On Fri, Jan 16, 2015 at 12:53:40PM +0530, Jayachandran C wrote:
> From: Subhendu Sekhar Behera <sbehera@xxxxxxxxxxxx>
>
> 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.
>
> Also add document Documentation/devicetree/bindings/i2c/i2c-xlp9xx.txt
> for DT compatible string "netlogic,xlp9xx-i2c".
>
> Signed-off-by: Subhendu Sekhar Behera <sbehera@xxxxxxxxxxxx>
> Signed-off-by: Jayachandran C <jchandra@xxxxxxxxxxxx>
I would like to request some in-house teaching here. Ray Jui (also from
Broadcom and on CC now) just got his i2c driver applied. He should be
able to help you and spot a few issues which he had to solve just
recently, too. That would save me some bandwidth which would go into
other I2C maintenance. OK, guys?
> ---
> .../devicetree/bindings/i2c/i2c-xlp9xx.txt | 19 +
> drivers/i2c/busses/Kconfig | 10 +
> drivers/i2c/busses/Makefile | 1 +
> drivers/i2c/busses/i2c-xlp9xx.c | 447 +++++++++++++++++++++
> 4 files changed, 477 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/i2c/i2c-xlp9xx.txt
> create mode 100644 drivers/i2c/busses/i2c-xlp9xx.c
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-xlp9xx.txt b/Documentation/devicetree/bindings/i2c/i2c-xlp9xx.txt
> new file mode 100644
> index 00000000..dca75d1
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/i2c-xlp9xx.txt
> @@ -0,0 +1,19 @@
> +XLP9XX/5XX I2C Bus Controller Driver
> +
> +Required properties:
> +- compatible : Should be "netlogic,xlp9xx-i2c".
> +- reg: Requires register offset and length.
> +- interrupts: Should contain irq number.
> +- clock-frequency: I2C clock frequency required.
> +
> +Example:
> +
> +i2c0: i2c@113100 {
> + compatible = "netlogic,xlp9xx-i2c";
> + #address-cells = <1>;
> + #size-cells = <0>;
> + reg = <0 0x113100 0x100>;
> + clock-frequency = <133000000>;
> + interrupts = <30>;
> + interrupt-parent = <&pic>;
> +};
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 31e8308..44ba68e 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -878,6 +878,16 @@ config I2C_XLR
> This driver can also be built as a module. If so, the module
> will be called i2c-xlr.
>
> +config I2C_XLP9XX
> + tristate "XLP9XX I2C support"
> + depends on CPU_XLP
> + help
> + This driver enables support for the on-chip I2C interface of
> + the Broadcom XLP9xx/XLP5xx MIPS processors.
> +
> + This driver can also be built as a module. If so, the module will
> + be called i2c-xlp9xx.
> +
> config I2C_RCAR
> tristate "Renesas R-Car I2C Controller"
> depends on ARCH_SHMOBILE || COMPILE_TEST
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index 56388f6..f61a198 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -85,6 +85,7 @@ obj-$(CONFIG_I2C_WMT) += i2c-wmt.o
> obj-$(CONFIG_I2C_OCTEON) += i2c-octeon.o
> obj-$(CONFIG_I2C_XILINX) += i2c-xiic.o
> obj-$(CONFIG_I2C_XLR) += i2c-xlr.o
> +obj-$(CONFIG_I2C_XLP9XX) += i2c-xlp9xx.o
> obj-$(CONFIG_I2C_RCAR) += i2c-rcar.o
>
> # External I2C/SMBus adapter drivers
> diff --git a/drivers/i2c/busses/i2c-xlp9xx.c b/drivers/i2c/busses/i2c-xlp9xx.c
> new file mode 100644
> index 00000000..8ff1137
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-xlp9xx.c
> @@ -0,0 +1,447 @@
> +/*
> + * 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/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/errno.h>
> +#include <linux/io.h>
> +#include <linux/platform_device.h>
> +#include <linux/i2c.h>
> +#include <linux/interrupt.h>
> +#include <linux/completion.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_TIMEOUT_MS 1000
> +#define XLP9XX_I2C_DEFAULT_FREQ 133000000UL
> +
> +#define XLP9XX_I2C_FIFO_SIZE 0x80U
> +
> +#define XLP9XX_I2C_FIFO_WCNT_MASK 0xff
> +#define XLP9XX_I2C_FIFO_CTRL_MASK 0xffff
> +
> +#define XLP9XX_I2C_CTRL_MCTLEN_SHIFT 16
> +#define XLP9XX_I2C_MFIFOCTRL_HITH_SHIFT 8
> +#define XLP9XX_I2C_MFIFOCTRL_LOTH_SHIFT 0
> +#define XLP9XX_I2C_SLAVEADDR_ADDR_SHIFT 1
> +
> +#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_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_INTEN_NACKADDR BIT(25)
> +#define XLP9XX_I2C_INTEN_DATADONE BIT(12)
> +#define XLP9XX_I2C_INTEN_ARLOST BIT(11)
> +#define XLP9XX_I2C_INTEN_MDATARDY BIT(5)
> +#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_STATUS_ERRMASK (XLP9XX_I2C_INTEN_ARLOST | \
> + XLP9XX_I2C_INTEN_NACKADDR | XLP9XX_I2C_INTEN_BUSERR)
> +
> +#define XLP9XX_I2C_MFIFOCTRL_RST BIT(16)
> +
> +#define XLP9XX_I2C_SLAVEADDR_RW BIT(0)
> +
> +struct xlp9xx_i2c_dev {
> + struct device *dev;
> + struct i2c_adapter adapter;
> + struct completion msg_complete;
> + unsigned int msg_buf_remaining;
> + int irq;
> + bool msg_read;
> + u32 __iomem *base;
> + u32 clk_mhz;
> + 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 int_mask;
> +
> + int_mask = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTEN) & ~mask;
> + xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, int_mask);
> +}
> +
> +static void xlp9xx_i2c_unmask_irq(struct xlp9xx_i2c_dev *priv, u32 mask)
> +{
> + u32 int_unmask;
> +
> + int_unmask = xlp9xx_read_i2c_reg(priv, XLP9XX_I2C_INTEN) | mask;
> + xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, int_unmask);
> +}
> +
> +static void xlp9xx_i2c_set_rx_fifo_thres(struct xlp9xx_i2c_dev *priv,
> + uint32_t th)
> +{
> + xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MFIFOCTRL,
> + (th << XLP9XX_I2C_MFIFOCTRL_HITH_SHIFT));
> +}
> +
> +static void xlp9xx_i2c_fill_tx_fifo(struct xlp9xx_i2c_dev *priv)
> +{
> + int i;
> + unsigned int len;
> + 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)
> +{
> + int i;
> + unsigned int len;
> + 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_set_rx_fifo_thres(priv,
> + min(priv->msg_buf_remaining, XLP9XX_I2C_FIFO_SIZE));
> +}
> +
> +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) || (status & XLP9XX_I2C_STATUS_ERRMASK))
> + goto isr_err;
> +
> + if (!priv->msg_read) {
> + /* TX FIFO got empty, fill it up again */
> + if (status & XLP9XX_I2C_INTEN_MFIFOEMTY) {
> + if (priv->msg_buf_remaining)
> + xlp9xx_i2c_fill_tx_fifo(priv);
> + else
> + xlp9xx_i2c_mask_irq(priv,
> + XLP9XX_I2C_INTEN_MFIFOEMTY);
> + }
> + } else {
> + /* data is in FIFO, read it */
> + if (status & (XLP9XX_I2C_INTEN_MDATARDY |
> + XLP9XX_I2C_INTEN_DATADONE |
> + XLP9XX_I2C_INTEN_MFIFOHI)) {
> + if (status & XLP9XX_I2C_INTEN_MDATARDY)
> + xlp9xx_i2c_mask_irq(priv,
> + XLP9XX_I2C_INTEN_MDATARDY);
> + if (priv->msg_buf_remaining)
> + xlp9xx_i2c_drain_rx_fifo(priv);
> + }
> + }
> +
> + xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTST, status);
> +
> + /* Transfer complete */
> + if (status & XLP9XX_I2C_INTEN_DATADONE)
> + complete(&priv->msg_complete);
> +
> + return IRQ_HANDLED;
> +
> +isr_err:
> + priv->msg_err = status;
> + xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTEN, 0);
> + xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_INTST, status);
> + complete(&priv->msg_complete);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int xlp9xx_i2c_init(struct xlp9xx_i2c_dev *priv)
> +{
> + u32 prescale;
> +
> + prescale = (((priv->clk_mhz * 1000) / 400 - 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 ret;
> + u32 intr_mask, cmd, val;
> +
> + priv->msg_buf = msg->buf;
> + priv->msg_buf_remaining = msg->len;
> + priv->msg_err = 0;
> + priv->msg_read = (msg->flags & I2C_M_RD);
> +
> + if (msg->len == 0)
> + return -EINVAL;
> +
> + /* Reset FIFO */
> + xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_MFIFOCTRL,
> + XLP9XX_I2C_MFIFOCTRL_RST);
> +
> + /* set FIFO threshold if reading */
> + if (priv->msg_read) {
> + val = min(priv->msg_buf_remaining, XLP9XX_I2C_FIFO_SIZE);
> + xlp9xx_i2c_set_rx_fifo_thres(priv, val);
> + }
> +
> + /* 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*/
> +
> + /* set data length to be transferred */
> + val = (val & XLP9XX_I2C_FIFO_CTRL_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_MDATARDY |
> + XLP9XX_I2C_INTEN_MFIFOHI);
> + else
> + intr_mask |= XLP9XX_I2C_INTEN_MFIFOEMTY;
> +
> + xlp9xx_i2c_unmask_irq(priv, intr_mask);
> +
> + /* set cmd reg */
> + cmd = XLP9XX_I2C_CMD_START | XLP9XX_I2C_CMD_STOP;
> + cmd |= (priv->msg_read ? XLP9XX_I2C_CMD_READ : XLP9XX_I2C_CMD_WRITE);
> +
> + xlp9xx_write_i2c_reg(priv, XLP9XX_I2C_CMD, cmd);
> +
> + ret = wait_for_completion_timeout(&priv->msg_complete,
> + msecs_to_jiffies(XLP9XX_I2C_TIMEOUT_MS));
> +
> + xlp9xx_i2c_mask_irq(priv, intr_mask);
> +
> + if (priv->msg_err) {
> + dev_err(priv->dev, "Transfer error %x!\n", priv->msg_err);
> + xlp9xx_i2c_init(priv);
> + return -ERESTART;
> + }
> +
> + if (ret == 0) {
> + dev_err(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)
> +{
> + struct i2c_msg *msg;
> + int i, ret = 0;
> + struct xlp9xx_i2c_dev *priv = i2c_get_adapdata(adap);
> +
> + for (i = 0; ret == 0 && i < num; i++) {
> + msg = &msgs[i];
> + ret = xlp9xx_i2c_xfer_msg(priv, msg);
> + }
> +
> + return (ret != 0) ? ret : num;
> +}
> +
> +static u32 xlp9xx_i2c_functionality(struct i2c_adapter *adapter)
> +{
> + return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C;
> +}
> +
> +static struct i2c_algorithm xlp9xx_i2c_algo = {
> + .master_xfer = xlp9xx_i2c_xfer,
> + .functionality = xlp9xx_i2c_functionality,
> +};
> +
> +static int xlp9xx_i2c_of_probe(struct platform_device *pdev,
> + struct xlp9xx_i2c_dev *priv)
> +{
> + struct device_node *np = pdev->dev.of_node;
> +
> + if (of_property_read_u32(np, "clock-frequency", &priv->clk_mhz)) {
> + dev_info(&pdev->dev, "setting clock frequency to default\n");
> + priv->clk_mhz = XLP9XX_I2C_DEFAULT_FREQ;
> + }
> + priv->clk_mhz = priv->clk_mhz / (1000 * 1000);
> +
> + 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);
> + if (!res) {
> + dev_err(&pdev->dev, "no mem resource!\n");
> + return -EINVAL;
> + }
> +
> + priv->base = devm_ioremap_resource(&pdev->dev, res);
> + if (!priv->base) {
> + dev_err(&pdev->dev, "device io mapping failed!\n");
> + return -EIO;
> + }
> +
> + priv->irq = platform_get_irq(pdev, 0);
> + if (priv->irq < 0) {
> + dev_err(&pdev->dev, "invalid irq!\n");
> + return priv->irq;
> + }
> +
> + err = xlp9xx_i2c_of_probe(pdev, priv);
> + if (err) {
> + dev_err(&pdev->dev, "xlp9xx_i2c_of_probe failed!\n");
> + return err;
> + }
> +
> + err = xlp9xx_i2c_init(priv);
> + if (err) {
> + dev_err(&pdev->dev, "I2C:%d initialization failed!\n",
> + pdev->id);
> + return err;
> + }
> +
> + 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.owner = THIS_MODULE;
> + priv->adapter.dev.parent = &pdev->dev;
> + priv->adapter.algo = &xlp9xx_i2c_algo;
> + priv->adapter.nr = pdev->id;
> + priv->adapter.dev.of_node = pdev->dev.of_node;
> + priv->adapter.class = I2C_CLASS_HWMON;
> + priv->dev = &pdev->dev;
> +
> + snprintf(priv->adapter.name, sizeof(priv->adapter.name), "xlp9xx-i2c");
> + i2c_set_adapdata(&priv->adapter, priv);
> +
> + err = i2c_add_numbered_adapter(&priv->adapter);
> + if (err) {
> + dev_err(&pdev->dev, "failed to add I2C:%d adapter!\n",
> + pdev->id);
> + return err;
> + }
> +
> + platform_set_drvdata(pdev, priv);
> + dev_info(&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);
> + i2c_del_adapter(&priv->adapter);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id xlp9xx_i2c_of_match[] = {
> + { .compatible = "netlogic,xlp9xx-i2c", .data = NULL, },
> + {},
> +};
> +
> +static struct platform_driver xlp9xx_i2c_driver = {
> + .probe = xlp9xx_i2c_probe,
> + .remove = xlp9xx_i2c_remove,
> + .driver = {
> + .name = "xlp9xx-i2c",
> + .owner = THIS_MODULE,
> + .of_match_table = xlp9xx_i2c_of_match,
> + },
> +};
> +
> +module_platform_driver(xlp9xx_i2c_driver);
> +
> +MODULE_AUTHOR("Subhendu Sekhar Behera <sbehera@xxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("XLP9XX/5XX I2C Bus Controller Driver");
> +MODULE_LICENSE("GPL v2");
> --
> 1.9.1
>
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