diff options
Diffstat (limited to 'kernel/drivers/mfd/ssbi.c')
| -rw-r--r-- | kernel/drivers/mfd/ssbi.c | 338 |
1 files changed, 338 insertions, 0 deletions
diff --git a/kernel/drivers/mfd/ssbi.c b/kernel/drivers/mfd/ssbi.c new file mode 100644 index 000000000..27986f641 --- /dev/null +++ b/kernel/drivers/mfd/ssbi.c @@ -0,0 +1,338 @@ +/* Copyright (c) 2009-2013, The Linux Foundation. All rights reserved. + * Copyright (c) 2010, Google Inc. + * + * Original authors: Code Aurora Forum + * + * Author: Dima Zavin <dima@android.com> + * - Largely rewritten from original to not be an i2c driver. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * 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. + */ + +#define pr_fmt(fmt) "%s: " fmt, __func__ + +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/ssbi.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> + +/* SSBI 2.0 controller registers */ +#define SSBI2_CMD 0x0008 +#define SSBI2_RD 0x0010 +#define SSBI2_STATUS 0x0014 +#define SSBI2_MODE2 0x001C + +/* SSBI_CMD fields */ +#define SSBI_CMD_RDWRN (1 << 24) + +/* SSBI_STATUS fields */ +#define SSBI_STATUS_RD_READY (1 << 2) +#define SSBI_STATUS_READY (1 << 1) +#define SSBI_STATUS_MCHN_BUSY (1 << 0) + +/* SSBI_MODE2 fields */ +#define SSBI_MODE2_REG_ADDR_15_8_SHFT 0x04 +#define SSBI_MODE2_REG_ADDR_15_8_MASK (0x7f << SSBI_MODE2_REG_ADDR_15_8_SHFT) + +#define SET_SSBI_MODE2_REG_ADDR_15_8(MD, AD) \ + (((MD) & 0x0F) | ((((AD) >> 8) << SSBI_MODE2_REG_ADDR_15_8_SHFT) & \ + SSBI_MODE2_REG_ADDR_15_8_MASK)) + +/* SSBI PMIC Arbiter command registers */ +#define SSBI_PA_CMD 0x0000 +#define SSBI_PA_RD_STATUS 0x0004 + +/* SSBI_PA_CMD fields */ +#define SSBI_PA_CMD_RDWRN (1 << 24) +#define SSBI_PA_CMD_ADDR_MASK 0x7fff /* REG_ADDR_7_0, REG_ADDR_8_14*/ + +/* SSBI_PA_RD_STATUS fields */ +#define SSBI_PA_RD_STATUS_TRANS_DONE (1 << 27) +#define SSBI_PA_RD_STATUS_TRANS_DENIED (1 << 26) + +#define SSBI_TIMEOUT_US 100 + +enum ssbi_controller_type { + MSM_SBI_CTRL_SSBI = 0, + MSM_SBI_CTRL_SSBI2, + MSM_SBI_CTRL_PMIC_ARBITER, +}; + +struct ssbi { + struct device *slave; + void __iomem *base; + spinlock_t lock; + enum ssbi_controller_type controller_type; + int (*read)(struct ssbi *, u16 addr, u8 *buf, int len); + int (*write)(struct ssbi *, u16 addr, const u8 *buf, int len); +}; + +#define to_ssbi(dev) platform_get_drvdata(to_platform_device(dev)) + +static inline u32 ssbi_readl(struct ssbi *ssbi, u32 reg) +{ + return readl(ssbi->base + reg); +} + +static inline void ssbi_writel(struct ssbi *ssbi, u32 val, u32 reg) +{ + writel(val, ssbi->base + reg); +} + +/* + * Via private exchange with one of the original authors, the hardware + * should generally finish a transaction in about 5us. The worst + * case, is when using the arbiter and both other CPUs have just + * started trying to use the SSBI bus will result in a time of about + * 20us. It should never take longer than this. + * + * As such, this wait merely spins, with a udelay. + */ +static int ssbi_wait_mask(struct ssbi *ssbi, u32 set_mask, u32 clr_mask) +{ + u32 timeout = SSBI_TIMEOUT_US; + u32 val; + + while (timeout--) { + val = ssbi_readl(ssbi, SSBI2_STATUS); + if (((val & set_mask) == set_mask) && ((val & clr_mask) == 0)) + return 0; + udelay(1); + } + + return -ETIMEDOUT; +} + +static int +ssbi_read_bytes(struct ssbi *ssbi, u16 addr, u8 *buf, int len) +{ + u32 cmd = SSBI_CMD_RDWRN | ((addr & 0xff) << 16); + int ret = 0; + + if (ssbi->controller_type == MSM_SBI_CTRL_SSBI2) { + u32 mode2 = ssbi_readl(ssbi, SSBI2_MODE2); + mode2 = SET_SSBI_MODE2_REG_ADDR_15_8(mode2, addr); + ssbi_writel(ssbi, mode2, SSBI2_MODE2); + } + + while (len) { + ret = ssbi_wait_mask(ssbi, SSBI_STATUS_READY, 0); + if (ret) + goto err; + + ssbi_writel(ssbi, cmd, SSBI2_CMD); + ret = ssbi_wait_mask(ssbi, SSBI_STATUS_RD_READY, 0); + if (ret) + goto err; + *buf++ = ssbi_readl(ssbi, SSBI2_RD) & 0xff; + len--; + } + +err: + return ret; +} + +static int +ssbi_write_bytes(struct ssbi *ssbi, u16 addr, const u8 *buf, int len) +{ + int ret = 0; + + if (ssbi->controller_type == MSM_SBI_CTRL_SSBI2) { + u32 mode2 = ssbi_readl(ssbi, SSBI2_MODE2); + mode2 = SET_SSBI_MODE2_REG_ADDR_15_8(mode2, addr); + ssbi_writel(ssbi, mode2, SSBI2_MODE2); + } + + while (len) { + ret = ssbi_wait_mask(ssbi, SSBI_STATUS_READY, 0); + if (ret) + goto err; + + ssbi_writel(ssbi, ((addr & 0xff) << 16) | *buf, SSBI2_CMD); + ret = ssbi_wait_mask(ssbi, 0, SSBI_STATUS_MCHN_BUSY); + if (ret) + goto err; + buf++; + len--; + } + +err: + return ret; +} + +/* + * See ssbi_wait_mask for an explanation of the time and the + * busywait. + */ +static inline int +ssbi_pa_transfer(struct ssbi *ssbi, u32 cmd, u8 *data) +{ + u32 timeout = SSBI_TIMEOUT_US; + u32 rd_status = 0; + + ssbi_writel(ssbi, cmd, SSBI_PA_CMD); + + while (timeout--) { + rd_status = ssbi_readl(ssbi, SSBI_PA_RD_STATUS); + + if (rd_status & SSBI_PA_RD_STATUS_TRANS_DENIED) + return -EPERM; + + if (rd_status & SSBI_PA_RD_STATUS_TRANS_DONE) { + if (data) + *data = rd_status & 0xff; + return 0; + } + udelay(1); + } + + return -ETIMEDOUT; +} + +static int +ssbi_pa_read_bytes(struct ssbi *ssbi, u16 addr, u8 *buf, int len) +{ + u32 cmd; + int ret = 0; + + cmd = SSBI_PA_CMD_RDWRN | (addr & SSBI_PA_CMD_ADDR_MASK) << 8; + + while (len) { + ret = ssbi_pa_transfer(ssbi, cmd, buf); + if (ret) + goto err; + buf++; + len--; + } + +err: + return ret; +} + +static int +ssbi_pa_write_bytes(struct ssbi *ssbi, u16 addr, const u8 *buf, int len) +{ + u32 cmd; + int ret = 0; + + while (len) { + cmd = (addr & SSBI_PA_CMD_ADDR_MASK) << 8 | *buf; + ret = ssbi_pa_transfer(ssbi, cmd, NULL); + if (ret) + goto err; + buf++; + len--; + } + +err: + return ret; +} + +int ssbi_read(struct device *dev, u16 addr, u8 *buf, int len) +{ + struct ssbi *ssbi = to_ssbi(dev); + unsigned long flags; + int ret; + + spin_lock_irqsave(&ssbi->lock, flags); + ret = ssbi->read(ssbi, addr, buf, len); + spin_unlock_irqrestore(&ssbi->lock, flags); + + return ret; +} +EXPORT_SYMBOL_GPL(ssbi_read); + +int ssbi_write(struct device *dev, u16 addr, const u8 *buf, int len) +{ + struct ssbi *ssbi = to_ssbi(dev); + unsigned long flags; + int ret; + + spin_lock_irqsave(&ssbi->lock, flags); + ret = ssbi->write(ssbi, addr, buf, len); + spin_unlock_irqrestore(&ssbi->lock, flags); + + return ret; +} +EXPORT_SYMBOL_GPL(ssbi_write); + +static int ssbi_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct resource *mem_res; + struct ssbi *ssbi; + const char *type; + + ssbi = devm_kzalloc(&pdev->dev, sizeof(*ssbi), GFP_KERNEL); + if (!ssbi) + return -ENOMEM; + + mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + ssbi->base = devm_ioremap_resource(&pdev->dev, mem_res); + if (IS_ERR(ssbi->base)) + return PTR_ERR(ssbi->base); + + platform_set_drvdata(pdev, ssbi); + + type = of_get_property(np, "qcom,controller-type", NULL); + if (type == NULL) { + dev_err(&pdev->dev, "Missing qcom,controller-type property\n"); + return -EINVAL; + } + dev_info(&pdev->dev, "SSBI controller type: '%s'\n", type); + if (strcmp(type, "ssbi") == 0) + ssbi->controller_type = MSM_SBI_CTRL_SSBI; + else if (strcmp(type, "ssbi2") == 0) + ssbi->controller_type = MSM_SBI_CTRL_SSBI2; + else if (strcmp(type, "pmic-arbiter") == 0) + ssbi->controller_type = MSM_SBI_CTRL_PMIC_ARBITER; + else { + dev_err(&pdev->dev, "Unknown qcom,controller-type\n"); + return -EINVAL; + } + + if (ssbi->controller_type == MSM_SBI_CTRL_PMIC_ARBITER) { + ssbi->read = ssbi_pa_read_bytes; + ssbi->write = ssbi_pa_write_bytes; + } else { + ssbi->read = ssbi_read_bytes; + ssbi->write = ssbi_write_bytes; + } + + spin_lock_init(&ssbi->lock); + + return of_platform_populate(np, NULL, NULL, &pdev->dev); +} + +static const struct of_device_id ssbi_match_table[] = { + { .compatible = "qcom,ssbi" }, + {} +}; +MODULE_DEVICE_TABLE(of, ssbi_match_table); + +static struct platform_driver ssbi_driver = { + .probe = ssbi_probe, + .driver = { + .name = "ssbi", + .of_match_table = ssbi_match_table, + }, +}; +module_platform_driver(ssbi_driver); + +MODULE_LICENSE("GPL v2"); +MODULE_VERSION("1.0"); +MODULE_ALIAS("platform:ssbi"); +MODULE_AUTHOR("Dima Zavin <dima@android.com>"); |