diff options
| -rw-r--r-- | drivers/i2c/busses/i2c-imx.c | 189 |
1 files changed, 187 insertions, 2 deletions
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index a35c366..6617e60 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -53,6 +53,11 @@ #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" @@ -117,6 +122,54 @@ #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 @@ -210,6 +263,12 @@ 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 = { @@ -879,6 +938,78 @@ 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 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) { @@ -894,8 +1025,13 @@ 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->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) @@ -1039,6 +1175,50 @@ 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 pinmux_cfg *pinmux_cfg; + struct device_node *scfg_node; + void __iomem *scfg_base = NULL; + + i2c_imx->gpio = of_get_named_gpio(np, "fsl-scl-gpio", 0); + if (!gpio_is_valid(i2c_imx->gpio)) { + dev_info(&pdev->dev, "fsl-scl-gpio 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 @@ -1094,6 +1274,11 @@ 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) + return ret; + /* Get I2C clock */ i2c_imx->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(i2c_imx->clk)) { |