cros_ec: Support the LDO access method used by spring

Add a driver to support the special LDO access used by spring. This is a custom method in the cros_ec protocol - it does not use an I2C pass-through. There are two implementation choices: 1. Write a special LDO driver which can talk across the EC. Duplicate all the logic from TPS65090 for retrying when the LDO fails to come up. 2. Write a special I2C bus driver which pretends to be a TPS65090 and transfers reads and writes using the LDO message. Either is distasteful. The latter method is chosen since it results in less code duplication and a fairly simple (30-line) implementation of the core logic. The crosec 'ldo' subcommand could be removed (since i2c md/mw will work instead) but is retained as a convenience. Signed-off-by: Simon Glass <sjg@chromium.org>

cros_ec: Support the LDO access method used by spring
Add a driver to support the special LDO access used by spring. This is a custom method in the cros_ec protocol - it does not use an I2C pass-through. There are two implementation choices: 1. Write a special LDO driver which can talk across the EC. Duplicate all the logic from TPS65090 for retrying when the LDO fails to come up. 2. Write a special I2C bus driver which pretends to be a TPS65090 and transfers reads and writes using the LDO message. Either is distasteful. The latter method is chosen since it results in less code duplication and a fairly simple (30-line) implementation of the core logic. The crosec 'ldo' subcommand could be removed (since i2c md/mw will work instead) but is retained as a convenience. Signed-off-by: Simon Glass <sjg@chromium.org>
Simon Glass
1 parent cc456bd7df
Showing 5 changed files with 104 additions and 12 deletions Side-by-side Diff
drivers/i2c/Kconfig
drivers/i2c/Makefile
drivers/i2c/cros_ec_ldo.c
drivers/misc/cros_ec.c
include/cros_ec.h
@@ -29,6 +29,19 @@
 	  I2C or LPC). Some Chromebooks use this when the hardware design
 	  does not allow direct access to the main PMIC from the AP.
  
+config I2C_CROS_EC_LDO
+	bool "Provide access to LDOs on the Chrome OS EC"
+	depends on CROS_EC
+	---help---
+	On many Chromebooks the main PMIC is inaccessible to the AP. This is
+	often dealt with by using an I2C pass-through interface provided by
+	the EC. On some unfortunate models (e.g. Spring) the pass-through
+	is not available, and an LDO message is available instead. This
+	option enables a driver which provides very basic access to those
+	regulators, via the EC. We implement this as an I2C bus	which
+	emulates just the TPS65090 messages we know about. This is done to
+	avoid duplicating the logic in the TPS65090 regulator driver for
+	enabling/disabling an LDO.
  
 config DM_I2C_GPIO
 	bool "Enable Driver Model for software emulated I2C bus driver"
@@ -8,6 +8,7 @@
 obj-$(CONFIG_DM_I2C_COMPAT) += i2c-uclass-compat.o
 obj-$(CONFIG_DM_I2C_GPIO) += i2c-gpio.o
 obj-$(CONFIG_I2C_CROS_EC_TUNNEL) += cros_ec_tunnel.o
+obj-$(CONFIG_I2C_CROS_EC_LDO) += cros_ec_ldo.o
  
 obj-$(CONFIG_SYS_I2C_ADI) += adi_i2c.o
 obj-$(CONFIG_I2C_MV) += mv_i2c.o
+/*
+ * Copyright (c) 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <cros_ec.h>
+#include <errno.h>
+#include <i2c.h>
+#include <power/tps65090.h>
+
+static int cros_ec_ldo_set_bus_speed(struct udevice *dev, unsigned int speed)
+{
+	return 0;
+}
+
+static int cros_ec_ldo_xfer(struct udevice *dev, struct i2c_msg *msg,
+			    int nmsgs)
+{
+	bool is_read = nmsgs > 1;
+	int fet_id, ret;
+
+	/*
+	 * Look for reads and writes of the LDO registers. In either case the
+	 * first message is a write with the register number as the first byte.
+	 */
+	if (!nmsgs || !msg->len || (msg->flags & I2C_M_RD)) {
+		debug("%s: Invalid message\n", __func__);
+		goto err;
+	}
+
+	fet_id = msg->buf[0] - REG_FET_BASE;
+	if (fet_id < 1 || fet_id > MAX_FET_NUM) {
+		debug("%s: Invalid FET %d\n", __func__, fet_id);
+		goto err;
+	}
+
+	if (is_read) {
+		uint8_t state;
+
+		ret = cros_ec_get_ldo(dev->parent, fet_id, &state);
+		if (!ret)
+			msg[1].buf[0] = state ?
+				FET_CTRL_ENFET | FET_CTRL_PGFET : 0;
+	} else {
+		bool on = msg->buf[1] & FET_CTRL_ENFET;
+
+		ret = cros_ec_set_ldo(dev->parent, fet_id, on);
+	}
+
+	return ret;
+
+err:
+	/* Indicate that the message is unimplemented */
+	return -ENOSYS;
+}
+
+static const struct dm_i2c_ops cros_ec_i2c_ops = {
+	.xfer		= cros_ec_ldo_xfer,
+	.set_bus_speed	= cros_ec_ldo_set_bus_speed,
+};
+
+static const struct udevice_id cros_ec_i2c_ids[] = {
+	{ .compatible = "google,cros-ec-ldo-tunnel" },
+	{ }
+};
+
+U_BOOT_DRIVER(cros_ec_ldo) = {
+	.name	= "cros_ec_ldo_tunnel",
+	.id	= UCLASS_I2C,
+	.of_match = cros_ec_i2c_ids,
+	.per_child_auto_alloc_size = sizeof(struct dm_i2c_chip),
+	.ops	= &cros_ec_i2c_ops,
+};
@@ -931,31 +931,32 @@
 	return 0;
 }
  
-int cros_ec_set_ldo(struct cros_ec_dev *dev, uint8_t index, uint8_t state)
+int cros_ec_set_ldo(struct udevice *dev, uint8_t index, uint8_t state)
 {
+	struct cros_ec_dev *cdev = dev_get_uclass_priv(dev);
 	struct ec_params_ldo_set params;
  
 	params.index = index;
 	params.state = state;
  
-	if (ec_command_inptr(dev, EC_CMD_LDO_SET, 0,
-		       &params, sizeof(params),
-		       NULL, 0))
+	if (ec_command_inptr(cdev, EC_CMD_LDO_SET, 0, &params, sizeof(params),
+			     NULL, 0))
 		return -1;
  
 	return 0;
 }
  
-int cros_ec_get_ldo(struct cros_ec_dev *dev, uint8_t index, uint8_t *state)
+int cros_ec_get_ldo(struct udevice *dev, uint8_t index, uint8_t *state)
 {
+	struct cros_ec_dev *cdev = dev_get_uclass_priv(dev);
 	struct ec_params_ldo_get params;
 	struct ec_response_ldo_get *resp;
  
 	params.index = index;
  
-	if (ec_command_inptr(dev, EC_CMD_LDO_GET, 0,
-		       &params, sizeof(params),
-		       (uint8_t **)&resp, sizeof(*resp)) != sizeof(*resp))
+	if (ec_command_inptr(cdev, EC_CMD_LDO_GET, 0, &params, sizeof(params),
+			     (uint8_t **)&resp, sizeof(*resp)) !=
+			     sizeof(*resp))
 		return -1;
  
 	*state = resp->state;
  
@@ -1681,9 +1682,9 @@
 			state = simple_strtoul(argv[3], &endp, 10);
 			if (*argv[3] == 0 || *endp != 0)
 				return CMD_RET_USAGE;
-			ret = cros_ec_set_ldo(dev, index, state);
+			ret = cros_ec_set_ldo(udev, index, state);
 		} else {
-			ret = cros_ec_get_ldo(dev, index, &state);
+			ret = cros_ec_get_ldo(udev, index, &state);
 			if (!ret) {
 				printf("LDO%d: %s\n", index,
 					state == EC_LDO_STATE_ON ?
@@ -350,7 +350,7 @@
  * @param state		new state of the LDO/FET : EC_LDO_STATE_ON|OFF
  * @return 0 if ok, -1 on error
  */
-int cros_ec_set_ldo(struct cros_ec_dev *dev, uint8_t index, uint8_t state);
+int cros_ec_set_ldo(struct udevice *dev, uint8_t index, uint8_t state);
  
 /**
  * Read back a LDO / FET current state.
@@ -360,7 +360,7 @@
  * @param state		current state of the LDO/FET : EC_LDO_STATE_ON|OFF
  * @return 0 if ok, -1 on error
  */
-int cros_ec_get_ldo(struct cros_ec_dev *dev, uint8_t index, uint8_t *state);
+int cros_ec_get_ldo(struct udevice *dev, uint8_t index, uint8_t *state);
  
 /**
  * Get access to the error reported when cros_ec_board_init() was called
...	...	@@ -29,6 +29,19 @@
29	29	I2C or LPC). Some Chromebooks use this when the hardware design
30	30	does not allow direct access to the main PMIC from the AP.
31	31
	32	+config I2C_CROS_EC_LDO
	33	+ bool "Provide access to LDOs on the Chrome OS EC"
	34	+ depends on CROS_EC
	35	+ ---help---
	36	+ On many Chromebooks the main PMIC is inaccessible to the AP. This is
	37	+ often dealt with by using an I2C pass-through interface provided by
	38	+ the EC. On some unfortunate models (e.g. Spring) the pass-through
	39	+ is not available, and an LDO message is available instead. This
	40	+ option enables a driver which provides very basic access to those
	41	+ regulators, via the EC. We implement this as an I2C bus which
	42	+ emulates just the TPS65090 messages we know about. This is done to
	43	+ avoid duplicating the logic in the TPS65090 regulator driver for
	44	+ enabling/disabling an LDO.
32	45
33	46	config DM_I2C_GPIO
34	47	bool "Enable Driver Model for software emulated I2C bus driver"
...	...	@@ -8,6 +8,7 @@
8	8	obj-$(CONFIG_DM_I2C_COMPAT) += i2c-uclass-compat.o
9	9	obj-$(CONFIG_DM_I2C_GPIO) += i2c-gpio.o
10	10	obj-$(CONFIG_I2C_CROS_EC_TUNNEL) += cros_ec_tunnel.o
	11	+obj-$(CONFIG_I2C_CROS_EC_LDO) += cros_ec_ldo.o
11	12
12	13	obj-$(CONFIG_SYS_I2C_ADI) += adi_i2c.o
13	14	obj-$(CONFIG_I2C_MV) += mv_i2c.o
	1	+/*
	2	+ * Copyright (c) 2015 Google, Inc
	3	+ * Written by Simon Glass <sjg@chromium.org>
	4	+ *
	5	+ * SPDX-License-Identifier: GPL-2.0+
	6	+ */
	7	+
	8	+#include <common.h>
	9	+#include <dm.h>
	10	+#include <cros_ec.h>
	11	+#include <errno.h>
	12	+#include <i2c.h>
	13	+#include <power/tps65090.h>
	14	+
	15	+static int cros_ec_ldo_set_bus_speed(struct udevice *dev, unsigned int speed)
	16	+{
	17	+ return 0;
	18	+}
	19	+
	20	+static int cros_ec_ldo_xfer(struct udevice dev, struct i2c_msg msg,
	21	+ int nmsgs)
	22	+{
	23	+ bool is_read = nmsgs > 1;
	24	+ int fet_id, ret;
	25	+
	26	+ /*
	27	+ * Look for reads and writes of the LDO registers. In either case the
	28	+ * first message is a write with the register number as the first byte.
	29	+ */
	30	+ if (!nmsgs \|\| !msg->len \|\| (msg->flags & I2C_M_RD)) {
	31	+ debug("%s: Invalid message\n", __func__);
	32	+ goto err;
	33	+ }
	34	+
	35	+ fet_id = msg->buf[0] - REG_FET_BASE;
	36	+ if (fet_id < 1 \|\| fet_id > MAX_FET_NUM) {
	37	+ debug("%s: Invalid FET %d\n", __func__, fet_id);
	38	+ goto err;
	39	+ }
	40	+
	41	+ if (is_read) {
	42	+ uint8_t state;
	43	+
	44	+ ret = cros_ec_get_ldo(dev->parent, fet_id, &state);
	45	+ if (!ret)
	46	+ msg[1].buf[0] = state ?
	47	+ FET_CTRL_ENFET \| FET_CTRL_PGFET : 0;
	48	+ } else {
	49	+ bool on = msg->buf[1] & FET_CTRL_ENFET;
	50	+
	51	+ ret = cros_ec_set_ldo(dev->parent, fet_id, on);
	52	+ }
	53	+
	54	+ return ret;
	55	+
	56	+err:
	57	+ /* Indicate that the message is unimplemented */
	58	+ return -ENOSYS;
	59	+}
	60	+
	61	+static const struct dm_i2c_ops cros_ec_i2c_ops = {
	62	+ .xfer = cros_ec_ldo_xfer,
	63	+ .set_bus_speed = cros_ec_ldo_set_bus_speed,
	64	+};
	65	+
	66	+static const struct udevice_id cros_ec_i2c_ids[] = {
	67	+ { .compatible = "google,cros-ec-ldo-tunnel" },
	68	+ { }
	69	+};
	70	+
	71	+U_BOOT_DRIVER(cros_ec_ldo) = {
	72	+ .name = "cros_ec_ldo_tunnel",
	73	+ .id = UCLASS_I2C,
	74	+ .of_match = cros_ec_i2c_ids,
	75	+ .per_child_auto_alloc_size = sizeof(struct dm_i2c_chip),
	76	+ .ops = &cros_ec_i2c_ops,
	77	+};
...	...	@@ -931,31 +931,32 @@
931	931	return 0;
932	932	}
933	933
934		-int cros_ec_set_ldo(struct cros_ec_dev *dev, uint8_t index, uint8_t state)
	934	+int cros_ec_set_ldo(struct udevice *dev, uint8_t index, uint8_t state)
935	935	{
	936	+ struct cros_ec_dev *cdev = dev_get_uclass_priv(dev);
936	937	struct ec_params_ldo_set params;
937	938
938	939	params.index = index;
939	940	params.state = state;
940	941
941		- if (ec_command_inptr(dev, EC_CMD_LDO_SET, 0,
942		- &params, sizeof(params),
943		- NULL, 0))
	942	+ if (ec_command_inptr(cdev, EC_CMD_LDO_SET, 0, &params, sizeof(params),
	943	+ NULL, 0))
944	944	return -1;
945	945
946	946	return 0;
947	947	}
948	948
949		-int cros_ec_get_ldo(struct cros_ec_dev dev, uint8_t index, uint8_t state)
	949	+int cros_ec_get_ldo(struct udevice dev, uint8_t index, uint8_t state)
950	950	{
	951	+ struct cros_ec_dev *cdev = dev_get_uclass_priv(dev);
951	952	struct ec_params_ldo_get params;
952	953	struct ec_response_ldo_get *resp;
953	954
954	955	params.index = index;
955	956
956		- if (ec_command_inptr(dev, EC_CMD_LDO_GET, 0,
957		- &params, sizeof(params),
958		- (uint8_t *)&resp, sizeof(resp)) != sizeof(*resp))
	957	+ if (ec_command_inptr(cdev, EC_CMD_LDO_GET, 0, &params, sizeof(params),
	958	+ (uint8_t *)&resp, sizeof(resp)) !=
	959	+ sizeof(*resp))
959	960	return -1;
960	961
961	962	*state = resp->state;
962	963
...	...	@@ -1681,9 +1682,9 @@
1681	1682	state = simple_strtoul(argv[3], &endp, 10);
1682	1683	if (argv[3] == 0 \|\| endp != 0)
1683	1684	return CMD_RET_USAGE;
1684		- ret = cros_ec_set_ldo(dev, index, state);
	1685	+ ret = cros_ec_set_ldo(udev, index, state);
1685	1686	} else {
1686		- ret = cros_ec_get_ldo(dev, index, &state);
	1687	+ ret = cros_ec_get_ldo(udev, index, &state);
1687	1688	if (!ret) {
1688	1689	printf("LDO%d: %s\n", index,
1689	1690	state == EC_LDO_STATE_ON ?
...	...	@@ -350,7 +350,7 @@
350	350	* @param state new state of the LDO/FET : EC_LDO_STATE_ON\|OFF
351	351	* @return 0 if ok, -1 on error
352	352	*/
353		-int cros_ec_set_ldo(struct cros_ec_dev *dev, uint8_t index, uint8_t state);
	353	+int cros_ec_set_ldo(struct udevice *dev, uint8_t index, uint8_t state);
354	354
355	355	/**
356	356	* Read back a LDO / FET current state.
...	...	@@ -360,7 +360,7 @@
360	360	* @param state current state of the LDO/FET : EC_LDO_STATE_ON\|OFF
361	361	* @return 0 if ok, -1 on error
362	362	*/
363		-int cros_ec_get_ldo(struct cros_ec_dev dev, uint8_t index, uint8_t state);
	363	+int cros_ec_get_ldo(struct udevice dev, uint8_t index, uint8_t state);
364	364
365	365	/**
366	366	* Get access to the error reported when cros_ec_board_init() was called