From b0de83e10498f0905187dc538a29ad8d50e7357b Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Fri, 19 May 2017 09:56:40 +0100 Subject: [PATCH] i2c: designware: don't infer timings described by ACPI from clock rate Commit 372205e6212f1 ("i2c: designware: Get selected speed mode sda-hold-time via ACPI") updated the logic that reads the timing parameters for various I2C bus rates from the DSDT, to only read the timing parameters for the currently selected mode. This causes a WARN_ON() splat on platforms that legally omit the clock frequency from the ACPI description, because in the new situation, the core I2C designware driver still accesses the fields in the driver struct that we no longer populate, and proceeds to calculate them from the clock frequency. Since the clock frequency is unspecified, the driver complains loudly using a WARN_ON(). So revert back to the old situation, where the struct fields for all timings are populated, but retain the new logic which chooses the SDA hold time from the timing mode that is currently in use. Fixes: 372205e6212f1 ("i2c: designware: Get selected speed mode ...") Signed-off-by: Ard Biesheuvel Reported-by: Lorenzo Pieralisi Acked-by: Jarkko Nikula Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-designware-platdrv.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c index f2acd4b6bf011..6283b99d2b17f 100644 --- a/drivers/i2c/busses/i2c-designware-platdrv.c +++ b/drivers/i2c/busses/i2c-designware-platdrv.c @@ -96,6 +96,7 @@ static int dw_i2c_acpi_configure(struct platform_device *pdev) struct dw_i2c_dev *dev = platform_get_drvdata(pdev); acpi_handle handle = ACPI_HANDLE(&pdev->dev); const struct acpi_device_id *id; + u32 ss_ht, fp_ht, hs_ht, fs_ht; struct acpi_device *adev; const char *uid; @@ -107,23 +108,24 @@ static int dw_i2c_acpi_configure(struct platform_device *pdev) * Try to get SDA hold time and *CNT values from an ACPI method for * selected speed modes. */ + dw_i2c_acpi_params(pdev, "SSCN", &dev->ss_hcnt, &dev->ss_lcnt, &ss_ht); + dw_i2c_acpi_params(pdev, "FPCN", &dev->fp_hcnt, &dev->fp_lcnt, &fp_ht); + dw_i2c_acpi_params(pdev, "HSCN", &dev->hs_hcnt, &dev->hs_lcnt, &hs_ht); + dw_i2c_acpi_params(pdev, "FMCN", &dev->fs_hcnt, &dev->fs_lcnt, &fs_ht); + switch (dev->clk_freq) { case 100000: - dw_i2c_acpi_params(pdev, "SSCN", &dev->ss_hcnt, &dev->ss_lcnt, - &dev->sda_hold_time); + dev->sda_hold_time = ss_ht; break; case 1000000: - dw_i2c_acpi_params(pdev, "FPCN", &dev->fp_hcnt, &dev->fp_lcnt, - &dev->sda_hold_time); + dev->sda_hold_time = fp_ht; break; case 3400000: - dw_i2c_acpi_params(pdev, "HSCN", &dev->hs_hcnt, &dev->hs_lcnt, - &dev->sda_hold_time); + dev->sda_hold_time = hs_ht; break; case 400000: default: - dw_i2c_acpi_params(pdev, "FMCN", &dev->fs_hcnt, &dev->fs_lcnt, - &dev->sda_hold_time); + dev->sda_hold_time = fs_ht; break; } -- 2.39.5