--- /dev/null
+Rockchip SRAM for IO Voltage Domains:
+-------------------------------------
+
+IO domain voltages on some Rockchip SoCs are variable but need to be
+kept in sync between the regulators and the SoC using a special
+register.
+
+A specific example using rk3288:
+- If the regulator hooked up to a pin like SDMMC0_VDD is 3.3V then
+ bit 7 of GRF_IO_VSEL needs to be 0. If the regulator hooked up to
+ that same pin is 1.8V then bit 7 of GRF_IO_VSEL needs to be 1.
+
+Said another way, this driver simply handles keeping bits in the SoC's
+general register file (GRF) in sync with the actual value of a voltage
+hooked up to the pins.
+
+Note that this driver specifically doesn't include:
+- any logic for deciding what voltage we should set regulators to
+- any logic for deciding whether regulators (or internal SoC blocks)
+ should have power or not have power
+
+If there were some other software that had the smarts of making
+decisions about regulators, it would work in conjunction with this
+driver. When that other software adjusted a regulator's voltage then
+this driver would handle telling the SoC about it. A good example is
+vqmmc for SD. In that case the dw_mmc driver simply is told about a
+regulator. It changes the regulator between 3.3V and 1.8V at the
+right time. This driver notices the change and makes sure that the
+SoC is on the same page.
+
+
+Required properties:
+- compatible: should be one of:
+ - "rockchip,rk3188-io-voltage-domain" for rk3188
+ - "rockchip,rk3288-io-voltage-domain" for rk3288
+- rockchip,grf: phandle to the syscon managing the "general register files"
+
+
+You specify supplies using the standard regulator bindings by including
+a phandle the the relevant regulator. All specified supplies must be able
+to report their voltage. The IO Voltage Domain for any non-specified
+supplies will be not be touched.
+
+Possible supplies for rk3188:
+- ap0-supply: The supply connected to AP0_VCC.
+- ap1-supply: The supply connected to AP1_VCC.
+- cif-supply: The supply connected to CIF_VCC.
+- flash-supply: The supply connected to FLASH_VCC.
+- lcdc0-supply: The supply connected to LCD0_VCC.
+- lcdc1-supply: The supply connected to LCD1_VCC.
+- vccio0-supply: The supply connected to VCCIO0.
+- vccio1-supply: The supply connected to VCCIO1.
+ Sometimes also labeled VCCIO1 and VCCIO2.
+
+Possible supplies for rk3288:
+- audio-supply: The supply connected to APIO4_VDD.
+- bb-supply: The supply connected to APIO5_VDD.
+- dvp-supply: The supply connected to DVPIO_VDD.
+- flash0-supply: The supply connected to FLASH0_VDD. Typically for eMMC
+- flash1-supply: The supply connected to FLASH1_VDD. Also known as SDIO1.
+- gpio30-supply: The supply connected to APIO1_VDD.
+- gpio1830 The supply connected to APIO2_VDD.
+- lcdc-supply: The supply connected to LCDC_VDD.
+- sdcard-supply: The supply connected to SDMMC0_VDD.
+- wifi-supply: The supply connected to APIO3_VDD. Also known as SDIO0.
+
+
+Example:
+
+ io-domains {
+ compatible = "rockchip,rk3288-io-voltage-domain";
+ rockchip,grf = <&grf>;
+
+ audio-supply = <&vcc18_codec>;
+ bb-supply = <&vcc33_io>;
+ dvp-supply = <&vcc_18>;
+ flash0-supply = <&vcc18_flashio>;
+ gpio1830-supply = <&vcc33_io>;
+ gpio30-supply = <&vcc33_pmuio>;
+ lcdc-supply = <&vcc33_lcd>;
+ sdcard-supply = <&vccio_sd>;
+ wifi-supply = <&vcc18_wl>;
+ };
--- /dev/null
+/*
+ * 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");
projects / GitHub / exynos8895 / android_kernel_samsung_universal8895.git / commitdiff