diff options
Diffstat (limited to 'target/linux/generic/backport-5.4/821-v5.8-i2c-pxa-implement-generic-i2c-bus-recovery.patch')
| -rw-r--r-- | target/linux/generic/backport-5.4/821-v5.8-i2c-pxa-implement-generic-i2c-bus-recovery.patch | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/target/linux/generic/backport-5.4/821-v5.8-i2c-pxa-implement-generic-i2c-bus-recovery.patch b/target/linux/generic/backport-5.4/821-v5.8-i2c-pxa-implement-generic-i2c-bus-recovery.patch new file mode 100644 index 0000000000..745cb6567c --- /dev/null +++ b/target/linux/generic/backport-5.4/821-v5.8-i2c-pxa-implement-generic-i2c-bus-recovery.patch @@ -0,0 +1,290 @@ +From: Russell King <rmk+kernel@armlinux.org.uk> +Bcc: linux@mail.armlinux.org.uk +Subject: [PATCH 7/7] i2c: pxa: implement generic i2c bus recovery +MIME-Version: 1.0 +Content-Disposition: inline +Content-Transfer-Encoding: 8bit +Content-Type: text/plain; charset="utf-8" + +Implement generic GPIO-based I2C bus recovery for the PXA I2C driver. + +Reviewed-by: Andrew Lunn <andrew@lunn.ch> +Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> +--- + drivers/i2c/busses/i2c-pxa.c | 176 +++++++++++++++++++++++++++++++---- + 1 file changed, 159 insertions(+), 17 deletions(-) + +diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c +index 0e194d6cd1b5..a7885b8b5031 100644 +--- a/drivers/i2c/busses/i2c-pxa.c ++++ b/drivers/i2c/busses/i2c-pxa.c +@@ -20,6 +20,7 @@ + #include <linux/delay.h> + #include <linux/err.h> + #include <linux/errno.h> ++#include <linux/gpio/consumer.h> + #include <linux/i2c.h> + #include <linux/init.h> + #include <linux/interrupt.h> +@@ -28,6 +29,7 @@ + #include <linux/module.h> + #include <linux/of.h> + #include <linux/of_device.h> ++#include <linux/pinctrl/consumer.h> + #include <linux/platform_device.h> + #include <linux/platform_data/i2c-pxa.h> + #include <linux/slab.h> +@@ -260,6 +262,11 @@ struct pxa_i2c { + bool highmode_enter; + u32 fm_mask; + u32 hs_mask; ++ ++ struct i2c_bus_recovery_info recovery; ++ struct pinctrl *pinctrl; ++ struct pinctrl_state *pinctrl_default; ++ struct pinctrl_state *pinctrl_recovery; + }; + + #define _IBMR(i2c) ((i2c)->reg_ibmr) +@@ -559,13 +566,8 @@ static void i2c_pxa_set_slave(struct pxa_i2c *i2c, int errcode) + #define i2c_pxa_set_slave(i2c, err) do { } while (0) + #endif + +-static void i2c_pxa_reset(struct pxa_i2c *i2c) ++static void i2c_pxa_do_reset(struct pxa_i2c *i2c) + { +- pr_debug("Resetting I2C Controller Unit\n"); +- +- /* abort any transfer currently under way */ +- i2c_pxa_abort(i2c); +- + /* reset according to 9.8 */ + writel(ICR_UR, _ICR(i2c)); + writel(I2C_ISR_INIT, _ISR(i2c)); +@@ -584,12 +586,25 @@ static void i2c_pxa_reset(struct pxa_i2c *i2c) + #endif + + i2c_pxa_set_slave(i2c, 0); ++} + ++static void i2c_pxa_enable(struct pxa_i2c *i2c) ++{ + /* enable unit */ + writel(readl(_ICR(i2c)) | ICR_IUE, _ICR(i2c)); + udelay(100); + } + ++static void i2c_pxa_reset(struct pxa_i2c *i2c) ++{ ++ pr_debug("Resetting I2C Controller Unit\n"); ++ ++ /* abort any transfer currently under way */ ++ i2c_pxa_abort(i2c); ++ i2c_pxa_do_reset(i2c); ++ i2c_pxa_enable(i2c); ++} ++ + + #ifdef CONFIG_I2C_PXA_SLAVE + /* +@@ -1043,6 +1058,7 @@ static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num) + ret = i2c_pxa_wait_bus_not_busy(i2c); + if (ret) { + dev_err(&i2c->adap.dev, "i2c_pxa: timeout waiting for bus free\n"); ++ i2c_recover_bus(&i2c->adap); + goto out; + } + +@@ -1088,6 +1104,7 @@ static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num) + + if (!timeout && i2c->msg_num) { + i2c_pxa_scream_blue_murder(i2c, "timeout with active message"); ++ i2c_recover_bus(&i2c->adap); + ret = I2C_RETRY; + } + +@@ -1277,6 +1294,129 @@ static int i2c_pxa_probe_pdata(struct platform_device *pdev, + return 0; + } + ++static void i2c_pxa_prepare_recovery(struct i2c_adapter *adap) ++{ ++ struct pxa_i2c *i2c = adap->algo_data; ++ u32 ibmr = readl(_IBMR(i2c)); ++ ++ /* ++ * Program the GPIOs to reflect the current I2C bus state while ++ * we transition to recovery; this avoids glitching the bus. ++ */ ++ gpiod_set_value(i2c->recovery.scl_gpiod, ibmr & IBMR_SCLS); ++ gpiod_set_value(i2c->recovery.sda_gpiod, ibmr & IBMR_SDAS); ++ ++ WARN_ON(pinctrl_select_state(i2c->pinctrl, i2c->pinctrl_recovery)); ++} ++ ++static void i2c_pxa_unprepare_recovery(struct i2c_adapter *adap) ++{ ++ struct pxa_i2c *i2c = adap->algo_data; ++ u32 isr; ++ ++ /* ++ * The bus should now be free. Clear up the I2C controller before ++ * handing control of the bus back to avoid the bus changing state. ++ */ ++ isr = readl(_ISR(i2c)); ++ if (isr & (ISR_UB | ISR_IBB)) { ++ dev_dbg(&i2c->adap.dev, ++ "recovery: resetting controller, ISR=0x%08x\n", isr); ++ i2c_pxa_do_reset(i2c); ++ } ++ ++ WARN_ON(pinctrl_select_state(i2c->pinctrl, i2c->pinctrl_default)); ++ ++ dev_dbg(&i2c->adap.dev, "recovery: IBMR 0x%08x ISR 0x%08x\n", ++ readl(_IBMR(i2c)), readl(_ISR(i2c))); ++ ++ i2c_pxa_enable(i2c); ++} ++ ++static int i2c_pxa_init_recovery(struct pxa_i2c *i2c) ++{ ++ struct i2c_bus_recovery_info *bri = &i2c->recovery; ++ struct device *dev = i2c->adap.dev.parent; ++ ++ /* ++ * When slave mode is enabled, we are not the only master on the bus. ++ * Bus recovery can only be performed when we are the master, which ++ * we can't be certain of. Therefore, when slave mode is enabled, do ++ * not configure bus recovery. ++ */ ++ if (IS_ENABLED(CONFIG_I2C_PXA_SLAVE)) ++ return 0; ++ ++ i2c->pinctrl = devm_pinctrl_get(dev); ++ if (IS_ERR(i2c->pinctrl)) ++ return PTR_ERR(i2c->pinctrl); ++ ++ if (!i2c->pinctrl) ++ return 0; ++ ++ i2c->pinctrl_default = pinctrl_lookup_state(i2c->pinctrl, ++ PINCTRL_STATE_DEFAULT); ++ i2c->pinctrl_recovery = pinctrl_lookup_state(i2c->pinctrl, "recovery"); ++ ++ if (IS_ERR(i2c->pinctrl_default) || IS_ERR(i2c->pinctrl_recovery)) { ++ dev_info(dev, "missing pinmux recovery information: %ld %ld\n", ++ PTR_ERR(i2c->pinctrl_default), ++ PTR_ERR(i2c->pinctrl_recovery)); ++ return 0; ++ } ++ ++ /* ++ * Claiming GPIOs can influence the pinmux state, and may glitch the ++ * I2C bus. Do this carefully. ++ */ ++ bri->scl_gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN); ++ if (bri->scl_gpiod == ERR_PTR(-EPROBE_DEFER)) ++ return -EPROBE_DEFER; ++ if (IS_ERR(bri->scl_gpiod)) { ++ dev_info(dev, "missing scl gpio recovery information: %pe\n", ++ bri->scl_gpiod); ++ return 0; ++ } ++ ++ /* ++ * We have SCL. Pull SCL low and wait a bit so that SDA glitches ++ * have no effect. ++ */ ++ gpiod_direction_output(bri->scl_gpiod, 0); ++ udelay(10); ++ bri->sda_gpiod = devm_gpiod_get(dev, "sda", GPIOD_OUT_HIGH_OPEN_DRAIN); ++ ++ /* Wait a bit in case of a SDA glitch, and then release SCL. */ ++ udelay(10); ++ gpiod_direction_output(bri->scl_gpiod, 1); ++ ++ if (bri->sda_gpiod == ERR_PTR(-EPROBE_DEFER)) ++ return -EPROBE_DEFER; ++ ++ if (IS_ERR(bri->sda_gpiod)) { ++ dev_info(dev, "missing sda gpio recovery information: %pe\n", ++ bri->sda_gpiod); ++ return 0; ++ } ++ ++ bri->prepare_recovery = i2c_pxa_prepare_recovery; ++ bri->unprepare_recovery = i2c_pxa_unprepare_recovery; ++ bri->recover_bus = i2c_generic_scl_recovery; ++ ++ i2c->adap.bus_recovery_info = bri; ++ ++ /* ++ * Claiming GPIOs can change the pinmux state, which confuses the ++ * pinctrl since pinctrl's idea of the current setting is unaffected ++ * by the pinmux change caused by claiming the GPIO. Work around that ++ * by switching pinctrl to the GPIO state here. We do it this way to ++ * avoid glitching the I2C bus. ++ */ ++ pinctrl_select_state(i2c->pinctrl, i2c->pinctrl_recovery); ++ ++ return pinctrl_select_state(i2c->pinctrl, i2c->pinctrl_default); ++} ++ + static int i2c_pxa_probe(struct platform_device *dev) + { + struct i2c_pxa_platform_data *plat = dev_get_platdata(&dev->dev); +@@ -1289,6 +1429,16 @@ static int i2c_pxa_probe(struct platform_device *dev) + if (!i2c) + return -ENOMEM; + ++ /* Default adapter num to device id; i2c_pxa_probe_dt can override. */ ++ i2c->adap.nr = dev->id; ++ i2c->adap.owner = THIS_MODULE; ++ i2c->adap.retries = 5; ++ i2c->adap.algo_data = i2c; ++ i2c->adap.dev.parent = &dev->dev; ++#ifdef CONFIG_OF ++ i2c->adap.dev.of_node = dev->dev.of_node; ++#endif ++ + res = platform_get_resource(dev, IORESOURCE_MEM, 0); + i2c->reg_base = devm_ioremap_resource(&dev->dev, res); + if (IS_ERR(i2c->reg_base)) +@@ -1298,8 +1448,9 @@ static int i2c_pxa_probe(struct platform_device *dev) + if (irq < 0) + return irq; + +- /* Default adapter num to device id; i2c_pxa_probe_dt can override. */ +- i2c->adap.nr = dev->id; ++ ret = i2c_pxa_init_recovery(i2c); ++ if (ret) ++ return ret; + + ret = i2c_pxa_probe_dt(dev, i2c, &i2c_type); + if (ret > 0) +@@ -1307,9 +1458,6 @@ static int i2c_pxa_probe(struct platform_device *dev) + if (ret < 0) + return ret; + +- i2c->adap.owner = THIS_MODULE; +- i2c->adap.retries = 5; +- + spin_lock_init(&i2c->lock); + init_waitqueue_head(&i2c->wait); + +@@ -1375,12 +1523,6 @@ static int i2c_pxa_probe(struct platform_device *dev) + + i2c_pxa_reset(i2c); + +- i2c->adap.algo_data = i2c; +- i2c->adap.dev.parent = &dev->dev; +-#ifdef CONFIG_OF +- i2c->adap.dev.of_node = dev->dev.of_node; +-#endif +- + ret = i2c_add_numbered_adapter(&i2c->adap); + if (ret < 0) + goto ereqirq; +-- +2.20.1 + |