@@ -53,6 +53,11 @@
#include <linux/pm_runtime.h>
#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/libata.h>
/* This will be the driver name the kernel reports */
#define DRIVER_NAME "imx-i2c"
@@ -117,6 +122,39 @@
#define I2C_PM_TIMEOUT 10 /* ms */
+enum pinmux_endian_type {
+ BIG_ENDIAN,
+ LITTLE_ENDIAN,
+};
+
+struct pinmux_cfg {
+ enum pinmux_endian_type big_endian; /* endian of RCWPMUXCR0 */
+ u32 pmuxcr_set_bit; /* pin mux of RCWPMUXCR0 */
+};
+
+static struct pinmux_cfg ls1012a_pinmux_cfg = {
+ .big_endian = BIG_ENDIAN,
+ .pmuxcr_set_bit = 0x10,
+};
+
+static struct pinmux_cfg ls1043a_pinmux_cfg = {
+ .big_endian = BIG_ENDIAN,
+ .pmuxcr_set_bit = 0x10,
+};
+
+static struct pinmux_cfg ls1046a_pinmux_cfg = {
+ .big_endian = BIG_ENDIAN,
+ .pmuxcr_set_bit = 0x80000000,
+};
+
+static const struct of_device_id pinmux_of_match[] = {
+ { .compatible = "fsl,ls1012a-vf610-i2c", .data = &ls1012a_pinmux_cfg},
+ { .compatible = "fsl,ls1043a-vf610-i2c", .data = &ls1043a_pinmux_cfg},
+ { .compatible = "fsl,ls1046a-vf610-i2c", .data = &ls1046a_pinmux_cfg},
+ {},
+};
+MODULE_DEVICE_TABLE(of, pinmux_of_match);
+
/*
* sorted list of clock divider, register value pairs
* taken from table 26-5, p.26-9, Freescale i.MX
@@ -210,6 +248,12 @@ struct imx_i2c_struct {
struct pinctrl_state *pinctrl_pins_gpio;
struct imx_i2c_dma *dma;
+ int bus_recover;
+ int gpio;
+ int need_set_pmuxcr;
+ int pmuxcr_set;
+ int pmuxcr_endia;
+ void __iomem *pmuxcr_addr;
};
static const struct imx_i2c_hwdata imx1_i2c_hwdata = {
@@ -879,6 +923,78 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, bo
return 0;
}
+/*
+ * Based on the I2C specification, if the data line (SDA) is
+ * stuck low, the master should send nine * clock pulses.
+ * The I2C slave device that held the bus low should release it
+ * sometime within * those nine clocks. Due to this erratum,
+ * the I2C controller cannot generate nine clock pulses.
+ */
+static int i2c_imx_recovery_for_layerscape(struct imx_i2c_struct *i2c_imx)
+{
+ u32 ulPMUXCR0 = 0;
+ int ret;
+ unsigned int i, temp;
+
+ /* configure IICx_SCL/GPIO pin as a GPIO */
+ if (i2c_imx->need_set_pmuxcr == 1) {
+ ulPMUXCR0 = ioread32be(i2c_imx->pmuxcr_addr);
+ if (i2c_imx->pmuxcr_endia == BIG_ENDIAN)
+ iowrite32be(i2c_imx->pmuxcr_set|ulPMUXCR0,
+ i2c_imx->pmuxcr_addr);
+ else
+ iowrite32(i2c_imx->pmuxcr_set|ulPMUXCR0,
+ i2c_imx->pmuxcr_addr);
+ }
+
+ ret = gpio_request(i2c_imx->gpio, i2c_imx->adapter.name);
+ if (ret != 0) {
+ dev_err(&i2c_imx->adapter.dev,
+ "can't get gpio: %d\n", ret);
+ return ret;
+ }
+
+ /* Configure GPIO pin as an output and open drain. */
+ gpio_direction_output(i2c_imx->gpio, 1);
+ udelay(10);
+
+ /* Write data to generate 9 pulses */
+ for (i = 0; i < 9; i++) {
+ gpio_set_value(i2c_imx->gpio, 1);
+ udelay(10);
+ gpio_set_value(i2c_imx->gpio, 0);
+ udelay(10);
+ }
+ /* ensure that the last level sent is always high */
+ gpio_set_value(i2c_imx->gpio, 1);
+
+ /*
+ * Set I2Cx_IBCR = 0h00 to generate a STOP and then
+ * set I2Cx_IBCR = 0h80 to reset
+ */
+ temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
+ temp &= ~(I2CR_MSTA | I2CR_MTX);
+ imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
+
+ /* Restore the saved value of the register SCFG_RCWPMUXCR0 */
+ if (i2c_imx->need_set_pmuxcr == 1) {
+ if (i2c_imx->pmuxcr_endia == BIG_ENDIAN)
+ iowrite32be(ulPMUXCR0, i2c_imx->pmuxcr_addr);
+ else
+ iowrite32(ulPMUXCR0, i2c_imx->pmuxcr_addr);
+ }
+ /*
+ * Set I2C_IBSR[IBAL] to clear the IBAL bit if-
+ * I2C_IBSR[IBAL] = 1
+ */
+ temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
+ if (temp & I2SR_IAL) {
+ temp &= ~I2SR_IAL;
+ imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
+ }
+ return 0;
+}
+
static int i2c_imx_xfer(struct i2c_adapter *adapter,
struct i2c_msg *msgs, int num)
{
@@ -894,8 +1010,13 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter,
* before switching to master mode and attempting a Start cycle
*/
result = i2c_imx_bus_busy(i2c_imx, 0);
- if (result)
- goto out;
+ if (result) {
+ /* timeout */
+ if ((result == -ETIMEDOUT) && (i2c_imx->bus_recover == 1))
+ i2c_imx_recovery_for_layerscape(i2c_imx);
+ else
+ goto out;
+ }
result = pm_runtime_get_sync(i2c_imx->adapter.dev.parent);
if (result < 0)
@@ -1039,6 +1160,51 @@ static int i2c_imx_init_recovery_info(struct imx_i2c_struct *i2c_imx,
return 0;
}
+/*
+ * switch SCL and SDA to their GPIO function and do some bitbanging
+ * for bus recovery.
+ * There are platforms such as Layerscape that don't support pinctrl, so add
+ * workaround for layerscape, it has no effect for other platforms.
+ */
+static int i2c_imx_init_recovery_for_layerscape(
+ struct imx_i2c_struct *i2c_imx,
+ struct platform_device *pdev)
+{
+ const struct of_device_id *of_id;
+ struct device_node *np = pdev->dev.of_node;
+ struct resource *r;
+ struct pinmux_cfg *pinmux_cfg;
+
+ i2c_imx->gpio = of_get_named_gpio(np, "fsl-scl-gpio", 0);
+ if (!gpio_is_valid(i2c_imx->gpio)) {
+ dev_info(&pdev->dev, "recovery information incomplete\n");
+ return 0;
+ }
+ pinmux_cfg = devm_kzalloc(&pdev->dev, sizeof(*pinmux_cfg), GFP_KERNEL);
+ if (!pinmux_cfg)
+ return -ENOMEM;
+
+ of_id = of_match_node(pinmux_of_match, np);
+ if (of_id) {
+ i2c_imx->need_set_pmuxcr = 1;
+ pinmux_cfg = (struct pinmux_cfg *)of_id->data;
+ i2c_imx->pmuxcr_endia = pinmux_cfg->big_endian;
+ i2c_imx->pmuxcr_set = pinmux_cfg->pmuxcr_set_bit;
+ r = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+ "SCFG_RCWPMUXCR0");
+ if (r) {
+ i2c_imx->pmuxcr_addr = devm_ioremap_resource(&pdev->dev, r);
+ if (IS_ERR(i2c_imx->pmuxcr_addr))
+ return PTR_ERR(i2c_imx->pmuxcr_addr);
+ } else {
+ i2c_imx->need_set_pmuxcr = 0;
+ }
+ }
+
+ i2c_imx->bus_recover = 1;
+ return 0;
+}
+
static u32 i2c_imx_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
@@ -1094,6 +1260,11 @@ static int i2c_imx_probe(struct platform_device *pdev)
i2c_imx->adapter.dev.of_node = pdev->dev.of_node;
i2c_imx->base = base;
+ /* Init optional bus recovery for layerscape */
+ ret = i2c_imx_init_recovery_for_layerscape(i2c_imx, pdev);
+ if (ret != 0)
+ return ret;
+
/* Get I2C clock */
i2c_imx->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(i2c_imx->clk)) {