ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
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 0000000..592b763
--- /dev/null
+++ b/target/linux/generic/backport-5.4/821-v5.8-i2c-pxa-implement-generic-i2c-bus-recovery.patch
@@ -0,0 +1,285 @@
+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(-)
+
+--- 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/i2c-pxa.h>
+ #include <linux/init.h>
+@@ -29,6 +30,7 @@
+ #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>
+@@ -261,6 +263,11 @@ 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)
+@@ -560,13 +567,8 @@ static void i2c_pxa_set_slave(struct pxa
+ #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));
+@@ -585,12 +587,25 @@ static void i2c_pxa_reset(struct pxa_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
+ /*
+@@ -1002,6 +1017,7 @@ static int i2c_pxa_do_xfer(struct pxa_i2
+ 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;
+ }
+
+@@ -1047,6 +1063,7 @@ static int i2c_pxa_do_xfer(struct pxa_i2
+
+ if (!timeout && i2c->msg_num) {
+ i2c_pxa_scream_blue_murder(i2c, "timeout with active message");
++ i2c_recover_bus(&i2c->adap);
+ ret = I2C_RETRY;
+ }
+
+@@ -1228,6 +1245,129 @@ static int i2c_pxa_probe_pdata(struct pl
+ 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);
+@@ -1240,6 +1380,16 @@ static int i2c_pxa_probe(struct platform
+ 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))
+@@ -1251,8 +1401,9 @@ static int i2c_pxa_probe(struct platform
+ 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)
+@@ -1260,9 +1411,6 @@ static int i2c_pxa_probe(struct platform
+ if (ret < 0)
+ return ret;
+
+- i2c->adap.owner = THIS_MODULE;
+- i2c->adap.retries = 5;
+-
+ spin_lock_init(&i2c->lock);
+ init_waitqueue_head(&i2c->wait);
+
+@@ -1332,12 +1480,6 @@ static int i2c_pxa_probe(struct platform
+
+ 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;