From 102eb97564c73ea73645b38599c5cbe6f54b030c Mon Sep 17 00:00:00 2001 From: Grant Likely Date: Wed, 23 Jul 2008 21:29:55 -0700 Subject: spi: make spi_board_info.modalias a char array Currently, 'modalias' in the spi_device structure is a 'const char *'. The spi_new_device() function fills in the modalias value from a passed in spi_board_info data block. Since it is a pointer copy, the new spi_device remains dependent on the spi_board_info structure after the new spi_device is registered (no other fields in spi_device directly depend on the spi_board_info structure; all of the other data is copied). This causes a problem when dynamically propulating the list of attached SPI devices. For example, in arch/powerpc, the list of SPI devices can be populated from data in the device tree. With the current code, the device tree adapter must kmalloc() a new spi_board_info structure for each new SPI device it finds in the device tree, and there is no simple mechanism in place for keeping track of these allocations. This patch changes modalias from a 'const char *' to a fixed char array. By copying the modalias string instead of referencing it, the dependency on the spi_board_info structure is eliminated and an outside caller does not need to maintain a separate spi_board_info allocation for each device. If searched through the code to the best of my ability for any references to modalias which may be affected by this change and haven't found anything. It has been tested with the lite5200b platform in arch/powerpc. [dbrownell@users.sourceforge.net: cope with linux-next changes: KOBJ_NAME_LEN obliterated, etc] Signed-off-by: Grant Likely Signed-off-by: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/spi/spi.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/spi') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index b9a76c97208..a9cc29d4665 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -82,7 +82,7 @@ struct spi_device { int irq; void *controller_state; void *controller_data; - const char *modalias; + char modalias[32]; /* * likely need more hooks for more protocol options affecting how -- cgit v1.2.3 From 53e84b672c1a8190af2b376c35c7a39cf1214f59 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Wed, 23 Jul 2008 21:30:36 -0700 Subject: rtc: ds1305/ds1306 driver Support the Dallas/Maxim DS1305 and DS1306 RTC chips. These use SPI, and support alarms, NVRAM, and a trickle charger for use when their backup power supply is a supercap or rechargeable cell. This basic driver doesn't yet support suspend/resume or wakealarms. Signed-off-by: David Brownell Cc: Alessandro Zummo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/spi/ds1305.h | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 include/linux/spi/ds1305.h (limited to 'include/linux/spi') diff --git a/include/linux/spi/ds1305.h b/include/linux/spi/ds1305.h new file mode 100644 index 00000000000..287ec830eab --- /dev/null +++ b/include/linux/spi/ds1305.h @@ -0,0 +1,35 @@ +#ifndef __LINUX_SPI_DS1305_H +#define __LINUX_SPI_DS1305_H + +/* + * One-time configuration for ds1305 and ds1306 RTC chips. + * + * Put a pointer to this in spi_board_info.platform_data if you want to + * be sure that Linux (re)initializes this as needed ... after losing + * backup power, and potentially on the first boot. + */ +struct ds1305_platform_data { + + /* Trickle charge configuration: it's OK to leave out the MAGIC + * bitmask; mask in either DS1 or DS2, and then one of 2K/4k/8K. + */ +#define DS1305_TRICKLE_MAGIC 0xa0 +#define DS1305_TRICKLE_DS2 0x08 /* two diodes */ +#define DS1305_TRICKLE_DS1 0x04 /* one diode */ +#define DS1305_TRICKLE_2K 0x01 /* 2 KOhm resistance */ +#define DS1305_TRICKLE_4K 0x02 /* 4 KOhm resistance */ +#define DS1305_TRICKLE_8K 0x03 /* 8 KOhm resistance */ + u8 trickle; + + /* set only on ds1306 parts */ + bool is_ds1306; + + /* ds1306 only: enable 1 Hz output */ + bool en_1hz; + + /* REVISIT: the driver currently expects nINT0 to be wired + * as the alarm IRQ. ALM1 may also need to be set up ... + */ +}; + +#endif /* __LINUX_SPI_DS1305_H */ -- cgit v1.2.3 From 8f1cc3b10e6ee0c5c7c8ed27f8771c4f252b4862 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Fri, 25 Jul 2008 01:46:09 -0700 Subject: gpio: mcp23s08 handles multiple chips per chipselect Teach the mcp23s08 driver about a curious feature of these chips: up to four of them can share the same chipselect, with the SPI signals wired in parallel, by matching two bits in the first protocol byte against two address lines on the chip. This is handled by three software changes: * Platform data now holds an array of per-chip structs, not just one chip's address and pullup configuration. * Probe() and remove() now use another level of structure, wrapping an instance of the original structure for each mcp23s08 chip sharing that chipselect. * The HAEN bit is set, so that the hardware address bits can no longer be ignored (boot firmware may not have enabled them). The "one struct per chip" preserves the guts of the current code, but platform_data will need minor changes. OLD: /* incorrect "slave" ID may not have mattered */ .slave = 3, .pullups = BIT(3) | BIT(1) | BIT(0), NEW: /* slave address _must_ match chip's wiring */ .chip[3] = { .is_present = true, .pullups = BIT(3) | BIT(1) | BIT(0), }, There's no change in how things _behave_ for spi_device nodes with a single mcp23s08 chip. New multi-chip configurations assign GPIOs in sequence, without holes. The spi_device just resembles a bigger controller, but internally it has multiple gpio_chip instances. Signed-off-by: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/spi/mcp23s08.h | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) (limited to 'include/linux/spi') diff --git a/include/linux/spi/mcp23s08.h b/include/linux/spi/mcp23s08.h index 835ddf47d45..22ef107d770 100644 --- a/include/linux/spi/mcp23s08.h +++ b/include/linux/spi/mcp23s08.h @@ -1,18 +1,25 @@ -/* FIXME driver should be able to handle all four slaves that - * can be hooked up to each chipselect, as well as IRQs... - */ +/* FIXME driver should be able to handle IRQs... */ + +struct mcp23s08_chip_info { + bool is_present; /* true iff populated */ + u8 pullups; /* BIT(x) means enable pullup x */ +}; struct mcp23s08_platform_data { - /* four slaves can share one SPI chipselect */ - u8 slave; + /* Four slaves (numbered 0..3) can share one SPI chipselect, and + * will provide 8..32 GPIOs using 1..4 gpio_chip instances. + */ + struct mcp23s08_chip_info chip[4]; - /* number assigned to the first GPIO */ + /* "base" is the number of the first GPIO. Dynamic assignment is + * not currently supported, and even if there are gaps in chip + * addressing the GPIO numbers are sequential .. so for example + * if only slaves 0 and 3 are present, their GPIOs range from + * base to base+15. + */ unsigned base; - /* pins with pullups */ - u8 pullups; - void *context; /* param to setup/teardown */ int (*setup)(struct spi_device *spi, -- cgit v1.2.3