Patchwork [v3,2/2] platform-drivers: msm: add single-wire serial bus interface (SSBI) driver

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Submitter Kenneth Heitke
Date March 2, 2011, 4:01 a.m.
Message ID <1299038465-11782-3-git-send-email-kheitke@codeaurora.org>
Download mbox | patch
Permalink /patch/601771/
State New, archived
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Patch

diff --git a/drivers/platform/Kconfig b/drivers/platform/Kconfig
index 8390dca..17b5df5 100644
--- a/drivers/platform/Kconfig
+++ b/drivers/platform/Kconfig
@@ -1,3 +1,6 @@ 
 if X86
 source "drivers/platform/x86/Kconfig"
 endif
+if ARCH_MSM
+source "drivers/platform/msm/Kconfig"
+endif
diff --git a/drivers/platform/Makefile b/drivers/platform/Makefile
index 782953a..58c62bd 100644
--- a/drivers/platform/Makefile
+++ b/drivers/platform/Makefile
@@ -3,3 +3,4 @@ 
 #
 
 obj-$(CONFIG_X86)		+= x86/
+obj-$(CONFIG_ARCH_MSM)		+= msm/
diff --git a/drivers/platform/msm/Kconfig b/drivers/platform/msm/Kconfig
new file mode 100644
index 0000000..413bb65
--- /dev/null
+++ b/drivers/platform/msm/Kconfig
@@ -0,0 +1,13 @@ 
+menu "Qualcomm MSM specific device drivers"
+	depends on ARCH_MSM
+
+config MSM_SSBI
+	bool "Qualcomm Single-wire Serial Bus Interface (SSBI)"
+	help
+	  If you say yes to this option, support will be included for the
+	  built-in SSBI interface on Qualcomm MSM family processors.
+
+	  This is required for communicating with Qualcomm PMICs and
+	  other devices that have the SSBI interface.
+
+endmenu
diff --git a/drivers/platform/msm/Makefile b/drivers/platform/msm/Makefile
new file mode 100644
index 0000000..ea8c1e4
--- /dev/null
+++ b/drivers/platform/msm/Makefile
@@ -0,0 +1,4 @@ 
+#
+# Makefile for the MSM specific device drivers.
+#
+obj-$(CONFIG_MSM_SSBI) += ssbi.o
diff --git a/drivers/platform/msm/ssbi.c b/drivers/platform/msm/ssbi.c
new file mode 100644
index 0000000..b4fd02e
--- /dev/null
+++ b/drivers/platform/msm/ssbi.c
@@ -0,0 +1,396 @@ 
+/* Copyright (c) 2009-2011, Code Aurora Forum. 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/msm_ssbi.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
+
+struct msm_ssbi {
+	struct device		*dev;
+	struct device		*slave;
+	void __iomem		*base;
+	spinlock_t		lock;
+	enum msm_ssbi_controller_type controller_type;
+	int (*read)(struct msm_ssbi *, u16 addr, u8 *buf, int len);
+	int (*write)(struct msm_ssbi *, u16 addr, u8 *buf, int len);
+};
+
+#define to_msm_ssbi(dev)	platform_get_drvdata(to_platform_device(dev))
+
+static inline u32 ssbi_readl(struct msm_ssbi *ssbi, u32 reg)
+{
+	return readl(ssbi->base + reg);
+}
+
+static inline void ssbi_writel(struct msm_ssbi *ssbi, u32 val, u32 reg)
+{
+	writel(val, ssbi->base + reg);
+}
+
+static int ssbi_wait_mask(struct msm_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);
+	}
+
+	dev_err(ssbi->dev, "%s: timeout (status %x set_mask %x clr_mask %x)\n",
+		__func__, ssbi_readl(ssbi, SSBI2_STATUS), set_mask, clr_mask);
+	return -ETIMEDOUT;
+}
+
+static int
+msm_ssbi_read_bytes(struct msm_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
+msm_ssbi_write_bytes(struct msm_ssbi *ssbi, u16 addr, 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;
+}
+
+static inline int
+msm_ssbi_pa_transfer(struct msm_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) {
+			dev_err(ssbi->dev, "%s: transaction denied (0x%x)\n",
+					__func__, rd_status);
+			return -EPERM;
+		}
+
+		if (rd_status & SSBI_PA_RD_STATUS_TRANS_DONE) {
+			if (data)
+				*data = rd_status & 0xff;
+			return 0;
+		}
+		udelay(1);
+	}
+
+	dev_err(ssbi->dev, "%s: timeout, status 0x%x\n", __func__, rd_status);
+	return -ETIMEDOUT;
+}
+
+static int
+msm_ssbi_pa_read_bytes(struct msm_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 = msm_ssbi_pa_transfer(ssbi, cmd, buf);
+		if (ret)
+			goto err;
+		buf++;
+		len--;
+	}
+
+err:
+	return ret;
+}
+
+static int
+msm_ssbi_pa_write_bytes(struct msm_ssbi *ssbi, u16 addr, u8 *buf, int len)
+{
+	u32 cmd;
+	int ret = 0;
+
+	while (len) {
+		cmd = (addr & SSBI_PA_CMD_ADDR_MASK) << 8 | *buf;
+		ret = msm_ssbi_pa_transfer(ssbi, cmd, NULL);
+		if (ret)
+			goto err;
+		buf++;
+		len--;
+	}
+
+err:
+	return ret;
+}
+
+int msm_ssbi_read(struct device *dev, u16 addr, u8 *buf, int len)
+{
+	struct msm_ssbi *ssbi = to_msm_ssbi(dev);
+	unsigned long flags;
+	int ret;
+
+	if (ssbi->dev != dev)
+		return -ENXIO;
+
+	spin_lock_irqsave(&ssbi->lock, flags);
+	ret = ssbi->read(ssbi, addr, buf, len);
+	spin_unlock_irqrestore(&ssbi->lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(msm_ssbi_read);
+
+int msm_ssbi_write(struct device *dev, u16 addr, u8 *buf, int len)
+{
+	struct msm_ssbi *ssbi = to_msm_ssbi(dev);
+	unsigned long flags;
+	int ret;
+
+	if (ssbi->dev != dev)
+		return -ENXIO;
+
+	spin_lock_irqsave(&ssbi->lock, flags);
+	ret = ssbi->write(ssbi, addr, buf, len);
+	spin_unlock_irqrestore(&ssbi->lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(msm_ssbi_write);
+
+static int __devinit msm_ssbi_add_slave(struct msm_ssbi *ssbi,
+				const struct msm_ssbi_slave_info *slave)
+{
+	struct platform_device *slave_pdev;
+	int ret;
+
+	if (ssbi->slave) {
+		pr_err("slave already attached??\n");
+		return -EBUSY;
+	}
+
+	slave_pdev = platform_device_alloc(slave->name, -1);
+	if (!slave_pdev) {
+		pr_err("cannot allocate pdev for slave '%s'", slave->name);
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	slave_pdev->dev.parent = ssbi->dev;
+	slave_pdev->dev.platform_data = slave->platform_data;
+
+	ret = platform_device_add(slave_pdev);
+	if (ret) {
+		pr_err("cannot add slave platform device for '%s'\n",
+				slave->name);
+		goto err;
+	}
+
+	ssbi->slave = &slave_pdev->dev;
+	return 0;
+
+err:
+	if (slave_pdev)
+		platform_device_put(slave_pdev);
+	return ret;
+}
+
+static int __devinit msm_ssbi_probe(struct platform_device *pdev)
+{
+	const struct msm_ssbi_platform_data *pdata = pdev->dev.platform_data;
+	struct resource *mem_res;
+	struct msm_ssbi *ssbi;
+	int ret = 0;
+
+	if (!pdata) {
+		pr_err("missing platform data\n");
+		return -EINVAL;
+	}
+
+	pr_debug("%s\n", pdata->slave.name);
+
+	ssbi = kzalloc(sizeof(struct msm_ssbi), GFP_KERNEL);
+	if (!ssbi) {
+		pr_err("can not allocate ssbi_data\n");
+		return -ENOMEM;
+	}
+
+	mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!mem_res) {
+		pr_err("missing mem resource\n");
+		ret = -EINVAL;
+		goto err_get_mem_res;
+	}
+
+	ssbi->base = ioremap(mem_res->start, resource_size(mem_res));
+	if (!ssbi->base) {
+		pr_err("ioremap of 0x%p failed\n", (void *)mem_res->start);
+		ret = -EINVAL;
+		goto err_ioremap;
+	}
+	ssbi->dev = &pdev->dev;
+	platform_set_drvdata(pdev, ssbi);
+
+	ssbi->controller_type = pdata->controller_type;
+	if (ssbi->controller_type == MSM_SBI_CTRL_PMIC_ARBITER) {
+		ssbi->read = msm_ssbi_pa_read_bytes;
+		ssbi->write = msm_ssbi_pa_write_bytes;
+	} else {
+		ssbi->read = msm_ssbi_read_bytes;
+		ssbi->write = msm_ssbi_write_bytes;
+	}
+
+	spin_lock_init(&ssbi->lock);
+
+	ret = msm_ssbi_add_slave(ssbi, &pdata->slave);
+	if (ret)
+		goto err_ssbi_add_slave;
+
+	return 0;
+
+err_ssbi_add_slave:
+	platform_set_drvdata(pdev, NULL);
+	iounmap(ssbi->base);
+err_ioremap:
+err_get_mem_res:
+	kfree(ssbi);
+	return ret;
+}
+
+static int __devexit msm_ssbi_remove(struct platform_device *pdev)
+{
+	struct msm_ssbi *ssbi = platform_get_drvdata(pdev);
+
+	platform_set_drvdata(pdev, NULL);
+	iounmap(ssbi->base);
+	kfree(ssbi);
+	return 0;
+}
+
+static struct platform_driver msm_ssbi_driver = {
+	.probe		= msm_ssbi_probe,
+	.remove		= __exit_p(msm_ssbi_remove),
+	.driver		= {
+		.name	= "msm_ssbi",
+		.owner	= THIS_MODULE,
+	},
+};
+
+static int __init msm_ssbi_init(void)
+{
+	return platform_driver_register(&msm_ssbi_driver);
+}
+postcore_initcall(msm_ssbi_init);
+
+static void __exit msm_ssbi_exit(void)
+{
+	platform_driver_unregister(&msm_ssbi_driver);
+}
+module_exit(msm_ssbi_exit)
+
+MODULE_LICENSE("GPL v2");
+MODULE_VERSION("1.0");
+MODULE_ALIAS("platform:msm_ssbi");
+MODULE_AUTHOR("Dima Zavin <dima@android.com>");
diff --git a/include/linux/msm_ssbi.h b/include/linux/msm_ssbi.h
new file mode 100644
index 0000000..cfa47df
--- /dev/null
+++ b/include/linux/msm_ssbi.h
@@ -0,0 +1,49 @@ 
+/* Copyright (C) 2010 Google, Inc.
+ * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
+ * Author: Dima Zavin <dima@android.com>
+ *
+ * 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.
+ */
+
+#ifndef _LINUX_MSM_SSBI_H
+#define _LINUX_MSM_SSBI_H
+
+#include <linux/types.h>
+
+struct msm_ssbi_slave_info {
+	const char	*name;
+	void		*platform_data;
+};
+
+enum msm_ssbi_controller_type {
+	MSM_SBI_CTRL_SSBI = 0,
+	MSM_SBI_CTRL_SSBI2,
+	MSM_SBI_CTRL_PMIC_ARBITER,
+};
+
+struct msm_ssbi_platform_data {
+	struct msm_ssbi_slave_info	slave;
+	enum msm_ssbi_controller_type controller_type;
+};
+
+#ifdef CONFIG_MSM_SSBI
+int msm_ssbi_write(struct device *dev, u16 addr, u8 *buf, int len);
+int msm_ssbi_read(struct device *dev, u16 addr, u8 *buf, int len);
+#else
+static inline int msm_ssbi_write(struct device *dev, u16 addr, u8 *buf, int len)
+{
+	return -ENXIO;
+}
+static inline int msm_ssbi_read(struct device *dev, u16 addr, u8 *buf, int len)
+{
+	return -ENXIO;
+}
+#endif
+#endif