diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-exynos5.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-exynos5.c | 139 |
1 files changed, 116 insertions, 23 deletions
diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c index f378cd479e55..9c1c5f3c09f6 100644 --- a/drivers/i2c/busses/i2c-exynos5.c +++ b/drivers/i2c/busses/i2c-exynos5.c @@ -18,9 +18,7 @@ #include <linux/clk.h> #include <linux/slab.h> #include <linux/io.h> -#include <linux/of_address.h> -#include <linux/of_device.h> -#include <linux/of_irq.h> +#include <linux/of.h> #include <linux/spinlock.h> /* @@ -170,6 +168,7 @@ enum i2c_type_exynos { I2C_TYPE_EXYNOS5, I2C_TYPE_EXYNOS7, I2C_TYPE_EXYNOSAUTOV9, + I2C_TYPE_EXYNOS8895, }; struct exynos5_i2c { @@ -196,6 +195,11 @@ struct exynos5_i2c { */ int trans_done; + /* + * Called from atomic context, don't use interrupts. + */ + unsigned int atomic; + /* Controller operating frequency */ unsigned int op_clock; @@ -237,6 +241,11 @@ static const struct exynos_hsi2c_variant exynosautov9_hsi2c_data = { .hw = I2C_TYPE_EXYNOSAUTOV9, }; +static const struct exynos_hsi2c_variant exynos8895_hsi2c_data = { + .fifo_depth = 64, + .hw = I2C_TYPE_EXYNOS8895, +}; + static const struct of_device_id exynos5_i2c_match[] = { { .compatible = "samsung,exynos5-hsi2c", @@ -253,6 +262,9 @@ static const struct of_device_id exynos5_i2c_match[] = { }, { .compatible = "samsung,exynosautov9-hsi2c", .data = &exynosautov9_hsi2c_data + }, { + .compatible = "samsung,exynos8895-hsi2c", + .data = &exynos8895_hsi2c_data }, {}, }; MODULE_DEVICE_TABLE(of, exynos5_i2c_match); @@ -267,7 +279,7 @@ static void exynos5_i2c_clr_pend_irq(struct exynos5_i2c *i2c) * exynos5_i2c_set_timing: updates the registers with appropriate * timing values calculated * - * Timing values for operation are calculated against either 100kHz + * Timing values for operation are calculated against 100kHz, 400kHz * or 1MHz controller operating frequency. * * Returns 0 on success, -EINVAL if the cycle length cannot @@ -328,23 +340,67 @@ static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, bool hs_timings) * clk_cycle := TSCLK_L + TSCLK_H * temp := (CLK_DIV + 1) * (clk_cycle + 2) * + * In case of HSI2C controllers in Exynos8895 + * FPCLK / FI2C = + * (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + + * 2 * ((FLT_CYCLE + 3) - (FLT_CYCLE + 3) % (CLK_DIV + 1)) + * + * clk_cycle := TSCLK_L + TSCLK_H + * temp := (FPCLK / FI2C) - (FLT_CYCLE + 3) * 2 + * * Constraints: 4 <= temp, 0 <= CLK_DIV < 256, 2 <= clk_cycle <= 510 * + * To split SCL clock into low, high periods appropriately, one + * proportion factor for each I2C mode is used, which is calculated + * using this formula. + * ``` + * ((t_low_min + (scl_clock - t_low_min - t_high_min) / 2) / scl_clock) + * ``` + * where: + * t_low_min is the minimal value of low period of the SCL clock in us; + * t_high_min is the minimal value of high period of the SCL clock in us; + * scl_clock is converted from SCL clock frequency into us. + * + * Below are the proportion factors for these I2C modes: + * t_low_min, t_high_min, scl_clock, proportion + * Standard Mode: 4.7us, 4.0us, 10us, 0.535 + * Fast Mode: 1.3us, 0.6us, 2.5us, 0.64 + * Fast-Plus Mode: 0.5us, 0.26us, 1us, 0.62 + * */ t_ftl_cycle = (readl(i2c->regs + HSI2C_CONF) >> 16) & 0x7; - temp = clkin / op_clk - 8 - t_ftl_cycle; - if (i2c->variant->hw != I2C_TYPE_EXYNOS7) - temp -= t_ftl_cycle; + if (i2c->variant->hw == I2C_TYPE_EXYNOS8895) + temp = clkin / op_clk - (t_ftl_cycle + 3) * 2; + else if (i2c->variant->hw == I2C_TYPE_EXYNOS7) + temp = clkin / op_clk - 8 - t_ftl_cycle; + else + temp = clkin / op_clk - 8 - (t_ftl_cycle * 2); div = temp / 512; - clk_cycle = temp / (div + 1) - 2; + + if (i2c->variant->hw == I2C_TYPE_EXYNOS8895) + clk_cycle = (temp + ((t_ftl_cycle + 3) % (div + 1)) * 2) / + (div + 1) - 2; + else + clk_cycle = temp / (div + 1) - 2; if (temp < 4 || div >= 256 || clk_cycle < 2) { dev_err(i2c->dev, "%s clock set-up failed\n", hs_timings ? "HS" : "FS"); return -EINVAL; } - t_scl_l = clk_cycle / 2; - t_scl_h = clk_cycle / 2; + /* + * Scale clk_cycle to get t_scl_l using the proption factors for individual I2C modes. + */ + if (op_clk <= I2C_MAX_STANDARD_MODE_FREQ) + t_scl_l = clk_cycle * 535 / 1000; + else if (op_clk <= I2C_MAX_FAST_MODE_FREQ) + t_scl_l = clk_cycle * 64 / 100; + else + t_scl_l = clk_cycle * 62 / 100; + + if (t_scl_l > 0xFF) + t_scl_l = 0xFF; + t_scl_h = clk_cycle - t_scl_l; t_start_su = t_scl_l; t_start_hd = t_scl_l; t_stop_su = t_scl_l; @@ -460,6 +516,8 @@ static irqreturn_t exynos5_i2c_irq(int irqno, void *dev_id) switch (i2c->variant->hw) { case I2C_TYPE_EXYNOSAUTOV9: fallthrough; + case I2C_TYPE_EXYNOS8895: + fallthrough; case I2C_TYPE_EXYNOS7: if (int_status & HSI2C_INT_TRANS_DONE) { i2c->trans_done = 1; @@ -713,10 +771,26 @@ static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop) spin_unlock_irqrestore(&i2c->lock, flags); } +static bool exynos5_i2c_poll_irqs_timeout(struct exynos5_i2c *i2c, + unsigned long timeout) +{ + unsigned long time_left = jiffies + timeout; + + while (time_before(jiffies, time_left) && + !((i2c->trans_done && (i2c->msg->len == i2c->msg_ptr)) || + (i2c->state < 0))) { + while (readl(i2c->regs + HSI2C_INT_ENABLE) & + readl(i2c->regs + HSI2C_INT_STATUS)) + exynos5_i2c_irq(i2c->irq, i2c); + usleep_range(100, 200); + } + return time_before(jiffies, time_left); +} + static int exynos5_i2c_xfer_msg(struct exynos5_i2c *i2c, struct i2c_msg *msgs, int stop) { - unsigned long timeout; + unsigned long time_left; int ret; i2c->msg = msgs; @@ -727,15 +801,20 @@ static int exynos5_i2c_xfer_msg(struct exynos5_i2c *i2c, exynos5_i2c_message_start(i2c, stop); - timeout = wait_for_completion_timeout(&i2c->msg_complete, - EXYNOS5_I2C_TIMEOUT); - if (timeout == 0) + if (!i2c->atomic) + time_left = wait_for_completion_timeout(&i2c->msg_complete, + EXYNOS5_I2C_TIMEOUT); + else + time_left = exynos5_i2c_poll_irqs_timeout(i2c, + EXYNOS5_I2C_TIMEOUT); + + if (time_left == 0) ret = -ETIMEDOUT; else ret = i2c->state; /* - * If this is the last message to be transfered (stop == 1) + * If this is the last message to be transferred (stop == 1) * Then check if the bus can be brought back to idle. */ if (ret == 0 && stop) @@ -779,14 +858,30 @@ err_pclk: return ret ?: num; } +static int exynos5_i2c_xfer_atomic(struct i2c_adapter *adap, + struct i2c_msg *msgs, int num) +{ + struct exynos5_i2c *i2c = adap->algo_data; + int ret; + + disable_irq(i2c->irq); + i2c->atomic = true; + ret = exynos5_i2c_xfer(adap, msgs, num); + i2c->atomic = false; + enable_irq(i2c->irq); + + return ret; +} + static u32 exynos5_i2c_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); } static const struct i2c_algorithm exynos5_i2c_algorithm = { - .master_xfer = exynos5_i2c_xfer, - .functionality = exynos5_i2c_func, + .xfer = exynos5_i2c_xfer, + .xfer_atomic = exynos5_i2c_xfer_atomic, + .functionality = exynos5_i2c_func, }; static int exynos5_i2c_probe(struct platform_device *pdev) @@ -892,7 +987,6 @@ static void exynos5_i2c_remove(struct platform_device *pdev) clk_unprepare(i2c->pclk); } -#ifdef CONFIG_PM_SLEEP static int exynos5_i2c_suspend_noirq(struct device *dev) { struct exynos5_i2c *i2c = dev_get_drvdata(dev); @@ -934,19 +1028,18 @@ err_pclk: clk_disable_unprepare(i2c->pclk); return ret; } -#endif static const struct dev_pm_ops exynos5_i2c_dev_pm_ops = { - SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(exynos5_i2c_suspend_noirq, - exynos5_i2c_resume_noirq) + NOIRQ_SYSTEM_SLEEP_PM_OPS(exynos5_i2c_suspend_noirq, + exynos5_i2c_resume_noirq) }; static struct platform_driver exynos5_i2c_driver = { .probe = exynos5_i2c_probe, - .remove_new = exynos5_i2c_remove, + .remove = exynos5_i2c_remove, .driver = { .name = "exynos5-hsi2c", - .pm = &exynos5_i2c_dev_pm_ops, + .pm = pm_sleep_ptr(&exynos5_i2c_dev_pm_ops), .of_match_table = exynos5_i2c_match, }, }; |