Staging: IIO: max1363 ADC driver

Core support for MAX1361, MAX1362, MAX1363, MAX1364,
MAX1136, MAX1137, MAX1138, MAX1139, MAX1236, MAX1237,
MAX1238, MAX1239.

Ring buffer support later in series.
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/Kconfig

@@ -9,3 +9,8 @@ menuconfig IIO
 	  drivers for many different types of embedded sensors using a
 	  number of different physical interfaces (i2c, spi etc). See
 	  Documentation/industrialio for more information.
+if IIO
+
+source "drivers/staging/iio/adc/Kconfig"
+
+endif # IIO

drivers/staging/iio/Makefile

@@ -4,3 +4,5 @@
 
 obj-$(CONFIG_IIO) += industrialio.o
 industrialio-y := industrialio-core.o
+
+obj-y += adc/
\ No newline at end of file

drivers/staging/iio/adc/Kconfig

+#
+# ADC drivers
+#
+comment "Analog to digital convertors"
+
+config MAX1363
+	tristate "MAXIM max1363 ADC driver"
+	depends on I2C
+	help
+	  Say yes here to build support for many MAXIM i2c analog to digital
+	  convertors (ADC). (max1361, max1362, max1363, max1364, max1136,
+	  max1136, max1137, max1138, max1139, max1236, max1237, max11238,
+	  max1239) Provides direct access via sysfs.

drivers/staging/iio/adc/Makefile

+
+# Makefile for industrial I/O ADC drivers
+#
+
+max1363-y := max1363_core.o
+
+obj-$(CONFIG_MAX1363) += max1363.o

drivers/staging/iio/adc/max1363.h

+#ifndef _MAX1363_H_
+#define  _MAX1363_H_
+
+#define MAX1363_SETUP_BYTE(a) ((a) | 0x80)
+
+/* There is a fair bit more defined here than currently
+ * used, but the intention is to support everything these
+ * chips do in the long run */
+
+/* see data sheets */
+/* max1363 and max1236, max1237, max1238, max1239 */
+#define MAX1363_SETUP_AIN3_IS_AIN3_REF_IS_VDD	0x00
+#define MAX1363_SETUP_AIN3_IS_REF_EXT_TO_REF	0x20
+#define MAX1363_SETUP_AIN3_IS_AIN3_REF_IS_INT	0x40
+#define MAX1363_SETUP_AIN3_IS_REF_REF_IS_INT	0x60
+#define MAX1363_SETUP_POWER_UP_INT_REF		0x10
+#define MAX1363_SETUP_POWER_DOWN_INT_REF	0x00
+
+/* think about includeing max11600 etc - more settings */
+#define MAX1363_SETUP_EXT_CLOCK			0x08
+#define MAX1363_SETUP_INT_CLOCK			0x00
+#define MAX1363_SETUP_UNIPOLAR			0x00
+#define MAX1363_SETUP_BIPOLAR			0x04
+#define MAX1363_SETUP_RESET			0x00
+#define MAX1363_SETUP_NORESET			0x02
+/* max1363 only - though don't care on others.
+ * For now monitor modes are not implemented as the relevant
+ * line is not connected on my test board.
+ * The definitions are here as I intend to add this soon.
+ */
+#define MAX1363_SETUP_MONITOR_SETUP		0x01
+
+/* Specific to the max1363 */
+#define MAX1363_MON_RESET_CHAN(a) (1 << ((a) + 4))
+#define MAX1363_MON_CONV_RATE_133ksps		0
+#define MAX1363_MON_CONV_RATE_66_5ksps		0x02
+#define MAX1363_MON_CONV_RATE_33_3ksps		0x04
+#define MAX1363_MON_CONV_RATE_16_6ksps		0x06
+#define MAX1363_MON_CONV_RATE_8_3ksps		0x08
+#define MAX1363_MON_CONV_RATE_4_2ksps		0x0A
+#define MAX1363_MON_CONV_RATE_2_0ksps		0x0C
+#define MAX1363_MON_CONV_RATE_1_0ksps		0x0E
+#define MAX1363_MON_INT_ENABLE			0x01
+
+/* defined for readability reasons */
+/* All chips */
+#define MAX1363_CONFIG_BYTE(a) ((a))
+
+#define MAX1363_CONFIG_SE			0x01
+#define MAX1363_CONFIG_DE			0x00
+#define MAX1363_CONFIG_SCAN_TO_CS		0x00
+#define MAX1363_CONFIG_SCAN_SINGLE_8		0x20
+#define MAX1363_CONFIG_SCAN_MONITOR_MODE	0x40
+#define MAX1363_CONFIG_SCAN_SINGLE_1		0x60
+/* max123{6-9} only */
+#define MAX1236_SCAN_MID_TO_CHANNEL		0x40
+
+/* max1363 only - merely part of channel selects or don't care for others*/
+#define MAX1363_CONFIG_EN_MON_MODE_READ 0x18
+
+#define MAX1363_CHANNEL_SEL(a) ((a) << 1)
+
+/* max1363 strictly 0x06 - but doesn't matter */
+#define MAX1363_CHANNEL_SEL_MASK		0x1E
+#define MAX1363_SCAN_MASK			0x60
+#define MAX1363_SE_DE_MASK			0x01
+
+/**
+ * struct max1363_mode - scan mode information
+ * @name:	Name used to identify the scan mode.
+ * @conf:	The corresponding value of the configuration register
+ * @numvals:	The number of values returned by a single scan
+ */
+struct max1363_mode {
+	const char	*name;
+	int8_t		conf;
+	int		numvals;
+};
+
+#define MAX1363_MODE_SINGLE(_num) {					\
+		.name = #_num,						\
+			.conf = MAX1363_CHANNEL_SEL(_num)		\
+			| MAX1363_CONFIG_SCAN_SINGLE_1			\
+			| MAX1363_CONFIG_SE,				\
+			.numvals = 1,					\
+			}
+
+#define MAX1363_MODE_SINGLE_TIMES_8(_num) {				\
+		.name = #_num"x8",					\
+			.conf = MAX1363_CHANNEL_SEL(_num)		\
+			| MAX1363_CONFIG_SCAN_SINGLE_8			\
+			| MAX1363_CONFIG_SE,				\
+			.numvals = 8,					\
+			}
+
+#define MAX1363_MODE_SCAN_TO_CHANNEL(_num) {				\
+		.name = "0..."#_num,					\
+			.conf = MAX1363_CHANNEL_SEL(_num)		\
+			| MAX1363_CONFIG_SCAN_TO_CS			\
+			| MAX1363_CONFIG_SE,				\
+			.numvals = _num + 1,				\
+			}
+
+
+/* note not available for max1363 hence naming */
+#define MAX1236_MODE_SCAN_MID_TO_CHANNEL(_mid, _num) {			\
+		.name = #_mid"..."#_num,				\
+			.conf = MAX1363_CHANNEL_SEL(_num)		\
+			| MAX1236_SCAN_MID_TO_CHANNEL			\
+			| MAX1363_CONFIG_SE,				\
+			.numvals = _num - _mid + 1			\
+}
+
+#define MAX1363_MODE_DIFF_SINGLE(_nump, _numm) {			\
+		.name = #_nump"-"#_numm,				\
+			.conf = MAX1363_CHANNEL_SEL(_nump)		\
+			| MAX1363_CONFIG_SCAN_SINGLE_1			\
+			| MAX1363_CONFIG_DE,				\
+			.numvals = 1,					\
+			}
+
+#define MAX1363_MODE_DIFF_SINGLE_TIMES_8(_nump, _numm) {		\
+		.name = #_nump"-"#_numm,				\
+			.conf = MAX1363_CHANNEL_SEL(_nump)		\
+			| MAX1363_CONFIG_SCAN_SINGLE_8			\
+			| MAX1363_CONFIG_DE,				\
+			.numvals = 1,					\
+			}
+
+/* Can't think how to automate naming so specify for now */
+#define MAX1363_MODE_DIFF_SCAN_TO_CHANNEL_NAMED(_name, _num, _numvals) { \
+		.name = #_name,						\
+			.conf = MAX1363_CHANNEL_SEL(_num)		\
+			| MAX1363_CONFIG_SCAN_TO_CS			\
+			| MAX1363_CONFIG_DE,				\
+			.numvals = _numvals,				\
+			}
+
+/* note only available for max1363 hence naming */
+#define MAX1236_MODE_DIFF_SCAN_MID_TO_CHANNEL_NAMED(_name, _num, _numvals) { \
+    .name = #_name,							\
+			.conf = MAX1363_CHANNEL_SEL(_num)		\
+			| MAX1236_SCAN_MID_TO_CHANNEL			\
+			| MAX1363_CONFIG_SE,				\
+			.numvals = _numvals,				\
+}
+
+/* Not currently handled */
+#define MAX1363_MODE_MONITOR {					\
+		.name = "monitor",				\
+			.conf = MAX1363_CHANNEL_SEL(3)		\
+			| MAX1363_CONFIG_SCAN_MONITOR_MODE	\
+			| MAX1363_CONFIG_SE,			\
+			.numvals = 10,				\
+		}
+
+/* This may seem an overly long winded way to do this, but at least it makes
+ * clear what all the various options actually do. Alternative suggestions
+ * that don't require user to have intimate knowledge of the chip welcomed.
+ */
+
+/* This must be maintained along side the max1363_mode_table in max1363_core */
+enum max1363_modes {
+	/* Single read of a single channel */
+	_s0, _s1, _s2, _s3, _s4, _s5, _s6, _s7, _s8, _s9, _s10, _s11,
+	/* Eight reads of a single channel */
+	se0, se1, se2, se3, se4, se5, se6, se7, se8, se9, se10, se11,
+	/* Scan to channel */
+	s0to1, s0to2, s0to3, s0to4, s0to5, s0to6,
+	s0to7, s0to8, s0to9, s0to10, s0to11,
+	/* Differential single read */
+	d0m1, d2m3, d4m5, d6m7, d8m9, d10m11,
+	d1m0, d3m2, d5m4, d7m6, d9m8, d11m10,
+	/* Differential single read 8 times */
+	de0m1, de2m3, de4m5, de6m7, de8m9, de10m11,
+	de1m0, de3m2, de5m4, de7m6, de9m8, de11m10,
+	/* Differential scan to channel */
+	d0m1to2m3, d0m1to4m5, d0m1to6m7, d0m1to8m9, d0m1to10m11,
+	d1m0to3m2, d1m0to5m4, d1m0to7m6, d1m0to9m8, d1m0to11m10,
+	/* Scan mid to channel max123{6-9} only */
+	s2to3, s6to7, s6to8, s6to9, s6to10, s6to11,
+	/* Differential scan mid to channel */
+	s6m7to8m9, s6m7to10m11, s7m6to9m8, s7m6to11m10,
+};
+
+/**
+ * struct max1363_chip_info - chip specifc information
+ * @name:		indentification string for chip
+ * @num_inputs:		number of physical inputs on chip
+ * @int_vref_mv:	the internal reference voltage
+ * @monitor_mode:	whether the chip supports monitor interrupts
+ * @mode_list:		array of available scan modes
+ * @num_modes:		the number of scan modes available
+ * @default_mode:	the scan mode in which the chip starts up
+ */
+struct max1363_chip_info {
+	const char			*name;
+	u8				num_inputs;
+	u16				int_vref_mv;
+	bool				monitor_mode;
+	const enum max1363_modes	*mode_list;
+	int				num_modes;
+	enum max1363_modes		default_mode;
+};
+
+
+/**
+ * struct max1363_state - driver instance specific data
+ * @indio_dev:		the industrial I/O device
+ * @client:		i2c_client
+ * @setupbyte:		cache of current device setup byte
+ * @configbyte:		cache of current device config byte
+ * @chip_info:		chip model specific constants, available modes etc
+ * @current_mode:	the scan mode of this chip
+ * @poll_work:		bottom half of polling interrupt handler
+ * @protect_ring:	used to ensure only one polling bh running at a time
+ * @reg:		supply regulator
+ */
+struct max1363_state {
+	struct iio_dev			*indio_dev;
+	struct i2c_client		*client;
+	char				setupbyte;
+	char				configbyte;
+	const struct max1363_chip_info	*chip_info;
+	const struct max1363_mode	*current_mode;
+	struct work_struct		poll_work;
+	atomic_t			protect_ring;
+	struct iio_trigger		*trig;
+	struct regulator		*reg;
+};
+
+static inline void max1363_uninitialize_ring(struct iio_ring_buffer *ring)
+{
+};
+
+static inline int max1363_initialize_ring(struct iio_ring_buffer *ring)
+{
+	return 0;
+};
+
+
+static inline ssize_t max1363_scan_from_ring(struct device *dev,
+					     struct device_attribute *attr,
+					     char *buf)
+{
+	return 0;
+};
+
+static inline int
+max1363_register_ring_funcs_and_init(struct iio_dev *indio_dev)
+{
+	return 0;
+};
+
+static inline void max1363_ring_cleanup(struct iio_dev *indio_dev) {};
+
+#endif /* _MAX1363_H_ */