/* * drivers/i2c/busses/i2c-s6000.c * * Description: Driver for S6000 Family I2C Interface * Copyright (c) 2008 emlix GmbH * Author: Oskar Schirmer * * Partially based on i2c-bfin-twi.c driver by * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #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 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 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); 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 s6i2c_remove(struct platform_device *pdev) { struct s6i2c_if *iface = platform_get_drvdata(pdev); i2c_wr16(iface, S6_I2C_ENABLE, 0); 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 = 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);