Re: [PATCH v3 4/7] Input: synaptics-rmi4 - f55: handle zero electrode count
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: 2025-03-10 19:00:16
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linux-devicetree, lkml, phone-devel
On Sat, Mar 08, 2025 at 03:08:40PM +0100, David Heidelberg via B4 Relay wrote:
quoted hunk ↗ jump to hunk
From: methanal <redacted> Some third party ICs claim to support f55 but report an electrode count of 0. Catch this and bail out early so that we don't confuse the i2c bus with 0 sized reads. Signed-off-by: methanal <redacted> [simplify code, adjust wording] Signed-off-by: Caleb Connolly <redacted> --- drivers/input/rmi4/rmi_f55.c | 5 +++++ 1 file changed, 5 insertions(+)diff --git a/drivers/input/rmi4/rmi_f55.c b/drivers/input/rmi4/rmi_f55.c index 488adaca4dd00482cd1106d813b32871092c83a0..ad2ef14ae9f4e897473db43334792cc3de966d52 100644 --- a/drivers/input/rmi4/rmi_f55.c +++ b/drivers/input/rmi4/rmi_f55.c@@ -52,6 +52,11 @@ static int rmi_f55_detect(struct rmi_function *fn) f55->num_rx_electrodes = f55->qry[F55_NUM_RX_OFFSET]; f55->num_tx_electrodes = f55->qry[F55_NUM_TX_OFFSET]; + if (!f55->num_rx_electrodes || !f55->num_tx_electrodes) { + rmi_dbg(RMI_DEBUG_FN, &fn->dev, + "F55 query returned no electrodes, giving up\n"); + return 0;
0 here means "successfully detected" and will result in F55 probe succeeding. I expect you want -EINVAL or -ENODEV here. Thanks. -- Dmitry