3 files changed, 360 insertions, 0 deletions

diff --git a/drivers/power/avs/Kconfig b/drivers/power/avs/Kconfig
index 2a1008b61121..7f3d389bd601 100644
--- a/drivers/power/avs/Kconfig
+++ b/drivers/power/avs/Kconfig
@@ -10,3 +10,11 @@ menuconfig POWER_AVS
           AVS is also called SmartReflex on OMAP devices.
 
           Say Y here to enable Adaptive Voltage Scaling class support.
+
+config ROCKCHIP_IODOMAIN
+        tristate "Rockchip IO domain support"
+        depends on ARCH_ROCKCHIP && OF
+        help
+          Say y here to enable support io domains on Rockchip SoCs. It is
+          necessary for the io domain setting of the SoC to match the
+          voltage supplied by the regulators.
diff --git a/drivers/power/avs/Makefile b/drivers/power/avs/Makefile
index 0843386a6c19..ba4c7bc69225 100644
--- a/drivers/power/avs/Makefile
+++ b/drivers/power/avs/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_POWER_AVS_OMAP)            += smartreflex.o
+obj-$(CONFIG_ROCKCHIP_IODOMAIN)         += rockchip-io-domain.o
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");