diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-s6000.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-s6000.c | 407 |
1 files changed, 407 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-s6000.c b/drivers/i2c/busses/i2c-s6000.c new file mode 100644 index 00000000..cb5d01e2 --- /dev/null +++ b/drivers/i2c/busses/i2c-s6000.c @@ -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 <linux/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: can't 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); |