From ab5ec06a7070840bb64a125fe6e5b0ddcb36346c Mon Sep 17 00:00:00 2001 From: Kenny Levinsen Date: Tue, 30 Apr 2024 01:33:14 +0200 Subject: HID: i2c-hid: Retry address probe after delay MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Some STM microcontrollers need 400µs after rising clock edge in order to come out of their deep sleep state. This in turn means that our address probe will fail as the device is not ready to service it. Retry the probe once after a delay to see if the device came alive, otherwise treat the device as missing. Link: https://lore.kernel.org/all/20240405102436.3479210-1-lma@chromium.org/#t Co-developed-by: Radoslaw Biernacki Co-developed-by: Lukasz Majczak Signed-off-by: Kenny Levinsen Signed-off-by: Jiri Kosina --- drivers/hid/i2c-hid/i2c-hid-core.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) (limited to 'drivers/hid/i2c-hid') diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c index 2df1ab3c31cc..39ed58a8a04c 100644 --- a/drivers/hid/i2c-hid/i2c-hid-core.c +++ b/drivers/hid/i2c-hid/i2c-hid-core.c @@ -164,6 +164,24 @@ static u32 i2c_hid_lookup_quirk(const u16 idVendor, const u16 idProduct) return quirks; } +static int i2c_hid_probe_address(struct i2c_hid *ihid) +{ + int ret; + + /* + * Some STM-based devices need 400µs after a rising clock edge to wake + * from deep sleep, in which case the first read will fail. Try after a + * short sleep to see if the device came alive on the bus. Certain + * Weida Tech devices also need this. + */ + ret = i2c_smbus_read_byte(ihid->client); + if (ret < 0) { + usleep_range(400, 500); + ret = i2c_smbus_read_byte(ihid->client); + } + return ret < 0 ? ret : 0; +} + static int i2c_hid_xfer(struct i2c_hid *ihid, u8 *send_buf, int send_len, u8 *recv_buf, int recv_len) { @@ -1014,8 +1032,7 @@ static int __i2c_hid_core_probe(struct i2c_hid *ihid) struct hid_device *hid = ihid->hid; int ret; - /* Make sure there is something at this address */ - ret = i2c_smbus_read_byte(client); + ret = i2c_hid_probe_address(ihid); if (ret < 0) { i2c_hid_dbg(ihid, "nothing at this address: %d\n", ret); return -ENXIO; -- cgit v1.2.3 From 7d6f065de37c31c37e56611efd41260c66c868ca Mon Sep 17 00:00:00 2001 From: Kenny Levinsen Date: Tue, 30 Apr 2024 01:33:15 +0200 Subject: HID: i2c-hid: Use address probe to wake on resume Certain devices, both from STM and Weida Tech, need to be woken up after having entered a deeper sleep state. The relevant places to wake up such device is during our initial HID probe, and after resuming. A retry for power commands was previously added to i2c_hid_set_power to wake up Weida Tech devices, but lacked sufficient sleep for STM devices. Replace the power command retry with the same address probe we using during our initial HID probe. Signed-off-by: Kenny Levinsen Signed-off-by: Jiri Kosina --- drivers/hid/i2c-hid/i2c-hid-core.c | 21 ++++++++------------- 1 file changed, 8 insertions(+), 13 deletions(-) (limited to 'drivers/hid/i2c-hid') diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c index 39ed58a8a04c..13666c27b02e 100644 --- a/drivers/hid/i2c-hid/i2c-hid-core.c +++ b/drivers/hid/i2c-hid/i2c-hid-core.c @@ -408,19 +408,6 @@ static int i2c_hid_set_power(struct i2c_hid *ihid, int power_state) i2c_hid_dbg(ihid, "%s\n", __func__); - /* - * Some devices require to send a command to wakeup before power on. - * The call will get a return value (EREMOTEIO) but device will be - * triggered and activated. After that, it goes like a normal device. - */ - if (power_state == I2C_HID_PWR_ON) { - ret = i2c_hid_set_power_command(ihid, I2C_HID_PWR_ON); - - /* Device was already activated */ - if (!ret) - goto set_pwr_exit; - } - ret = i2c_hid_set_power_command(ihid, power_state); if (ret) dev_err(&ihid->client->dev, @@ -999,6 +986,14 @@ static int i2c_hid_core_resume(struct i2c_hid *ihid) enable_irq(client->irq); + /* Make sure the device is awake on the bus */ + ret = i2c_hid_probe_address(ihid); + if (ret < 0) { + dev_err(&client->dev, "nothing at address after resume: %d\n", + ret); + return -ENXIO; + } + /* Instead of resetting device, simply powers the device on. This * solves "incomplete reports" on Raydium devices 2386:3118 and * 2386:4B33 and fixes various SIS touchscreens no longer sending -- cgit v1.2.3 From d2b34fa81445193532e7012106f60426de3b3718 Mon Sep 17 00:00:00 2001 From: Kenny Levinsen Date: Tue, 7 May 2024 08:36:56 +0200 Subject: HID: i2c-hid: Remove unused label in i2c_hid_set_power This label was left behind when the wake-up logic was moved from i2c_hid_set_power to i2c_hid_probe_address. Clean it up as it causes warnings-as-errors builds to fail. Fixes: bb1033c8a3ea ("HID: i2c-hid: Use address probe to wake on resume") Reported-by: Stephen Rothwell Signed-off-by: Kenny Levinsen Signed-off-by: Jiri Kosina --- drivers/hid/i2c-hid/i2c-hid-core.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'drivers/hid/i2c-hid') diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c index 13666c27b02e..aa460f67c7b5 100644 --- a/drivers/hid/i2c-hid/i2c-hid-core.c +++ b/drivers/hid/i2c-hid/i2c-hid-core.c @@ -413,8 +413,6 @@ static int i2c_hid_set_power(struct i2c_hid *ihid, int power_state) dev_err(&ihid->client->dev, "failed to change power setting.\n"); -set_pwr_exit: - /* * The HID over I2C specification states that if a DEVICE needs time * after the PWR_ON request, it should utilise CLOCK stretching. -- cgit v1.2.3