diff options
Diffstat (limited to 'kernel/drivers/i2c/busses/i2c-pmcmsp.c')
-rw-r--r-- | kernel/drivers/i2c/busses/i2c-pmcmsp.c | 617 |
1 files changed, 617 insertions, 0 deletions
diff --git a/kernel/drivers/i2c/busses/i2c-pmcmsp.c b/kernel/drivers/i2c/busses/i2c-pmcmsp.c new file mode 100644 index 000000000..2c40edbf6 --- /dev/null +++ b/kernel/drivers/i2c/busses/i2c-pmcmsp.c @@ -0,0 +1,617 @@ +/* + * Specific bus support for PMC-TWI compliant implementation on MSP71xx. + * + * Copyright 2005-2007 PMC-Sierra, 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 SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN + * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON + * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/completion.h> +#include <linux/mutex.h> +#include <linux/delay.h> +#include <linux/io.h> + +#define DRV_NAME "pmcmsptwi" + +#define MSP_TWI_SF_CLK_REG_OFFSET 0x00 +#define MSP_TWI_HS_CLK_REG_OFFSET 0x04 +#define MSP_TWI_CFG_REG_OFFSET 0x08 +#define MSP_TWI_CMD_REG_OFFSET 0x0c +#define MSP_TWI_ADD_REG_OFFSET 0x10 +#define MSP_TWI_DAT_0_REG_OFFSET 0x14 +#define MSP_TWI_DAT_1_REG_OFFSET 0x18 +#define MSP_TWI_INT_STS_REG_OFFSET 0x1c +#define MSP_TWI_INT_MSK_REG_OFFSET 0x20 +#define MSP_TWI_BUSY_REG_OFFSET 0x24 + +#define MSP_TWI_INT_STS_DONE (1 << 0) +#define MSP_TWI_INT_STS_LOST_ARBITRATION (1 << 1) +#define MSP_TWI_INT_STS_NO_RESPONSE (1 << 2) +#define MSP_TWI_INT_STS_DATA_COLLISION (1 << 3) +#define MSP_TWI_INT_STS_BUSY (1 << 4) +#define MSP_TWI_INT_STS_ALL 0x1f + +#define MSP_MAX_BYTES_PER_RW 8 +#define MSP_MAX_POLL 5 +#define MSP_POLL_DELAY 10 +#define MSP_IRQ_TIMEOUT (MSP_MAX_POLL * MSP_POLL_DELAY) + +/* IO Operation macros */ +#define pmcmsptwi_readl __raw_readl +#define pmcmsptwi_writel __raw_writel + +/* TWI command type */ +enum pmcmsptwi_cmd_type { + MSP_TWI_CMD_WRITE = 0, /* Write only */ + MSP_TWI_CMD_READ = 1, /* Read only */ + MSP_TWI_CMD_WRITE_READ = 2, /* Write then Read */ +}; + +/* The possible results of the xferCmd */ +enum pmcmsptwi_xfer_result { + MSP_TWI_XFER_OK = 0, + MSP_TWI_XFER_TIMEOUT, + MSP_TWI_XFER_BUSY, + MSP_TWI_XFER_DATA_COLLISION, + MSP_TWI_XFER_NO_RESPONSE, + MSP_TWI_XFER_LOST_ARBITRATION, +}; + +/* Corresponds to a PMCTWI clock configuration register */ +struct pmcmsptwi_clock { + u8 filter; /* Bits 15:12, default = 0x03 */ + u16 clock; /* Bits 9:0, default = 0x001f */ +}; + +struct pmcmsptwi_clockcfg { + struct pmcmsptwi_clock standard; /* The standard/fast clock config */ + struct pmcmsptwi_clock highspeed; /* The highspeed clock config */ +}; + +/* Corresponds to the main TWI configuration register */ +struct pmcmsptwi_cfg { + u8 arbf; /* Bits 15:12, default=0x03 */ + u8 nak; /* Bits 11:8, default=0x03 */ + u8 add10; /* Bit 7, default=0x00 */ + u8 mst_code; /* Bits 6:4, default=0x00 */ + u8 arb; /* Bit 1, default=0x01 */ + u8 highspeed; /* Bit 0, default=0x00 */ +}; + +/* A single pmctwi command to issue */ +struct pmcmsptwi_cmd { + u16 addr; /* The slave address (7 or 10 bits) */ + enum pmcmsptwi_cmd_type type; /* The command type */ + u8 write_len; /* Number of bytes in the write buffer */ + u8 read_len; /* Number of bytes in the read buffer */ + u8 *write_data; /* Buffer of characters to send */ + u8 *read_data; /* Buffer to fill with incoming data */ +}; + +/* The private data */ +struct pmcmsptwi_data { + void __iomem *iobase; /* iomapped base for IO */ + int irq; /* IRQ to use (0 disables) */ + struct completion wait; /* Completion for xfer */ + struct mutex lock; /* Used for threadsafeness */ + enum pmcmsptwi_xfer_result last_result; /* result of last xfer */ +}; + +/* The default settings */ +static const struct pmcmsptwi_clockcfg pmcmsptwi_defclockcfg = { + .standard = { + .filter = 0x3, + .clock = 0x1f, + }, + .highspeed = { + .filter = 0x3, + .clock = 0x1f, + }, +}; + +static const struct pmcmsptwi_cfg pmcmsptwi_defcfg = { + .arbf = 0x03, + .nak = 0x03, + .add10 = 0x00, + .mst_code = 0x00, + .arb = 0x01, + .highspeed = 0x00, +}; + +static struct pmcmsptwi_data pmcmsptwi_data; + +static struct i2c_adapter pmcmsptwi_adapter; + +/* inline helper functions */ +static inline u32 pmcmsptwi_clock_to_reg( + const struct pmcmsptwi_clock *clock) +{ + return ((clock->filter & 0xf) << 12) | (clock->clock & 0x03ff); +} + +static inline u32 pmcmsptwi_cfg_to_reg(const struct pmcmsptwi_cfg *cfg) +{ + return ((cfg->arbf & 0xf) << 12) | + ((cfg->nak & 0xf) << 8) | + ((cfg->add10 & 0x1) << 7) | + ((cfg->mst_code & 0x7) << 4) | + ((cfg->arb & 0x1) << 1) | + (cfg->highspeed & 0x1); +} + +static inline void pmcmsptwi_reg_to_cfg(u32 reg, struct pmcmsptwi_cfg *cfg) +{ + cfg->arbf = (reg >> 12) & 0xf; + cfg->nak = (reg >> 8) & 0xf; + cfg->add10 = (reg >> 7) & 0x1; + cfg->mst_code = (reg >> 4) & 0x7; + cfg->arb = (reg >> 1) & 0x1; + cfg->highspeed = reg & 0x1; +} + +/* + * Sets the current clock configuration + */ +static void pmcmsptwi_set_clock_config(const struct pmcmsptwi_clockcfg *cfg, + struct pmcmsptwi_data *data) +{ + mutex_lock(&data->lock); + pmcmsptwi_writel(pmcmsptwi_clock_to_reg(&cfg->standard), + data->iobase + MSP_TWI_SF_CLK_REG_OFFSET); + pmcmsptwi_writel(pmcmsptwi_clock_to_reg(&cfg->highspeed), + data->iobase + MSP_TWI_HS_CLK_REG_OFFSET); + mutex_unlock(&data->lock); +} + +/* + * Gets the current TWI bus configuration + */ +static void pmcmsptwi_get_twi_config(struct pmcmsptwi_cfg *cfg, + struct pmcmsptwi_data *data) +{ + mutex_lock(&data->lock); + pmcmsptwi_reg_to_cfg(pmcmsptwi_readl( + data->iobase + MSP_TWI_CFG_REG_OFFSET), cfg); + mutex_unlock(&data->lock); +} + +/* + * Sets the current TWI bus configuration + */ +static void pmcmsptwi_set_twi_config(const struct pmcmsptwi_cfg *cfg, + struct pmcmsptwi_data *data) +{ + mutex_lock(&data->lock); + pmcmsptwi_writel(pmcmsptwi_cfg_to_reg(cfg), + data->iobase + MSP_TWI_CFG_REG_OFFSET); + mutex_unlock(&data->lock); +} + +/* + * Parses the 'int_sts' register and returns a well-defined error code + */ +static enum pmcmsptwi_xfer_result pmcmsptwi_get_result(u32 reg) +{ + if (reg & MSP_TWI_INT_STS_LOST_ARBITRATION) { + dev_dbg(&pmcmsptwi_adapter.dev, + "Result: Lost arbitration\n"); + return MSP_TWI_XFER_LOST_ARBITRATION; + } else if (reg & MSP_TWI_INT_STS_NO_RESPONSE) { + dev_dbg(&pmcmsptwi_adapter.dev, + "Result: No response\n"); + return MSP_TWI_XFER_NO_RESPONSE; + } else if (reg & MSP_TWI_INT_STS_DATA_COLLISION) { + dev_dbg(&pmcmsptwi_adapter.dev, + "Result: Data collision\n"); + return MSP_TWI_XFER_DATA_COLLISION; + } else if (reg & MSP_TWI_INT_STS_BUSY) { + dev_dbg(&pmcmsptwi_adapter.dev, + "Result: Bus busy\n"); + return MSP_TWI_XFER_BUSY; + } + + dev_dbg(&pmcmsptwi_adapter.dev, "Result: Operation succeeded\n"); + return MSP_TWI_XFER_OK; +} + +/* + * In interrupt mode, handle the interrupt. + * NOTE: Assumes data->lock is held. + */ +static irqreturn_t pmcmsptwi_interrupt(int irq, void *ptr) +{ + struct pmcmsptwi_data *data = ptr; + + u32 reason = pmcmsptwi_readl(data->iobase + + MSP_TWI_INT_STS_REG_OFFSET); + pmcmsptwi_writel(reason, data->iobase + MSP_TWI_INT_STS_REG_OFFSET); + + dev_dbg(&pmcmsptwi_adapter.dev, "Got interrupt 0x%08x\n", reason); + if (!(reason & MSP_TWI_INT_STS_DONE)) + return IRQ_NONE; + + data->last_result = pmcmsptwi_get_result(reason); + complete(&data->wait); + + return IRQ_HANDLED; +} + +/* + * Probe for and register the device and return 0 if there is one. + */ +static int pmcmsptwi_probe(struct platform_device *pldev) +{ + struct resource *res; + int rc = -ENODEV; + + /* get the static platform resources */ + res = platform_get_resource(pldev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(&pldev->dev, "IOMEM resource not found\n"); + goto ret_err; + } + + /* reserve the memory region */ + if (!request_mem_region(res->start, resource_size(res), + pldev->name)) { + dev_err(&pldev->dev, + "Unable to get memory/io address region 0x%08x\n", + res->start); + rc = -EBUSY; + goto ret_err; + } + + /* remap the memory */ + pmcmsptwi_data.iobase = ioremap_nocache(res->start, + resource_size(res)); + if (!pmcmsptwi_data.iobase) { + dev_err(&pldev->dev, + "Unable to ioremap address 0x%08x\n", res->start); + rc = -EIO; + goto ret_unreserve; + } + + /* request the irq */ + pmcmsptwi_data.irq = platform_get_irq(pldev, 0); + if (pmcmsptwi_data.irq) { + rc = request_irq(pmcmsptwi_data.irq, &pmcmsptwi_interrupt, + IRQF_SHARED, pldev->name, &pmcmsptwi_data); + if (rc == 0) { + /* + * Enable 'DONE' interrupt only. + * + * If you enable all interrupts, you will get one on + * error and another when the operation completes. + * This way you only have to handle one interrupt, + * but you can still check all result flags. + */ + pmcmsptwi_writel(MSP_TWI_INT_STS_DONE, + pmcmsptwi_data.iobase + + MSP_TWI_INT_MSK_REG_OFFSET); + } else { + dev_warn(&pldev->dev, + "Could not assign TWI IRQ handler " + "to irq %d (continuing with poll)\n", + pmcmsptwi_data.irq); + pmcmsptwi_data.irq = 0; + } + } + + init_completion(&pmcmsptwi_data.wait); + mutex_init(&pmcmsptwi_data.lock); + + pmcmsptwi_set_clock_config(&pmcmsptwi_defclockcfg, &pmcmsptwi_data); + pmcmsptwi_set_twi_config(&pmcmsptwi_defcfg, &pmcmsptwi_data); + + printk(KERN_INFO DRV_NAME ": Registering MSP71xx I2C adapter\n"); + + pmcmsptwi_adapter.dev.parent = &pldev->dev; + platform_set_drvdata(pldev, &pmcmsptwi_adapter); + i2c_set_adapdata(&pmcmsptwi_adapter, &pmcmsptwi_data); + + rc = i2c_add_adapter(&pmcmsptwi_adapter); + if (rc) { + dev_err(&pldev->dev, "Unable to register I2C adapter\n"); + goto ret_unmap; + } + + return 0; + +ret_unmap: + if (pmcmsptwi_data.irq) { + pmcmsptwi_writel(0, + pmcmsptwi_data.iobase + MSP_TWI_INT_MSK_REG_OFFSET); + free_irq(pmcmsptwi_data.irq, &pmcmsptwi_data); + } + + iounmap(pmcmsptwi_data.iobase); + +ret_unreserve: + release_mem_region(res->start, resource_size(res)); + +ret_err: + return rc; +} + +/* + * Release the device and return 0 if there is one. + */ +static int pmcmsptwi_remove(struct platform_device *pldev) +{ + struct resource *res; + + i2c_del_adapter(&pmcmsptwi_adapter); + + if (pmcmsptwi_data.irq) { + pmcmsptwi_writel(0, + pmcmsptwi_data.iobase + MSP_TWI_INT_MSK_REG_OFFSET); + free_irq(pmcmsptwi_data.irq, &pmcmsptwi_data); + } + + iounmap(pmcmsptwi_data.iobase); + + res = platform_get_resource(pldev, IORESOURCE_MEM, 0); + release_mem_region(res->start, resource_size(res)); + + return 0; +} + +/* + * Polls the 'busy' register until the command is complete. + * NOTE: Assumes data->lock is held. + */ +static void pmcmsptwi_poll_complete(struct pmcmsptwi_data *data) +{ + int i; + + for (i = 0; i < MSP_MAX_POLL; i++) { + u32 val = pmcmsptwi_readl(data->iobase + + MSP_TWI_BUSY_REG_OFFSET); + if (val == 0) { + u32 reason = pmcmsptwi_readl(data->iobase + + MSP_TWI_INT_STS_REG_OFFSET); + pmcmsptwi_writel(reason, data->iobase + + MSP_TWI_INT_STS_REG_OFFSET); + data->last_result = pmcmsptwi_get_result(reason); + return; + } + udelay(MSP_POLL_DELAY); + } + + dev_dbg(&pmcmsptwi_adapter.dev, "Result: Poll timeout\n"); + data->last_result = MSP_TWI_XFER_TIMEOUT; +} + +/* + * Do the transfer (low level): + * May use interrupt-driven or polling, depending on if an IRQ is + * presently registered. + * NOTE: Assumes data->lock is held. + */ +static enum pmcmsptwi_xfer_result pmcmsptwi_do_xfer( + u32 reg, struct pmcmsptwi_data *data) +{ + dev_dbg(&pmcmsptwi_adapter.dev, "Writing cmd reg 0x%08x\n", reg); + pmcmsptwi_writel(reg, data->iobase + MSP_TWI_CMD_REG_OFFSET); + if (data->irq) { + unsigned long timeleft = wait_for_completion_timeout( + &data->wait, MSP_IRQ_TIMEOUT); + if (timeleft == 0) { + dev_dbg(&pmcmsptwi_adapter.dev, + "Result: IRQ timeout\n"); + complete(&data->wait); + data->last_result = MSP_TWI_XFER_TIMEOUT; + } + } else + pmcmsptwi_poll_complete(data); + + return data->last_result; +} + +/* + * Helper routine, converts 'pmctwi_cmd' struct to register format + */ +static inline u32 pmcmsptwi_cmd_to_reg(const struct pmcmsptwi_cmd *cmd) +{ + return ((cmd->type & 0x3) << 8) | + (((cmd->write_len - 1) & 0x7) << 4) | + ((cmd->read_len - 1) & 0x7); +} + +/* + * Do the transfer (high level) + */ +static enum pmcmsptwi_xfer_result pmcmsptwi_xfer_cmd( + struct pmcmsptwi_cmd *cmd, + struct pmcmsptwi_data *data) +{ + enum pmcmsptwi_xfer_result retval; + + if ((cmd->type == MSP_TWI_CMD_WRITE && cmd->write_len == 0) || + (cmd->type == MSP_TWI_CMD_READ && cmd->read_len == 0) || + (cmd->type == MSP_TWI_CMD_WRITE_READ && + (cmd->read_len == 0 || cmd->write_len == 0))) { + dev_err(&pmcmsptwi_adapter.dev, + "%s: Cannot transfer less than 1 byte\n", + __func__); + return -EINVAL; + } + + mutex_lock(&data->lock); + dev_dbg(&pmcmsptwi_adapter.dev, + "Setting address to 0x%04x\n", cmd->addr); + pmcmsptwi_writel(cmd->addr, data->iobase + MSP_TWI_ADD_REG_OFFSET); + + if (cmd->type == MSP_TWI_CMD_WRITE || + cmd->type == MSP_TWI_CMD_WRITE_READ) { + u64 tmp = be64_to_cpup((__be64 *)cmd->write_data); + tmp >>= (MSP_MAX_BYTES_PER_RW - cmd->write_len) * 8; + dev_dbg(&pmcmsptwi_adapter.dev, "Writing 0x%016llx\n", tmp); + pmcmsptwi_writel(tmp & 0x00000000ffffffffLL, + data->iobase + MSP_TWI_DAT_0_REG_OFFSET); + if (cmd->write_len > 4) + pmcmsptwi_writel(tmp >> 32, + data->iobase + MSP_TWI_DAT_1_REG_OFFSET); + } + + retval = pmcmsptwi_do_xfer(pmcmsptwi_cmd_to_reg(cmd), data); + if (retval != MSP_TWI_XFER_OK) + goto xfer_err; + + if (cmd->type == MSP_TWI_CMD_READ || + cmd->type == MSP_TWI_CMD_WRITE_READ) { + int i; + u64 rmsk = ~(0xffffffffffffffffLL << (cmd->read_len * 8)); + u64 tmp = (u64)pmcmsptwi_readl(data->iobase + + MSP_TWI_DAT_0_REG_OFFSET); + if (cmd->read_len > 4) + tmp |= (u64)pmcmsptwi_readl(data->iobase + + MSP_TWI_DAT_1_REG_OFFSET) << 32; + tmp &= rmsk; + dev_dbg(&pmcmsptwi_adapter.dev, "Read 0x%016llx\n", tmp); + + for (i = 0; i < cmd->read_len; i++) + cmd->read_data[i] = tmp >> i; + } + +xfer_err: + mutex_unlock(&data->lock); + + return retval; +} + +/* -- Algorithm functions -- */ + +/* + * Sends an i2c command out on the adapter + */ +static int pmcmsptwi_master_xfer(struct i2c_adapter *adap, + struct i2c_msg *msg, int num) +{ + struct pmcmsptwi_data *data = i2c_get_adapdata(adap); + struct pmcmsptwi_cmd cmd; + struct pmcmsptwi_cfg oldcfg, newcfg; + int ret; + + if (num == 2) { + struct i2c_msg *nextmsg = msg + 1; + + cmd.type = MSP_TWI_CMD_WRITE_READ; + cmd.write_len = msg->len; + cmd.write_data = msg->buf; + cmd.read_len = nextmsg->len; + cmd.read_data = nextmsg->buf; + } else if (msg->flags & I2C_M_RD) { + cmd.type = MSP_TWI_CMD_READ; + cmd.read_len = msg->len; + cmd.read_data = msg->buf; + cmd.write_len = 0; + cmd.write_data = NULL; + } else { + cmd.type = MSP_TWI_CMD_WRITE; + cmd.read_len = 0; + cmd.read_data = NULL; + cmd.write_len = msg->len; + cmd.write_data = msg->buf; + } + + if (msg->len == 0) { + dev_err(&adap->dev, "Zero-byte messages unsupported\n"); + return -EINVAL; + } + + cmd.addr = msg->addr; + + if (msg->flags & I2C_M_TEN) { + pmcmsptwi_get_twi_config(&newcfg, data); + memcpy(&oldcfg, &newcfg, sizeof(oldcfg)); + + /* Set the special 10-bit address flag */ + newcfg.add10 = 1; + + pmcmsptwi_set_twi_config(&newcfg, data); + } + + /* Execute the command */ + ret = pmcmsptwi_xfer_cmd(&cmd, data); + + if (msg->flags & I2C_M_TEN) + pmcmsptwi_set_twi_config(&oldcfg, data); + + dev_dbg(&adap->dev, "I2C %s of %d bytes %s\n", + (msg->flags & I2C_M_RD) ? "read" : "write", msg->len, + (ret == MSP_TWI_XFER_OK) ? "succeeded" : "failed"); + + if (ret != MSP_TWI_XFER_OK) { + /* + * TODO: We could potentially loop and retry in the case + * of MSP_TWI_XFER_TIMEOUT. + */ + return -1; + } + + return 0; +} + +static u32 pmcmsptwi_i2c_func(struct i2c_adapter *adapter) +{ + return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | + I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA | + I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_PROC_CALL; +} + +static struct i2c_adapter_quirks pmcmsptwi_i2c_quirks = { + .flags = I2C_AQ_COMB_WRITE_THEN_READ, + .max_write_len = MSP_MAX_BYTES_PER_RW, + .max_read_len = MSP_MAX_BYTES_PER_RW, + .max_comb_1st_msg_len = MSP_MAX_BYTES_PER_RW, + .max_comb_2nd_msg_len = MSP_MAX_BYTES_PER_RW, +}; + +/* -- Initialization -- */ + +static struct i2c_algorithm pmcmsptwi_algo = { + .master_xfer = pmcmsptwi_master_xfer, + .functionality = pmcmsptwi_i2c_func, +}; + +static struct i2c_adapter pmcmsptwi_adapter = { + .owner = THIS_MODULE, + .class = I2C_CLASS_HWMON | I2C_CLASS_SPD, + .algo = &pmcmsptwi_algo, + .quirks = &pmcmsptwi_i2c_quirks, + .name = DRV_NAME, +}; + +static struct platform_driver pmcmsptwi_driver = { + .probe = pmcmsptwi_probe, + .remove = pmcmsptwi_remove, + .driver = { + .name = DRV_NAME, + }, +}; + +module_platform_driver(pmcmsptwi_driver); + +MODULE_DESCRIPTION("PMC MSP TWI/SMBus/I2C driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:" DRV_NAME); |