From b7169a57982383a81d4227712c894e6ec2516e8c Mon Sep 17 00:00:00 2001 From: Eugen Hristev Date: Mon, 9 Dec 2019 10:20:02 +0000 Subject: i2c: at91: fix clk_offset for sam9x60 In SAM9X60 datasheet, FLEX_TWI_CWGR register description mentions clock offset of 3 cycles (compared to 4 in eg. SAMA5D3). This is the same offset as in SAMA5D2. Fixes: b00277923743 ("i2c: at91: add new platform support for sam9x60") Suggested-by: Codrin Ciubotariu Signed-off-by: Eugen Hristev Acked-by: Ludovic Desroches Reviewed-by: Codrin Ciubotariu Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-at91-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/i2c') diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c index e13af4874976..5137e6297022 100644 --- a/drivers/i2c/busses/i2c-at91-core.c +++ b/drivers/i2c/busses/i2c-at91-core.c @@ -174,7 +174,7 @@ static struct at91_twi_pdata sama5d2_config = { static struct at91_twi_pdata sam9x60_config = { .clk_max_div = 7, - .clk_offset = 4, + .clk_offset = 3, .has_unre_flag = true, .has_alt_cmd = true, .has_hold_field = true, -- cgit v1.2.3 From 3b722da6672df8392f9c43d7c7e04bddd81d7e37 Mon Sep 17 00:00:00 2001 From: Stefan Wahren Date: Sat, 4 Jan 2020 16:13:20 +0100 Subject: i2c: bcm2835: Store pointer to bus clock The commit bebff81fb8b9 ("i2c: bcm2835: Model Divider in CCF") introduced a NULL pointer dereference on driver unload. It seems that we can't fetch the bus clock via devm_clk_get in bcm2835_i2c_remove. As an alternative approach store a pointer to the bus clock in the private driver structure. Fixes: bebff81fb8b9 ("i2c: bcm2835: Model Divider in CCF") Signed-off-by: Stefan Wahren Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-bcm2835.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) (limited to 'drivers/i2c') diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c index e01b2b57e724..5ab901ad615d 100644 --- a/drivers/i2c/busses/i2c-bcm2835.c +++ b/drivers/i2c/busses/i2c-bcm2835.c @@ -58,6 +58,7 @@ struct bcm2835_i2c_dev { struct i2c_adapter adapter; struct completion completion; struct i2c_msg *curr_msg; + struct clk *bus_clk; int num_msgs; u32 msg_err; u8 *msg_buf; @@ -404,7 +405,6 @@ static int bcm2835_i2c_probe(struct platform_device *pdev) struct resource *mem, *irq; int ret; struct i2c_adapter *adap; - struct clk *bus_clk; struct clk *mclk; u32 bus_clk_rate; @@ -427,11 +427,11 @@ static int bcm2835_i2c_probe(struct platform_device *pdev) return PTR_ERR(mclk); } - bus_clk = bcm2835_i2c_register_div(&pdev->dev, mclk, i2c_dev); + i2c_dev->bus_clk = bcm2835_i2c_register_div(&pdev->dev, mclk, i2c_dev); - if (IS_ERR(bus_clk)) { + if (IS_ERR(i2c_dev->bus_clk)) { dev_err(&pdev->dev, "Could not register clock\n"); - return PTR_ERR(bus_clk); + return PTR_ERR(i2c_dev->bus_clk); } ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency", @@ -442,13 +442,13 @@ static int bcm2835_i2c_probe(struct platform_device *pdev) bus_clk_rate = 100000; } - ret = clk_set_rate_exclusive(bus_clk, bus_clk_rate); + ret = clk_set_rate_exclusive(i2c_dev->bus_clk, bus_clk_rate); if (ret < 0) { dev_err(&pdev->dev, "Could not set clock frequency\n"); return ret; } - ret = clk_prepare_enable(bus_clk); + ret = clk_prepare_enable(i2c_dev->bus_clk); if (ret) { dev_err(&pdev->dev, "Couldn't prepare clock"); return ret; @@ -491,10 +491,9 @@ static int bcm2835_i2c_probe(struct platform_device *pdev) static int bcm2835_i2c_remove(struct platform_device *pdev) { struct bcm2835_i2c_dev *i2c_dev = platform_get_drvdata(pdev); - struct clk *bus_clk = devm_clk_get(i2c_dev->dev, "div"); - clk_rate_exclusive_put(bus_clk); - clk_disable_unprepare(bus_clk); + clk_rate_exclusive_put(i2c_dev->bus_clk); + clk_disable_unprepare(i2c_dev->bus_clk); free_irq(i2c_dev->irq, i2c_dev); i2c_del_adapter(&i2c_dev->adapter); -- cgit v1.2.3 From cf8ce8b80f8bf9669f6ec4e71e16668430febdac Mon Sep 17 00:00:00 2001 From: Russell King Date: Sun, 15 Dec 2019 16:39:05 +0000 Subject: i2c: fix bus recovery stop mode timing The I2C specification states that tsu:sto for standard mode timing must be at minimum 4us. Pictographically, this is: SCL: ____/~~~~~~~~~ SDA: _________/~~~~ ->| |<- 4us minimum We are currently waiting 2.5us between asserting SCL and SDA, which is in violation of the standard. Adjust the timings to ensure that we meet what is stipulated as the minimum timings to ensure that all devices correctly interpret the STOP bus transition. This is more important than trying to generate a square wave with even duty cycle. Signed-off-by: Russell King Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-core-base.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'drivers/i2c') diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 9f8dcd3f8385..35b209797d7b 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -186,10 +186,11 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) * If we can set SDA, we will always create a STOP to ensure additional * pulses will do no harm. This is achieved by letting SDA follow SCL * half a cycle later. Check the 'incomplete_write_byte' fault injector - * for details. + * for details. Note that we must honour tsu:sto, 4us, but lets use 5us + * here for simplicity. */ bri->set_scl(adap, scl); - ndelay(RECOVERY_NDELAY / 2); + ndelay(RECOVERY_NDELAY); if (bri->set_sda) bri->set_sda(adap, scl); ndelay(RECOVERY_NDELAY / 2); @@ -211,7 +212,13 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) scl = !scl; bri->set_scl(adap, scl); /* Creating STOP again, see above */ - ndelay(RECOVERY_NDELAY / 2); + if (scl) { + /* Honour minimum tsu:sto */ + ndelay(RECOVERY_NDELAY); + } else { + /* Honour minimum tf and thd:dat */ + ndelay(RECOVERY_NDELAY / 2); + } if (bri->set_sda) bri->set_sda(adap, scl); ndelay(RECOVERY_NDELAY / 2); -- cgit v1.2.3 From 9f42de8d4ec2304f10bbc51dc0484f3503d61196 Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko Date: Tue, 14 Jan 2020 04:34:35 +0300 Subject: i2c: tegra: Fix suspending in active runtime PM state I noticed that sometime I2C clock is kept enabled during suspend-resume. This happens because runtime PM defers dynamic suspension and thus it may happen that runtime PM is in active state when system enters into suspend. In particular I2C controller that is used for CPU's DVFS is often kept ON during suspend because CPU's voltage scaling happens quite often. Fixes: 8ebf15e9c869 ("i2c: tegra: Move suspend handling to NOIRQ phase") Cc: # v5.4+ Tested-by: Thierry Reding Signed-off-by: Dmitry Osipenko Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-tegra.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'drivers/i2c') diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index a98bf31d0e5c..79d19f6ce94e 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -1710,9 +1710,14 @@ static int tegra_i2c_remove(struct platform_device *pdev) static int __maybe_unused tegra_i2c_suspend(struct device *dev) { struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev); + int err; i2c_mark_adapter_suspended(&i2c_dev->adapter); + err = pm_runtime_force_suspend(dev); + if (err < 0) + return err; + return 0; } @@ -1733,6 +1738,10 @@ static int __maybe_unused tegra_i2c_resume(struct device *dev) if (err) return err; + err = pm_runtime_force_resume(dev); + if (err < 0) + return err; + i2c_mark_adapter_resumed(&i2c_dev->adapter); return 0; -- cgit v1.2.3 From 24a49678f5e20f18006e71b90ac1531876b27eb1 Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko Date: Tue, 14 Jan 2020 04:34:36 +0300 Subject: i2c: tegra: Properly disable runtime PM on driver's probe error One of the recent Tegra I2C commits made a change that resumes runtime PM during driver's probe, but it missed to put the RPM in a case of error. Note that it's not correct to use pm_runtime_status_suspended because it breaks RPM refcounting. Fixes: 8ebf15e9c869 ("i2c: tegra: Move suspend handling to NOIRQ phase") Cc: # v5.4+ Tested-by: Thierry Reding Signed-off-by: Dmitry Osipenko Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-tegra.c | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-) (limited to 'drivers/i2c') diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index 79d19f6ce94e..61339c665ebd 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -1608,14 +1608,18 @@ static int tegra_i2c_probe(struct platform_device *pdev) } pm_runtime_enable(&pdev->dev); - if (!pm_runtime_enabled(&pdev->dev)) + if (!pm_runtime_enabled(&pdev->dev)) { ret = tegra_i2c_runtime_resume(&pdev->dev); - else + if (ret < 0) { + dev_err(&pdev->dev, "runtime resume failed\n"); + goto unprepare_div_clk; + } + } else { ret = pm_runtime_get_sync(i2c_dev->dev); - - if (ret < 0) { - dev_err(&pdev->dev, "runtime resume failed\n"); - goto unprepare_div_clk; + if (ret < 0) { + dev_err(&pdev->dev, "runtime resume failed\n"); + goto disable_rpm; + } } if (i2c_dev->is_multimaster_mode) { @@ -1623,7 +1627,7 @@ static int tegra_i2c_probe(struct platform_device *pdev) if (ret < 0) { dev_err(i2c_dev->dev, "div_clk enable failed %d\n", ret); - goto disable_rpm; + goto put_rpm; } } @@ -1671,11 +1675,16 @@ disable_div_clk: if (i2c_dev->is_multimaster_mode) clk_disable(i2c_dev->div_clk); -disable_rpm: - pm_runtime_disable(&pdev->dev); - if (!pm_runtime_status_suspended(&pdev->dev)) +put_rpm: + if (pm_runtime_enabled(&pdev->dev)) + pm_runtime_put_sync(&pdev->dev); + else tegra_i2c_runtime_suspend(&pdev->dev); +disable_rpm: + if (pm_runtime_enabled(&pdev->dev)) + pm_runtime_disable(&pdev->dev); + unprepare_div_clk: clk_unprepare(i2c_dev->div_clk); -- cgit v1.2.3