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