diff options
Diffstat (limited to 'target/linux/layerscape/patches-5.4/808-i2c-0008-i2c-imx-implement-bus-recovery-with-gpio-for-Layersc.patch')
| -rw-r--r-- | target/linux/layerscape/patches-5.4/808-i2c-0008-i2c-imx-implement-bus-recovery-with-gpio-for-Layersc.patch | 268 |
1 files changed, 268 insertions, 0 deletions
diff --git a/target/linux/layerscape/patches-5.4/808-i2c-0008-i2c-imx-implement-bus-recovery-with-gpio-for-Layersc.patch b/target/linux/layerscape/patches-5.4/808-i2c-0008-i2c-imx-implement-bus-recovery-with-gpio-for-Layersc.patch new file mode 100644 index 0000000000..dacee2af8a --- /dev/null +++ b/target/linux/layerscape/patches-5.4/808-i2c-0008-i2c-imx-implement-bus-recovery-with-gpio-for-Layersc.patch @@ -0,0 +1,268 @@ +From ddf55be668a5e5a22d4b7729e7ba92d928983168 Mon Sep 17 00:00:00 2001 +From: Zhang Ying-22455 <ying.zhang22455@nxp.com> +Date: Fri, 1 Dec 2017 15:59:28 +0800 +Subject: [PATCH] i2c: imx: implement bus recovery with gpio for Layerscape + +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. + +Because pinctrl is not supported on Layerscape, current bus recovery +is not avalible for Layerscape. This patch uses an open drain GPIO +pin to connect to the IICx_SCL to drive nine clock pulses to unlock +the I2C bus. + +Signed-off-by: Zhang Ying-22455 <ying.zhang22455@nxp.com> +--- + drivers/i2c/busses/i2c-imx.c | 190 ++++++++++++++++++++++++++++++++++++++++++- + 1 file changed, 188 insertions(+), 2 deletions(-) + +--- a/drivers/i2c/busses/i2c-imx.c ++++ b/drivers/i2c/busses/i2c-imx.c +@@ -39,12 +39,18 @@ + #include <linux/of.h> + #include <linux/of_device.h> + #include <linux/of_dma.h> ++#include <linux/of_gpio.h> + #include <linux/pinctrl/consumer.h> + #include <linux/platform_data/i2c-imx.h> + #include <linux/platform_device.h> + #include <linux/pm_runtime.h> + #include <linux/sched.h> + #include <linux/slab.h> ++#include <linux/gpio.h> ++#include <linux/of_address.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" +@@ -110,6 +116,54 @@ + + #define I2C_PM_TIMEOUT 10 /* ms */ + ++enum pinmux_endian_type { ++ BIG_ENDIAN, ++ LITTLE_ENDIAN, ++}; ++ ++struct pinmux_cfg { ++ enum pinmux_endian_type endian; /* endian of RCWPMUXCR0 */ ++ u32 pmuxcr_offset; ++ u32 pmuxcr_set_bit; /* pin mux of RCWPMUXCR0 */ ++}; ++ ++static struct pinmux_cfg ls1012a_pinmux_cfg = { ++ .endian = BIG_ENDIAN, ++ .pmuxcr_offset = 0x430, ++ .pmuxcr_set_bit = 0x10, ++}; ++ ++static struct pinmux_cfg ls1043a_pinmux_cfg = { ++ .endian = BIG_ENDIAN, ++ .pmuxcr_offset = 0x40C, ++ .pmuxcr_set_bit = 0x10, ++}; ++ ++static struct pinmux_cfg ls1046a_pinmux_cfg = { ++ .endian = BIG_ENDIAN, ++ .pmuxcr_offset = 0x40C, ++ .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); ++ ++/* The SCFG, Supplemental Configuration Unit, provides SoC specific ++ * configuration and status registers for the device. There is a ++ * SDHC IO VSEL control register on SCFG for some platforms. It's ++ * used to support SDHC IO voltage switching. ++ */ ++static const struct of_device_id scfg_device_ids[] = { ++ { .compatible = "fsl,ls1012a-scfg", }, ++ { .compatible = "fsl,ls1043a-scfg", }, ++ { .compatible = "fsl,ls1046a-scfg", }, ++ {} ++}; + /* + * sorted list of clock divider, register value pairs + * taken from table 26-5, p.26-9, Freescale i.MX +@@ -205,6 +259,12 @@ struct imx_i2c_struct { + struct pinctrl_state *pinctrl_pins_gpio; + + struct imx_i2c_dma *dma; ++ int layerscape_bus_recover; ++ int gpio; ++ int need_set_pmuxcr; ++ int pmuxcr_set; ++ int pmuxcr_endian; ++ void __iomem *pmuxcr_addr; + }; + + static const struct imx_i2c_hwdata imx1_i2c_hwdata = { +@@ -923,6 +983,78 @@ static int i2c_imx_read(struct imx_i2c_s + 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 pmuxcr = 0; ++ int ret; ++ unsigned int i, temp; ++ ++ /* configure IICx_SCL/GPIO pin as a GPIO */ ++ if (i2c_imx->need_set_pmuxcr == 1) { ++ pmuxcr = ioread32be(i2c_imx->pmuxcr_addr); ++ if (i2c_imx->pmuxcr_endian == BIG_ENDIAN) ++ iowrite32be(i2c_imx->pmuxcr_set|pmuxcr, ++ i2c_imx->pmuxcr_addr); ++ else ++ iowrite32(i2c_imx->pmuxcr_set|pmuxcr, ++ i2c_imx->pmuxcr_addr); ++ } ++ ++ ret = gpio_request(i2c_imx->gpio, i2c_imx->adapter.name); ++ if (ret) { ++ 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_endian == BIG_ENDIAN) ++ iowrite32be(pmuxcr, i2c_imx->pmuxcr_addr); ++ else ++ iowrite32(pmuxcr, 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) + { +@@ -945,8 +1077,13 @@ static int i2c_imx_xfer(struct i2c_adapt + * 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->layerscape_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) +@@ -1093,6 +1230,50 @@ static int i2c_imx_init_recovery_info(st + 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 pinmux_cfg *pinmux_cfg; ++ struct device_node *scfg_node; ++ void __iomem *scfg_base = NULL; ++ ++ i2c_imx->gpio = of_get_named_gpio(np, "scl-gpios", 0); ++ if (!gpio_is_valid(i2c_imx->gpio)) { ++ dev_info(&pdev->dev, "scl-gpios not found\n"); ++ return 0; ++ } ++ pinmux_cfg = devm_kzalloc(&pdev->dev, sizeof(*pinmux_cfg), GFP_KERNEL); ++ if (!pinmux_cfg) ++ return -ENOMEM; ++ ++ i2c_imx->need_set_pmuxcr = 0; ++ of_id = of_match_node(pinmux_of_match, np); ++ if (of_id) { ++ pinmux_cfg = (struct pinmux_cfg *)of_id->data; ++ i2c_imx->pmuxcr_endian = pinmux_cfg->endian; ++ i2c_imx->pmuxcr_set = pinmux_cfg->pmuxcr_set_bit; ++ scfg_node = of_find_matching_node(NULL, scfg_device_ids); ++ if (scfg_node) { ++ scfg_base = of_iomap(scfg_node, 0); ++ if (scfg_base) { ++ i2c_imx->pmuxcr_addr = scfg_base + pinmux_cfg->pmuxcr_offset; ++ i2c_imx->need_set_pmuxcr = 1; ++ } ++ } ++ } ++ i2c_imx->layerscape_bus_recover = 1; ++ return 0; ++} ++ + static u32 i2c_imx_func(struct i2c_adapter *adapter) + { + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL +@@ -1217,8 +1398,13 @@ static int i2c_imx_probe(struct platform + i2c_imx, IMX_I2C_I2CR); + imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR); + ++#ifdef CONFIG_ARCH_LAYERSCAPE ++ /* Init optional bus recovery for layerscape */ ++ ret = i2c_imx_init_recovery_for_layerscape(i2c_imx, pdev); ++#else + /* Init optional bus recovery function */ + ret = i2c_imx_init_recovery_info(i2c_imx, pdev); ++#endif + /* Give it another chance if pinctrl used is not ready yet */ + if (ret == -EPROBE_DEFER) + goto clk_notifier_unregister; |