linux-mips
[Top] [All Lists]

[PATCH] i2c: Support for Netlogic XLR/XLS I2C controller.

To: <linux-i2c@vger.kernel.org>
Subject: [PATCH] i2c: Support for Netlogic XLR/XLS I2C controller.
From: "Jayachandran C." <jayachandranc@netlogicmicro.com>
Date: Tue, 15 Nov 2011 23:24:45 +0530
Cc: <ben-linux@fluff.org>, <linux-mips@linux-mips.org>, Ganesan Ramalingam <ganesanr@netlogicmicro.com>, Jayachandran C <jayachandranc@netlogicmicro.com>
Sender: linux-mips-bounce@linux-mips.org
From: Ganesan Ramalingam <ganesanr@netlogicmicro.com>

Add support for the intergrated I2C controller on Netlogic
XLR/XLS MIPS SoC.

The changes are to add a new file i2c/buses/i2c-xlr.c, containing the
i2c bus implementation, and to update i2c/buses/{Kconfig,Makefile} to
add the CONFIG_I2C_XLR option.

Signed-off-by: Ganesan Ramalingam <ganesanr@netlogicmicro.com>
Signed-off-by: Jayachandran C <jayachandranc@netlogicmicro.com>
---

Changes from the last version is to remove the custom IO functions from
netlogic headers and use __raw_readl/__raw_writel

This has been sent out too many times now, please let me know if there 
are any comments.

 drivers/i2c/busses/Kconfig   |   11 ++
 drivers/i2c/busses/Makefile  |    1 +
 drivers/i2c/busses/i2c-xlr.c |  318 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 330 insertions(+), 0 deletions(-)
 create mode 100644 drivers/i2c/busses/i2c-xlr.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index a3afac4..c9f3db3 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -308,6 +308,17 @@ config I2C_AU1550
          This driver can also be built as a module.  If so, the module
          will be called i2c-au1550.
 
+config I2C_XLR
+       tristate "XLR I2C support"
+       depends on CPU_XLR
+       help
+         This driver enables support for the on-chip I2C interface of
+         the Netlogic XLR/XLS MIPS processors.
+
+         Say yes to this option if you have a Netlogic XLR/XLS based
+         board and you need to access the I2C devices (typically the
+         RTC, sensors, EEPROM) connected to this interface.
+
 config I2C_BLACKFIN_TWI
        tristate "Blackfin TWI I2C support"
        depends on BLACKFIN
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index fba6da6..4372dee 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_I2C_TEGRA)               += i2c-tegra.o
 obj-$(CONFIG_I2C_VERSATILE)    += i2c-versatile.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_EG20T)         += i2c-eg20t.o
 
 # External I2C/SMBus adapter drivers
diff --git a/drivers/i2c/busses/i2c-xlr.c b/drivers/i2c/busses/i2c-xlr.c
new file mode 100644
index 0000000..cc2f0a5
--- /dev/null
+++ b/drivers/i2c/busses/i2c-xlr.c
@@ -0,0 +1,318 @@
+/*
+ * Copyright 2011, Netlogic Microsystems Inc.
+ * Copyright 2004, Matt Porter <mporter@kernel.crashing.org>
+ *
+ * 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/module.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+
+/* XLR I2C REGISTERS */
+#define XLR_I2C_CFG            0x00
+#define XLR_I2C_CLKDIV         0x01
+#define XLR_I2C_DEVADDR                0x02
+#define XLR_I2C_ADDR           0x03
+#define XLR_I2C_DATAOUT                0x04
+#define XLR_I2C_DATAIN         0x05
+#define XLR_I2C_STATUS         0x06
+#define XLR_I2C_STARTXFR       0x07
+#define XLR_I2C_BYTECNT                0x08
+#define XLR_I2C_HDSTATIM       0x09
+
+/* XLR I2C REGISTERS FLAGS */
+#define XLR_I2C_BUS_BUSY       0x01
+#define XLR_I2C_SDOEMPTY       0x02
+#define XLR_I2C_RXRDY          0x04
+#define XLR_I2C_ACK_ERR                0x08
+#define XLR_I2C_ARB_STARTERR   0x30
+
+/* Register Programming Values!! Change as required */
+#define XLR_I2C_CFG_ADDR       0xF8    /* 8-Bit dev Addr + POR Values */
+#define XLR_I2C_CFG_NOADDR     0xFA    /* 8-Bit reg Addr + POR Values */
+#define XLR_I2C_STARTXFR_ND    0x02    /* No data , only addr */
+#define XLR_I2C_STARTXFR_RD    0x01    /* Read */
+#define XLR_I2C_STARTXFR_WR    0x00    /* Write */
+#define XLR_I2C_CLKDIV_DEF     0x14A   /* 0x00000052 */
+#define XLR_I2C_HDSTATIM_DEF   0x107   /* 0x00000000 */
+
+#define XLR_I2C_IO_SIZE                0x1000
+
+
+/* 
+ * Need un-swapped IO for the SoC I2C registers, use __raw_ IO
+ */
+static inline void xlr_i2c_wreg(u32 __iomem *base, unsigned int reg, u32 val)
+{
+       base += reg;
+       __raw_writel(val, base);
+}
+
+static inline u32 xlr_i2c_rdreg(u32 __iomem *base, unsigned int reg)
+{
+       base += reg;
+       return __raw_readl(base);
+}
+
+struct xlr_i2c_private {
+       struct i2c_adapter adap;
+       u32 __iomem *iobase;
+};
+
+static int xlr_i2c_tx(struct xlr_i2c_private *priv,  u16 len,
+               u8 *buf, u16 addr)
+{
+       u32 i2c_status = 0x00;
+       u8 nb;
+       int pos, timeout = 0;
+       struct i2c_adapter *adap = &priv->adap;
+       u8 offset = buf[0];
+
+       xlr_i2c_wreg(priv->iobase, XLR_I2C_ADDR, offset);
+       xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr);
+       xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG, XLR_I2C_CFG_ADDR);
+       xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len-1);
+
+retry:
+       timeout = 0;
+       pos = 1;
+       if (len == 1) {
+               xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR,
+                               XLR_I2C_STARTXFR_ND);
+       } else {
+               xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT, buf[pos]);
+               xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR,
+                               XLR_I2C_STARTXFR_WR);
+       }
+
+       while (1) {
+               if (timeout++ > 0x1000) {
+                       dev_err(&adap->dev, "XLR_I2C_STARTXFR_RD Rx Timeout\n");
+                       return -ETIMEDOUT;
+               }
+
+               i2c_status = xlr_i2c_rdreg(priv->iobase,
+                               XLR_I2C_STATUS);
+
+               if (i2c_status & XLR_I2C_SDOEMPTY) {
+                       pos++;
+                       nb = (pos < len) ? buf[pos] : 0;
+                       xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT, nb);
+               }
+
+               if (i2c_status & XLR_I2C_ARB_STARTERR)
+                       goto retry;
+
+               if (i2c_status & XLR_I2C_ACK_ERR) {
+                       return -EIO;
+               }
+
+               if (i2c_status & XLR_I2C_BUS_BUSY) {
+                       udelay(1);
+                       continue;
+               }
+
+               if (pos >= len)
+                       break;
+       }
+
+       return 0;
+}
+
+static int xlr_i2c_rx(struct xlr_i2c_private *priv, u16 len,
+               u8 *buf, u16 addr)
+{
+       u32 i2c_status = 0x00;
+       int pos = 0;
+       int timeout = 0;
+       struct i2c_adapter *adap = &priv->adap;
+
+       xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG, XLR_I2C_CFG_NOADDR);
+       xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len);
+       xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr);
+
+retry:
+       timeout = 0;
+       xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR,
+                       XLR_I2C_STARTXFR_RD);
+
+       while (1) {
+               if (timeout++ > 0x1000) {
+                       dev_err(&adap->dev, "XLR_I2C_STARTXFR_RD Rx Timeout\n");
+                       return -ETIMEDOUT;
+               }
+
+               i2c_status = xlr_i2c_rdreg(priv->iobase,
+                               XLR_I2C_STATUS);
+               if (i2c_status & XLR_I2C_RXRDY) {
+                       buf[pos++] = (u8)xlr_i2c_rdreg(priv->iobase,
+                                       XLR_I2C_DATAIN);
+               }
+
+               if (i2c_status & XLR_I2C_ARB_STARTERR)
+                       goto retry;
+
+               if (i2c_status & XLR_I2C_ACK_ERR) {
+                       dev_err(&adap->dev, "XLR_I2C_STARTXFR_RD ACK ERR\n");
+                       return -EIO;
+               }
+
+               if ((i2c_status & XLR_I2C_BUS_BUSY) == 0)
+                       break;
+               udelay(1);
+       }
+       return 0;
+}
+
+static int xlr_i2c_xfer(struct i2c_adapter *adap,
+               struct i2c_msg *msgs, int num)
+{
+       struct i2c_msg *msg;
+       int i;
+       int ret = 0;
+       struct xlr_i2c_private *priv = i2c_get_adapdata(adap);
+
+       for (i = 0; ret == 0 && i < num; i++) {
+               msg = &msgs[i];
+               if (msg->flags & I2C_M_RD)
+                       ret = xlr_i2c_rx(priv, msg->len, &msg->buf[0],
+                                       msg->addr);
+               else
+                       ret = xlr_i2c_tx(priv, msg->len, &msg->buf[0],
+                                       msg->addr);
+       }
+
+       return (ret != 0) ? ret : num;
+}
+
+static u32 xlr_func(struct i2c_adapter *adap)
+{
+       /* Emulate SMBUS over I2C */
+       return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C;
+}
+
+static struct i2c_algorithm xlr_i2c_algo = {
+       .master_xfer    = xlr_i2c_xfer,
+       .functionality  = xlr_func,
+};
+
+static int xlr_i2c_add_bus(struct xlr_i2c_private *priv)
+{
+       priv->adap.owner        = THIS_MODULE;
+       priv->adap.algo_data    = priv;
+       priv->adap.nr           = 1;
+       priv->adap.algo         = &xlr_i2c_algo;
+       priv->adap.class        = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+       snprintf(priv->adap.name, sizeof(priv->adap.name),
+                       "SMBus XLR I2C Adapter");
+       i2c_set_adapdata(&priv->adap, priv);
+       /* register new adapter to i2c module... */
+       if (i2c_add_numbered_adapter(&priv->adap))
+               return -1;
+
+       return 0;
+}
+
+static int __devinit xlr_i2c_probe(struct platform_device *pdev)
+{
+       struct xlr_i2c_private  *priv;
+       struct resource *res;
+       int ret;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+       if (!res) {
+               ret = -ENXIO;
+               goto err1;
+       }
+
+       if (!request_mem_region(res->start, XLR_I2C_IO_SIZE, pdev->name)) {
+               dev_err(&pdev->dev, "request_mem_region failed\n");
+               ret = -ENOMEM;
+               goto err1;
+       }
+
+       priv = kzalloc(sizeof(struct xlr_i2c_private), GFP_KERNEL);
+       if (!priv) {
+               ret = -ENOMEM;
+               goto err2;
+       }
+
+       priv->adap.dev.parent = &pdev->dev;
+       priv->iobase = (u32 *)ioremap(res->start, XLR_I2C_IO_SIZE);
+       if (!priv->iobase) {
+               ret = -ENOMEM;
+               goto err3;
+       }
+
+       platform_set_drvdata(pdev, priv);
+       ret = xlr_i2c_add_bus(priv);
+
+       if (ret < 0) {
+               dev_err(&priv->adap.dev, "Failed to add i2c bus\n");
+               ret = -ENXIO;
+               goto err4;
+       } else
+               dev_info(&priv->adap.dev, "Added I2C Bus.\n");
+
+       return 0;
+err4:
+       iounmap(priv->iobase);
+       platform_set_drvdata(pdev, NULL);
+err3:
+       kfree(priv);
+err2:
+       release_mem_region(res->start, IORESOURCE_MEM);
+err1:
+       return ret;
+}
+
+static int __devexit xlr_i2c_remove(struct platform_device *pdev)
+{
+       struct xlr_i2c_private *priv = platform_get_drvdata(pdev);
+       struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+       i2c_del_adapter(&priv->adap);
+       iounmap(priv->iobase);
+       kfree(priv);
+       release_mem_region(res->start, IORESOURCE_MEM);
+       platform_set_drvdata(pdev, NULL);
+       return 0;
+}
+
+static struct platform_driver xlr_i2c_driver = {
+       .probe  = xlr_i2c_probe,
+       .remove = __devexit_p(xlr_i2c_remove),
+       .driver = {
+               .owner  = THIS_MODULE,
+               .name   = "xlr-i2cbus",
+       },
+};
+
+static int __init xlr_i2c_init(void)
+{
+       return platform_driver_register(&xlr_i2c_driver);
+}
+
+static void __exit xlr_i2c_exit(void)
+{
+       platform_driver_unregister(&xlr_i2c_driver);
+}
+
+MODULE_AUTHOR("Ganesan Ramalingam <ganesanr@netlogicmicro.com>");
+MODULE_DESCRIPTION("XLR I2C SMBus driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:xlr-i2cbus");
+
+module_init(xlr_i2c_init);
+module_exit(xlr_i2c_exit);
-- 
1.7.5.4


<Prev in Thread] Current Thread [Next in Thread>