From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932422Ab3BSIgo (ORCPT ); Tue, 19 Feb 2013 03:36:44 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:24561 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1757736Ab3BSIgm convert rfc822-to-8bit (ORCPT ); Tue, 19 Feb 2013 03:36:42 -0500 X-IronPort-AV: E=Sophos;i="4.84,693,1355068800"; d="scan'208";a="6729143" Subject: Re: [PATCH v4 6/6] Input: Add ChromeOS EC keyboard driver From: li guang To: Simon Glass Cc: LKML , Samuel Ortiz , Luigi Semenzato , Vincent Palatin , Grant Likely , Rob Herring , Rob Landley , Dmitry Torokhov , Felipe Balbi , Sourav Poddar , Tony Lindgren , Greg Kroah-Hartman , "Mike A. Chan" , Jun Nakajima , Tom Keel , devicetree-discuss@lists.ozlabs.org, linux-doc@vger.kernel.org, linux-input@vger.kernel.org In-Reply-To: <1360988172-15380-7-git-send-email-sjg@chromium.org> References: <1360988172-15380-1-git-send-email-sjg@chromium.org> <1360988172-15380-7-git-send-email-sjg@chromium.org> Date: Tue, 19 Feb 2013 16:36:41 +0800 Message-ID: <1361263001.7859.11.camel@liguang.fnst.cn.fujitsu.com> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/02/19 16:35:56, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/02/19 16:35:58, Serialize complete at 2013/02/19 16:35:58 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2013-02-15五的 20:16 -0800，Simon Glass写道： > Use the key-matrix layer to interpret key scan information from the EC > and inject input based on the FDT-supplied key map. This driver registers > itself with the ChromeOS EC driver to perform communications. [snip ...] > +/* > + * Returns true when there is at least one combination of pressed keys that > + * results in ghosting. > + */ > +static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb *ckdev, uint8_t *buf) > +{ > + int row; > + > + /* > + * Ghosting happens if for any pressed key X there are other keys > + * pressed both in the same row and column of X as, for instance, > + * in the following diagram: > + * > + * . . Y . g . > + * . . . . . . > + * . . . . . . > + * . . X . Z . > + * > + * In this case only X, Y, and Z are pressed, but g appears to be > + * pressed too (see Wikipedia). > + * > + * We can detect ghosting in a single pass (*) over the keyboard state > + * by maintaining two arrays. pressed_in_row counts how many pressed > + * keys we have found in a row. row_has_teeth is true if any of the > + * pressed keys for this row has other pressed keys in its column. If > + * at any point of the scan we find that a row has multiple pressed > + * keys, and at least one of them is at the intersection with a column > + * with multiple pressed keys, we're sure there is ghosting. > + * Conversely, if there is ghosting, we will detect such situation for > + * at least one key during the pass. > + * > + * (*) This looks linear in the number of keys, but it's not. We can > + * cheat because the number of rows is small. > + */ > + for (row = 0; row < ckdev->rows; row++) { > + if (cros_ec_keyb_row_has_ghosting(ckdev, buf, row)) > + return true; > + } > + > + return false; > +} are you sure your EC's firmware did not do ghost-key detection? or, did you test ghost-key with/without your own ghost-key detection? as far as I know, ghost-key should be take care either by keyboard designer or firmware. > + > +/* > + * Compares the new keyboard state to the old one and produces key > + * press/release events accordingly. The keyboard state is 13 bytes (one byte > + * per column) > + */ > +static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev, > + uint8_t *kb_state, int len) > +{ > + int col, row; > + int new_state; > + int num_cols; > + > + num_cols = len; > + > + if (ckdev->ghost_filter && cros_ec_keyb_has_ghosting(ckdev, kb_state)) { > + /* > + * Simple-minded solution: ignore this state. The obvious > + * improvement is to only ignore changes to keys involved in > + * the ghosting, but process the other changes. > + */ > + dev_dbg(ckdev->dev, "ghosting found\n"); > + return; > + } > + > + for (col = 0; col < ckdev->cols; col++) { > + for (row = 0; row < ckdev->rows; row++) { > + int code = MATRIX_SCAN_CODE(row, col, ckdev->row_shift); > + > + new_state = kb_state[col] & (1 << row); > + if (!!new_state != test_bit(code, ckdev->idev->key)) { > + dev_dbg(ckdev->dev, > + "changed: [r%d c%d]: byte %02x\n", > + row, col, new_state); > + > + input_report_key(ckdev->idev, code, new_state); > + } > + } > + } > + input_sync(ckdev->idev); > +} > + > +static int cros_ec_keyb_open(struct input_dev *dev) > +{ > + struct cros_ec_keyb *ckdev = input_get_drvdata(dev); > + > + return blocking_notifier_chain_register(&ckdev->ec->event_notifier, > + &ckdev->notifier); > +} > + > +static void cros_ec_keyb_close(struct input_dev *dev) > +{ > + struct cros_ec_keyb *ckdev = input_get_drvdata(dev); > + > + blocking_notifier_chain_unregister(&ckdev->ec->event_notifier, > + &ckdev->notifier); > +} > + > +static int cros_ec_keyb_get_state(struct cros_ec_keyb *ckdev, uint8_t *kb_state) > +{ > + return ckdev->ec->command_recv(ckdev->ec, EC_CMD_MKBP_STATE, > + kb_state, ckdev->cols); > +} > + > +static int cros_ec_keyb_work(struct notifier_block *nb, > + unsigned long state, void *_notify) > +{ > + int ret; > + struct cros_ec_keyb *ckdev = container_of(nb, struct cros_ec_keyb, > + notifier); > + uint8_t kb_state[ckdev->cols]; > + > + ret = cros_ec_keyb_get_state(ckdev, kb_state); > + if (ret >= 0) > + cros_ec_keyb_process(ckdev, kb_state, ret); > + > + return NOTIFY_DONE; > +} > + > +/* Clear any keys in the buffer */ > +static void cros_ec_keyb_clear_keyboard(struct cros_ec_keyb *ckdev) > +{ > + uint8_t old_state[ckdev->cols]; > + uint8_t new_state[ckdev->cols]; > + unsigned long duration; > + int i, ret; > + > + /* > + * Keep reading until we see that the scan state does not change. > + * That indicates that we are done. > + * > + * Assume that the EC keyscan buffer is at most 32 deep. > + */ > + duration = jiffies; > + ret = cros_ec_keyb_get_state(ckdev, new_state); > + for (i = 1; !ret && i < 32; i++) { > + memcpy(old_state, new_state, sizeof(old_state)); > + ret = cros_ec_keyb_get_state(ckdev, new_state); > + if (0 == memcmp(old_state, new_state, sizeof(old_state))) > + break; > + } > + duration = jiffies - duration; > + dev_info(ckdev->dev, "Discarded %d keyscan(s) in %dus\n", i, > + jiffies_to_usecs(duration)); > +} > + > +static int cros_ec_keyb_probe(struct platform_device *pdev) > +{ > + struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent); > + struct device *dev = ec->dev; > + struct cros_ec_keyb *ckdev = NULL; > + struct input_dev *idev = NULL; > + struct device_node *np; > + int err; > + > + np = pdev->dev.of_node; > + if (!np) > + return -ENODEV; > + > + ckdev = kzalloc(sizeof(*ckdev), GFP_KERNEL); > + if (!ckdev) { > + dev_err(dev, "cannot allocate memory for ckdev\n"); > + return -ENOMEM; > + } > + err = matrix_keypad_parse_of_params(&pdev->dev, &ckdev->rows, > + &ckdev->cols); > + if (err) > + goto fail_alloc_dev; > + > + idev = input_allocate_device(); > + if (!idev) { > + err = -ENOMEM; > + dev_err(dev, "cannot allocate memory for input device\n"); > + goto fail_alloc_dev; > + } > + > + ckdev->ec = ec; > + ckdev->notifier.notifier_call = cros_ec_keyb_work; > + ckdev->dev = dev; > + dev_set_drvdata(&pdev->dev, ckdev); > + > + idev->name = ec->get_name(ec); > + idev->phys = ec->get_phys_name(ec); > + __set_bit(EV_REP, idev->evbit); > + > + idev->id.bustype = BUS_VIRTUAL; > + idev->id.version = 1; > + idev->id.product = 0; > + idev->dev.parent = &pdev->dev; > + idev->open = cros_ec_keyb_open; > + idev->close = cros_ec_keyb_close; > + > + ckdev->ghost_filter = of_property_read_bool(np, > + "google,needs-ghost-filter"); > + > + err = matrix_keypad_build_keymap(NULL, NULL, ckdev->rows, ckdev->cols, > + NULL, idev); > + if (err) { > + dev_err(dev, "cannot build key matrix\n"); > + goto fail_matrix; > + } > + > + ckdev->row_shift = get_count_order(ckdev->cols); > + > + input_set_capability(idev, EV_MSC, MSC_SCAN); > + input_set_drvdata(idev, ckdev); > + ckdev->idev = idev; > + err = input_register_device(ckdev->idev); > + if (err) { > + dev_err(dev, "cannot register input device\n"); > + goto fail_register; > + } > + > + return 0; > + > +fail_register: > + kfree(idev->keycode); > +fail_matrix: > + input_free_device(idev); > +fail_alloc_dev: > + kfree(ckdev); > + return err; > +} > + > +static int cros_ec_keyb_remove(struct platform_device *pdev) > +{ > + struct cros_ec_keyb *ckdev = platform_get_drvdata(pdev); > + struct input_dev *idev = ckdev->idev; > + > + input_unregister_device(idev); > + kfree(ckdev); > + > + return 0; > +} > + > +#ifdef CONFIG_PM_SLEEP > +static int cros_ec_keyb_resume(struct device *dev) > +{ > + struct cros_ec_keyb *ckdev = dev_get_drvdata(dev); > + > + /* > + * When the EC is not a wake source, then it could not have caused the > + * resume, so we clear the EC's key scan buffer. If the EC was a > + * wake source (e.g. the lid is open and the user might press a key to > + * wake) then the key scan buffer should be preserved. > + */ > + if (ckdev->ec->was_wake_device) > + cros_ec_keyb_clear_keyboard(ckdev); > + > + return 0; > +} > + > +#endif > + > +static SIMPLE_DEV_PM_OPS(cros_ec_keyb_pm_ops, NULL, cros_ec_keyb_resume); > + > +static struct platform_driver cros_ec_keyb_driver = { > + .probe = cros_ec_keyb_probe, > + .remove = cros_ec_keyb_remove, > + .driver = { > + .name = "cros-ec-keyb", > + .pm = &cros_ec_keyb_pm_ops, > + }, > +}; > + > +module_platform_driver(cros_ec_keyb_driver); > + > +MODULE_LICENSE("GPL"); > +MODULE_DESCRIPTION("ChromeOS EC keyboard driver"); > +MODULE_ALIAS("platform:cros-ec-keyb");