1 files changed, 328 insertions, 0 deletions
diff --git a/drivers/mfd/ssbi.c b/drivers/mfd/ssbi.c
new file mode 100644
index 000000000..94f60df0d
--- /dev/null
+++ b/drivers/mfd/ssbi.c
@@ -0,0 +1,328 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* 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.
+ */
+
+#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);
+};
+
+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 = dev_get_drvdata(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 = dev_get_drvdata(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 devm_of_platform_populate(&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>");