/* * TI DAVINCI I2C adapter driver. * * Copyright (C) 2006 Texas Instruments. * Copyright (C) 2007 MontaVista Software Inc. * * Updated by Vinod & Sudhakar Feb 2005 * * ---------------------------------------------------------------------------- * * 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., 675 Mass Ave, Cambridge, MA 02139, USA. * ---------------------------------------------------------------------------- * */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/delay.h> #include <linux/i2c.h> #include <linux/clk.h> #include <linux/errno.h> #include <linux/sched.h> #include <linux/err.h> #include <linux/interrupt.h> #include <linux/platform_device.h> #include <linux/io.h> #include <linux/slab.h> #include <linux/cpufreq.h> #include <linux/gpio.h> #include <linux/of_i2c.h> #include <linux/of_device.h> #include <mach/hardware.h> #include <linux/platform_data/i2c-davinci.h> /* ----- global defines ----------------------------------------------- */ #define DAVINCI_I2C_TIMEOUT (1*HZ) #define DAVINCI_I2C_MAX_TRIES 2 #define I2C_DAVINCI_INTR_ALL (DAVINCI_I2C_IMR_AAS | \ DAVINCI_I2C_IMR_SCD | \ DAVINCI_I2C_IMR_ARDY | \ DAVINCI_I2C_IMR_NACK | \ DAVINCI_I2C_IMR_AL) #define DAVINCI_I2C_OAR_REG 0x00 #define DAVINCI_I2C_IMR_REG 0x04 #define DAVINCI_I2C_STR_REG 0x08 #define DAVINCI_I2C_CLKL_REG 0x0c #define DAVINCI_I2C_CLKH_REG 0x10 #define DAVINCI_I2C_CNT_REG 0x14 #define DAVINCI_I2C_DRR_REG 0x18 #define DAVINCI_I2C_SAR_REG 0x1c #define DAVINCI_I2C_DXR_REG 0x20 #define DAVINCI_I2C_MDR_REG 0x24 #define DAVINCI_I2C_IVR_REG 0x28 #define DAVINCI_I2C_EMDR_REG 0x2c #define DAVINCI_I2C_PSC_REG 0x30 #define DAVINCI_I2C_IVR_AAS 0x07 #define DAVINCI_I2C_IVR_SCD 0x06 #define DAVINCI_I2C_IVR_XRDY 0x05 #define DAVINCI_I2C_IVR_RDR 0x04 #define DAVINCI_I2C_IVR_ARDY 0x03 #define DAVINCI_I2C_IVR_NACK 0x02 #define DAVINCI_I2C_IVR_AL 0x01 #define DAVINCI_I2C_STR_BB BIT(12) #define DAVINCI_I2C_STR_RSFULL BIT(11) #define DAVINCI_I2C_STR_SCD BIT(5) #define DAVINCI_I2C_STR_ARDY BIT(2) #define DAVINCI_I2C_STR_NACK BIT(1) #define DAVINCI_I2C_STR_AL BIT(0) #define DAVINCI_I2C_MDR_NACK BIT(15) #define DAVINCI_I2C_MDR_STT BIT(13) #define DAVINCI_I2C_MDR_STP BIT(11) #define DAVINCI_I2C_MDR_MST BIT(10) #define DAVINCI_I2C_MDR_TRX BIT(9) #define DAVINCI_I2C_MDR_XA BIT(8) #define DAVINCI_I2C_MDR_RM BIT(7) #define DAVINCI_I2C_MDR_IRS BIT(5) #define DAVINCI_I2C_IMR_AAS BIT(6) #define DAVINCI_I2C_IMR_SCD BIT(5) #define DAVINCI_I2C_IMR_XRDY BIT(4) #define DAVINCI_I2C_IMR_RRDY BIT(3) #define DAVINCI_I2C_IMR_ARDY BIT(2) #define DAVINCI_I2C_IMR_NACK BIT(1) #define DAVINCI_I2C_IMR_AL BIT(0) struct davinci_i2c_dev { struct device *dev; void __iomem *base; struct completion cmd_complete; struct clk *clk; int cmd_err; u8 *buf; size_t buf_len; int irq; int stop; u8 terminate; struct i2c_adapter adapter; #ifdef CONFIG_CPU_FREQ struct completion xfr_complete; struct notifier_block freq_transition; #endif struct davinci_i2c_platform_data *pdata; }; /* default platform data to use if not supplied in the platform_device */ static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = { .bus_freq = 100, .bus_delay = 0, }; static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev, int reg, u16 val) { __raw_writew(val, i2c_dev->base + reg); } static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg) { return __raw_readw(i2c_dev->base + reg); } /* Generate a pulse on the i2c clock pin. */ static void davinci_i2c_clock_pulse(unsigned int scl_pin) { u16 i; if (scl_pin) { /* Send high and low on the SCL line */ for (i = 0; i < 9; i++) { gpio_set_value(scl_pin, 0); udelay(20); gpio_set_value(scl_pin, 1); udelay(20); } } } /* This routine does i2c bus recovery as specified in the * i2c protocol Rev. 03 section 3.16 titled "Bus clear" */ static void davinci_i2c_recover_bus(struct davinci_i2c_dev *dev) { u32 flag = 0; struct davinci_i2c_platform_data *pdata = dev->pdata; dev_err(dev->dev, "initiating i2c bus recovery\n"); /* Send NACK to the slave */ flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); flag |= DAVINCI_I2C_MDR_NACK; /* write the data into mode register */ davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); davinci_i2c_clock_pulse(pdata->scl_pin); /* Send STOP */ flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); flag |= DAVINCI_I2C_MDR_STP; davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); } static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev, int val) { u16 w; w = davinci_i2c_read_reg(i2c_dev, DAVINCI_I2C_MDR_REG); if (!val) /* put I2C into reset */ w &= ~DAVINCI_I2C_MDR_IRS; else /* take I2C out of reset */ w |= DAVINCI_I2C_MDR_IRS; davinci_i2c_write_reg(i2c_dev, DAVINCI_I2C_MDR_REG, w); } static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev) { struct davinci_i2c_platform_data *pdata = dev->pdata; u16 psc; u32 clk; u32 d; u32 clkh; u32 clkl; u32 input_clock = clk_get_rate(dev->clk); /* NOTE: I2C Clock divider programming info * As per I2C specs the following formulas provide prescaler * and low/high divider values * input clk --> PSC Div -----------> ICCL/H Div --> output clock * module clk * * output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ] * * Thus, * (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d; * * where if PSC == 0, d = 7, * if PSC == 1, d = 6 * if PSC > 1 , d = 5 */ /* get minimum of 7 MHz clock, but max of 12 MHz */ psc = (input_clock / 7000000) - 1; if ((input_clock / (psc + 1)) > 12000000) psc++; /* better to run under spec than over */ d = (psc >= 2) ? 5 : 7 - psc; clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - (d << 1); clkh = clk >> 1; clkl = clk - clkh; davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc); davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh); davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl); dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk); } /* * This function configures I2C and brings I2C out of reset. * This function is called during I2C init function. This function * also gets called if I2C encounters any errors. */ static int i2c_davinci_init(struct davinci_i2c_dev *dev) { struct davinci_i2c_platform_data *pdata = dev->pdata; /* put I2C into reset */ davinci_i2c_reset_ctrl(dev, 0); /* compute clock dividers */ i2c_davinci_calc_clk_dividers(dev); /* Respond at reserved "SMBus Host" slave address" (and zero); * we seem to have no option to not respond... */ davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, 0x08); dev_dbg(dev->dev, "PSC = %d\n", davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG)); dev_dbg(dev->dev, "CLKL = %d\n", davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG)); dev_dbg(dev->dev, "CLKH = %d\n", davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG)); dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n", pdata->bus_freq, pdata->bus_delay); /* Take the I2C module out of reset: */ davinci_i2c_reset_ctrl(dev, 1); /* Enable interrupts */ davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL); return 0; } /* * Waiting for bus not busy */ static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev, char allow_sleep) { unsigned long timeout; static u16 to_cnt; timeout = jiffies + dev->adapter.timeout; while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG) & DAVINCI_I2C_STR_BB) { if (to_cnt <= DAVINCI_I2C_MAX_TRIES) { if (time_after(jiffies, timeout)) { dev_warn(dev->dev, "timeout waiting for bus ready\n"); to_cnt++; return -ETIMEDOUT; } else { to_cnt = 0; davinci_i2c_recover_bus(dev); i2c_davinci_init(dev); } } if (allow_sleep) schedule_timeout(1); } return 0; } /* * Low level master read/write transaction. This function is called * from i2c_davinci_xfer. */ static int i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop) { struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); struct davinci_i2c_platform_data *pdata = dev->pdata; u32 flag; u16 w; int r; /* Introduce a delay, required for some boards (e.g Davinci EVM) */ if (pdata->bus_delay) udelay(pdata->bus_delay); /* set the slave address */ davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr); dev->buf = msg->buf; dev->buf_len = msg->len; dev->stop = stop; davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len); INIT_COMPLETION(dev->cmd_complete); dev->cmd_err = 0; /* Take I2C out of reset and configure it as master */ flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST; /* if the slave address is ten bit address, enable XA bit */ if (msg->flags & I2C_M_TEN) flag |= DAVINCI_I2C_MDR_XA; if (!(msg->flags & I2C_M_RD)) flag |= DAVINCI_I2C_MDR_TRX; if (msg->len == 0) flag |= DAVINCI_I2C_MDR_RM; /* Enable receive or transmit interrupts */ w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG); if (msg->flags & I2C_M_RD) w |= DAVINCI_I2C_IMR_RRDY; else w |= DAVINCI_I2C_IMR_XRDY; davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w); dev->terminate = 0; /* * Write mode register first as needed for correct behaviour * on OMAP-L138, but don't set STT yet to avoid a race with XRDY * occurring before we have loaded DXR */ davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); /* * First byte should be set here, not after interrupt, * because transmit-data-ready interrupt can come before * NACK-interrupt during sending of previous message and * ICDXR may have wrong data * It also saves us one interrupt, slightly faster */ if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) { davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++); dev->buf_len--; } /* Set STT to begin transmit now DXR is loaded */ flag |= DAVINCI_I2C_MDR_STT; if (stop && msg->len != 0) flag |= DAVINCI_I2C_MDR_STP; davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); r = wait_for_completion_interruptible_timeout(&dev->cmd_complete, dev->adapter.timeout); if (r == 0) { dev_err(dev->dev, "controller timed out\n"); davinci_i2c_recover_bus(dev); i2c_davinci_init(dev); dev->buf_len = 0; return -ETIMEDOUT; } if (dev->buf_len) { /* This should be 0 if all bytes were transferred * or dev->cmd_err denotes an error. * A signal may have aborted the transfer. */ if (r >= 0) { dev_err(dev->dev, "abnormal termination buf_len=%i\n", dev->buf_len); r = -EREMOTEIO; } dev->terminate = 1; wmb(); dev->buf_len = 0; } if (r < 0) return r; /* no error */ if (likely(!dev->cmd_err)) return msg->len; /* We have an error */ if (dev->cmd_err & DAVINCI_I2C_STR_AL) { i2c_davinci_init(dev); return -EIO; } if (dev->cmd_err & DAVINCI_I2C_STR_NACK) { if (msg->flags & I2C_M_IGNORE_NAK) return msg->len; if (stop) { w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); w |= DAVINCI_I2C_MDR_STP; davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w); } return -EREMOTEIO; } return -EIO; } /* * Prepare controller for a transaction and call i2c_davinci_xfer_msg */ static int i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) { struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); int i; int ret; dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num); ret = i2c_davinci_wait_bus_not_busy(dev, 1); if (ret < 0) { dev_warn(dev->dev, "timeout waiting for bus ready\n"); return ret; } for (i = 0; i < num; i++) { ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1))); dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num, ret); if (ret < 0) return ret; } #ifdef CONFIG_CPU_FREQ complete(&dev->xfr_complete); #endif return num; } static u32 i2c_davinci_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; } static void terminate_read(struct davinci_i2c_dev *dev) { u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); w |= DAVINCI_I2C_MDR_NACK; davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w); /* Throw away data */ davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG); if (!dev->terminate) dev_err(dev->dev, "RDR IRQ while no data requested\n"); } static void terminate_write(struct davinci_i2c_dev *dev) { u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP; davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w); if (!dev->terminate) dev_dbg(dev->dev, "TDR IRQ while no data to send\n"); } /* * Interrupt service routine. This gets called whenever an I2C interrupt * occurs. */ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id) { struct davinci_i2c_dev *dev = dev_id; u32 stat; int count = 0; u16 w; while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) { dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat); if (count++ == 100) { dev_warn(dev->dev, "Too much work in one IRQ\n"); break; } switch (stat) { case DAVINCI_I2C_IVR_AL: /* Arbitration lost, must retry */ dev->cmd_err |= DAVINCI_I2C_STR_AL; dev->buf_len = 0; complete(&dev->cmd_complete); break; case DAVINCI_I2C_IVR_NACK: dev->cmd_err |= DAVINCI_I2C_STR_NACK; dev->buf_len = 0; complete(&dev->cmd_complete); break; case DAVINCI_I2C_IVR_ARDY: davinci_i2c_write_reg(dev, DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY); if (((dev->buf_len == 0) && (dev->stop != 0)) || (dev->cmd_err & DAVINCI_I2C_STR_NACK)) { w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); w |= DAVINCI_I2C_MDR_STP; davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w); } complete(&dev->cmd_complete); break; case DAVINCI_I2C_IVR_RDR: if (dev->buf_len) { *dev->buf++ = davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG); dev->buf_len--; if (dev->buf_len) continue; davinci_i2c_write_reg(dev, DAVINCI_I2C_STR_REG, DAVINCI_I2C_IMR_RRDY); } else { /* signal can terminate transfer */ terminate_read(dev); } break; case DAVINCI_I2C_IVR_XRDY: if (dev->buf_len) { davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++); dev->buf_len--; if (dev->buf_len) continue; w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG); w &= ~DAVINCI_I2C_IMR_XRDY; davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w); } else { /* signal can terminate transfer */ terminate_write(dev); } break; case DAVINCI_I2C_IVR_SCD: davinci_i2c_write_reg(dev, DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD); complete(&dev->cmd_complete); break; case DAVINCI_I2C_IVR_AAS: dev_dbg(dev->dev, "Address as slave interrupt\n"); break; default: dev_warn(dev->dev, "Unrecognized irq stat %d\n", stat); break; } } return count ? IRQ_HANDLED : IRQ_NONE; } #ifdef CONFIG_CPU_FREQ static int i2c_davinci_cpufreq_transition(struct notifier_block *nb, unsigned long val, void *data) { struct davinci_i2c_dev *dev; dev = container_of(nb, struct davinci_i2c_dev, freq_transition); if (val == CPUFREQ_PRECHANGE) { wait_for_completion(&dev->xfr_complete); davinci_i2c_reset_ctrl(dev, 0); } else if (val == CPUFREQ_POSTCHANGE) { i2c_davinci_calc_clk_dividers(dev); davinci_i2c_reset_ctrl(dev, 1); } return 0; } static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev) { dev->freq_transition.notifier_call = i2c_davinci_cpufreq_transition; return cpufreq_register_notifier(&dev->freq_transition, CPUFREQ_TRANSITION_NOTIFIER); } static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev) { cpufreq_unregister_notifier(&dev->freq_transition, CPUFREQ_TRANSITION_NOTIFIER); } #else static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev) { return 0; } static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev) { } #endif static struct i2c_algorithm i2c_davinci_algo = { .master_xfer = i2c_davinci_xfer, .functionality = i2c_davinci_func, }; static const struct of_device_id davinci_i2c_of_match[] = { {.compatible = "ti,davinci-i2c", }, {}, }; MODULE_DEVICE_TABLE(of, davinci_i2c_of_match); static int davinci_i2c_probe(struct platform_device *pdev) { struct davinci_i2c_dev *dev; struct i2c_adapter *adap; struct resource *mem, *irq; int r; /* NOTE: driver uses the static register mapping */ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!mem) { dev_err(&pdev->dev, "no mem resource?\n"); return -ENODEV; } irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); if (!irq) { dev_err(&pdev->dev, "no irq resource?\n"); return -ENODEV; } dev = devm_kzalloc(&pdev->dev, sizeof(struct davinci_i2c_dev), GFP_KERNEL); if (!dev) { dev_err(&pdev->dev, "Memory allocation failed\n"); return -ENOMEM; } init_completion(&dev->cmd_complete); #ifdef CONFIG_CPU_FREQ init_completion(&dev->xfr_complete); #endif dev->dev = &pdev->dev; dev->irq = irq->start; dev->pdata = dev->dev->platform_data; platform_set_drvdata(pdev, dev); if (!dev->pdata && pdev->dev.of_node) { u32 prop; dev->pdata = devm_kzalloc(&pdev->dev, sizeof(struct davinci_i2c_platform_data), GFP_KERNEL); if (!dev->pdata) return -ENOMEM; memcpy(dev->pdata, &davinci_i2c_platform_data_default, sizeof(struct davinci_i2c_platform_data)); if (!of_property_read_u32(pdev->dev.of_node, "clock-frequency", &prop)) dev->pdata->bus_freq = prop / 1000; } else if (!dev->pdata) { dev->pdata = &davinci_i2c_platform_data_default; } dev->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(dev->clk)) return -ENODEV; clk_prepare_enable(dev->clk); dev->base = devm_ioremap_resource(&pdev->dev, mem); if (IS_ERR(dev->base)) { r = PTR_ERR(dev->base); goto err_unuse_clocks; } i2c_davinci_init(dev); r = devm_request_irq(&pdev->dev, dev->irq, i2c_davinci_isr, 0, pdev->name, dev); if (r) { dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq); goto err_unuse_clocks; } r = i2c_davinci_cpufreq_register(dev); if (r) { dev_err(&pdev->dev, "failed to register cpufreq\n"); goto err_unuse_clocks; } adap = &dev->adapter; i2c_set_adapdata(adap, dev); adap->owner = THIS_MODULE; adap->class = I2C_CLASS_HWMON; strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name)); adap->algo = &i2c_davinci_algo; adap->dev.parent = &pdev->dev; adap->timeout = DAVINCI_I2C_TIMEOUT; adap->dev.of_node = pdev->dev.of_node; adap->nr = pdev->id; r = i2c_add_numbered_adapter(adap); if (r) { dev_err(&pdev->dev, "failure adding adapter\n"); goto err_unuse_clocks; } of_i2c_register_devices(adap); return 0; err_unuse_clocks: clk_disable_unprepare(dev->clk); dev->clk = NULL; return r; } static int davinci_i2c_remove(struct platform_device *pdev) { struct davinci_i2c_dev *dev = platform_get_drvdata(pdev); i2c_davinci_cpufreq_deregister(dev); i2c_del_adapter(&dev->adapter); clk_disable_unprepare(dev->clk); dev->clk = NULL; davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0); return 0; } #ifdef CONFIG_PM static int davinci_i2c_suspend(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev); /* put I2C into reset */ davinci_i2c_reset_ctrl(i2c_dev, 0); clk_disable_unprepare(i2c_dev->clk); return 0; } static int davinci_i2c_resume(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev); clk_prepare_enable(i2c_dev->clk); /* take I2C out of reset */ davinci_i2c_reset_ctrl(i2c_dev, 1); return 0; } static const struct dev_pm_ops davinci_i2c_pm = { .suspend = davinci_i2c_suspend, .resume = davinci_i2c_resume, }; #define davinci_i2c_pm_ops (&davinci_i2c_pm) #else #define davinci_i2c_pm_ops NULL #endif /* work with hotplug and coldplug */ MODULE_ALIAS("platform:i2c_davinci"); static struct platform_driver davinci_i2c_driver = { .probe = davinci_i2c_probe, .remove = davinci_i2c_remove, .driver = { .name = "i2c_davinci", .owner = THIS_MODULE, .pm = davinci_i2c_pm_ops, .of_match_table = of_match_ptr(davinci_i2c_of_match), }, }; /* I2C may be needed to bring up other drivers */ static int __init davinci_i2c_init_driver(void) { return platform_driver_register(&davinci_i2c_driver); } subsys_initcall(davinci_i2c_init_driver); static void __exit davinci_i2c_exit_driver(void) { platform_driver_unregister(&davinci_i2c_driver); } module_exit(davinci_i2c_exit_driver); MODULE_AUTHOR("Texas Instruments India"); MODULE_DESCRIPTION("TI DaVinci I2C bus adapter"); MODULE_LICENSE("GPL");