i2c: xtensa s6000 i2c driver
Oskar Schirmer [Thu, 2 Apr 2009 11:19:07 +0000 (13:19 +0200)]
Support for the s6000 on-chip i2c controller.

Signed-off-by: Oskar Schirmer <os@emlix.com>
Signed-off-by: Daniel Glöckner <dg@emlix.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

drivers/i2c/busses/Kconfig
drivers/i2c/busses/Makefile
drivers/i2c/busses/i2c-s6000.c [new file with mode: 0644]
drivers/i2c/busses/i2c-s6000.h [new file with mode: 0644]
include/linux/i2c/s6000.h [new file with mode: 0644]

index 5d4aa5e..94eae5c 100644 (file)
@@ -472,6 +472,16 @@ config I2C_S3C2410
          Say Y here to include support for I2C controller in the
          Samsung S3C2410 based System-on-Chip devices.
 
+config I2C_S6000
+       tristate "S6000 I2C support"
+       depends on XTENSA_VARIANT_S6000
+       help
+         This driver supports the on chip I2C device on the
+         S6000 xtensa processor family.
+
+         To compile this driver as a module, choose M here. The module
+         will be called i2c-s6000.
+
 config I2C_SH7760
        tristate "Renesas SH7760 I2C Controller"
        depends on CPU_SUBTYPE_SH7760
index 657ab24..776acb6 100644 (file)
@@ -44,6 +44,7 @@ obj-$(CONFIG_I2C_PASEMI)      += i2c-pasemi.o
 obj-$(CONFIG_I2C_PNX)          += i2c-pnx.o
 obj-$(CONFIG_I2C_PXA)          += i2c-pxa.o
 obj-$(CONFIG_I2C_S3C2410)      += i2c-s3c2410.o
+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
diff --git a/drivers/i2c/busses/i2c-s6000.c b/drivers/i2c/busses/i2c-s6000.c
new file mode 100644 (file)
index 0000000..c91359f
--- /dev/null
@@ -0,0 +1,407 @@
+/*
+ * drivers/i2c/busses/i2c-s6000.c
+ *
+ * Description: Driver for S6000 Family I2C Interface
+ * Copyright (c) 2008 emlix GmbH
+ * Author:     Oskar Schirmer <os@emlix.com>
+ *
+ * Partially based on i2c-bfin-twi.c driver by <sonic.zhang@analog.com>
+ * Copyright (c) 2005-2007 Analog Devices, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/i2c/s6000.h>
+#include <linux/timer.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+
+#include <asm/io.h>
+#include "i2c-s6000.h"
+
+#define DRV_NAME "i2c-s6000"
+
+#define POLL_TIMEOUT   (2 * HZ)
+
+struct s6i2c_if {
+       u8 __iomem              *reg; /* memory mapped registers */
+       int                     irq;
+       spinlock_t              lock;
+       struct i2c_msg          *msgs; /* messages currently handled */
+       int                     msgs_num; /* nb of msgs to do */
+       int                     msgs_push; /* nb of msgs read/written */
+       int                     msgs_done; /* nb of msgs finally handled */
+       unsigned                push; /* nb of bytes read/written in msg */
+       unsigned                done; /* nb of bytes finally handled */
+       int                     timeout_count; /* timeout retries left */
+       struct timer_list       timeout_timer;
+       struct i2c_adapter      adap;
+       struct completion       complete;
+       struct clk              *clk;
+       struct resource         *res;
+};
+
+static inline u16 i2c_rd16(struct s6i2c_if *iface, unsigned n)
+{
+       return readw(iface->reg + (n));
+}
+
+static inline void i2c_wr16(struct s6i2c_if *iface, unsigned n, u16 v)
+{
+       writew(v, iface->reg + (n));
+}
+
+static inline u32 i2c_rd32(struct s6i2c_if *iface, unsigned n)
+{
+       return readl(iface->reg + (n));
+}
+
+static inline void i2c_wr32(struct s6i2c_if *iface, unsigned n, u32 v)
+{
+       writel(v, iface->reg + (n));
+}
+
+static struct s6i2c_if s6i2c_if;
+
+static void s6i2c_handle_interrupt(struct s6i2c_if *iface)
+{
+       if (i2c_rd16(iface, S6_I2C_INTRSTAT) & (1 << S6_I2C_INTR_TXABRT)) {
+               i2c_rd16(iface, S6_I2C_CLRTXABRT);
+               i2c_wr16(iface, S6_I2C_INTRMASK, 0);
+               complete(&iface->complete);
+               return;
+       }
+       if (iface->msgs_done >= iface->msgs_num) {
+               dev_err(&iface->adap.dev, "s6i2c: spurious I2C irq: %04x\n",
+                       i2c_rd16(iface, S6_I2C_INTRSTAT));
+               i2c_wr16(iface, S6_I2C_INTRMASK, 0);
+               return;
+       }
+       while ((iface->msgs_push < iface->msgs_num)
+           && (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_TFNF))) {
+               struct i2c_msg *m = &iface->msgs[iface->msgs_push];
+               if (!(m->flags & I2C_M_RD))
+                       i2c_wr16(iface, S6_I2C_DATACMD, m->buf[iface->push]);
+               else
+                       i2c_wr16(iface, S6_I2C_DATACMD,
+                                1 << S6_I2C_DATACMD_READ);
+               if (++iface->push >= m->len) {
+                       iface->push = 0;
+                       iface->msgs_push += 1;
+               }
+       }
+       do {
+               struct i2c_msg *m = &iface->msgs[iface->msgs_done];
+               if (!(m->flags & I2C_M_RD)) {
+                       if (iface->msgs_done < iface->msgs_push)
+                               iface->msgs_done += 1;
+                       else
+                               break;
+               } else if (i2c_rd16(iface, S6_I2C_STATUS)
+                               & (1 << S6_I2C_STATUS_RFNE)) {
+                       m->buf[iface->done] = i2c_rd16(iface, S6_I2C_DATACMD);
+                       if (++iface->done >= m->len) {
+                               iface->done = 0;
+                               iface->msgs_done += 1;
+                       }
+               } else{
+                       break;
+               }
+       } while (iface->msgs_done < iface->msgs_num);
+       if (iface->msgs_done >= iface->msgs_num) {
+               i2c_wr16(iface, S6_I2C_INTRMASK, 1 << S6_I2C_INTR_TXABRT);
+               complete(&iface->complete);
+       } else if (iface->msgs_push >= iface->msgs_num) {
+               i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
+                                                (1 << S6_I2C_INTR_RXFULL));
+       } else {
+               i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
+                                                (1 << S6_I2C_INTR_TXEMPTY) |
+                                                (1 << S6_I2C_INTR_RXFULL));
+       }
+}
+
+static irqreturn_t s6i2c_interrupt_entry(int irq, void *dev_id)
+{
+       struct s6i2c_if *iface = dev_id;
+       if (!(i2c_rd16(iface, S6_I2C_STATUS) & ((1 << S6_I2C_INTR_RXUNDER)
+                                             | (1 << S6_I2C_INTR_RXOVER)
+                                             | (1 << S6_I2C_INTR_RXFULL)
+                                             | (1 << S6_I2C_INTR_TXOVER)
+                                             | (1 << S6_I2C_INTR_TXEMPTY)
+                                             | (1 << S6_I2C_INTR_RDREQ)
+                                             | (1 << S6_I2C_INTR_TXABRT)
+                                             | (1 << S6_I2C_INTR_RXDONE)
+                                             | (1 << S6_I2C_INTR_ACTIVITY)
+                                             | (1 << S6_I2C_INTR_STOPDET)
+                                             | (1 << S6_I2C_INTR_STARTDET)
+                                             | (1 << S6_I2C_INTR_GENCALL))))
+               return IRQ_NONE;
+
+       spin_lock(&iface->lock);
+       del_timer(&iface->timeout_timer);
+       s6i2c_handle_interrupt(iface);
+       spin_unlock(&iface->lock);
+       return IRQ_HANDLED;
+}
+
+static void s6i2c_timeout(unsigned long data)
+{
+       struct s6i2c_if *iface = (struct s6i2c_if *)data;
+       unsigned long flags;
+
+       spin_lock_irqsave(&iface->lock, flags);
+       s6i2c_handle_interrupt(iface);
+       if (--iface->timeout_count > 0) {
+               iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
+               add_timer(&iface->timeout_timer);
+       } else {
+               complete(&iface->complete);
+               i2c_wr16(iface, S6_I2C_INTRMASK, 0);
+       }
+       spin_unlock_irqrestore(&iface->lock, flags);
+}
+
+static int s6i2c_master_xfer(struct i2c_adapter *adap,
+                               struct i2c_msg *msgs, int num)
+{
+       struct s6i2c_if *iface = adap->algo_data;
+       int i;
+       if (num == 0)
+               return 0;
+       if (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
+               yield();
+       i2c_wr16(iface, S6_I2C_INTRMASK, 0);
+       i2c_rd16(iface, S6_I2C_CLRINTR);
+       for (i = 0; i < num; i++) {
+               if (msgs[i].flags & I2C_M_TEN) {
+                       dev_err(&adap->dev,
+                               "s6i2c: 10 bits addr not supported\n");
+                       return -EINVAL;
+               }
+               if (msgs[i].len == 0) {
+                       dev_err(&adap->dev,
+                               "s6i2c: zero length message not supported\n");
+                       return -EINVAL;
+               }
+               if (msgs[i].addr != msgs[0].addr) {
+                       dev_err(&adap->dev,
+                               "s6i2c: multiple xfer cannot change target\n");
+                       return -EINVAL;
+               }
+       }
+
+       iface->msgs = msgs;
+       iface->msgs_num = num;
+       iface->msgs_push = 0;
+       iface->msgs_done = 0;
+       iface->push = 0;
+       iface->done = 0;
+       iface->timeout_count = 10;
+       i2c_wr16(iface, S6_I2C_TAR, msgs[0].addr);
+       i2c_wr16(iface, S6_I2C_ENABLE, 1);
+       i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXEMPTY) |
+                                        (1 << S6_I2C_INTR_TXABRT));
+
+       iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
+       add_timer(&iface->timeout_timer);
+       wait_for_completion(&iface->complete);
+       del_timer_sync(&iface->timeout_timer);
+       while (i2c_rd32(iface, S6_I2C_TXFLR) > 0)
+               schedule();
+       while (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
+               schedule();
+
+       i2c_wr16(iface, S6_I2C_INTRMASK, 0);
+       i2c_wr16(iface, S6_I2C_ENABLE, 0);
+       return iface->msgs_done;
+}
+
+static u32 s6i2c_functionality(struct i2c_adapter *adap)
+{
+       return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static struct i2c_algorithm s6i2c_algorithm = {
+       .master_xfer   = s6i2c_master_xfer,
+       .functionality = s6i2c_functionality,
+};
+
+static u16 __devinit nanoseconds_on_clk(struct s6i2c_if *iface, u32 ns)
+{
+       u32 dividend = ((clk_get_rate(iface->clk) / 1000) * ns) / 1000000;
+       if (dividend > 0xffff)
+               return 0xffff;
+       return dividend;
+}
+
+static int __devinit s6i2c_probe(struct platform_device *dev)
+{
+       struct s6i2c_if *iface = &s6i2c_if;
+       struct i2c_adapter *p_adap;
+       const char *clock;
+       int bus_num, rc;
+       spin_lock_init(&iface->lock);
+       init_completion(&iface->complete);
+       iface->irq = platform_get_irq(dev, 0);
+       if (iface->irq < 0) {
+               rc = iface->irq;
+               goto err_out;
+       }
+       iface->res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+       if (!iface->res) {
+               rc = -ENXIO;
+               goto err_out;
+       }
+       iface->res = request_mem_region(iface->res->start,
+                                       resource_size(iface->res),
+                                       dev->dev.bus_id);
+       if (!iface->res) {
+               rc = -EBUSY;
+               goto err_out;
+       }
+       iface->reg = ioremap_nocache(iface->res->start,
+                                    resource_size(iface->res));
+       if (!iface->reg) {
+               rc = -ENOMEM;
+               goto err_reg;
+       }
+
+       clock = 0;
+       bus_num = -1;
+       if (dev->dev.platform_data) {
+               struct s6_i2c_platform_data *pdata = dev->dev.platform_data;
+               bus_num = pdata->bus_num;
+               clock = pdata->clock;
+       }
+       iface->clk = clk_get(&dev->dev, clock);
+       if (IS_ERR(iface->clk)) {
+               rc = PTR_ERR(iface->clk);
+               goto err_map;
+       }
+       rc = clk_enable(iface->clk);
+       if (rc < 0)
+               goto err_clk_put;
+       init_timer(&iface->timeout_timer);
+       iface->timeout_timer.function = s6i2c_timeout;
+       iface->timeout_timer.data = (unsigned long)iface;
+
+       p_adap = &iface->adap;
+       strlcpy(p_adap->name, dev->name, sizeof(p_adap->name));
+       p_adap->algo = &s6i2c_algorithm;
+       p_adap->algo_data = iface;
+       p_adap->nr = bus_num;
+       p_adap->class = 0;
+       p_adap->dev.parent = &dev->dev;
+       i2c_wr16(iface, S6_I2C_INTRMASK, 0);
+       rc = request_irq(iface->irq, s6i2c_interrupt_entry,
+                        IRQF_SHARED, dev->name, iface);
+       if (rc) {
+               dev_err(&p_adap->dev, "s6i2c: cant get IRQ %d\n", iface->irq);
+               goto err_clk_dis;
+       }
+
+       i2c_wr16(iface, S6_I2C_ENABLE, 0);
+       udelay(1);
+       i2c_wr32(iface, S6_I2C_SRESET, 1 << S6_I2C_SRESET_IC_SRST);
+       i2c_wr16(iface, S6_I2C_CLRTXABRT, 1);
+       i2c_wr16(iface, S6_I2C_CON,
+                       (1 << S6_I2C_CON_MASTER) |
+                       (S6_I2C_CON_SPEED_NORMAL << S6_I2C_CON_SPEED) |
+                       (0 << S6_I2C_CON_10BITSLAVE) |
+                       (0 << S6_I2C_CON_10BITMASTER) |
+                       (1 << S6_I2C_CON_RESTARTENA) |
+                       (1 << S6_I2C_CON_SLAVEDISABLE));
+       i2c_wr16(iface, S6_I2C_SSHCNT, nanoseconds_on_clk(iface, 4000));
+       i2c_wr16(iface, S6_I2C_SSLCNT, nanoseconds_on_clk(iface, 4700));
+       i2c_wr16(iface, S6_I2C_FSHCNT, nanoseconds_on_clk(iface, 600));
+       i2c_wr16(iface, S6_I2C_FSLCNT, nanoseconds_on_clk(iface, 1300));
+       i2c_wr16(iface, S6_I2C_RXTL, 0);
+       i2c_wr16(iface, S6_I2C_TXTL, 0);
+
+       platform_set_drvdata(dev, iface);
+       if (bus_num < 0)
+               rc = i2c_add_adapter(p_adap);
+       else
+               rc = i2c_add_numbered_adapter(p_adap);
+       if (rc)
+               goto err_irq_free;
+       return 0;
+
+err_irq_free:
+       free_irq(iface->irq, iface);
+err_clk_dis:
+       clk_disable(iface->clk);
+err_clk_put:
+       clk_put(iface->clk);
+err_map:
+       iounmap(iface->reg);
+err_reg:
+       release_mem_region(iface->res->start,
+                          resource_size(iface->res));
+err_out:
+       return rc;
+}
+
+static int __devexit s6i2c_remove(struct platform_device *pdev)
+{
+       struct s6i2c_if *iface = platform_get_drvdata(pdev);
+       i2c_wr16(iface, S6_I2C_ENABLE, 0);
+       platform_set_drvdata(pdev, NULL);
+       i2c_del_adapter(&iface->adap);
+       free_irq(iface->irq, iface);
+       clk_disable(iface->clk);
+       clk_put(iface->clk);
+       iounmap(iface->reg);
+       release_mem_region(iface->res->start,
+                          resource_size(iface->res));
+       return 0;
+}
+
+static struct platform_driver s6i2c_driver = {
+       .probe          = s6i2c_probe,
+       .remove         = __devexit_p(s6i2c_remove),
+       .driver         = {
+               .name   = DRV_NAME,
+               .owner  = THIS_MODULE,
+       },
+};
+
+static int __init s6i2c_init(void)
+{
+       pr_info("I2C: S6000 I2C driver\n");
+       return platform_driver_register(&s6i2c_driver);
+}
+
+static void __exit s6i2c_exit(void)
+{
+       platform_driver_unregister(&s6i2c_driver);
+}
+
+MODULE_DESCRIPTION("I2C-Bus adapter routines for S6000 I2C");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRV_NAME);
+
+subsys_initcall(s6i2c_init);
+module_exit(s6i2c_exit);
diff --git a/drivers/i2c/busses/i2c-s6000.h b/drivers/i2c/busses/i2c-s6000.h
new file mode 100644 (file)
index 0000000..ff23b81
--- /dev/null
@@ -0,0 +1,79 @@
+/*
+ * drivers/i2c/busses/i2c-s6000.h
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2008 Emlix GmbH <info@emlix.com>
+ * Author:     Oskar Schirmer <os@emlix.com>
+ */
+
+#ifndef __DRIVERS_I2C_BUSSES_I2C_S6000_H
+#define __DRIVERS_I2C_BUSSES_I2C_S6000_H
+
+#define S6_I2C_CON             0x000
+#define S6_I2C_CON_MASTER              0
+#define S6_I2C_CON_SPEED               1
+#define S6_I2C_CON_SPEED_NORMAL                        1
+#define S6_I2C_CON_SPEED_FAST                  2
+#define S6_I2C_CON_SPEED_MASK                  3
+#define S6_I2C_CON_10BITSLAVE          3
+#define S6_I2C_CON_10BITMASTER         4
+#define S6_I2C_CON_RESTARTENA          5
+#define S6_I2C_CON_SLAVEDISABLE                6
+#define S6_I2C_TAR             0x004
+#define S6_I2C_TAR_GCORSTART           10
+#define S6_I2C_TAR_SPECIAL             11
+#define S6_I2C_SAR             0x008
+#define S6_I2C_HSMADDR         0x00C
+#define S6_I2C_DATACMD         0x010
+#define S6_I2C_DATACMD_READ            8
+#define S6_I2C_SSHCNT          0x014
+#define S6_I2C_SSLCNT          0x018
+#define S6_I2C_FSHCNT          0x01C
+#define S6_I2C_FSLCNT          0x020
+#define S6_I2C_INTRSTAT                0x02C
+#define S6_I2C_INTRMASK                0x030
+#define S6_I2C_RAWINTR         0x034
+#define S6_I2C_INTR_RXUNDER            0
+#define S6_I2C_INTR_RXOVER             1
+#define S6_I2C_INTR_RXFULL             2
+#define S6_I2C_INTR_TXOVER             3
+#define S6_I2C_INTR_TXEMPTY            4
+#define S6_I2C_INTR_RDREQ              5
+#define S6_I2C_INTR_TXABRT             6
+#define S6_I2C_INTR_RXDONE             7
+#define S6_I2C_INTR_ACTIVITY           8
+#define S6_I2C_INTR_STOPDET            9
+#define S6_I2C_INTR_STARTDET           10
+#define S6_I2C_INTR_GENCALL            11
+#define S6_I2C_RXTL            0x038
+#define S6_I2C_TXTL            0x03C
+#define S6_I2C_CLRINTR         0x040
+#define S6_I2C_CLRRXUNDER      0x044
+#define S6_I2C_CLRRXOVER       0x048
+#define S6_I2C_CLRTXOVER       0x04C
+#define S6_I2C_CLRRDREQ                0x050
+#define S6_I2C_CLRTXABRT       0x054
+#define S6_I2C_CLRRXDONE       0x058
+#define S6_I2C_CLRACTIVITY     0x05C
+#define S6_I2C_CLRSTOPDET      0x060
+#define S6_I2C_CLRSTARTDET     0x064
+#define S6_I2C_CLRGENCALL      0x068
+#define S6_I2C_ENABLE          0x06C
+#define S6_I2C_STATUS          0x070
+#define S6_I2C_STATUS_ACTIVITY         0
+#define S6_I2C_STATUS_TFNF             1
+#define S6_I2C_STATUS_TFE              2
+#define S6_I2C_STATUS_RFNE             3
+#define S6_I2C_STATUS_RFF              4
+#define S6_I2C_TXFLR           0x074
+#define S6_I2C_RXFLR           0x078
+#define S6_I2C_SRESET          0x07C
+#define S6_I2C_SRESET_IC_SRST          0
+#define S6_I2C_SRESET_IC_MASTER_SRST   1
+#define S6_I2C_SRESET_IC_SLAVE_SRST    2
+#define S6_I2C_TXABRTSOURCE    0x080
+
+#endif
diff --git a/include/linux/i2c/s6000.h b/include/linux/i2c/s6000.h
new file mode 100644 (file)
index 0000000..d9b34bf
--- /dev/null
@@ -0,0 +1,10 @@
+#ifndef __LINUX_I2C_S6000_H
+#define __LINUX_I2C_S6000_H
+
+struct s6_i2c_platform_data {
+       const char *clock; /* the clock to use */
+       int bus_num; /* the bus number to register */
+};
+
+#endif
+