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author | Ahmad Fatoum <a.fatoum@pengutronix.de> | 2019-10-11 18:27:50 +0200 |
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committer | Sascha Hauer <s.hauer@pengutronix.de> | 2019-10-14 15:18:16 +0200 |
commit | efd517c35f122bb08ebc1fc29e741a5211553acc (patch) | |
tree | c74ed2f4b48b7397b65d6a3edafc87449da5a3b2 /drivers/mfd/superio.c | |
parent | 6fa1b91f6e7596472c5197f6960e3e14b9c30795 (diff) | |
download | barebox-efd517c35f122bb08ebc1fc29e741a5211553acc.tar.gz barebox-efd517c35f122bb08ebc1fc29e741a5211553acc.tar.xz |
mfd: add basic Super I/O chip helpers
Super I/O chips are ICs common to x86 that are used for interfacing
to low-bandwidth peripherals. They often contain serial ports, watchdog
timers and hardware monitoring units.
They are usually addressable via one of two I/O port pairs, either
0x2e-0x2f or 0x4e-0x4f, but they don't typically respond to reads from
their range unless a device-specific 'password' has been poked in.
After this is done, they are read and written in the same manner however.
On Linux, these devices aren't subject to any device/driver model.
Each driver for some function (e.g. watchdog or GPIO) duplicates the
device probe in the module_init and board-specific configuration
is handled via module parameters.
Lets do it a bit fancier in barebox and add a helper to register chips
and a regmap for the control and configuration registers as well as a
helper to register child devices for each function contained within the
Super I/O chip.
Board-specific configuration, e.g. which pin to use as a watchdog reset,
can then be realized using barebox device-specific parameters.
The regmap will be more of a debugging aid, however.
For ease of porting from Linux, it's expected that access to the
I/O ports won't happen via the regmap. For this reason, the new
<superio.h> header offers functions to read/write these chips' registers
as well.
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'drivers/mfd/superio.c')
-rw-r--r-- | drivers/mfd/superio.c | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/drivers/mfd/superio.c b/drivers/mfd/superio.c new file mode 100644 index 0000000000..0f08d56cb3 --- /dev/null +++ b/drivers/mfd/superio.c @@ -0,0 +1,98 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 Ahmad Fatoum, Pengutronix + */ + +#define pr_fmt(fmt) "superio: " fmt + +#include <common.h> +#include <superio.h> +#include <regmap.h> + +struct device_d *superio_func_add(struct superio_chip *siochip, const char *name) +{ + struct device_d *dev; + int ret; + + dev = device_alloc(name, DEVICE_ID_DYNAMIC); + dev->parent = siochip->dev; + + + ret = platform_device_register(dev); + if (ret) + return NULL; + + return dev; +} +EXPORT_SYMBOL(superio_func_add) + +static int superio_reg_read(void *ctx, unsigned int reg, unsigned int *val) +{ + struct superio_chip *siochip = ctx; + + siochip->enter(siochip->sioaddr); + + *val = superio_inb(siochip->sioaddr, reg); + + siochip->exit(siochip->sioaddr); + + return 0; +} + +static int superio_reg_write(void *ctx, unsigned int reg, unsigned int val) +{ + struct superio_chip *siochip = ctx; + + siochip->enter(siochip->sioaddr); + + superio_outb(siochip->sioaddr, reg, val); + + siochip->exit(siochip->sioaddr); + + return 0; +} + +static struct regmap_bus superio_regmap_bus = { + .reg_write = superio_reg_write, + .reg_read = superio_reg_read, +}; + +static struct regmap_config superio_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .reg_stride = 1, + .max_register = 0xff, +}; + +void superio_chip_add(struct superio_chip *siochip) +{ + struct regmap *regmap; + char *chipname; + char str[5]; + int ret; + + chipname = xasprintf("superio-%04x:%04x@%02x", + siochip->vid, siochip->devid, siochip->sioaddr); + siochip->dev = add_generic_device(chipname, DEVICE_ID_SINGLE, NULL, + siochip->sioaddr, 2, IORESOURCE_IO, + NULL); + + siochip->dev->priv = siochip; + + sprintf(str, "%04x", siochip->vid); + dev_add_param_fixed(siochip->dev, "vendor", str); + sprintf(str, "%04x", siochip->devid); + dev_add_param_fixed(siochip->dev, "device", str); + + regmap = regmap_init(siochip->dev, &superio_regmap_bus, siochip, + &superio_regmap_config); + if (IS_ERR(regmap)) + pr_warn("creating %s regmap failed: %s\n", + chipname, strerror(-PTR_ERR(regmap))); + + ret = regmap_register_cdev(regmap, chipname); + if (ret) + pr_warn("registering %s regmap cdev failed: %s\n", + chipname, strerror(-ret)); +} +EXPORT_SYMBOL(superio_chip_add) |