diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/i2c/busses/i2c-sprd.c | 659 |
1 files changed, 659 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-sprd.c b/drivers/i2c/busses/i2c-sprd.c new file mode 100644 index 000000000..a520aa06d --- /dev/null +++ b/drivers/i2c/busses/i2c-sprd.c @@ -0,0 +1,659 @@ +/* + * Copyright (C) 2017 Spreadtrum Communications Inc. + * + * SPDX-License-Identifier: (GPL-2.0+ OR MIT) + */ + +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> + +#define I2C_CTL 0x00 +#define I2C_ADDR_CFG 0x04 +#define I2C_COUNT 0x08 +#define I2C_RX 0x0c +#define I2C_TX 0x10 +#define I2C_STATUS 0x14 +#define I2C_HSMODE_CFG 0x18 +#define I2C_VERSION 0x1c +#define ADDR_DVD0 0x20 +#define ADDR_DVD1 0x24 +#define ADDR_STA0_DVD 0x28 +#define ADDR_RST 0x2c + +/* I2C_CTL */ +#define STP_EN BIT(20) +#define FIFO_AF_LVL_MASK GENMASK(19, 16) +#define FIFO_AF_LVL 16 +#define FIFO_AE_LVL_MASK GENMASK(15, 12) +#define FIFO_AE_LVL 12 +#define I2C_DMA_EN BIT(11) +#define FULL_INTEN BIT(10) +#define EMPTY_INTEN BIT(9) +#define I2C_DVD_OPT BIT(8) +#define I2C_OUT_OPT BIT(7) +#define I2C_TRIM_OPT BIT(6) +#define I2C_HS_MODE BIT(4) +#define I2C_MODE BIT(3) +#define I2C_EN BIT(2) +#define I2C_INT_EN BIT(1) +#define I2C_START BIT(0) + +/* I2C_STATUS */ +#define SDA_IN BIT(21) +#define SCL_IN BIT(20) +#define FIFO_FULL BIT(4) +#define FIFO_EMPTY BIT(3) +#define I2C_INT BIT(2) +#define I2C_RX_ACK BIT(1) +#define I2C_BUSY BIT(0) + +/* ADDR_RST */ +#define I2C_RST BIT(0) + +#define I2C_FIFO_DEEP 12 +#define I2C_FIFO_FULL_THLD 15 +#define I2C_FIFO_EMPTY_THLD 4 +#define I2C_DATA_STEP 8 +#define I2C_ADDR_DVD0_CALC(high, low) \ + ((((high) & GENMASK(15, 0)) << 16) | ((low) & GENMASK(15, 0))) +#define I2C_ADDR_DVD1_CALC(high, low) \ + (((high) & GENMASK(31, 16)) | (((low) & GENMASK(31, 16)) >> 16)) + +/* timeout (ms) for pm runtime autosuspend */ +#define SPRD_I2C_PM_TIMEOUT 1000 +/* timeout (ms) for transfer message */ +#define I2C_XFER_TIMEOUT 1000 + +/* SPRD i2c data structure */ +struct sprd_i2c { + struct i2c_adapter adap; + struct device *dev; + void __iomem *base; + struct i2c_msg *msg; + struct clk *clk; + u32 src_clk; + u32 bus_freq; + struct completion complete; + u8 *buf; + u32 count; + int irq; + int err; +}; + +static void sprd_i2c_set_count(struct sprd_i2c *i2c_dev, u32 count) +{ + writel(count, i2c_dev->base + I2C_COUNT); +} + +static void sprd_i2c_send_stop(struct sprd_i2c *i2c_dev, int stop) +{ + u32 tmp = readl(i2c_dev->base + I2C_CTL); + + if (stop) + writel(tmp & ~STP_EN, i2c_dev->base + I2C_CTL); + else + writel(tmp | STP_EN, i2c_dev->base + I2C_CTL); +} + +static void sprd_i2c_clear_start(struct sprd_i2c *i2c_dev) +{ + u32 tmp = readl(i2c_dev->base + I2C_CTL); + + writel(tmp & ~I2C_START, i2c_dev->base + I2C_CTL); +} + +static void sprd_i2c_clear_ack(struct sprd_i2c *i2c_dev) +{ + u32 tmp = readl(i2c_dev->base + I2C_STATUS); + + writel(tmp & ~I2C_RX_ACK, i2c_dev->base + I2C_STATUS); +} + +static void sprd_i2c_clear_irq(struct sprd_i2c *i2c_dev) +{ + u32 tmp = readl(i2c_dev->base + I2C_STATUS); + + writel(tmp & ~I2C_INT, i2c_dev->base + I2C_STATUS); +} + +static void sprd_i2c_reset_fifo(struct sprd_i2c *i2c_dev) +{ + writel(I2C_RST, i2c_dev->base + ADDR_RST); +} + +static void sprd_i2c_set_devaddr(struct sprd_i2c *i2c_dev, struct i2c_msg *m) +{ + writel(m->addr << 1, i2c_dev->base + I2C_ADDR_CFG); +} + +static void sprd_i2c_write_bytes(struct sprd_i2c *i2c_dev, u8 *buf, u32 len) +{ + u32 i; + + for (i = 0; i < len; i++) + writeb(buf[i], i2c_dev->base + I2C_TX); +} + +static void sprd_i2c_read_bytes(struct sprd_i2c *i2c_dev, u8 *buf, u32 len) +{ + u32 i; + + for (i = 0; i < len; i++) + buf[i] = readb(i2c_dev->base + I2C_RX); +} + +static void sprd_i2c_set_full_thld(struct sprd_i2c *i2c_dev, u32 full_thld) +{ + u32 tmp = readl(i2c_dev->base + I2C_CTL); + + tmp &= ~FIFO_AF_LVL_MASK; + tmp |= full_thld << FIFO_AF_LVL; + writel(tmp, i2c_dev->base + I2C_CTL); +}; + +static void sprd_i2c_set_empty_thld(struct sprd_i2c *i2c_dev, u32 empty_thld) +{ + u32 tmp = readl(i2c_dev->base + I2C_CTL); + + tmp &= ~FIFO_AE_LVL_MASK; + tmp |= empty_thld << FIFO_AE_LVL; + writel(tmp, i2c_dev->base + I2C_CTL); +}; + +static void sprd_i2c_set_fifo_full_int(struct sprd_i2c *i2c_dev, int enable) +{ + u32 tmp = readl(i2c_dev->base + I2C_CTL); + + if (enable) + tmp |= FULL_INTEN; + else + tmp &= ~FULL_INTEN; + + writel(tmp, i2c_dev->base + I2C_CTL); +}; + +static void sprd_i2c_set_fifo_empty_int(struct sprd_i2c *i2c_dev, int enable) +{ + u32 tmp = readl(i2c_dev->base + I2C_CTL); + + if (enable) + tmp |= EMPTY_INTEN; + else + tmp &= ~EMPTY_INTEN; + + writel(tmp, i2c_dev->base + I2C_CTL); +}; + +static void sprd_i2c_opt_start(struct sprd_i2c *i2c_dev) +{ + u32 tmp = readl(i2c_dev->base + I2C_CTL); + + writel(tmp | I2C_START, i2c_dev->base + I2C_CTL); +} + +static void sprd_i2c_opt_mode(struct sprd_i2c *i2c_dev, int rw) +{ + u32 cmd = readl(i2c_dev->base + I2C_CTL) & ~I2C_MODE; + + writel(cmd | rw << 3, i2c_dev->base + I2C_CTL); +} + +static void sprd_i2c_data_transfer(struct sprd_i2c *i2c_dev) +{ + u32 i2c_count = i2c_dev->count; + u32 need_tran = i2c_count <= I2C_FIFO_DEEP ? i2c_count : I2C_FIFO_DEEP; + struct i2c_msg *msg = i2c_dev->msg; + + if (msg->flags & I2C_M_RD) { + sprd_i2c_read_bytes(i2c_dev, i2c_dev->buf, I2C_FIFO_FULL_THLD); + i2c_dev->count -= I2C_FIFO_FULL_THLD; + i2c_dev->buf += I2C_FIFO_FULL_THLD; + + /* + * If the read data count is larger than rx fifo full threshold, + * we should enable the rx fifo full interrupt to read data + * again. + */ + if (i2c_dev->count >= I2C_FIFO_FULL_THLD) + sprd_i2c_set_fifo_full_int(i2c_dev, 1); + } else { + sprd_i2c_write_bytes(i2c_dev, i2c_dev->buf, need_tran); + i2c_dev->buf += need_tran; + i2c_dev->count -= need_tran; + + /* + * If the write data count is arger than tx fifo depth which + * means we can not write all data in one time, then we should + * enable the tx fifo empty interrupt to write again. + */ + if (i2c_count > I2C_FIFO_DEEP) + sprd_i2c_set_fifo_empty_int(i2c_dev, 1); + } +} + +static int sprd_i2c_handle_msg(struct i2c_adapter *i2c_adap, + struct i2c_msg *msg, bool is_last_msg) +{ + struct sprd_i2c *i2c_dev = i2c_adap->algo_data; + unsigned long time_left; + + i2c_dev->msg = msg; + i2c_dev->buf = msg->buf; + i2c_dev->count = msg->len; + + reinit_completion(&i2c_dev->complete); + sprd_i2c_reset_fifo(i2c_dev); + sprd_i2c_set_devaddr(i2c_dev, msg); + sprd_i2c_set_count(i2c_dev, msg->len); + + if (msg->flags & I2C_M_RD) { + sprd_i2c_opt_mode(i2c_dev, 1); + sprd_i2c_send_stop(i2c_dev, 1); + } else { + sprd_i2c_opt_mode(i2c_dev, 0); + sprd_i2c_send_stop(i2c_dev, !!is_last_msg); + } + + /* + * We should enable rx fifo full interrupt to get data when receiving + * full data. + */ + if (msg->flags & I2C_M_RD) + sprd_i2c_set_fifo_full_int(i2c_dev, 1); + else + sprd_i2c_data_transfer(i2c_dev); + + sprd_i2c_opt_start(i2c_dev); + + time_left = wait_for_completion_timeout(&i2c_dev->complete, + msecs_to_jiffies(I2C_XFER_TIMEOUT)); + if (!time_left) + return -ETIMEDOUT; + + return i2c_dev->err; +} + +static int sprd_i2c_master_xfer(struct i2c_adapter *i2c_adap, + struct i2c_msg *msgs, int num) +{ + struct sprd_i2c *i2c_dev = i2c_adap->algo_data; + int im, ret; + + ret = pm_runtime_resume_and_get(i2c_dev->dev); + if (ret < 0) + return ret; + + for (im = 0; im < num - 1; im++) { + ret = sprd_i2c_handle_msg(i2c_adap, &msgs[im], 0); + if (ret) + goto err_msg; + } + + ret = sprd_i2c_handle_msg(i2c_adap, &msgs[im++], 1); + +err_msg: + pm_runtime_mark_last_busy(i2c_dev->dev); + pm_runtime_put_autosuspend(i2c_dev->dev); + + return ret < 0 ? ret : im; +} + +static u32 sprd_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static const struct i2c_algorithm sprd_i2c_algo = { + .master_xfer = sprd_i2c_master_xfer, + .functionality = sprd_i2c_func, +}; + +static void sprd_i2c_set_clk(struct sprd_i2c *i2c_dev, u32 freq) +{ + u32 apb_clk = i2c_dev->src_clk; + /* + * From I2C databook, the prescale calculation formula: + * prescale = freq_i2c / (4 * freq_scl) - 1; + */ + u32 i2c_dvd = apb_clk / (4 * freq) - 1; + /* + * From I2C databook, the high period of SCL clock is recommended as + * 40% (2/5), and the low period of SCL clock is recommended as 60% + * (3/5), then the formula should be: + * high = (prescale * 2 * 2) / 5 + * low = (prescale * 2 * 3) / 5 + */ + u32 high = ((i2c_dvd << 1) * 2) / 5; + u32 low = ((i2c_dvd << 1) * 3) / 5; + u32 div0 = I2C_ADDR_DVD0_CALC(high, low); + u32 div1 = I2C_ADDR_DVD1_CALC(high, low); + + writel(div0, i2c_dev->base + ADDR_DVD0); + writel(div1, i2c_dev->base + ADDR_DVD1); + + /* Start hold timing = hold time(us) * source clock */ + if (freq == I2C_MAX_FAST_MODE_FREQ) + writel((6 * apb_clk) / 10000000, i2c_dev->base + ADDR_STA0_DVD); + else if (freq == I2C_MAX_STANDARD_MODE_FREQ) + writel((4 * apb_clk) / 1000000, i2c_dev->base + ADDR_STA0_DVD); +} + +static void sprd_i2c_enable(struct sprd_i2c *i2c_dev) +{ + u32 tmp = I2C_DVD_OPT; + + writel(tmp, i2c_dev->base + I2C_CTL); + + sprd_i2c_set_full_thld(i2c_dev, I2C_FIFO_FULL_THLD); + sprd_i2c_set_empty_thld(i2c_dev, I2C_FIFO_EMPTY_THLD); + + sprd_i2c_set_clk(i2c_dev, i2c_dev->bus_freq); + sprd_i2c_reset_fifo(i2c_dev); + sprd_i2c_clear_irq(i2c_dev); + + tmp = readl(i2c_dev->base + I2C_CTL); + writel(tmp | I2C_EN | I2C_INT_EN, i2c_dev->base + I2C_CTL); +} + +static irqreturn_t sprd_i2c_isr_thread(int irq, void *dev_id) +{ + struct sprd_i2c *i2c_dev = dev_id; + struct i2c_msg *msg = i2c_dev->msg; + bool ack = !(readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK); + u32 i2c_tran; + + if (msg->flags & I2C_M_RD) + i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD; + else + i2c_tran = i2c_dev->count; + + /* + * If we got one ACK from slave when writing data, and we did not + * finish this transmission (i2c_tran is not zero), then we should + * continue to write data. + * + * For reading data, ack is always true, if i2c_tran is not 0 which + * means we still need to contine to read data from slave. + */ + if (i2c_tran && ack) { + sprd_i2c_data_transfer(i2c_dev); + return IRQ_HANDLED; + } + + i2c_dev->err = 0; + + /* + * If we did not get one ACK from slave when writing data, we should + * return -EIO to notify users. + */ + if (!ack) + i2c_dev->err = -EIO; + else if (msg->flags & I2C_M_RD && i2c_dev->count) + sprd_i2c_read_bytes(i2c_dev, i2c_dev->buf, i2c_dev->count); + + /* Transmission is done and clear ack and start operation */ + sprd_i2c_clear_ack(i2c_dev); + sprd_i2c_clear_start(i2c_dev); + complete(&i2c_dev->complete); + + return IRQ_HANDLED; +} + +static irqreturn_t sprd_i2c_isr(int irq, void *dev_id) +{ + struct sprd_i2c *i2c_dev = dev_id; + struct i2c_msg *msg = i2c_dev->msg; + bool ack = !(readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK); + u32 i2c_tran; + + if (msg->flags & I2C_M_RD) + i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD; + else + i2c_tran = i2c_dev->count; + + /* + * If we did not get one ACK from slave when writing data, then we + * should finish this transmission since we got some errors. + * + * When writing data, if i2c_tran == 0 which means we have writen + * done all data, then we can finish this transmission. + * + * When reading data, if conut < rx fifo full threshold, which + * means we can read all data in one time, then we can finish this + * transmission too. + */ + if (!i2c_tran || !ack) { + sprd_i2c_clear_start(i2c_dev); + sprd_i2c_clear_irq(i2c_dev); + } + + sprd_i2c_set_fifo_empty_int(i2c_dev, 0); + sprd_i2c_set_fifo_full_int(i2c_dev, 0); + + return IRQ_WAKE_THREAD; +} + +static int sprd_i2c_clk_init(struct sprd_i2c *i2c_dev) +{ + struct clk *clk_i2c, *clk_parent; + + clk_i2c = devm_clk_get(i2c_dev->dev, "i2c"); + if (IS_ERR(clk_i2c)) { + dev_warn(i2c_dev->dev, "i2c%d can't get the i2c clock\n", + i2c_dev->adap.nr); + clk_i2c = NULL; + } + + clk_parent = devm_clk_get(i2c_dev->dev, "source"); + if (IS_ERR(clk_parent)) { + dev_warn(i2c_dev->dev, "i2c%d can't get the source clock\n", + i2c_dev->adap.nr); + clk_parent = NULL; + } + + if (clk_set_parent(clk_i2c, clk_parent)) + i2c_dev->src_clk = clk_get_rate(clk_i2c); + else + i2c_dev->src_clk = 26000000; + + dev_dbg(i2c_dev->dev, "i2c%d set source clock is %d\n", + i2c_dev->adap.nr, i2c_dev->src_clk); + + i2c_dev->clk = devm_clk_get(i2c_dev->dev, "enable"); + if (IS_ERR(i2c_dev->clk)) { + dev_err(i2c_dev->dev, "i2c%d can't get the enable clock\n", + i2c_dev->adap.nr); + return PTR_ERR(i2c_dev->clk); + } + + return 0; +} + +static int sprd_i2c_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct sprd_i2c *i2c_dev; + u32 prop; + int ret; + + pdev->id = of_alias_get_id(dev->of_node, "i2c"); + + i2c_dev = devm_kzalloc(dev, sizeof(struct sprd_i2c), GFP_KERNEL); + if (!i2c_dev) + return -ENOMEM; + + i2c_dev->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(i2c_dev->base)) + return PTR_ERR(i2c_dev->base); + + i2c_dev->irq = platform_get_irq(pdev, 0); + if (i2c_dev->irq < 0) + return i2c_dev->irq; + + i2c_set_adapdata(&i2c_dev->adap, i2c_dev); + init_completion(&i2c_dev->complete); + snprintf(i2c_dev->adap.name, sizeof(i2c_dev->adap.name), + "%s", "sprd-i2c"); + + i2c_dev->bus_freq = I2C_MAX_STANDARD_MODE_FREQ; + i2c_dev->adap.owner = THIS_MODULE; + i2c_dev->dev = dev; + i2c_dev->adap.retries = 3; + i2c_dev->adap.algo = &sprd_i2c_algo; + i2c_dev->adap.algo_data = i2c_dev; + i2c_dev->adap.dev.parent = dev; + i2c_dev->adap.nr = pdev->id; + i2c_dev->adap.dev.of_node = dev->of_node; + + if (!of_property_read_u32(dev->of_node, "clock-frequency", &prop)) + i2c_dev->bus_freq = prop; + + /* We only support 100k and 400k now, otherwise will return error. */ + if (i2c_dev->bus_freq != I2C_MAX_STANDARD_MODE_FREQ && + i2c_dev->bus_freq != I2C_MAX_FAST_MODE_FREQ) + return -EINVAL; + + ret = sprd_i2c_clk_init(i2c_dev); + if (ret) + return ret; + + platform_set_drvdata(pdev, i2c_dev); + + ret = clk_prepare_enable(i2c_dev->clk); + if (ret) + return ret; + + sprd_i2c_enable(i2c_dev); + + pm_runtime_set_autosuspend_delay(i2c_dev->dev, SPRD_I2C_PM_TIMEOUT); + pm_runtime_use_autosuspend(i2c_dev->dev); + pm_runtime_set_active(i2c_dev->dev); + pm_runtime_enable(i2c_dev->dev); + + ret = pm_runtime_get_sync(i2c_dev->dev); + if (ret < 0) + goto err_rpm_put; + + ret = devm_request_threaded_irq(dev, i2c_dev->irq, + sprd_i2c_isr, sprd_i2c_isr_thread, + IRQF_NO_SUSPEND | IRQF_ONESHOT, + pdev->name, i2c_dev); + if (ret) { + dev_err(&pdev->dev, "failed to request irq %d\n", i2c_dev->irq); + goto err_rpm_put; + } + + ret = i2c_add_numbered_adapter(&i2c_dev->adap); + if (ret) { + dev_err(&pdev->dev, "add adapter failed\n"); + goto err_rpm_put; + } + + pm_runtime_mark_last_busy(i2c_dev->dev); + pm_runtime_put_autosuspend(i2c_dev->dev); + return 0; + +err_rpm_put: + pm_runtime_put_noidle(i2c_dev->dev); + pm_runtime_disable(i2c_dev->dev); + clk_disable_unprepare(i2c_dev->clk); + return ret; +} + +static int sprd_i2c_remove(struct platform_device *pdev) +{ + struct sprd_i2c *i2c_dev = platform_get_drvdata(pdev); + int ret; + + ret = pm_runtime_get_sync(i2c_dev->dev); + if (ret < 0) + dev_err(&pdev->dev, "Failed to resume device (%pe)\n", ERR_PTR(ret)); + + i2c_del_adapter(&i2c_dev->adap); + + if (ret >= 0) + clk_disable_unprepare(i2c_dev->clk); + + pm_runtime_put_noidle(i2c_dev->dev); + pm_runtime_disable(i2c_dev->dev); + + return 0; +} + +static int __maybe_unused sprd_i2c_suspend_noirq(struct device *dev) +{ + struct sprd_i2c *i2c_dev = dev_get_drvdata(dev); + + i2c_mark_adapter_suspended(&i2c_dev->adap); + return pm_runtime_force_suspend(dev); +} + +static int __maybe_unused sprd_i2c_resume_noirq(struct device *dev) +{ + struct sprd_i2c *i2c_dev = dev_get_drvdata(dev); + + i2c_mark_adapter_resumed(&i2c_dev->adap); + return pm_runtime_force_resume(dev); +} + +static int __maybe_unused sprd_i2c_runtime_suspend(struct device *dev) +{ + struct sprd_i2c *i2c_dev = dev_get_drvdata(dev); + + clk_disable_unprepare(i2c_dev->clk); + + return 0; +} + +static int __maybe_unused sprd_i2c_runtime_resume(struct device *dev) +{ + struct sprd_i2c *i2c_dev = dev_get_drvdata(dev); + int ret; + + ret = clk_prepare_enable(i2c_dev->clk); + if (ret) + return ret; + + sprd_i2c_enable(i2c_dev); + + return 0; +} + +static const struct dev_pm_ops sprd_i2c_pm_ops = { + SET_RUNTIME_PM_OPS(sprd_i2c_runtime_suspend, + sprd_i2c_runtime_resume, NULL) + + SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(sprd_i2c_suspend_noirq, + sprd_i2c_resume_noirq) +}; + +static const struct of_device_id sprd_i2c_of_match[] = { + { .compatible = "sprd,sc9860-i2c", }, + {}, +}; + +static struct platform_driver sprd_i2c_driver = { + .probe = sprd_i2c_probe, + .remove = sprd_i2c_remove, + .driver = { + .name = "sprd-i2c", + .of_match_table = sprd_i2c_of_match, + .pm = &sprd_i2c_pm_ops, + }, +}; + +module_platform_driver(sprd_i2c_driver); + +MODULE_DESCRIPTION("Spreadtrum I2C master controller driver"); +MODULE_LICENSE("GPL v2"); |