diff options
Diffstat (limited to 'drivers/power/regulator/stm32-vrefbuf.c')
-rw-r--r-- | drivers/power/regulator/stm32-vrefbuf.c | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/drivers/power/regulator/stm32-vrefbuf.c b/drivers/power/regulator/stm32-vrefbuf.c new file mode 100644 index 0000000000..0ad6833ed0 --- /dev/null +++ b/drivers/power/regulator/stm32-vrefbuf.c @@ -0,0 +1,155 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2018, STMicroelectronics - All Rights Reserved + * Author: Fabrice Gasnier <fabrice.gasnier@st.com> + * + * Originally based on the Linux kernel v4.16 drivers/regulator/stm32-vrefbuf.c + */ + +#include <common.h> +#include <clk.h> +#include <dm.h> +#include <asm/io.h> +#include <linux/iopoll.h> +#include <linux/kernel.h> +#include <power/regulator.h> + +/* STM32 VREFBUF registers */ +#define STM32_VREFBUF_CSR 0x00 + +/* STM32 VREFBUF CSR bitfields */ +#define STM32_VRS GENMASK(6, 4) +#define STM32_VRS_SHIFT 4 +#define STM32_VRR BIT(3) +#define STM32_HIZ BIT(1) +#define STM32_ENVR BIT(0) + +struct stm32_vrefbuf { + void __iomem *base; + struct clk clk; + struct udevice *vdda_supply; +}; + +static const unsigned int stm32_vrefbuf_voltages[] = { + /* Matches resp. VRS = 000b, 001b, 010b, 011b */ + 2500000, 2048000, 1800000, 1500000, +}; + +static int stm32_vrefbuf_set_enable(struct udevice *dev, bool enable) +{ + struct stm32_vrefbuf *priv = dev_get_priv(dev); + u32 val; + int ret; + + clrsetbits_le32(priv->base + STM32_VREFBUF_CSR, STM32_HIZ | STM32_ENVR, + enable ? STM32_ENVR : STM32_HIZ); + if (!enable) + return 0; + + /* + * Vrefbuf startup time depends on external capacitor: wait here for + * VRR to be set. That means output has reached expected value. + * ~650us sleep should be enough for caps up to 1.5uF. Use 10ms as + * arbitrary timeout. + */ + ret = readl_poll_timeout(priv->base + STM32_VREFBUF_CSR, val, + val & STM32_VRR, 10000); + if (ret < 0) { + dev_err(dev, "stm32 vrefbuf timed out: %d\n", ret); + clrsetbits_le32(priv->base + STM32_VREFBUF_CSR, STM32_ENVR, + STM32_HIZ); + return ret; + } + + return 0; +} + +static int stm32_vrefbuf_get_enable(struct udevice *dev) +{ + struct stm32_vrefbuf *priv = dev_get_priv(dev); + + return readl(priv->base + STM32_VREFBUF_CSR) & STM32_ENVR; +} + +static int stm32_vrefbuf_set_value(struct udevice *dev, int uV) +{ + struct stm32_vrefbuf *priv = dev_get_priv(dev); + unsigned int i; + + for (i = 0; i < ARRAY_SIZE(stm32_vrefbuf_voltages); i++) { + if (uV == stm32_vrefbuf_voltages[i]) { + clrsetbits_le32(priv->base + STM32_VREFBUF_CSR, + STM32_VRS, i << STM32_VRS_SHIFT); + return 0; + } + } + + return -EINVAL; +} + +static int stm32_vrefbuf_get_value(struct udevice *dev) +{ + struct stm32_vrefbuf *priv = dev_get_priv(dev); + u32 val; + + val = readl(priv->base + STM32_VREFBUF_CSR) & STM32_VRS; + val >>= STM32_VRS_SHIFT; + + return stm32_vrefbuf_voltages[val]; +} + +static const struct dm_regulator_ops stm32_vrefbuf_ops = { + .get_value = stm32_vrefbuf_get_value, + .set_value = stm32_vrefbuf_set_value, + .get_enable = stm32_vrefbuf_get_enable, + .set_enable = stm32_vrefbuf_set_enable, +}; + +static int stm32_vrefbuf_probe(struct udevice *dev) +{ + struct stm32_vrefbuf *priv = dev_get_priv(dev); + int ret; + + priv->base = dev_read_addr_ptr(dev); + + ret = clk_get_by_index(dev, 0, &priv->clk); + if (ret) { + dev_err(dev, "Can't get clock: %d\n", ret); + return ret; + } + + ret = clk_enable(&priv->clk); + if (ret) { + dev_err(dev, "Can't enable clock: %d\n", ret); + return ret; + } + + ret = device_get_supply_regulator(dev, "vdda-supply", + &priv->vdda_supply); + if (ret) { + dev_dbg(dev, "No vdda-supply: %d\n", ret); + return 0; + } + + ret = regulator_set_enable(priv->vdda_supply, true); + if (ret) { + dev_err(dev, "Can't enable vdda-supply: %d\n", ret); + clk_disable(&priv->clk); + } + + return ret; +} + +static const struct udevice_id stm32_vrefbuf_ids[] = { + { .compatible = "st,stm32-vrefbuf" }, + { } +}; + +U_BOOT_DRIVER(stm32_vrefbuf) = { + .name = "stm32-vrefbuf", + .id = UCLASS_REGULATOR, + .of_match = stm32_vrefbuf_ids, + .probe = stm32_vrefbuf_probe, + .ops = &stm32_vrefbuf_ops, + .priv_auto_alloc_size = sizeof(struct stm32_vrefbuf), +}; |