On 8.11.2016 11:19, Maxime Ripard wrote:
Add a bus driver for bitbanging a 1-Wire bus over a GPIO.
Signed-off-by: Maxime Ripard maxime.ripard@free-electrons.com
drivers/w1/Kconfig | 6 ++- drivers/w1/Makefile | 1 +- drivers/w1/w1-gpio.c | 160 ++++++++++++++++++++++++++++++++++++++++++++- 3 files changed, 167 insertions(+), 0 deletions(-) create mode 100644 drivers/w1/w1-gpio.c
diff --git a/drivers/w1/Kconfig b/drivers/w1/Kconfig index 0c056b4c06a9..ccc3ae15db86 100644 --- a/drivers/w1/Kconfig +++ b/drivers/w1/Kconfig @@ -12,6 +12,12 @@ config W1
if W1
+config W1_GPIO
- bool "Enable 1-Wire GPIO bitbanging"
- depends on DM_GPIO
- help
Emulate a 1-Wire bus using a GPIO.endif
endmenu diff --git a/drivers/w1/Makefile b/drivers/w1/Makefile index 26820fa209e1..7fd8697f8419 100644 --- a/drivers/w1/Makefile +++ b/drivers/w1/Makefile @@ -1,2 +1,3 @@ obj-$(CONFIG_W1) += w1-uclass.o
+obj-$(CONFIG_W1_GPIO) += w1-gpio.o diff --git a/drivers/w1/w1-gpio.c b/drivers/w1/w1-gpio.c new file mode 100644 index 000000000000..091849162533 --- /dev/null +++ b/drivers/w1/w1-gpio.c @@ -0,0 +1,160 @@ +/*
- Copyright (c) 2015 Free Electrons
- Copyright (c) 2015 NextThing Co
- Maxime Ripard maxime.ripard@free-electrons.com
- SPDX-License-Identifier: GPL-2.0+
- */
+#include <common.h> +#include <dm.h> +#include <w1.h>
+#include <asm/gpio.h>
+#define W1_TIMING_A 6 +#define W1_TIMING_B 64 +#define W1_TIMING_C 60 +#define W1_TIMING_D 10 +#define W1_TIMING_E 9 +#define W1_TIMING_F 55 +#define W1_TIMING_G 0 +#define W1_TIMING_H 480 +#define W1_TIMING_I 70 +#define W1_TIMING_J 410
+struct w1_gpio_pdata {
- struct gpio_desc gpio;
- u64 search_id;
+};
+static bool w1_gpio_read_bit(struct udevice *dev) +{
- struct w1_gpio_pdata *pdata = dev_get_platdata(dev);
- int val;
- dm_gpio_set_dir_flags(&pdata->gpio, GPIOD_IS_OUT);
- udelay(W1_TIMING_A);
- dm_gpio_set_dir_flags(&pdata->gpio, GPIOD_IS_IN);
- udelay(W1_TIMING_E);
- val = dm_gpio_get_value(&pdata->gpio);
- udelay(W1_TIMING_F);
- return val;
+}
+static u8 w1_gpio_read_byte(struct udevice *dev) +{
- int i;
- u8 ret = 0;
- for (i = 0; i < 8; ++i)
ret |= (w1_gpio_read_bit(dev) ? 1 : 0) << i;- return ret;
+}
+static void w1_gpio_write_bit(struct udevice *dev, bool bit) +{
- struct w1_gpio_pdata *pdata = dev_get_platdata(dev);
- dm_gpio_set_dir_flags(&pdata->gpio, GPIOD_IS_OUT);
- bit ? udelay(W1_TIMING_A) : udelay(W1_TIMING_C);
- dm_gpio_set_value(&pdata->gpio, 1);
- bit ? udelay(W1_TIMING_B) : udelay(W1_TIMING_D);
+}
+static void w1_gpio_write_byte(struct udevice *dev, u8 byte) +{
- int i;
- for (i = 0; i < 8; ++i)
w1_gpio_write_bit(dev, (byte >> i) & 0x1);+}
+static bool w1_gpio_reset(struct udevice *dev) +{
- struct w1_gpio_pdata *pdata = dev_get_platdata(dev);
- int val;
- dm_gpio_set_dir_flags(&pdata->gpio, GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE);
- udelay(W1_TIMING_G);
- dm_gpio_set_value(&pdata->gpio, 0);
- udelay(W1_TIMING_H);
- dm_gpio_set_dir_flags(&pdata->gpio, GPIOD_IS_IN);
- udelay(W1_TIMING_I);
- val = dm_gpio_get_value(&pdata->gpio);
- udelay(W1_TIMING_J);
- return val;
+}
+static u8 w1_gpio_triplet(struct udevice *dev, bool bdir) +{
- u8 id_bit = w1_gpio_read_bit(dev);
- u8 comp_bit = w1_gpio_read_bit(dev);
- u8 retval;
- if (id_bit && comp_bit)
return 0x03; /* error */- if (!id_bit && !comp_bit) {
/* Both bits are valid, take the direction given */retval = bdir ? 0x04 : 0;- } else {
/* Only one bit is valid, take that direction */bdir = id_bit;retval = id_bit ? 0x05 : 0x02;- }
- w1_gpio_write_bit(dev, bdir);
- return retval;
+}
+static const struct w1_ops w1_gpio_ops = {
- .read_byte = w1_gpio_read_byte,
- .reset = w1_gpio_reset,
- .triplet = w1_gpio_triplet,
- .write_byte = w1_gpio_write_byte,
+};
+static int w1_gpio_ofdata_to_platdata(struct udevice *dev) +{
- struct w1_gpio_pdata *pdata = dev_get_platdata(dev);
- int ret;
- ret = gpio_request_by_name(dev, "gpios", 0, &pdata->gpio, 0);
- if (ret < 0)
goto error;- return 0;
+error:
- printf("Error claiming GPIO %d\n", ret);
- return ret;
+};
+static const struct udevice_id w1_gpio_id[] = {
- { "w1-gpio", 0 },
- { },
+};
+U_BOOT_DRIVER(w1_gpio_drv) = {
- .id = UCLASS_W1,
- .name = "w1_gpio_drv",
- .of_match = w1_gpio_id,
- .ofdata_to_platdata = w1_gpio_ofdata_to_platdata,
- .ops = &w1_gpio_ops,
- .platdata_auto_alloc_size = sizeof(struct w1_gpio_pdata),
+};
Has someone test this on different HW?
As I went through the series will be good to have cmd/w1.c to be able to test that devices.
Thanks, Michal