[BUG] i2c-hid: ELAN Touchpad does not work on ASUS X580GD - Jian-Hong Pan

From: Jian-Hong Pan <jian-hong@endlessm.com>
To: Jiri Kosina <jikos@kernel.org>,
	Benjamin Tissoires <benjamin.tissoires@redhat.com>,
	Jani Nikula <jani.nikula@intel.com>,
	Hans de Goede <hdegoede@redhat.com>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Adrian Salido <salidoa@google.com>,
	Jason Gerecke <killertofu@gmail.com>,
	linux-input@vger.kernel.org,
	Jarkko Nikula <jarkko.nikula@linux.intel.com>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	Wolfram Sang <wsa@the-dreams.de>,
	linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
	Chris Chiu <chiu@endlessm.com>, Daniel Drake <drake@endlessm.com>,
	Linux Upstreaming Team <linux@endlessm.com>
Subject: [BUG] i2c-hid: ELAN Touchpad does not work on ASUS X580GD
Date: Fri, 4 May 2018 14:55:51 +0800	[thread overview]
Message-ID: <CAPpJ_ed-JPOzQPtyCdH4_C7dzEeM3fznus8XDuaojaiM_4nFpw@mail.gmail.com> (raw)

Hi,

We have an ASUS X580GD (Intel(R) Core(TM) i5-8300H CPU @ 2.30GHz) laptop
equipped with ELAN1200 touchpad which does not work totally, but the
external mouse works fine.

We have checked the input devices by "cat /proc/bus/input/devices", and
the touchpad does not appear in the list.

According to ASUS' information, the ELAN touchpad is attached to the i2c
bus of the system.  Then, we do find the corresponding error messages in
dmesg:

with kernel 4.15.15
[   10.290192] i2c_hid i2c-ELAN1200:00: i2c-ELAN1200:00 supply vdd not
found, using dummy regulator
[   10.290818] i2c_hid i2c-ELAN1200:00: can't add hid device: -22
[   10.290852] i2c_hid: probe of i2c-ELAN1200:00 failed with error -22

with kernel 4.16.7
[   10.638729] i2c_hid i2c-ELAN1200:00: i2c-ELAN1200:00 supply vdd not
found, using dummy regulator
[   10.639304] i2c_hid i2c-ELAN1200:00: unexpected HID descriptor
bcdVersion (0xff00)

Then check the i2c bus and get:
i2c-7
  name: Synopsys DesignWare I2C adapter
  firmware_path: \_SB_.PCI0.I2C1
  driver: i2c_designware

i2c-ELAN1200:00
  name: ELAN1200:00
  firmware_path: \_SB_.PCI0.I2C1.ETPD

Besides, according to ASUS's input, they observed that after entering
the OS, the frequency of SCL is too fast (about 600kHz) and the SCL High
time is around 450ns, not following I2C spec which is 0.6us.
https://pasteboard.co/HjzSWXd.png

so, we get the kernel 4.17-rc3 and add some debug message:

diff --git a/drivers/i2c/busses/i2c-designware-master.c
b/drivers/i2c/busses/i2c-designware-master.c
index fd36c39ddf4e..bbe76e033133 100644
--- a/drivers/i2c/busses/i2c-designware-master.c
+++ b/drivers/i2c/busses/i2c-designware-master.c
@@ -88,10 +88,12 @@ static int i2c_dw_init_master(struct dw_i2c_dev *dev)
        sda_falling_time = dev->sda_falling_time ?: 300; /* ns */
        scl_falling_time = dev->scl_falling_time ?: 300; /* ns */

+printk("%s sda falling %u scl falling %u\n", __func__,
sda_falling_time, scl_falling_time);
        /* Set SCL timing parameters for standard-mode */
        if (dev->ss_hcnt && dev->ss_lcnt) {
                hcnt = dev->ss_hcnt;
                lcnt = dev->ss_lcnt;
+printk("%s ss set hcnt %u lcnt %u\n", __func__, hcnt, lcnt);
        } else {
                hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev),
                                        4000,   /* tHD;STA = tHIGH = 4.0 us */
@@ -102,10 +104,11 @@ static int i2c_dw_init_master(struct dw_i2c_dev *dev)
                                        4700,   /* tLOW = 4.7 us */
                                        scl_falling_time,
                                        0);     /* No offset */
+printk("%s ss no hcnt %u lcnt %u\n", __func__, hcnt, lcnt);
        }
        dw_writel(dev, hcnt, DW_IC_SS_SCL_HCNT);
        dw_writel(dev, lcnt, DW_IC_SS_SCL_LCNT);
-       dev_dbg(dev->dev, "Standard-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
+       dev_err(dev->dev, "Standard-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);

        /* Set SCL timing parameters for fast-mode or fast-mode plus */
        if ((dev->clk_freq == 1000000) && dev->fp_hcnt && dev->fp_lcnt) {
@@ -114,6 +117,7 @@ static int i2c_dw_init_master(struct dw_i2c_dev *dev)
        } else if (dev->fs_hcnt && dev->fs_lcnt) {
                hcnt = dev->fs_hcnt;
                lcnt = dev->fs_lcnt;
+printk("%s fs set hcnt %u lcnt %u\n", __func__, hcnt, lcnt);
        } else {
                hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev),
                                        600,    /* tHD;STA = tHIGH = 0.6 us */
@@ -124,10 +128,11 @@ static int i2c_dw_init_master(struct dw_i2c_dev *dev)
                                        1300,   /* tLOW = 1.3 us */
                                        scl_falling_time,
                                        0);     /* No offset */
+printk("%s fs no hcnt %u lcnt %u\n", __func__, hcnt, lcnt);
        }
        dw_writel(dev, hcnt, DW_IC_FS_SCL_HCNT);
        dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT);
-       dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
+       dev_err(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);

        if ((dev->master_cfg & DW_IC_CON_SPEED_MASK) ==
                DW_IC_CON_SPEED_HIGH) {
@@ -141,7 +146,7 @@ static int i2c_dw_init_master(struct dw_i2c_dev *dev)
                        lcnt = dev->hs_lcnt;
                        dw_writel(dev, hcnt, DW_IC_HS_SCL_HCNT);
                        dw_writel(dev, lcnt, DW_IC_HS_SCL_LCNT);
-                       dev_dbg(dev->dev, "HighSpeed-mode HCNT:LCNT = %d:%d\n",
+                       dev_err(dev->dev, "HighSpeed-mode HCNT:LCNT = %d:%d\n",
                                hcnt, lcnt);
                }
        }
@@ -152,6 +157,7 @@ static int i2c_dw_init_master(struct dw_i2c_dev *dev)
                if (!dev->sda_hold_time) {
                        /* Keep previous hold time setting if no one set it */
                        dev->sda_hold_time = dw_readl(dev, DW_IC_SDA_HOLD);
+printk("%s no sda hold time and read from reg %u\n", __func__,
dev->sda_hold_time);
                }
                /*
                 * Workaround for avoiding TX arbitration lost in case I2C
@@ -163,7 +169,9 @@ static int i2c_dw_init_master(struct dw_i2c_dev *dev)
                if (!(dev->sda_hold_time & DW_IC_SDA_HOLD_RX_MASK))
                        dev->sda_hold_time |= 1 << DW_IC_SDA_HOLD_RX_SHIFT;
                dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD);
+printk("%s new ver sda hold time %u\n", __func__, dev->sda_hold_time);
        } else if (dev->sda_hold_time) {
+printk("%s old sda hold time %u\n", __func__, dev->sda_hold_time);
                dev_warn(dev->dev,
                        "Hardware too old to adjust SDA hold time.\n");
        }
diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c
b/drivers/i2c/busses/i2c-designware-pcidrv.c
index 86e1bd0b82e9..55ac4a6d31da 100644
--- a/drivers/i2c/busses/i2c-designware-pcidrv.c
+++ b/drivers/i2c/busses/i2c-designware-pcidrv.c
@@ -277,6 +277,7 @@ static int i2c_dw_pci_probe(struct pci_dev *pdev,
        dev->tx_fifo_depth = controller->tx_fifo_depth;
        dev->rx_fifo_depth = controller->rx_fifo_depth;

+printk("%s have scl sda config %s\n", __func__,
controller->scl_sda_cfg?"true":"false");
        adap = &dev->adapter;
        adap->owner = THIS_MODULE;
        adap->class = 0;
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c
b/drivers/i2c/busses/i2c-designware-platdrv.c
index 5660daf6c92e..90b443c6b472 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -115,6 +115,7 @@ static int dw_i2c_acpi_configure(struct
platform_device *pdev)
        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);

+printk("%s: freq %u and ss_ht %u fp_ht %u hs_ht %u fs_ht %u\n",
__func__, dev->clk_freq, ss_ht, fp_ht, hs_ht, fs_ht);
        switch (dev->clk_freq) {
        case 100000:
                dev->sda_hold_time = ss_ht;
@@ -310,6 +311,7 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
        if (has_acpi_companion(&pdev->dev))
                dw_i2c_acpi_configure(pdev);

+printk("%s clk freq %u\n", __func__, dev->clk_freq);
        /*
         * Only standard mode at 100kHz, fast mode at 400kHz,
         * fast mode plus at 1MHz and high speed mode at 3.4MHz are supported.
@@ -333,6 +335,9 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
                i2c_dw_configure_master(dev);

        dev->clk = devm_clk_get(&pdev->dev, NULL);
+printk("%s parent clk freq %u\n", __func__, clk_get_rate(dev->clk));
+if (dev->sda_hold_time)
+       printk("sda hold time %u\n", dev->sda_hold_time);
        if (!i2c_dw_prepare_clk(dev, true)) {
                dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;

Rebuild kernel, reboot and check dmesg again:
(the touchpad still not work)

[    5.004195] acpi PNP0C14:03: duplicate WMI GUID
05901221-D566-11D1-B2F0-00A0C9062910 (first instance was on
PNP0C14:02)
[    5.004250] acpi PNP0C14:04: duplicate WMI GUID
05901221-D566-11D1-B2F0-00A0C9062910 (first instance was on
PNP0C14:02)
[    5.022086] intel-lpss 0000:00:15.0: enabling device (0000 -> 0002)
[    5.056084] idma64 idma64.0: Found Intel integrated DMA 64-bit
[    5.057994] dw_i2c_acpi_configure: freq 400000 and ss_ht 0 fp_ht 0
hs_ht 0 fs_ht 0
[    5.057995] dw_i2c_plat_probe clk freq 400000
[    5.058001] dw_i2c_plat_probe parent clk freq 120000000
[    5.058025] i2c_dw_init_master sda falling 300 scl falling 300
[    5.058026] i2c_dw_init_master ss no hcnt 513 lcnt 599
[    5.058028] i2c_designware i2c_designware.0: Standard-mode
HCNT:LCNT = 513:599
[    5.058028] i2c_dw_init_master fs no hcnt 105 lcnt 191
[    5.058029] i2c_designware i2c_designware.0: Fast-mode HCNT:LCNT = 105:191
[    5.058033] i2c_dw_init_master new ver sda hold time 28
[    5.060998] Adding 7776500k swap on /dev/zram0.  Priority:-2
extents:1 across:7776500k SSFS
[    5.091397] cfg80211: Loading compiled-in X.509 certificates for
regulatory database
[    5.094840] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
[    5.097905] RAPL PMU: API unit is 2^-32 Joules, 5 fixed counters,
655360 ms ovfl timer
[    5.097907] RAPL PMU: hw unit of domain pp0-core 2^-14 Joules
[    5.097907] RAPL PMU: hw unit of domain package 2^-14 Joules
[    5.097908] RAPL PMU: hw unit of domain dram 2^-14 Joules
[    5.097908] RAPL PMU: hw unit of domain pp1-gpu 2^-14 Joules
[    5.097909] RAPL PMU: hw unit of domain psys 2^-14 Joules
[    5.098206] intel-lpss 0000:00:15.1: enabling device (0000 -> 0002)
[    5.098570] idma64 idma64.1: Found Intel integrated DMA 64-bit
[    5.098676] media: Linux media interface: v0.10
[    5.100423] dw_i2c_acpi_configure: freq 400000 and ss_ht 0 fp_ht 0
hs_ht 0 fs_ht 0
[    5.100424] dw_i2c_plat_probe clk freq 400000
[    5.100427] dw_i2c_plat_probe parent clk freq 120000000
[    5.100435] i2c_dw_init_master sda falling 300 scl falling 300
[    5.100436] i2c_dw_init_master ss no hcnt 513 lcnt 599
[    5.100437] i2c_designware i2c_designware.1: Standard-mode
HCNT:LCNT = 513:599
[    5.100438] i2c_dw_init_master fs no hcnt 105 lcnt 191
[    5.100439] i2c_designware i2c_designware.1: Fast-mode HCNT:LCNT = 105:191
[    5.100443] i2c_dw_init_master new ver sda hold time 28
[    5.102504] platform regulatory.0: Direct firmware load for
regulatory.db failed with error -2
[    5.102508] cfg80211: failed to load regulatory.db

According to the information "dw_i2c_plat_probe clk freq 400000" in the
dmesg, the system has the right SCL clock with 400K Hz.  But why it is
apparently not taking effect?

Thnaks,
Jian-Hong Pan
