diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/i2c/busses/i2c-sirf.c | 475 |
1 files changed, 475 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-sirf.c b/drivers/i2c/busses/i2c-sirf.c new file mode 100644 index 000000000..30db8fafe --- /dev/null +++ b/drivers/i2c/busses/i2c-sirf.c @@ -0,0 +1,475 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * I2C bus driver for CSR SiRFprimaII + * + * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company. + */ + +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/platform_device.h> +#include <linux/i2c.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/io.h> + +#define SIRFSOC_I2C_CLK_CTRL 0x00 +#define SIRFSOC_I2C_STATUS 0x0C +#define SIRFSOC_I2C_CTRL 0x10 +#define SIRFSOC_I2C_IO_CTRL 0x14 +#define SIRFSOC_I2C_SDA_DELAY 0x18 +#define SIRFSOC_I2C_CMD_START 0x1C +#define SIRFSOC_I2C_CMD_BUF 0x30 +#define SIRFSOC_I2C_DATA_BUF 0x80 + +#define SIRFSOC_I2C_CMD_BUF_MAX 16 +#define SIRFSOC_I2C_DATA_BUF_MAX 16 + +#define SIRFSOC_I2C_CMD(x) (SIRFSOC_I2C_CMD_BUF + (x)*0x04) +#define SIRFSOC_I2C_DATA_MASK(x) (0xFF<<(((x)&3)*8)) +#define SIRFSOC_I2C_DATA_SHIFT(x) (((x)&3)*8) + +#define SIRFSOC_I2C_DIV_MASK (0xFFFF) + +/* I2C status flags */ +#define SIRFSOC_I2C_STAT_BUSY BIT(0) +#define SIRFSOC_I2C_STAT_TIP BIT(1) +#define SIRFSOC_I2C_STAT_NACK BIT(2) +#define SIRFSOC_I2C_STAT_TR_INT BIT(4) +#define SIRFSOC_I2C_STAT_STOP BIT(6) +#define SIRFSOC_I2C_STAT_CMD_DONE BIT(8) +#define SIRFSOC_I2C_STAT_ERR BIT(9) +#define SIRFSOC_I2C_CMD_INDEX (0x1F<<16) + +/* I2C control flags */ +#define SIRFSOC_I2C_RESET BIT(0) +#define SIRFSOC_I2C_CORE_EN BIT(1) +#define SIRFSOC_I2C_MASTER_MODE BIT(2) +#define SIRFSOC_I2C_CMD_DONE_EN BIT(11) +#define SIRFSOC_I2C_ERR_INT_EN BIT(12) + +#define SIRFSOC_I2C_SDA_DELAY_MASK (0xFF) +#define SIRFSOC_I2C_SCLF_FILTER (3<<8) + +#define SIRFSOC_I2C_START_CMD BIT(0) + +#define SIRFSOC_I2C_CMD_RP(x) ((x)&0x7) +#define SIRFSOC_I2C_NACK BIT(3) +#define SIRFSOC_I2C_WRITE BIT(4) +#define SIRFSOC_I2C_READ BIT(5) +#define SIRFSOC_I2C_STOP BIT(6) +#define SIRFSOC_I2C_START BIT(7) + +#define SIRFSOC_I2C_ERR_NOACK 1 +#define SIRFSOC_I2C_ERR_TIMEOUT 2 + +struct sirfsoc_i2c { + void __iomem *base; + struct clk *clk; + u32 cmd_ptr; /* Current position in CMD buffer */ + u8 *buf; /* Buffer passed by user */ + u32 msg_len; /* Message length */ + u32 finished_len; /* number of bytes read/written */ + u32 read_cmd_len; /* number of read cmd sent */ + int msg_read; /* 1 indicates a read message */ + int err_status; /* 1 indicates an error on bus */ + + u32 sda_delay; /* For suspend/resume */ + u32 clk_div; + int last; /* Last message in transfer, STOP cmd can be sent */ + + struct completion done; /* indicates completion of message transfer */ + struct i2c_adapter adapter; +}; + +static void i2c_sirfsoc_read_data(struct sirfsoc_i2c *siic) +{ + u32 data = 0; + int i; + + for (i = 0; i < siic->read_cmd_len; i++) { + if (!(i & 0x3)) + data = readl(siic->base + SIRFSOC_I2C_DATA_BUF + i); + siic->buf[siic->finished_len++] = + (u8)((data & SIRFSOC_I2C_DATA_MASK(i)) >> + SIRFSOC_I2C_DATA_SHIFT(i)); + } +} + +static void i2c_sirfsoc_queue_cmd(struct sirfsoc_i2c *siic) +{ + u32 regval; + int i = 0; + + if (siic->msg_read) { + while (((siic->finished_len + i) < siic->msg_len) + && (siic->cmd_ptr < SIRFSOC_I2C_CMD_BUF_MAX)) { + regval = SIRFSOC_I2C_READ | SIRFSOC_I2C_CMD_RP(0); + if (((siic->finished_len + i) == + (siic->msg_len - 1)) && siic->last) + regval |= SIRFSOC_I2C_STOP | SIRFSOC_I2C_NACK; + writel(regval, + siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++)); + i++; + } + + siic->read_cmd_len = i; + } else { + while ((siic->cmd_ptr < SIRFSOC_I2C_CMD_BUF_MAX - 1) + && (siic->finished_len < siic->msg_len)) { + regval = SIRFSOC_I2C_WRITE | SIRFSOC_I2C_CMD_RP(0); + if ((siic->finished_len == (siic->msg_len - 1)) + && siic->last) + regval |= SIRFSOC_I2C_STOP; + writel(regval, + siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++)); + writel(siic->buf[siic->finished_len++], + siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++)); + } + } + siic->cmd_ptr = 0; + + /* Trigger the transfer */ + writel(SIRFSOC_I2C_START_CMD, siic->base + SIRFSOC_I2C_CMD_START); +} + +static irqreturn_t i2c_sirfsoc_irq(int irq, void *dev_id) +{ + struct sirfsoc_i2c *siic = (struct sirfsoc_i2c *)dev_id; + u32 i2c_stat = readl(siic->base + SIRFSOC_I2C_STATUS); + + if (i2c_stat & SIRFSOC_I2C_STAT_ERR) { + /* Error conditions */ + siic->err_status = SIRFSOC_I2C_ERR_NOACK; + writel(SIRFSOC_I2C_STAT_ERR, siic->base + SIRFSOC_I2C_STATUS); + + if (i2c_stat & SIRFSOC_I2C_STAT_NACK) + dev_dbg(&siic->adapter.dev, "ACK not received\n"); + else + dev_err(&siic->adapter.dev, "I2C error\n"); + + /* + * Due to hardware ANOMALY, we need to reset I2C earlier after + * we get NOACK while accessing non-existing clients, otherwise + * we will get errors even we access existing clients later + */ + writel(readl(siic->base + SIRFSOC_I2C_CTRL) | SIRFSOC_I2C_RESET, + siic->base + SIRFSOC_I2C_CTRL); + while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET) + cpu_relax(); + + complete(&siic->done); + } else if (i2c_stat & SIRFSOC_I2C_STAT_CMD_DONE) { + /* CMD buffer execution complete */ + if (siic->msg_read) + i2c_sirfsoc_read_data(siic); + if (siic->finished_len == siic->msg_len) + complete(&siic->done); + else /* Fill a new CMD buffer for left data */ + i2c_sirfsoc_queue_cmd(siic); + + writel(SIRFSOC_I2C_STAT_CMD_DONE, siic->base + SIRFSOC_I2C_STATUS); + } + + return IRQ_HANDLED; +} + +static void i2c_sirfsoc_set_address(struct sirfsoc_i2c *siic, + struct i2c_msg *msg) +{ + unsigned char addr; + u32 regval = SIRFSOC_I2C_START | SIRFSOC_I2C_CMD_RP(0) | SIRFSOC_I2C_WRITE; + + /* no data and last message -> add STOP */ + if (siic->last && (msg->len == 0)) + regval |= SIRFSOC_I2C_STOP; + + writel(regval, siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++)); + + addr = i2c_8bit_addr_from_msg(msg); + + /* Reverse direction bit */ + if (msg->flags & I2C_M_REV_DIR_ADDR) + addr ^= 1; + + writel(addr, siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++)); +} + +static int i2c_sirfsoc_xfer_msg(struct sirfsoc_i2c *siic, struct i2c_msg *msg) +{ + u32 regval = readl(siic->base + SIRFSOC_I2C_CTRL); + /* timeout waiting for the xfer to finish or fail */ + int timeout = msecs_to_jiffies((msg->len + 1) * 50); + + i2c_sirfsoc_set_address(siic, msg); + + writel(regval | SIRFSOC_I2C_CMD_DONE_EN | SIRFSOC_I2C_ERR_INT_EN, + siic->base + SIRFSOC_I2C_CTRL); + i2c_sirfsoc_queue_cmd(siic); + + if (wait_for_completion_timeout(&siic->done, timeout) == 0) { + siic->err_status = SIRFSOC_I2C_ERR_TIMEOUT; + dev_err(&siic->adapter.dev, "Transfer timeout\n"); + } + + writel(regval & ~(SIRFSOC_I2C_CMD_DONE_EN | SIRFSOC_I2C_ERR_INT_EN), + siic->base + SIRFSOC_I2C_CTRL); + writel(0, siic->base + SIRFSOC_I2C_CMD_START); + + /* i2c control doesn't response, reset it */ + if (siic->err_status == SIRFSOC_I2C_ERR_TIMEOUT) { + writel(readl(siic->base + SIRFSOC_I2C_CTRL) | SIRFSOC_I2C_RESET, + siic->base + SIRFSOC_I2C_CTRL); + while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET) + cpu_relax(); + } + return siic->err_status ? -EAGAIN : 0; +} + +static u32 i2c_sirfsoc_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static int i2c_sirfsoc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, + int num) +{ + struct sirfsoc_i2c *siic = adap->algo_data; + int i, ret; + + clk_enable(siic->clk); + + for (i = 0; i < num; i++) { + siic->buf = msgs[i].buf; + siic->msg_len = msgs[i].len; + siic->msg_read = !!(msgs[i].flags & I2C_M_RD); + siic->err_status = 0; + siic->cmd_ptr = 0; + siic->finished_len = 0; + siic->last = (i == (num - 1)); + + ret = i2c_sirfsoc_xfer_msg(siic, &msgs[i]); + if (ret) { + clk_disable(siic->clk); + return ret; + } + } + + clk_disable(siic->clk); + return num; +} + +/* I2C algorithms associated with this master controller driver */ +static const struct i2c_algorithm i2c_sirfsoc_algo = { + .master_xfer = i2c_sirfsoc_xfer, + .functionality = i2c_sirfsoc_func, +}; + +static int i2c_sirfsoc_probe(struct platform_device *pdev) +{ + struct sirfsoc_i2c *siic; + struct i2c_adapter *adap; + struct clk *clk; + int bitrate; + int ctrl_speed; + int irq; + + int err; + u32 regval; + + clk = clk_get(&pdev->dev, NULL); + if (IS_ERR(clk)) { + err = PTR_ERR(clk); + dev_err(&pdev->dev, "Clock get failed\n"); + goto err_get_clk; + } + + err = clk_prepare(clk); + if (err) { + dev_err(&pdev->dev, "Clock prepare failed\n"); + goto err_clk_prep; + } + + err = clk_enable(clk); + if (err) { + dev_err(&pdev->dev, "Clock enable failed\n"); + goto err_clk_en; + } + + ctrl_speed = clk_get_rate(clk); + + siic = devm_kzalloc(&pdev->dev, sizeof(*siic), GFP_KERNEL); + if (!siic) { + err = -ENOMEM; + goto out; + } + adap = &siic->adapter; + adap->class = I2C_CLASS_DEPRECATED; + + siic->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(siic->base)) { + err = PTR_ERR(siic->base); + goto out; + } + + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + err = irq; + goto out; + } + err = devm_request_irq(&pdev->dev, irq, i2c_sirfsoc_irq, 0, + dev_name(&pdev->dev), siic); + if (err) + goto out; + + adap->algo = &i2c_sirfsoc_algo; + adap->algo_data = siic; + adap->retries = 3; + + adap->dev.of_node = pdev->dev.of_node; + adap->dev.parent = &pdev->dev; + adap->nr = pdev->id; + + strlcpy(adap->name, "sirfsoc-i2c", sizeof(adap->name)); + + platform_set_drvdata(pdev, adap); + init_completion(&siic->done); + + /* Controller initialisation */ + + writel(SIRFSOC_I2C_RESET, siic->base + SIRFSOC_I2C_CTRL); + while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET) + cpu_relax(); + writel(SIRFSOC_I2C_CORE_EN | SIRFSOC_I2C_MASTER_MODE, + siic->base + SIRFSOC_I2C_CTRL); + + siic->clk = clk; + + err = of_property_read_u32(pdev->dev.of_node, + "clock-frequency", &bitrate); + if (err < 0) + bitrate = I2C_MAX_STANDARD_MODE_FREQ; + + /* + * Due to some hardware design issues, we need to tune the formula. + * Since i2c is open drain interface that allows the slave to + * stall the transaction by holding the SCL line at '0', the RTL + * implementation is waiting for SCL feedback from the pin after + * setting it to High-Z ('1'). This wait adds to the high-time + * interval counter few cycles of the input synchronization + * (depending on the SCL_FILTER_REG field), and also the time it + * takes for the board pull-up resistor to rise the SCL line. + * For slow SCL settings these additions are negligible, + * but they start to affect the speed when clock is set to faster + * frequencies. + * Through the actual tests, use the different user_div value(which + * in the divider formula 'Fio / (Fi2c * user_div)') to adapt + * the different ranges of i2c bus clock frequency, to make the SCL + * more accurate. + */ + if (bitrate <= 30000) + regval = ctrl_speed / (bitrate * 5); + else if (bitrate > 30000 && bitrate <= 280000) + regval = (2 * ctrl_speed) / (bitrate * 11); + else + regval = ctrl_speed / (bitrate * 6); + + writel(regval, siic->base + SIRFSOC_I2C_CLK_CTRL); + if (regval > 0xFF) + writel(0xFF, siic->base + SIRFSOC_I2C_SDA_DELAY); + else + writel(regval, siic->base + SIRFSOC_I2C_SDA_DELAY); + + err = i2c_add_numbered_adapter(adap); + if (err < 0) + goto out; + + clk_disable(clk); + + dev_info(&pdev->dev, " I2C adapter ready to operate\n"); + + return 0; + +out: + clk_disable(clk); +err_clk_en: + clk_unprepare(clk); +err_clk_prep: + clk_put(clk); +err_get_clk: + return err; +} + +static int i2c_sirfsoc_remove(struct platform_device *pdev) +{ + struct i2c_adapter *adapter = platform_get_drvdata(pdev); + struct sirfsoc_i2c *siic = adapter->algo_data; + + writel(SIRFSOC_I2C_RESET, siic->base + SIRFSOC_I2C_CTRL); + i2c_del_adapter(adapter); + clk_unprepare(siic->clk); + clk_put(siic->clk); + return 0; +} + +#ifdef CONFIG_PM +static int i2c_sirfsoc_suspend(struct device *dev) +{ + struct i2c_adapter *adapter = dev_get_drvdata(dev); + struct sirfsoc_i2c *siic = adapter->algo_data; + + clk_enable(siic->clk); + siic->sda_delay = readl(siic->base + SIRFSOC_I2C_SDA_DELAY); + siic->clk_div = readl(siic->base + SIRFSOC_I2C_CLK_CTRL); + clk_disable(siic->clk); + return 0; +} + +static int i2c_sirfsoc_resume(struct device *dev) +{ + struct i2c_adapter *adapter = dev_get_drvdata(dev); + struct sirfsoc_i2c *siic = adapter->algo_data; + + clk_enable(siic->clk); + writel(SIRFSOC_I2C_RESET, siic->base + SIRFSOC_I2C_CTRL); + while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET) + cpu_relax(); + writel(SIRFSOC_I2C_CORE_EN | SIRFSOC_I2C_MASTER_MODE, + siic->base + SIRFSOC_I2C_CTRL); + writel(siic->clk_div, siic->base + SIRFSOC_I2C_CLK_CTRL); + writel(siic->sda_delay, siic->base + SIRFSOC_I2C_SDA_DELAY); + clk_disable(siic->clk); + return 0; +} + +static const struct dev_pm_ops i2c_sirfsoc_pm_ops = { + .suspend = i2c_sirfsoc_suspend, + .resume = i2c_sirfsoc_resume, +}; +#endif + +static const struct of_device_id sirfsoc_i2c_of_match[] = { + { .compatible = "sirf,prima2-i2c", }, + {}, +}; +MODULE_DEVICE_TABLE(of, sirfsoc_i2c_of_match); + +static struct platform_driver i2c_sirfsoc_driver = { + .driver = { + .name = "sirfsoc_i2c", +#ifdef CONFIG_PM + .pm = &i2c_sirfsoc_pm_ops, +#endif + .of_match_table = sirfsoc_i2c_of_match, + }, + .probe = i2c_sirfsoc_probe, + .remove = i2c_sirfsoc_remove, +}; +module_platform_driver(i2c_sirfsoc_driver); + +MODULE_DESCRIPTION("SiRF SoC I2C master controller driver"); +MODULE_AUTHOR("Zhiwu Song <Zhiwu.Song@csr.com>"); +MODULE_AUTHOR("Xiangzhen Ye <Xiangzhen.Ye@csr.com>"); +MODULE_LICENSE("GPL v2"); |