From: Maxime Ripard maxime.ripard@free-electrons.com
We might want to use 1-Wire devices connected on boards such as EEPROMs in U-Boot.
Provide a framework to be able to do that.
Signed-off-by: Maxime Ripard maxime.ripard@bootlin.com [eugen.hristev@microchip.com: reworked] Signed-off-by: Eugen Hristev eugen.hristev@microchip.com --- drivers/Kconfig | 2 + drivers/Makefile | 1 + drivers/w1/Kconfig | 18 ++++ drivers/w1/Makefile | 1 + drivers/w1/w1-uclass.c | 236 +++++++++++++++++++++++++++++++++++++++++++++++++ include/dm/uclass-id.h | 1 + include/w1.h | 36 ++++++++ 7 files changed, 295 insertions(+) create mode 100644 drivers/w1/Kconfig create mode 100644 drivers/w1/Makefile create mode 100644 drivers/w1/w1-uclass.c create mode 100644 include/w1.h
diff --git a/drivers/Kconfig b/drivers/Kconfig index 56536c4..6f91eac 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -106,6 +106,8 @@ source "drivers/usb/Kconfig"
source "drivers/video/Kconfig"
+source "drivers/w1/Kconfig" + source "drivers/watchdog/Kconfig"
config PHYS_TO_BUS diff --git a/drivers/Makefile b/drivers/Makefile index 23ea609..4ca07c3 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -105,6 +105,7 @@ obj-y += smem/ obj-y += soc/ obj-y += thermal/ obj-y += axi/ +obj-$(CONFIG_W1) += w1/
obj-$(CONFIG_MACH_PIC32) += ddr/microchip/ endif diff --git a/drivers/w1/Kconfig b/drivers/w1/Kconfig new file mode 100644 index 0000000..64b27c6 --- /dev/null +++ b/drivers/w1/Kconfig @@ -0,0 +1,18 @@ +# +# W1 subsystem configuration +# + +menu "1-Wire support" + +config W1 + bool "Enable 1-wire controllers support" + default no + depends on DM + help + Support for the Dallas 1-Wire bus. + +if W1 + +endif + +endmenu diff --git a/drivers/w1/Makefile b/drivers/w1/Makefile new file mode 100644 index 0000000..f81693b --- /dev/null +++ b/drivers/w1/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_W1) += w1-uclass.o diff --git a/drivers/w1/w1-uclass.c b/drivers/w1/w1-uclass.c new file mode 100644 index 0000000..44759fe --- /dev/null +++ b/drivers/w1/w1-uclass.c @@ -0,0 +1,236 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * + * Copyright (c) 2015 Free Electrons + * Copyright (c) 2015 NextThing Co. + * Copyright (c) 2018 Microchip Technology, Inc. + * + * Maxime Ripard maxime.ripard@free-electrons.com + * Eugen Hristev eugen.hristev@microchip.com + * + */ + +#include <common.h> +#include <dm.h> +#include <w1.h> + +#include <dm/device-internal.h> + +#define W1_MATCH_ROM 0x55 +#define W1_SKIP_ROM 0xcc +#define W1_SEARCH 0xf0 + +struct w1_bus { + u64 search_id; +}; + +static int w1_enumerate(struct udevice *bus) +{ + const struct w1_ops *ops = device_get_ops(bus); + struct w1_bus *w1 = dev_get_uclass_priv(bus); + u64 last_rn, rn = w1->search_id, tmp64; + bool last_device = false; + int search_bit, desc_bit = 64; + int last_zero = -1; + u8 triplet_ret = 0; + int i; + + if (!ops->reset || !ops->write_byte || !ops->triplet) + return -ENOSYS; + + while (!last_device) { + last_rn = rn; + rn = 0; + + /* + * Reset bus and all 1-wire device state machines + * so they can respond to our requests. + * + * Return 0 - device(s) present, 1 - no devices present. + */ + if (ops->reset(bus)) { + debug("%s: No devices present on the wire.\n", + __func__); + break; + } + + /* Start the search */ + ops->write_byte(bus, W1_SEARCH); + for (i = 0; i < 64; ++i) { + /* Determine the direction/search bit */ + if (i == desc_bit) + /* took the 0 path last time, so take the 1 path */ + search_bit = 1; + else if (i > desc_bit) + /* take the 0 path on the next branch */ + search_bit = 0; + else + search_bit = ((last_rn >> i) & 0x1); + + /* Read two bits and write one bit */ + triplet_ret = ops->triplet(bus, search_bit); + + /* quit if no device responded */ + if ((triplet_ret & 0x03) == 0x03) + break; + + /* If both directions were valid, and we took the 0 path... */ + if (triplet_ret == 0) + last_zero = i; + + /* extract the direction taken & update the device number */ + tmp64 = (triplet_ret >> 2); + rn |= (tmp64 << i); + } + + /* last device or error, aborting here */ + if ((triplet_ret & 0x03) == 0x03) + last_device = true; + + if ((triplet_ret & 0x03) != 0x03) { + if (desc_bit == last_zero || last_zero < 0) { + last_device = 1; + w1->search_id = 0; + } else { + w1->search_id = rn; + } + desc_bit = last_zero; + + debug("%s: Detected new device 0x%llx (family 0x%x)\n", + bus->name, rn, (u8)(rn & 0xff)); + } + } + + return 0; +} + +int w1_get_bus(int busnum, struct udevice **busp) +{ + int ret, i = 0; + + struct udevice *dev; + + for (ret = uclass_first_device(UCLASS_W1, &dev); + !ret; + uclass_next_device(&dev), i++) { + if (ret) { + debug("Cannot find w1 bus %d\n", busnum); + return ret; + } + if (i == busnum) { + *busp = dev; + return 0; + } + } + return ret; +} + +u8 w1_get_device_family(struct udevice *dev) +{ + struct w1_device *w1 = dev_get_parent_platdata(dev); + + return w1->id & 0xff; +} + +int w1_reset_select(struct udevice *dev) +{ + struct w1_device *w1 = dev_get_parent_platdata(dev); + struct udevice *bus = dev_get_parent(dev); + const struct w1_ops *ops = device_get_ops(bus); + int i; + + if (!ops->reset || !ops->write_byte) + return -ENOSYS; + + ops->reset(bus); + + ops->write_byte(bus, W1_MATCH_ROM); + + for (i = 0; i < sizeof(w1->id); i++) + ops->write_byte(bus, (w1->id >> (i * 8)) & 0xff); + + return 0; +} + +int w1_read_byte(struct udevice *dev) +{ + struct udevice *bus = dev_get_parent(dev); + const struct w1_ops *ops = device_get_ops(bus); + + if (!ops->read_byte) + return -ENOSYS; + + return ops->read_byte(bus); +} + +int w1_read_buf(struct udevice *dev, u8 *buf, unsigned int count) +{ + int i, ret; + + for (i = 0; i < count; i++) { + ret = w1_read_byte(dev); + if (ret < 0) + return ret; + + buf[i] = ret & 0xff; + } + + return 0; +} + +int w1_write_byte(struct udevice *dev, u8 byte) +{ + struct udevice *bus = dev_get_parent(dev); + const struct w1_ops *ops = device_get_ops(bus); + + if (!ops->write_byte) + return -ENOSYS; + + ops->write_byte(bus, byte); + + return 0; +} + +static int w1_post_probe(struct udevice *bus) +{ + w1_enumerate(bus); + + return 0; +} + +int w1_init(void) +{ + struct udevice *bus; + struct uclass *uc; + int ret; + + ret = uclass_get(UCLASS_W1, &uc); + if (ret) + return ret; + + uclass_foreach_dev(bus, uc) { + ret = device_probe(bus); + if (ret == -ENODEV) { /* No such device. */ + printf("W1 controller not available.\n"); + continue; + } + + if (ret) { /* Other error. */ + printf("W1 controller probe failed.\n"); + continue; + } + } + return 0; +} + +UCLASS_DRIVER(w1) = { + .name = "w1", + .id = UCLASS_W1, + .flags = DM_UC_FLAG_SEQ_ALIAS, + .per_device_auto_alloc_size = sizeof(struct w1_bus), + .post_probe = w1_post_probe, +#if CONFIG_IS_ENABLED(OF_CONTROL) + .post_bind = dm_scan_fdt_dev, +#endif + .per_child_platdata_auto_alloc_size = sizeof(struct w1_device), +}; diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h index 7027ea0..fa72afb 100644 --- a/include/dm/uclass-id.h +++ b/include/dm/uclass-id.h @@ -92,6 +92,7 @@ enum uclass_id { UCLASS_VIDEO, /* Video or LCD device */ UCLASS_VIDEO_BRIDGE, /* Video bridge, e.g. DisplayPort to LVDS */ UCLASS_VIDEO_CONSOLE, /* Text console driver for video device */ + UCLASS_W1, /* Dallas 1-Wire bus */ UCLASS_WDT, /* Watchdot Timer driver */
UCLASS_COUNT, diff --git a/include/w1.h b/include/w1.h new file mode 100644 index 0000000..b36e0f8 --- /dev/null +++ b/include/w1.h @@ -0,0 +1,36 @@ +/* SPDX-License-Identifier: GPL-2.0+ + * + * Copyright (c) 2015 Free Electrons + * Copyright (c) 2015 NextThing Co + * + */ + +#ifndef __W1_H +#define __W1_H + +#include <dm.h> + +#define W1_FAMILY_DS24B33 0x23 +#define W1_FAMILY_DS2431 0x2d + +struct w1_device { + u64 id; +}; + +struct w1_ops { + u8 (*read_byte)(struct udevice *dev); + bool (*reset)(struct udevice *dev); + u8 (*triplet)(struct udevice *dev, bool bdir); + void (*write_byte)(struct udevice *dev, u8 byte); +}; + +int w1_get_bus(int busnum, struct udevice **busp); +u8 w1_get_device_family(struct udevice *dev); + +int w1_read_buf(struct udevice *dev, u8 *buf, unsigned int count); +int w1_read_byte(struct udevice *dev); +int w1_reset_select(struct udevice *dev); +int w1_write_buf(struct udevice *dev, u8 *buf, unsigned int count); +int w1_write_byte(struct udevice *dev, u8 byte); + +#endif