1 files changed, 351 insertions, 0 deletions
diff --git a/drivers/power/avs/rockchip-io-domain.c b/drivers/power/avs/rockchip-io-domain.c
new file mode 100644
index 000000000000..3ae35d0590d2
--- /dev/null
+++ b/drivers/power/avs/rockchip-io-domain.c
@@ -0,0 +1,351 @@
+/*
+ * Rockchip IO Voltage Domain driver
+ *
+ * Copyright 2014 MundoReader S.L.
+ * Copyright 2014 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
+#define MAX_SUPPLIES		16
+
+/*
+ * The max voltage for 1.8V and 3.3V come from the Rockchip datasheet under
+ * "Recommended Operating Conditions" for "Digital GPIO".   When the typical
+ * is 3.3V the max is 3.6V.  When the typical is 1.8V the max is 1.98V.
+ *
+ * They are used like this:
+ * - If the voltage on a rail is above the "1.8" voltage (1.98V) we'll tell the
+ *   SoC we're at 3.3.
+ * - If the voltage on a rail is above the "3.3" voltage (3.6V) we'll consider
+ *   that to be an error.
+ */
+#define MAX_VOLTAGE_1_8		1980000
+#define MAX_VOLTAGE_3_3		3600000
+
+#define RK3288_SOC_CON2			0x24c
+#define RK3288_SOC_CON2_FLASH0		BIT(7)
+#define RK3288_SOC_FLASH_SUPPLY_NUM	2
+
+struct rockchip_iodomain;
+
+/**
+ * @supplies: voltage settings matching the register bits.
+ */
+struct rockchip_iodomain_soc_data {
+	int grf_offset;
+	const char *supply_names[MAX_SUPPLIES];
+	void (*init)(struct rockchip_iodomain *iod);
+};
+
+struct rockchip_iodomain_supply {
+	struct rockchip_iodomain *iod;
+	struct regulator *reg;
+	struct notifier_block nb;
+	int idx;
+};
+
+struct rockchip_iodomain {
+	struct device *dev;
+	struct regmap *grf;
+	struct rockchip_iodomain_soc_data *soc_data;
+	struct rockchip_iodomain_supply supplies[MAX_SUPPLIES];
+};
+
+static int rockchip_iodomain_write(struct rockchip_iodomain_supply *supply,
+				   int uV)
+{
+	struct rockchip_iodomain *iod = supply->iod;
+	u32 val;
+	int ret;
+
+	/* set value bit */
+	val = (uV > MAX_VOLTAGE_1_8) ? 0 : 1;
+	val <<= supply->idx;
+
+	/* apply hiword-mask */
+	val |= (BIT(supply->idx) << 16);
+
+	ret = regmap_write(iod->grf, iod->soc_data->grf_offset, val);
+	if (ret)
+		dev_err(iod->dev, "Couldn't write to GRF\n");
+
+	return ret;
+}
+
+static int rockchip_iodomain_notify(struct notifier_block *nb,
+				    unsigned long event,
+				    void *data)
+{
+	struct rockchip_iodomain_supply *supply =
+			container_of(nb, struct rockchip_iodomain_supply, nb);
+	int uV;
+	int ret;
+
+	/*
+	 * According to Rockchip it's important to keep the SoC IO domain
+	 * higher than (or equal to) the external voltage.  That means we need
+	 * to change it before external voltage changes happen in the case
+	 * of an increase.
+	 *
+	 * Note that in the "pre" change we pick the max possible voltage that
+	 * the regulator might end up at (the client requests a range and we
+	 * don't know for certain the exact voltage).  Right now we rely on the
+	 * slop in MAX_VOLTAGE_1_8 and MAX_VOLTAGE_3_3 to save us if clients
+	 * request something like a max of 3.6V when they really want 3.3V.
+	 * We could attempt to come up with better rules if this fails.
+	 */
+	if (event & REGULATOR_EVENT_PRE_VOLTAGE_CHANGE) {
+		struct pre_voltage_change_data *pvc_data = data;
+
+		uV = max_t(unsigned long, pvc_data->old_uV, pvc_data->max_uV);
+	} else if (event & (REGULATOR_EVENT_VOLTAGE_CHANGE |
+			    REGULATOR_EVENT_ABORT_VOLTAGE_CHANGE)) {
+		uV = (unsigned long)data;
+	} else {
+		return NOTIFY_OK;
+	}
+
+	dev_dbg(supply->iod->dev, "Setting to %d\n", uV);
+
+	if (uV > MAX_VOLTAGE_3_3) {
+		dev_err(supply->iod->dev, "Voltage too high: %d\n", uV);
+
+		if (event == REGULATOR_EVENT_PRE_VOLTAGE_CHANGE)
+			return NOTIFY_BAD;
+	}
+
+	ret = rockchip_iodomain_write(supply, uV);
+	if (ret && event == REGULATOR_EVENT_PRE_VOLTAGE_CHANGE)
+		return NOTIFY_BAD;
+
+	dev_info(supply->iod->dev, "Setting to %d done\n", uV);
+	return NOTIFY_OK;
+}
+
+static void rk3288_iodomain_init(struct rockchip_iodomain *iod)
+{
+	int ret;
+	u32 val;
+
+	/* if no flash supply we should leave things alone */
+	if (!iod->supplies[RK3288_SOC_FLASH_SUPPLY_NUM].reg)
+		return;
+
+	/*
+	 * set flash0 iodomain to also use this framework
+	 * instead of a special gpio.
+	 */
+	val = RK3288_SOC_CON2_FLASH0 | (RK3288_SOC_CON2_FLASH0 << 16);
+	ret = regmap_write(iod->grf, RK3288_SOC_CON2, val);
+	if (ret < 0)
+		dev_warn(iod->dev, "couldn't update flash0 ctrl\n");
+}
+
+/*
+ * On the rk3188 the io-domains are handled by a shared register with the
+ * lower 8 bits being still being continuing drive-strength settings.
+ */
+static const struct rockchip_iodomain_soc_data soc_data_rk3188 = {
+	.grf_offset = 0x104,
+	.supply_names = {
+		NULL,
+		NULL,
+		NULL,
+		NULL,
+		NULL,
+		NULL,
+		NULL,
+		NULL,
+		"ap0",
+		"ap1",
+		"cif",
+		"flash",
+		"vccio0",
+		"vccio1",
+		"lcdc0",
+		"lcdc1",
+	},
+};
+
+static const struct rockchip_iodomain_soc_data soc_data_rk3288 = {
+	.grf_offset = 0x380,
+	.supply_names = {
+		"lcdc",		/* LCDC_VDD */
+		"dvp",		/* DVPIO_VDD */
+		"flash0",	/* FLASH0_VDD (emmc) */
+		"flash1",	/* FLASH1_VDD (sdio1) */
+		"wifi",		/* APIO3_VDD  (sdio0) */
+		"bb",		/* APIO5_VDD */
+		"audio",	/* APIO4_VDD */
+		"sdcard",	/* SDMMC0_VDD (sdmmc) */
+		"gpio30",	/* APIO1_VDD */
+		"gpio1830",	/* APIO2_VDD */
+	},
+	.init = rk3288_iodomain_init,
+};
+
+static const struct of_device_id rockchip_iodomain_match[] = {
+	{
+		.compatible = "rockchip,rk3188-io-voltage-domain",
+		.data = (void *)&soc_data_rk3188
+	},
+	{
+		.compatible = "rockchip,rk3288-io-voltage-domain",
+		.data = (void *)&soc_data_rk3288
+	},
+	{ /* sentinel */ },
+};
+
+static int rockchip_iodomain_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	const struct of_device_id *match;
+	struct rockchip_iodomain *iod;
+	int i, ret = 0;
+
+	if (!np)
+		return -ENODEV;
+
+	iod = devm_kzalloc(&pdev->dev, sizeof(*iod), GFP_KERNEL);
+	if (!iod)
+		return -ENOMEM;
+
+	iod->dev = &pdev->dev;
+	platform_set_drvdata(pdev, iod);
+
+	match = of_match_node(rockchip_iodomain_match, np);
+	iod->soc_data = (struct rockchip_iodomain_soc_data *)match->data;
+
+	iod->grf = syscon_regmap_lookup_by_phandle(np, "rockchip,grf");
+	if (IS_ERR(iod->grf)) {
+		dev_err(&pdev->dev, "couldn't find grf regmap\n");
+		return PTR_ERR(iod->grf);
+	}
+
+	for (i = 0; i < MAX_SUPPLIES; i++) {
+		const char *supply_name = iod->soc_data->supply_names[i];
+		struct rockchip_iodomain_supply *supply = &iod->supplies[i];
+		struct regulator *reg;
+		int uV;
+
+		if (!supply_name)
+			continue;
+
+		reg = devm_regulator_get_optional(iod->dev, supply_name);
+		if (IS_ERR(reg)) {
+			ret = PTR_ERR(reg);
+
+			/* If a supply wasn't specified, that's OK */
+			if (ret == -ENODEV)
+				continue;
+			else if (ret != -EPROBE_DEFER)
+				dev_err(iod->dev, "couldn't get regulator %s\n",
+					supply_name);
+			goto unreg_notify;
+		}
+
+		/* set initial correct value */
+		uV = regulator_get_voltage(reg);
+
+		/* must be a regulator we can get the voltage of */
+		if (uV < 0) {
+			dev_err(iod->dev, "Can't determine voltage: %s\n",
+				supply_name);
+			goto unreg_notify;
+		}
+
+		if (uV > MAX_VOLTAGE_3_3) {
+			dev_crit(iod->dev,
+				 "%d uV is too high. May damage SoC!\n",
+				 uV);
+			ret = -EINVAL;
+			goto unreg_notify;
+		}
+
+		/* setup our supply */
+		supply->idx = i;
+		supply->iod = iod;
+		supply->reg = reg;
+		supply->nb.notifier_call = rockchip_iodomain_notify;
+
+		ret = rockchip_iodomain_write(supply, uV);
+		if (ret) {
+			supply->reg = NULL;
+			goto unreg_notify;
+		}
+
+		/* register regulator notifier */
+		ret = regulator_register_notifier(reg, &supply->nb);
+		if (ret) {
+			dev_err(&pdev->dev,
+				"regulator notifier request failed\n");
+			supply->reg = NULL;
+			goto unreg_notify;
+		}
+	}
+
+	if (iod->soc_data->init)
+		iod->soc_data->init(iod);
+
+	return 0;
+
+unreg_notify:
+	for (i = MAX_SUPPLIES - 1; i >= 0; i--) {
+		struct rockchip_iodomain_supply *io_supply = &iod->supplies[i];
+
+		if (io_supply->reg)
+			regulator_unregister_notifier(io_supply->reg,
+						      &io_supply->nb);
+	}
+
+	return ret;
+}
+
+static int rockchip_iodomain_remove(struct platform_device *pdev)
+{
+	struct rockchip_iodomain *iod = platform_get_drvdata(pdev);
+	int i;
+
+	for (i = MAX_SUPPLIES - 1; i >= 0; i--) {
+		struct rockchip_iodomain_supply *io_supply = &iod->supplies[i];
+
+		if (io_supply->reg)
+			regulator_unregister_notifier(io_supply->reg,
+						      &io_supply->nb);
+	}
+
+	return 0;
+}
+
+static struct platform_driver rockchip_iodomain_driver = {
+	.probe   = rockchip_iodomain_probe,
+	.remove  = rockchip_iodomain_remove,
+	.driver  = {
+		.name  = "rockchip-iodomain",
+		.of_match_table = rockchip_iodomain_match,
+	},
+};
+
+module_platform_driver(rockchip_iodomain_driver);
+
+MODULE_DESCRIPTION("Rockchip IO-domain driver");
+MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
+MODULE_AUTHOR("Doug Anderson <dianders@chromium.org>");
+MODULE_LICENSE("GPL v2");