Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757544Ab3FER6b (ORCPT ); Wed, 5 Jun 2013 13:58:31 -0400 Received: from kdh-gw.itdev.co.uk ([89.21.227.133]:26939 "EHLO hermes.kdh.itdev.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757100Ab3FERsO (ORCPT ); Wed, 5 Jun 2013 13:48:14 -0400 From: Nick Dyer To: Dmitry Torokhov , Daniel Kurtz , Henrik Rydberg , Joonyoung Shim , Alan.Bowens@atmel.com, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, pmeerw@pmeerw.net, bleung@chromium.org, olofj@chromium.org Cc: Nick Dyer Subject: [PATCH 13/53] Input: atmel_mxt_ts - Implement CRC check for configuration data Date: Wed, 5 Jun 2013 18:37:06 +0100 Message-Id: <1370453866-16534-14-git-send-email-nick.dyer@itdev.co.uk> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1370453866-16534-1-git-send-email-nick.dyer@itdev.co.uk> References: <1370453866-16534-1-git-send-email-nick.dyer@itdev.co.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5101 Lines: 169 The configuration is stored in NVRAM on the maXTouch chip. When the device is reset it reports a CRC of the stored configuration values. Therefore it isn't necessary to send the configuration on each probe - we can check the CRC matches and avoid a timeconsuming backup/reset cycle. Signed-off-by: Nick Dyer Acked-by: Benson Leung --- drivers/input/touchscreen/atmel_mxt_ts.c | 55 +++++++++++++++++++++++++----- include/linux/i2c/atmel_mxt_ts.h | 1 + 2 files changed, 48 insertions(+), 8 deletions(-) diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c index 82b001d..434e674 100644 --- a/drivers/input/touchscreen/atmel_mxt_ts.c +++ b/drivers/input/touchscreen/atmel_mxt_ts.c @@ -194,6 +194,7 @@ #define MXT_BACKUP_TIME 50 /* msec */ #define MXT_RESET_TIME 200 /* msec */ #define MXT_RESET_TIMEOUT 3000 /* msec */ +#define MXT_CRC_TIMEOUT 1000 /* msec */ #define MXT_FW_RESET_TIME 3000 /* msec */ #define MXT_FW_CHG_TIMEOUT 300 /* msec */ @@ -268,6 +269,7 @@ struct mxt_data { u16 mem_size; struct bin_attribute mem_access_attr; bool debug_enabled; + u32 config_crc; /* Cached parameters from object table */ u8 T6_reportid; @@ -282,6 +284,9 @@ struct mxt_data { /* for reset handling */ struct completion reset_completion; + /* for reset handling */ + struct completion crc_completion; + /* Enable reporting of input events */ bool enable_reporting; }; @@ -655,7 +660,7 @@ static void mxt_input_touchevent(struct mxt_data *data, } } -static unsigned mxt_extract_T6_csum(const u8 *csum) +static u16 mxt_extract_T6_csum(const u8 *csum) { return csum[0] | (csum[1] << 8) | (csum[2] << 16); } @@ -674,6 +679,7 @@ static irqreturn_t mxt_process_messages_until_invalid(struct mxt_data *data) u8 reportid; bool update_input = false; bool dump; + u32 crc; do { if (mxt_read_message(data, &message)) { @@ -686,9 +692,15 @@ static irqreturn_t mxt_process_messages_until_invalid(struct mxt_data *data) if (reportid == data->T6_reportid) { u8 status = payload[0]; - unsigned csum = mxt_extract_T6_csum(&payload[1]); + + crc = mxt_extract_T6_csum(&payload[1]); + if (crc != data->config_crc) { + data->config_crc = crc; + complete(&data->crc_completion); + } + dev_dbg(dev, "Status: %02x Config Checksum: %06x\n", - status, csum); + status, data->config_crc); if (status & MXT_T6_STATUS_RESET) complete(&data->reset_completion); @@ -784,6 +796,19 @@ static int mxt_soft_reset(struct mxt_data *data) return 0; } +static void mxt_update_crc(struct mxt_data *data, u8 cmd, u8 value) +{ + /* on failure, CRC is set to 0 and config will always be downloaded */ + data->config_crc = 0; + INIT_COMPLETION(data->crc_completion); + + mxt_t6_command(data, cmd, value, true); + + /* Wait for crc message. On failure, CRC is set to 0 and config will + * always be downloaded */ + mxt_wait_for_completion(data, &data->crc_completion, MXT_CRC_TIMEOUT); +} + static int mxt_check_reg_init(struct mxt_data *data) { const struct mxt_platform_data *pdata = data->pdata; @@ -798,6 +823,16 @@ static int mxt_check_reg_init(struct mxt_data *data) return 0; } + mxt_update_crc(data, MXT_COMMAND_REPORTALL, 1); + + if (data->config_crc == pdata->config_crc) { + dev_info(dev, "Config CRC 0x%06X: OK\n", data->config_crc); + return 0; + } else { + dev_info(dev, "Config CRC 0x%06X: does not match 0x%06X\n", + data->config_crc, pdata->config_crc); + } + for (i = 0; i < data->info.object_num; i++) { object = data->object_table + i; @@ -817,6 +852,14 @@ static int mxt_check_reg_init(struct mxt_data *data) index += size; } + mxt_update_crc(data, MXT_COMMAND_BACKUPNV, MXT_BACKUP_VALUE); + + ret = mxt_soft_reset(data); + if (ret) + return ret; + + dev_info(dev, "Config written\n"); + return 0; } @@ -982,11 +1025,6 @@ static int mxt_initialize(struct mxt_data *data) goto err_free_object_table; } - error = mxt_t6_command(data, MXT_COMMAND_BACKUPNV, - MXT_BACKUP_VALUE, false); - if (!error) - mxt_soft_reset(data); - /* Update matrix size at info struct */ error = mxt_read_reg(client, MXT_MATRIX_X_SIZE, &val); if (error) @@ -1392,6 +1430,7 @@ static int mxt_probe(struct i2c_client *client, init_completion(&data->bl_completion); init_completion(&data->reset_completion); + init_completion(&data->crc_completion); mxt_calc_resolution(data); diff --git a/include/linux/i2c/atmel_mxt_ts.h b/include/linux/i2c/atmel_mxt_ts.h index d26080d..9f92135 100644 --- a/include/linux/i2c/atmel_mxt_ts.h +++ b/include/linux/i2c/atmel_mxt_ts.h @@ -29,6 +29,7 @@ struct mxt_platform_data { const u8 *config; size_t config_length; + u32 config_crc; unsigned int x_size; unsigned int y_size; -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/