - platform data for ADC driver
+ * @channels_used:		channels in use on the board as a bitmask
+ * @num_channels:		global number of channels available on the board
+ * @registers:			Registers definition on the board
+ * @startup_time:		startup time of the ADC in microseconds
+ * @trigger_list:		Triggers available in the ADC
+ * @trigger_number:		Number of triggers available in the ADC
+ * @use_external_triggers:	does the board has external triggers availables
+ * @vref:			Reference voltage for the ADC in millivolts
+ */
+struct at91_adc_data {
+	unsigned long			channels_used;
+	u8				num_channels;
+	struct at91_adc_reg_desc	*registers;
+	u8				startup_time;
+	struct at91_adc_trigger		*trigger_list;
+	u8				trigger_number;
+	bool				use_external_triggers;
+	u16				vref;
+};
+
+extern void __init at91_add_device_adc(struct at91_adc_data *data);
+#endif