diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-designware-common.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-designware-common.c | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c new file mode 100644 index 000000000000..d1a69372432f --- /dev/null +++ b/drivers/i2c/busses/i2c-designware-common.c @@ -0,0 +1,281 @@ +/* + * Synopsys DesignWare I2C adapter driver. + * + * Based on the TI DAVINCI I2C adapter driver. + * + * Copyright (C) 2006 Texas Instruments. + * Copyright (C) 2007 MontaVista Software Inc. + * Copyright (C) 2009 Provigent Ltd. + * + * ---------------------------------------------------------------------------- + * + * 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. + * ---------------------------------------------------------------------------- + * + */ +#include <linux/delay.h> +#include <linux/export.h> +#include <linux/errno.h> +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/pm_runtime.h> + +#include "i2c-designware-core.h" + +static char *abort_sources[] = { + [ABRT_7B_ADDR_NOACK] = + "slave address not acknowledged (7bit mode)", + [ABRT_10ADDR1_NOACK] = + "first address byte not acknowledged (10bit mode)", + [ABRT_10ADDR2_NOACK] = + "second address byte not acknowledged (10bit mode)", + [ABRT_TXDATA_NOACK] = + "data not acknowledged", + [ABRT_GCALL_NOACK] = + "no acknowledgement for a general call", + [ABRT_GCALL_READ] = + "read after general call", + [ABRT_SBYTE_ACKDET] = + "start byte acknowledged", + [ABRT_SBYTE_NORSTRT] = + "trying to send start byte when restart is disabled", + [ABRT_10B_RD_NORSTRT] = + "trying to read when restart is disabled (10bit mode)", + [ABRT_MASTER_DIS] = + "trying to use disabled adapter", + [ARB_LOST] = + "lost arbitration", + [ABRT_SLAVE_FLUSH_TXFIFO] = + "read command so flush old data in the TX FIFO", + [ABRT_SLAVE_ARBLOST] = + "slave lost the bus while transmitting data to a remote master", + [ABRT_SLAVE_RD_INTX] = + "incorrect slave-transmitter mode configuration", +}; + +u32 dw_readl(struct dw_i2c_dev *dev, int offset) +{ + u32 value; + + if (dev->flags & ACCESS_16BIT) + value = readw_relaxed(dev->base + offset) | + (readw_relaxed(dev->base + offset + 2) << 16); + else + value = readl_relaxed(dev->base + offset); + + if (dev->flags & ACCESS_SWAP) + return swab32(value); + else + return value; +} + +void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset) +{ + if (dev->flags & ACCESS_SWAP) + b = swab32(b); + + if (dev->flags & ACCESS_16BIT) { + writew_relaxed((u16)b, dev->base + offset); + writew_relaxed((u16)(b >> 16), dev->base + offset + 2); + } else { + writel_relaxed(b, dev->base + offset); + } +} + +u32 i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset) +{ + /* + * DesignWare I2C core doesn't seem to have solid strategy to meet + * the tHD;STA timing spec. Configuring _HCNT based on tHIGH spec + * will result in violation of the tHD;STA spec. + */ + if (cond) + /* + * Conditional expression: + * + * IC_[FS]S_SCL_HCNT + (1+4+3) >= IC_CLK * tHIGH + * + * This is based on the DW manuals, and represents an ideal + * configuration. The resulting I2C bus speed will be + * faster than any of the others. + * + * If your hardware is free from tHD;STA issue, try this one. + */ + return (ic_clk * tSYMBOL + 500000) / 1000000 - 8 + offset; + else + /* + * Conditional expression: + * + * IC_[FS]S_SCL_HCNT + 3 >= IC_CLK * (tHD;STA + tf) + * + * This is just experimental rule; the tHD;STA period turned + * out to be proportinal to (_HCNT + 3). With this setting, + * we could meet both tHIGH and tHD;STA timing specs. + * + * If unsure, you'd better to take this alternative. + * + * The reason why we need to take into account "tf" here, + * is the same as described in i2c_dw_scl_lcnt(). + */ + return (ic_clk * (tSYMBOL + tf) + 500000) / 1000000 + - 3 + offset; +} + +u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset) +{ + /* + * Conditional expression: + * + * IC_[FS]S_SCL_LCNT + 1 >= IC_CLK * (tLOW + tf) + * + * DW I2C core starts counting the SCL CNTs for the LOW period + * of the SCL clock (tLOW) as soon as it pulls the SCL line. + * In order to meet the tLOW timing spec, we need to take into + * account the fall time of SCL signal (tf). Default tf value + * should be 0.3 us, for safety. + */ + return ((ic_clk * (tLOW + tf) + 500000) / 1000000) - 1 + offset; +} + +void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable) +{ + dw_writel(dev, enable, DW_IC_ENABLE); +} + +void __i2c_dw_enable_and_wait(struct dw_i2c_dev *dev, bool enable) +{ + int timeout = 100; + + do { + __i2c_dw_enable(dev, enable); + if ((dw_readl(dev, DW_IC_ENABLE_STATUS) & 1) == enable) + return; + + /* + * Wait 10 times the signaling period of the highest I2C + * transfer supported by the driver (for 400KHz this is + * 25us) as described in the DesignWare I2C databook. + */ + usleep_range(25, 250); + } while (timeout--); + + dev_warn(dev->dev, "timeout in %sabling adapter\n", + enable ? "en" : "dis"); +} + +unsigned long i2c_dw_clk_rate(struct dw_i2c_dev *dev) +{ + /* + * Clock is not necessary if we got LCNT/HCNT values directly from + * the platform code. + */ + if (WARN_ON_ONCE(!dev->get_clk_rate_khz)) + return 0; + return dev->get_clk_rate_khz(dev); +} + +int i2c_dw_acquire_lock(struct dw_i2c_dev *dev) +{ + int ret; + + if (!dev->acquire_lock) + return 0; + + ret = dev->acquire_lock(dev); + if (!ret) + return 0; + + dev_err(dev->dev, "couldn't acquire bus ownership\n"); + + return ret; +} + +void i2c_dw_release_lock(struct dw_i2c_dev *dev) +{ + if (dev->release_lock) + dev->release_lock(dev); +} + +/* + * Waiting for bus not busy + */ +int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev) +{ + int timeout = TIMEOUT; + + while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) { + if (timeout <= 0) { + dev_warn(dev->dev, "timeout waiting for bus ready\n"); + return -ETIMEDOUT; + } + timeout--; + usleep_range(1000, 1100); + } + + return 0; +} + +int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev) +{ + unsigned long abort_source = dev->abort_source; + int i; + + if (abort_source & DW_IC_TX_ABRT_NOACK) { + for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources)) + dev_dbg(dev->dev, + "%s: %s\n", __func__, abort_sources[i]); + return -EREMOTEIO; + } + + for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources)) + dev_err(dev->dev, "%s: %s\n", __func__, abort_sources[i]); + + if (abort_source & DW_IC_TX_ARB_LOST) + return -EAGAIN; + else if (abort_source & DW_IC_TX_ABRT_GCALL_READ) + return -EINVAL; /* wrong msgs[] data */ + else + return -EIO; +} + +u32 i2c_dw_func(struct i2c_adapter *adap) +{ + struct dw_i2c_dev *dev = i2c_get_adapdata(adap); + + return dev->functionality; +} + +void i2c_dw_disable(struct dw_i2c_dev *dev) +{ + /* Disable controller */ + __i2c_dw_enable_and_wait(dev, false); + + /* Disable all interupts */ + dw_writel(dev, 0, DW_IC_INTR_MASK); + dw_readl(dev, DW_IC_CLR_INTR); +} + +void i2c_dw_disable_int(struct dw_i2c_dev *dev) +{ + dw_writel(dev, 0, DW_IC_INTR_MASK); +} + +u32 i2c_dw_read_comp_param(struct dw_i2c_dev *dev) +{ + return dw_readl(dev, DW_IC_COMP_PARAM_1); +} +EXPORT_SYMBOL_GPL(i2c_dw_read_comp_param); + +MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter core"); +MODULE_LICENSE("GPL"); |