i2c: add CSR SiRFprimaII on-chip I2C controllers driver

SiRFprimaII is the latest generation application processor from CSR’s
multi-function SoC product family.
The SoC support codes are in arch/arm/mach-prima2 from Linux mainline
3.0.
There are two I2C controllers on primaII, features include:
* Two I2C controller modules are on chip
* RISC I/O bus read write register
* Up to 16 bytes data buffer for issuing commands and writing data
  at the same time
* Up to 16 commands, and receiving read data 16 bytes at a time
* Error INT report (ACK check)
* No-ACK bus protocols (SCCB bus protocols)

Signed-off-by: Zhiwu Song <Zhiwu.Song@csr.com>
Signed-off-by: Xiangzhen Ye <Xiangzhen.Ye@csr.com>
Signed-off-by: Yuping Luo <Yuping.Luo@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

3 files changed, 470 insertions, 0 deletions

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index e99bfa86ba71..71c1b0a7535c 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -645,6 +645,16 @@ config I2C_SIMTEC
           This driver can also be built as a module. If so, the module
           will be called i2c-simtec.
 
+config I2C_SIRF
+        tristate "CSR SiRFprimaII I2C interface"
+        depends on ARCH_PRIMA2
+        help
+          If you say yes to this option, support will be included for the
+          CSR SiRFprimaII I2C interface.
+
+          This driver can also be built as a module.  If so, the module
+          will be called i2c-sirf.
+
 config I2C_STU300
         tristate "ST Microelectronics DDC I2C interface"
         depends on MACH_U300
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 8f9e7b6677e1..569567b0d027 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_I2C_S6000)		+= i2c-s6000.o
 obj-$(CONFIG_I2C_SH7760)        += i2c-sh7760.o
 obj-$(CONFIG_I2C_SH_MOBILE)     += i2c-sh_mobile.o
 obj-$(CONFIG_I2C_SIMTEC)        += i2c-simtec.o
+obj-$(CONFIG_I2C_SIRF)          += i2c-sirf.o
 obj-$(CONFIG_I2C_STU300)        += i2c-stu300.o
 obj-$(CONFIG_I2C_TEGRA)         += i2c-tegra.o
 obj-$(CONFIG_I2C_VERSATILE)     += i2c-versatile.o
diff --git a/drivers/i2c/busses/i2c-sirf.c b/drivers/i2c/busses/i2c-sirf.c
new file mode 100644
index 000000000000..5574a47792fb
--- /dev/null
+++ b/drivers/i2c/busses/i2c-sirf.c
@@ -0,0 +1,459 @@
+/*
+ * I2C bus driver for CSR SiRFprimaII
+ *
+ * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
+ *
+ * Licensed under GPLv2 or later.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/i2c.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+
+#define SIRFSOC_I2C_CLK_CTRL            0x00
+#define SIRFSOC_I2C_STATUS              0x0C
+#define SIRFSOC_I2C_CTRL                0x10
+#define SIRFSOC_I2C_IO_CTRL             0x14
+#define SIRFSOC_I2C_SDA_DELAY           0x18
+#define SIRFSOC_I2C_CMD_START           0x1C
+#define SIRFSOC_I2C_CMD_BUF             0x30
+#define SIRFSOC_I2C_DATA_BUF            0x80
+
+#define SIRFSOC_I2C_CMD_BUF_MAX         16
+#define SIRFSOC_I2C_DATA_BUF_MAX        16
+
+#define SIRFSOC_I2C_CMD(x)              (SIRFSOC_I2C_CMD_BUF + (x)*0x04)
+#define SIRFSOC_I2C_DATA_MASK(x)        (0xFF<<(((x)&3)*8))
+#define SIRFSOC_I2C_DATA_SHIFT(x)       (((x)&3)*8)
+
+#define SIRFSOC_I2C_DIV_MASK            (0xFFFF)
+
+/* I2C status flags */
+#define SIRFSOC_I2C_STAT_BUSY           BIT(0)
+#define SIRFSOC_I2C_STAT_TIP            BIT(1)
+#define SIRFSOC_I2C_STAT_NACK           BIT(2)
+#define SIRFSOC_I2C_STAT_TR_INT         BIT(4)
+#define SIRFSOC_I2C_STAT_STOP           BIT(6)
+#define SIRFSOC_I2C_STAT_CMD_DONE       BIT(8)
+#define SIRFSOC_I2C_STAT_ERR            BIT(9)
+#define SIRFSOC_I2C_CMD_INDEX           (0x1F<<16)
+
+/* I2C control flags */
+#define SIRFSOC_I2C_RESET               BIT(0)
+#define SIRFSOC_I2C_CORE_EN             BIT(1)
+#define SIRFSOC_I2C_MASTER_MODE         BIT(2)
+#define SIRFSOC_I2C_CMD_DONE_EN         BIT(11)
+#define SIRFSOC_I2C_ERR_INT_EN          BIT(12)
+
+#define SIRFSOC_I2C_SDA_DELAY_MASK      (0xFF)
+#define SIRFSOC_I2C_SCLF_FILTER         (3<<8)
+
+#define SIRFSOC_I2C_START_CMD           BIT(0)
+
+#define SIRFSOC_I2C_CMD_RP(x)           ((x)&0x7)
+#define SIRFSOC_I2C_NACK                BIT(3)
+#define SIRFSOC_I2C_WRITE               BIT(4)
+#define SIRFSOC_I2C_READ                BIT(5)
+#define SIRFSOC_I2C_STOP                BIT(6)
+#define SIRFSOC_I2C_START               BIT(7)
+
+#define SIRFSOC_I2C_DEFAULT_SPEED 100000
+
+struct sirfsoc_i2c {
+        void __iomem *base;
+        struct clk *clk;
+        u32 cmd_ptr;            /* Current position in CMD buffer */
+        u8 *buf;                /* Buffer passed by user */
+        u32 msg_len;            /* Message length */
+        u32 finished_len;       /* number of bytes read/written */
+        u32 read_cmd_len;       /* number of read cmd sent */
+        int msg_read;           /* 1 indicates a read message */
+        int err_status;         /* 1 indicates an error on bus */
+
+        u32 sda_delay;          /* For suspend/resume */
+        u32 clk_div;
+        int last;               /* Last message in transfer, STOP cmd can be sent */
+
+        struct completion done; /* indicates completion of message transfer */
+        struct i2c_adapter adapter;
+};
+
+static void i2c_sirfsoc_read_data(struct sirfsoc_i2c *siic)
+{
+        u32 data = 0;
+        int i;
+
+        for (i = 0; i < siic->read_cmd_len; i++) {
+                if (!(i & 0x3))
+                        data = readl(siic->base + SIRFSOC_I2C_DATA_BUF + i);
+                siic->buf[siic->finished_len++] =
+                        (u8)((data & SIRFSOC_I2C_DATA_MASK(i)) >>
+                                SIRFSOC_I2C_DATA_SHIFT(i));
+        }
+}
+
+static void i2c_sirfsoc_queue_cmd(struct sirfsoc_i2c *siic)
+{
+        u32 regval;
+        int i = 0;
+
+        if (siic->msg_read) {
+                while (((siic->finished_len + i) < siic->msg_len)
+                                && (siic->cmd_ptr < SIRFSOC_I2C_CMD_BUF_MAX)) {
+                        regval = SIRFSOC_I2C_READ | SIRFSOC_I2C_CMD_RP(0);
+                        if (((siic->finished_len + i) ==
+                                        (siic->msg_len - 1)) && siic->last)
+                                regval |= SIRFSOC_I2C_STOP | SIRFSOC_I2C_NACK;
+                        writel(regval,
+                                siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
+                        i++;
+                }
+
+                siic->read_cmd_len = i;
+        } else {
+                while ((siic->cmd_ptr < SIRFSOC_I2C_CMD_BUF_MAX - 1)
+                                && (siic->finished_len < siic->msg_len)) {
+                        regval = SIRFSOC_I2C_WRITE | SIRFSOC_I2C_CMD_RP(0);
+                        if ((siic->finished_len == (siic->msg_len - 1))
+                                && siic->last)
+                                regval |= SIRFSOC_I2C_STOP;
+                        writel(regval,
+                                siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
+                        writel(siic->buf[siic->finished_len++],
+                                siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
+                }
+        }
+        siic->cmd_ptr = 0;
+
+        /* Trigger the transfer */
+        writel(SIRFSOC_I2C_START_CMD, siic->base + SIRFSOC_I2C_CMD_START);
+}
+
+static irqreturn_t i2c_sirfsoc_irq(int irq, void *dev_id)
+{
+        struct sirfsoc_i2c *siic = (struct sirfsoc_i2c *)dev_id;
+        u32 i2c_stat = readl(siic->base + SIRFSOC_I2C_STATUS);
+
+        if (i2c_stat & SIRFSOC_I2C_STAT_ERR) {
+                /* Error conditions */
+                siic->err_status = 1;
+                writel(SIRFSOC_I2C_STAT_ERR, siic->base + SIRFSOC_I2C_STATUS);
+
+                if (i2c_stat & SIRFSOC_I2C_STAT_NACK)
+                        dev_err(&siic->adapter.dev, "ACK not received\n");
+                else
+                        dev_err(&siic->adapter.dev, "I2C error\n");
+
+                complete(&siic->done);
+        } else if (i2c_stat & SIRFSOC_I2C_STAT_CMD_DONE) {
+                /* CMD buffer execution complete */
+                if (siic->msg_read)
+                        i2c_sirfsoc_read_data(siic);
+                if (siic->finished_len == siic->msg_len)
+                        complete(&siic->done);
+                else /* Fill a new CMD buffer for left data */
+                        i2c_sirfsoc_queue_cmd(siic);
+
+                writel(SIRFSOC_I2C_STAT_CMD_DONE, siic->base + SIRFSOC_I2C_STATUS);
+        }
+
+        return IRQ_HANDLED;
+}
+
+static void i2c_sirfsoc_set_address(struct sirfsoc_i2c *siic,
+        struct i2c_msg *msg)
+{
+        unsigned char addr;
+        u32 regval = SIRFSOC_I2C_START | SIRFSOC_I2C_CMD_RP(0) | SIRFSOC_I2C_WRITE;
+
+        /* no data and last message -> add STOP */
+        if (siic->last && (msg->len == 0))
+                regval |= SIRFSOC_I2C_STOP;
+
+        writel(regval, siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
+
+        addr = msg->addr << 1;  /* Generate address */
+        if (msg->flags & I2C_M_RD)
+                addr |= 1;
+
+        writel(addr, siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
+}
+
+static int i2c_sirfsoc_xfer_msg(struct sirfsoc_i2c *siic, struct i2c_msg *msg)
+{
+        u32 regval = readl(siic->base + SIRFSOC_I2C_CTRL);
+        /* timeout waiting for the xfer to finish or fail */
+        int timeout = msecs_to_jiffies((msg->len + 1) * 50);
+        int ret = 0;
+
+        i2c_sirfsoc_set_address(siic, msg);
+
+        writel(regval | SIRFSOC_I2C_CMD_DONE_EN | SIRFSOC_I2C_ERR_INT_EN,
+                siic->base + SIRFSOC_I2C_CTRL);
+        i2c_sirfsoc_queue_cmd(siic);
+
+        if (wait_for_completion_timeout(&siic->done, timeout) == 0) {
+                siic->err_status = 1;
+                dev_err(&siic->adapter.dev, "Transfer timeout\n");
+        }
+
+        writel(regval & ~(SIRFSOC_I2C_CMD_DONE_EN | SIRFSOC_I2C_ERR_INT_EN),
+                siic->base + SIRFSOC_I2C_CTRL);
+        writel(0, siic->base + SIRFSOC_I2C_CMD_START);
+
+        if (siic->err_status) {
+                writel(readl(siic->base + SIRFSOC_I2C_CTRL) | SIRFSOC_I2C_RESET,
+                        siic->base + SIRFSOC_I2C_CTRL);
+                while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET)
+                        cpu_relax();
+
+                ret = -EIO;
+        }
+
+        return ret;
+}
+
+static u32 i2c_sirfsoc_func(struct i2c_adapter *adap)
+{
+        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static int i2c_sirfsoc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+        int num)
+{
+        struct sirfsoc_i2c *siic = adap->algo_data;
+        int i, ret;
+
+        clk_enable(siic->clk);
+
+        for (i = 0; i < num; i++) {
+                siic->buf = msgs[i].buf;
+                siic->msg_len = msgs[i].len;
+                siic->msg_read = !!(msgs[i].flags & I2C_M_RD);
+                siic->err_status = 0;
+                siic->cmd_ptr = 0;
+                siic->finished_len = 0;
+                siic->last = (i == (num - 1));
+
+                ret = i2c_sirfsoc_xfer_msg(siic, &msgs[i]);
+                if (ret) {
+                        clk_disable(siic->clk);
+                        return ret;
+                }
+        }
+
+        clk_disable(siic->clk);
+        return num;
+}
+
+/* I2C algorithms associated with this master controller driver */
+static const struct i2c_algorithm i2c_sirfsoc_algo = {
+        .master_xfer = i2c_sirfsoc_xfer,
+        .functionality = i2c_sirfsoc_func,
+};
+
+static int __devinit i2c_sirfsoc_probe(struct platform_device *pdev)
+{
+        struct sirfsoc_i2c *siic;
+        struct i2c_adapter *adap;
+        struct resource *mem_res;
+        struct clk *clk;
+        int bitrate;
+        int ctrl_speed;
+        int irq;
+
+        int err;
+        u32 regval;
+
+        clk = clk_get(&pdev->dev, NULL);
+        if (IS_ERR(clk)) {
+                err = PTR_ERR(clk);
+                dev_err(&pdev->dev, "Clock get failed\n");
+                goto err_get_clk;
+        }
+
+        err = clk_prepare(clk);
+        if (err) {
+                dev_err(&pdev->dev, "Clock prepare failed\n");
+                goto err_clk_prep;
+        }
+
+        err = clk_enable(clk);
+        if (err) {
+                dev_err(&pdev->dev, "Clock enable failed\n");
+                goto err_clk_en;
+        }
+
+        ctrl_speed = clk_get_rate(clk);
+
+        siic = devm_kzalloc(&pdev->dev, sizeof(*siic), GFP_KERNEL);
+        if (!siic) {
+                dev_err(&pdev->dev, "Can't allocate driver data\n");
+                err = -ENOMEM;
+                goto out;
+        }
+        adap = &siic->adapter;
+        adap->class = I2C_CLASS_HWMON;
+
+        mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (mem_res == NULL) {
+                dev_err(&pdev->dev, "Unable to get MEM resource\n");
+                err = -EINVAL;
+                goto out;
+        }
+
+        siic->base = devm_request_and_ioremap(&pdev->dev, mem_res);
+        if (siic->base == NULL) {
+                dev_err(&pdev->dev, "IO remap failed!\n");
+                err = -ENOMEM;
+                goto out;
+        }
+
+        irq = platform_get_irq(pdev, 0);
+        if (irq < 0) {
+                err = irq;
+                goto out;
+        }
+        err = devm_request_irq(&pdev->dev, irq, i2c_sirfsoc_irq, 0,
+                dev_name(&pdev->dev), siic);
+        if (err)
+                goto out;
+
+        adap->algo = &i2c_sirfsoc_algo;
+        adap->algo_data = siic;
+
+        adap->dev.parent = &pdev->dev;
+        adap->nr = pdev->id;
+
+        strlcpy(adap->name, "sirfsoc-i2c", sizeof(adap->name));
+
+        platform_set_drvdata(pdev, adap);
+        init_completion(&siic->done);
+
+        /* Controller Initalisation */
+
+        writel(SIRFSOC_I2C_RESET, siic->base + SIRFSOC_I2C_CTRL);
+        while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET)
+                cpu_relax();
+        writel(SIRFSOC_I2C_CORE_EN | SIRFSOC_I2C_MASTER_MODE,
+                siic->base + SIRFSOC_I2C_CTRL);
+
+        siic->clk = clk;
+
+        err = of_property_read_u32(pdev->dev.of_node,
+                "clock-frequency", &bitrate);
+        if (err < 0)
+                bitrate = SIRFSOC_I2C_DEFAULT_SPEED;
+
+        if (bitrate < 100000)
+                regval =
+                        (2 * ctrl_speed) / (2 * bitrate * 11);
+        else
+                regval = ctrl_speed / (bitrate * 5);
+
+        writel(regval, siic->base + SIRFSOC_I2C_CLK_CTRL);
+        if (regval > 0xFF)
+                writel(0xFF, siic->base + SIRFSOC_I2C_SDA_DELAY);
+        else
+                writel(regval, siic->base + SIRFSOC_I2C_SDA_DELAY);
+
+        err = i2c_add_numbered_adapter(adap);
+        if (err < 0) {
+                dev_err(&pdev->dev, "Can't add new i2c adapter\n");
+                goto out;
+        }
+
+        clk_disable(clk);
+
+        dev_info(&pdev->dev, " I2C adapter ready to operate\n");
+
+        return 0;
+
+out:
+        clk_disable(clk);
+err_clk_en:
+        clk_unprepare(clk);
+err_clk_prep:
+        clk_put(clk);
+err_get_clk:
+        return err;
+}
+
+static int __devexit i2c_sirfsoc_remove(struct platform_device *pdev)
+{
+        struct i2c_adapter *adapter = platform_get_drvdata(pdev);
+        struct sirfsoc_i2c *siic = adapter->algo_data;
+
+        writel(SIRFSOC_I2C_RESET, siic->base + SIRFSOC_I2C_CTRL);
+        i2c_del_adapter(adapter);
+        clk_unprepare(siic->clk);
+        clk_put(siic->clk);
+        return 0;
+}
+
+#ifdef CONFIG_PM
+static int i2c_sirfsoc_suspend(struct device *dev)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct i2c_adapter *adapter = platform_get_drvdata(pdev);
+        struct sirfsoc_i2c *siic = adapter->algo_data;
+
+        clk_enable(siic->clk);
+        siic->sda_delay = readl(siic->base + SIRFSOC_I2C_SDA_DELAY);
+        siic->clk_div = readl(siic->base + SIRFSOC_I2C_CLK_CTRL);
+        clk_disable(siic->clk);
+        return 0;
+}
+
+static int i2c_sirfsoc_resume(struct device *dev)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct i2c_adapter *adapter = platform_get_drvdata(pdev);
+        struct sirfsoc_i2c *siic = adapter->algo_data;
+
+        clk_enable(siic->clk);
+        writel(SIRFSOC_I2C_RESET, siic->base + SIRFSOC_I2C_CTRL);
+        writel(SIRFSOC_I2C_CORE_EN | SIRFSOC_I2C_MASTER_MODE,
+                siic->base + SIRFSOC_I2C_CTRL);
+        writel(siic->clk_div, siic->base + SIRFSOC_I2C_CLK_CTRL);
+        writel(siic->sda_delay, siic->base + SIRFSOC_I2C_SDA_DELAY);
+        clk_disable(siic->clk);
+        return 0;
+}
+
+static const struct dev_pm_ops i2c_sirfsoc_pm_ops = {
+        .suspend = i2c_sirfsoc_suspend,
+        .resume = i2c_sirfsoc_resume,
+};
+#endif
+
+static const struct of_device_id sirfsoc_i2c_of_match[] __devinitconst = {
+        { .compatible = "sirf,prima2-i2c", },
+        {},
+};
+MODULE_DEVICE_TABLE(of, sirfsoc_i2c_of_match);
+
+static struct platform_driver i2c_sirfsoc_driver = {
+        .driver = {
+                .name = "sirfsoc_i2c",
+                .owner = THIS_MODULE,
+#ifdef CONFIG_PM
+                .pm = &i2c_sirfsoc_pm_ops,
+#endif
+                .of_match_table = sirfsoc_i2c_of_match,
+        },
+        .probe = i2c_sirfsoc_probe,
+        .remove = __devexit_p(i2c_sirfsoc_remove),
+};
+module_platform_driver(i2c_sirfsoc_driver);
+
+MODULE_DESCRIPTION("SiRF SoC I2C master controller driver");
+MODULE_AUTHOR("Zhiwu Song <Zhiwu.Song@csr.com>, "
+        "Xiangzhen Ye <Xiangzhen.Ye@csr.com>");
+MODULE_LICENSE("GPL v2");