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authorSubhendu Sekhar Behera <sbehera@broadcom.com>2015-03-18 17:20:29 +0530
committerWolfram Sang <wsa@the-dreams.de>2015-04-10 18:59:49 +0200
commit2bbd681ba2bfa0f3805fb541b0840b96893c5727 (patch)
tree8f14e38ee22683eca99f8a47fa9a58fa9e734328 /drivers/i2c/busses/i2c-xlp9xx.c
parent85e4564ab234221f81b13e08ec5eb235734e51b0 (diff)
downloadlinux-stericsson-2bbd681ba2bfa0f3805fb541b0840b96893c5727.tar.gz
i2c: xlp9xx: Driver for Netlogic XLP9XX/5XX I2C controller
Add an I2C bus driver i2c-xlp9xx.c to support the I2C block in the XLP9xx/XLP5xx MIPS SoC. Update Kconfig and Makefile to add the CONFIG_I2C_XLP9XX option. Signed-off-by: Subhendu Sekhar Behera <sbehera@broadcom.com> Signed-off-by: Jayachandran C <jchandra@broadcom.com> Reviewed-by: Ray Jui <rjui@broadcom.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c/busses/i2c-xlp9xx.c')
-rw-r--r--drivers/i2c/busses/i2c-xlp9xx.c445
1 files changed, 445 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-xlp9xx.c b/drivers/i2c/busses/i2c-xlp9xx.c
new file mode 100644
index 000000000000..c941418f06f5
--- /dev/null
+++ b/drivers/i2c/busses/i2c-xlp9xx.c
@@ -0,0 +1,445 @@
+/*
+ * Copyright (c) 2003-2015 Broadcom Corporation
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/completion.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define XLP9XX_I2C_DIV 0x0
+#define XLP9XX_I2C_CTRL 0x1
+#define XLP9XX_I2C_CMD 0x2
+#define XLP9XX_I2C_STATUS 0x3
+#define XLP9XX_I2C_MTXFIFO 0x4
+#define XLP9XX_I2C_MRXFIFO 0x5
+#define XLP9XX_I2C_MFIFOCTRL 0x6
+#define XLP9XX_I2C_STXFIFO 0x7
+#define XLP9XX_I2C_SRXFIFO 0x8
+#define XLP9XX_I2C_SFIFOCTRL 0x9
+#define XLP9XX_I2C_SLAVEADDR 0xA
+#define XLP9XX_I2C_OWNADDR 0xB
+#define XLP9XX_I2C_FIFOWCNT 0xC
+#define XLP9XX_I2C_INTEN 0xD
+#define XLP9XX_I2C_INTST 0xE
+#define XLP9XX_I2C_WAITCNT 0xF
+#define XLP9XX_I2C_TIMEOUT 0X10
+#define XLP9XX_I2C_GENCALLADDR 0x11
+
+#define XLP9XX_I2C_CMD_START BIT(7)
+#define XLP9XX_I2C_CMD_STOP BIT(6)
+#define XLP9XX_I2C_CMD_READ BIT(5)
+#define XLP9XX_I2C_CMD_WRITE BIT(4)
+#define XLP9XX_I2C_CMD_ACK BIT(3)
+
+#define XLP9XX_I2C_CTRL_MCTLEN_SHIFT 16
+#define XLP9XX_I2C_CTRL_MCTLEN_MASK 0xffff0000
+#define XLP9XX_I2C_CTRL_RST BIT(8)
+#define XLP9XX_I2C_CTRL_EN BIT(6)
+#define XLP9XX_I2C_CTRL_MASTER BIT(4)
+#define XLP9XX_I2C_CTRL_FIFORD BIT(1)
+#define XLP9XX_I2C_CTRL_ADDMODE BIT(0)
+
+#define XLP9XX_I2C_INTEN_NACKADDR BIT(25)
+#define XLP9XX_I2C_INTEN_SADDR BIT(13)
+#define XLP9XX_I2C_INTEN_DATADONE BIT(12)
+#define XLP9XX_I2C_INTEN_ARLOST BIT(11)
+#define XLP9XX_I2C_INTEN_MFIFOFULL BIT(4)
+#define XLP9XX_I2C_INTEN_MFIFOEMTY BIT(3)
+#define XLP9XX_I2C_INTEN_MFIFOHI BIT(2)
+#define XLP9XX_I2C_INTEN_BUSERR BIT(0)
+
+#define XLP9XX_I2C_MFIFOCTRL_HITH_SHIFT 8
+#define XLP9XX_I2C_MFIFOCTRL_LOTH_SHIFT 0
+#define XLP9XX_I2C_MFIFOCTRL_RST BIT(16)
+
+#define XLP9XX_I2C_SLAVEADDR_RW BIT(0)
+#define XLP9XX_I2C_SLAVEADDR_ADDR_SHIFT 1
+
+#define XLP9XX_I2C_IP_CLK_FREQ 133000000UL
+#define XLP9XX_I2C_DEFAULT_FREQ 100000
+#define XLP9XX_I2C_HIGH_FREQ 400000
+#define XLP9XX_I2C_FIFO_SIZE 0x80U
+#define XLP9XX_I2C_TIMEOUT_MS 1000
+
+#define XLP9XX_I2C_FIFO_WCNT_MASK 0xff
+#define XLP9XX_I2C_STATUS_ERRMASK (XLP9XX_I2C_INTEN_ARLOST | \
+ XLP9XX_I2C_INTEN_NACKADDR | XLP9XX_I2C_INTEN_BUSERR)
+
+struct xlp9xx_i2c_dev {
+ struct device *dev;
+ struct i2c_adapter adapter;
+ struct completion msg_complete;
+ int irq;
+ bool msg_read;
+ u32 __iomem *base;
+ u32 msg_buf_remaining;
+ u32 msg_len;
+ u32 clk_hz;
+ u32 msg_err;
+ u8 *msg_buf;
+};
+
+static inline void xlp9xx_write_i2c_reg(struct xlp9xx_i2c_dev *priv,
+ unsigned long reg, u32 val)
+{
+ writel(val, priv->base + reg);
+}
+
+static inline u32 xlp9xx_read_i2c_reg(struct xlp9xx_i2c_dev *priv,
+ unsigned long reg)
+{
+ return readl(priv->base + reg);
+}
+
+static void xlp9xx_i2c_mask_irq(struct xlp9xx_i2c_dev *priv, u32 mask)
+{
+ u32 inten;
+
+ inten = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTEN) & ~mask;
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, inten);
+}
+
+static void xlp9xx_i2c_unmask_irq(struct xlp9xx_i2c_dev *priv, u32 mask)
+{
+ u32 inten;
+
+ inten = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTEN) | mask;
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, inten);
+}
+
+static void xlp9xx_i2c_update_rx_fifo_thres(struct xlp9xx_i2c_dev *priv)
+{
+ u32 thres;
+
+ thres = min(priv->msg_buf_remaining, XLP9XX_I2C_FIFO_SIZE);
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MFIFOCTRL,
+ thres << XLP9XX_I2C_MFIFOCTRL_HITH_SHIFT);
+}
+
+static void xlp9xx_i2c_fill_tx_fifo(struct xlp9xx_i2c_dev *priv)
+{
+ u32 len, i;
+ u8 *buf = priv->msg_buf;
+
+ len = min(priv->msg_buf_remaining, XLP9XX_I2C_FIFO_SIZE);
+ for (i = 0; i < len; i++)
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MTXFIFO, buf[i]);
+ priv->msg_buf_remaining -= len;
+ priv->msg_buf += len;
+}
+
+static void xlp9xx_i2c_drain_rx_fifo(struct xlp9xx_i2c_dev *priv)
+{
+ u32 len, i;
+ u8 *buf = priv->msg_buf;
+
+ len = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_FIFOWCNT) &
+ XLP9XX_I2C_FIFO_WCNT_MASK;
+ len = min(priv->msg_buf_remaining, len);
+ for (i = 0; i < len; i++, buf++)
+ *buf = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_MRXFIFO);
+
+ priv->msg_buf_remaining -= len;
+ priv->msg_buf = buf;
+
+ if (priv->msg_buf_remaining)
+ xlp9xx_i2c_update_rx_fifo_thres(priv);
+}
+
+static irqreturn_t xlp9xx_i2c_isr(int irq, void *dev_id)
+{
+ struct xlp9xx_i2c_dev *priv = dev_id;
+ u32 status;
+
+ status = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTST);
+ if (status == 0)
+ return IRQ_NONE;
+
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTST, status);
+ if (status & XLP9XX_I2C_STATUS_ERRMASK) {
+ priv->msg_err = status;
+ goto xfer_done;
+ }
+
+ /* SADDR ACK for SMBUS_QUICK */
+ if ((status & XLP9XX_I2C_INTEN_SADDR) && (priv->msg_len == 0))
+ goto xfer_done;
+
+ if (!priv->msg_read) {
+ if (status & XLP9XX_I2C_INTEN_MFIFOEMTY) {
+ /* TX FIFO got empty, fill it up again */
+ if (priv->msg_buf_remaining)
+ xlp9xx_i2c_fill_tx_fifo(priv);
+ else
+ xlp9xx_i2c_mask_irq(priv,
+ XLP9XX_I2C_INTEN_MFIFOEMTY);
+ }
+ } else {
+ if (status & (XLP9XX_I2C_INTEN_DATADONE |
+ XLP9XX_I2C_INTEN_MFIFOHI)) {
+ /* data is in FIFO, read it */
+ if (priv->msg_buf_remaining)
+ xlp9xx_i2c_drain_rx_fifo(priv);
+ }
+ }
+
+ /* Transfer complete */
+ if (status & XLP9XX_I2C_INTEN_DATADONE)
+ goto xfer_done;
+
+ return IRQ_HANDLED;
+
+xfer_done:
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);
+ complete(&priv->msg_complete);
+ return IRQ_HANDLED;
+}
+
+static int xlp9xx_i2c_init(struct xlp9xx_i2c_dev *priv)
+{
+ u32 prescale;
+
+ /*
+ * The controller uses 5 * SCL clock internally.
+ * So prescale value should be divided by 5.
+ */
+ prescale = DIV_ROUND_UP(XLP9XX_I2C_IP_CLK_FREQ, priv->clk_hz);
+ prescale = ((prescale - 8) / 5) - 1;
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, XLP9XX_I2C_CTRL_RST);
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, XLP9XX_I2C_CTRL_EN |
+ XLP9XX_I2C_CTRL_MASTER);
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_DIV, prescale);
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);
+
+ return 0;
+}
+
+static int xlp9xx_i2c_xfer_msg(struct xlp9xx_i2c_dev *priv, struct i2c_msg *msg,
+ int last_msg)
+{
+ unsigned long timeleft;
+ u32 intr_mask, cmd, val;
+
+ priv->msg_buf = msg->buf;
+ priv->msg_buf_remaining = priv->msg_len = msg->len;
+ priv->msg_err = 0;
+ priv->msg_read = (msg->flags & I2C_M_RD);
+ reinit_completion(&priv->msg_complete);
+
+ /* Reset FIFO */
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MFIFOCTRL,
+ XLP9XX_I2C_MFIFOCTRL_RST);
+
+ /* set FIFO threshold if reading */
+ if (priv->msg_read)
+ xlp9xx_i2c_update_rx_fifo_thres(priv);
+
+ /* set slave addr */
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_SLAVEADDR,
+ (msg->addr << XLP9XX_I2C_SLAVEADDR_ADDR_SHIFT) |
+ (priv->msg_read ? XLP9XX_I2C_SLAVEADDR_RW : 0));
+
+ /* Build control word for transfer */
+ val = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_CTRL);
+ if (!priv->msg_read)
+ val &= ~XLP9XX_I2C_CTRL_FIFORD;
+ else
+ val |= XLP9XX_I2C_CTRL_FIFORD; /* read */
+
+ if (msg->flags & I2C_M_TEN)
+ val |= XLP9XX_I2C_CTRL_ADDMODE; /* 10-bit address mode*/
+ else
+ val &= ~XLP9XX_I2C_CTRL_ADDMODE;
+
+ /* set data length to be transferred */
+ val = (val & ~XLP9XX_I2C_CTRL_MCTLEN_MASK) |
+ (msg->len << XLP9XX_I2C_CTRL_MCTLEN_SHIFT);
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, val);
+
+ /* fill fifo during tx */
+ if (!priv->msg_read)
+ xlp9xx_i2c_fill_tx_fifo(priv);
+
+ /* set interrupt mask */
+ intr_mask = (XLP9XX_I2C_INTEN_ARLOST | XLP9XX_I2C_INTEN_BUSERR |
+ XLP9XX_I2C_INTEN_NACKADDR | XLP9XX_I2C_INTEN_DATADONE);
+
+ if (priv->msg_read) {
+ intr_mask |= XLP9XX_I2C_INTEN_MFIFOHI;
+ if (msg->len == 0)
+ intr_mask |= XLP9XX_I2C_INTEN_SADDR;
+ } else {
+ if (msg->len == 0)
+ intr_mask |= XLP9XX_I2C_INTEN_SADDR;
+ else
+ intr_mask |= XLP9XX_I2C_INTEN_MFIFOEMTY;
+ }
+ xlp9xx_i2c_unmask_irq(priv, intr_mask);
+
+ /* set cmd reg */
+ cmd = XLP9XX_I2C_CMD_START;
+ cmd |= (priv->msg_read ? XLP9XX_I2C_CMD_READ : XLP9XX_I2C_CMD_WRITE);
+ if (last_msg)
+ cmd |= XLP9XX_I2C_CMD_STOP;
+
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CMD, cmd);
+
+ timeleft = msecs_to_jiffies(XLP9XX_I2C_TIMEOUT_MS);
+ timeleft = wait_for_completion_timeout(&priv->msg_complete, timeleft);
+
+ if (priv->msg_err) {
+ dev_dbg(priv->dev, "transfer error %x!\n", priv->msg_err);
+ if (priv->msg_err & XLP9XX_I2C_INTEN_BUSERR)
+ xlp9xx_i2c_init(priv);
+ return -EIO;
+ }
+
+ if (timeleft == 0) {
+ dev_dbg(priv->dev, "i2c transfer timed out!\n");
+ xlp9xx_i2c_init(priv);
+ return -ETIMEDOUT;
+ }
+
+ return 0;
+}
+
+static int xlp9xx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+ int num)
+{
+ int i, ret;
+ struct xlp9xx_i2c_dev *priv = i2c_get_adapdata(adap);
+
+ for (i = 0; i < num; i++) {
+ ret = xlp9xx_i2c_xfer_msg(priv, &msgs[i], i == num - 1);
+ if (ret != 0)
+ return ret;
+ }
+
+ return num;
+}
+
+static u32 xlp9xx_i2c_functionality(struct i2c_adapter *adapter)
+{
+ return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C |
+ I2C_FUNC_10BIT_ADDR;
+}
+
+static struct i2c_algorithm xlp9xx_i2c_algo = {
+ .master_xfer = xlp9xx_i2c_xfer,
+ .functionality = xlp9xx_i2c_functionality,
+};
+
+static int xlp9xx_i2c_get_frequency(struct platform_device *pdev,
+ struct xlp9xx_i2c_dev *priv)
+{
+ struct device_node *np = pdev->dev.of_node;
+ u32 freq;
+ int err;
+
+ err = of_property_read_u32(np, "clock-frequency", &freq);
+ if (err) {
+ freq = XLP9XX_I2C_DEFAULT_FREQ;
+ dev_dbg(&pdev->dev, "using default frequency %u\n", freq);
+ } else if (freq == 0 || freq > XLP9XX_I2C_HIGH_FREQ) {
+ dev_warn(&pdev->dev, "invalid frequency %u, using default\n",
+ freq);
+ freq = XLP9XX_I2C_DEFAULT_FREQ;
+ }
+ priv->clk_hz = freq;
+
+ return 0;
+}
+
+static int xlp9xx_i2c_probe(struct platform_device *pdev)
+{
+ struct xlp9xx_i2c_dev *priv;
+ struct resource *res;
+ int err = 0;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ priv->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ priv->irq = platform_get_irq(pdev, 0);
+ if (priv->irq <= 0) {
+ dev_err(&pdev->dev, "invalid irq!\n");
+ return priv->irq;
+ }
+
+ xlp9xx_i2c_get_frequency(pdev, priv);
+ xlp9xx_i2c_init(priv);
+
+ err = devm_request_irq(&pdev->dev, priv->irq, xlp9xx_i2c_isr, 0,
+ pdev->name, priv);
+ if (err) {
+ dev_err(&pdev->dev, "IRQ request failed!\n");
+ return err;
+ }
+
+ init_completion(&priv->msg_complete);
+ priv->adapter.dev.parent = &pdev->dev;
+ priv->adapter.algo = &xlp9xx_i2c_algo;
+ priv->adapter.dev.of_node = pdev->dev.of_node;
+ priv->dev = &pdev->dev;
+
+ snprintf(priv->adapter.name, sizeof(priv->adapter.name), "xlp9xx-i2c");
+ i2c_set_adapdata(&priv->adapter, priv);
+
+ err = i2c_add_adapter(&priv->adapter);
+ if (err) {
+ dev_err(&pdev->dev, "failed to add I2C adapter!\n");
+ return err;
+ }
+
+ platform_set_drvdata(pdev, priv);
+ dev_dbg(&pdev->dev, "I2C bus:%d added\n", priv->adapter.nr);
+
+ return 0;
+}
+
+static int xlp9xx_i2c_remove(struct platform_device *pdev)
+{
+ struct xlp9xx_i2c_dev *priv;
+
+ priv = platform_get_drvdata(pdev);
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);
+ synchronize_irq(priv->irq);
+ i2c_del_adapter(&priv->adapter);
+ xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CTRL, 0);
+
+ return 0;
+}
+
+static const struct of_device_id xlp9xx_i2c_of_match[] = {
+ { .compatible = "netlogic,xlp980-i2c", },
+ { /* sentinel */ },
+};
+
+static struct platform_driver xlp9xx_i2c_driver = {
+ .probe = xlp9xx_i2c_probe,
+ .remove = xlp9xx_i2c_remove,
+ .driver = {
+ .name = "xlp9xx-i2c",
+ .of_match_table = xlp9xx_i2c_of_match,
+ },
+};
+
+module_platform_driver(xlp9xx_i2c_driver);
+
+MODULE_AUTHOR("Subhendu Sekhar Behera <sbehera@broadcom.com>");
+MODULE_DESCRIPTION("XLP9XX/5XX I2C Bus Controller Driver");
+MODULE_LICENSE("GPL v2");