From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4/A63MMCADie1/QJqVHGhGBEVnRfrIeL/LwmhSbG0LyHIzgoq/f+Wnz7moTexN6mIfJQoOD ARC-Seal: i=1; a=rsa-sha256; t=1523399723; cv=none; d=google.com; s=arc-20160816; b=lIALd54mkwwjWiRJB6AHoePaL/GNFV6b42mguIfmwqv+u17xtBWGgJyDNFA+G7LLPY Z0H96bu4ZnYZX0+yyzbTvkS88mDu8EvzY9ztoXcAN2X7HD4cVJFkGbFAJEo5JXvMZIb2 +tdQo0wKg9G6g0xNRbDMupC80adQNXbymBoXwQAzvewqTDTBftFGvxOluCr+bT+qyfIA 05rMiqgsrVRlpO89robTxOpT7iy3tOx+T7BJuFNakda6KoqmDR5FeIZ7WakFAF2xz+0n Bze85A9OwkTq5n89SnZfUOIMu2dkz1+vL5Y5WhZt2OXyVBVUZanwre5iwC0iVXHl8fp7 Qcsg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=VjDOYlGL2aHi130T9m/R6eEOPjit+HJ38YMC5sP9kDU=; b=Zr6ms9xJhlVC9H8N8seJrCFmi5QEFlqqeCQBddl6Uo130baeHdngb67t+ElLww60H7 R3/ilVIlah3zsv/7/BtFR3TxmDx4ogFOy0snB0mzBdqZ52biBU30lsU1iE2vyMXFR3A/ vmpZpxwAsuN/ZN91imwSEyv38u0HlYSetk3BKIRKOBMD6LQR+6u2GcHKV/e7qNLXYJ3s 3HPgCrvP6Qu3C4idREWauO39ng5/CqaXB0f9QbfnIrIksjLRj8Q6xI9DVkIx6pu5Zrxn 5utZHgacSJgNhTI2+SZ3cL3JqipHZUGdKnrhTVVh38HHZ85XRuwxU335KeOd1RY1eQIy bPaQ== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrea Adami , Robert Jarzmik , Daniel Thompson , Lee Jones , Sasha Levin Subject: [PATCH 4.14 041/138] backlight: tdo24m: Fix the SPI CS between transfers Date: Wed, 11 Apr 2018 00:23:51 +0200 Message-Id: <20180410212906.828064031@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180410212902.121524696@linuxfoundation.org> References: <20180410212902.121524696@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1597399987909827945?= X-GMAIL-MSGID: =?utf-8?q?1597400388688966987?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Robert Jarzmik [ Upstream commit 2023b0524a6310e9ea80daf085f51c71bff9289f ] Currently the LCD display (TD035S) on the cm-x300 platform is broken and remains blank. The TD0245S specification requires that the chipselect is toggled between commands sent to the panel. This was also the purpose of the former patch of commit f64dcac0b124 ("backlight: tdo24m: ensure chip select changes between transfers"). Unfortunately, the "cs_change" field of a SPI transfer is misleading. Its true meaning is that for a SPI message holding multiple transfers, the chip select is toggled between each transfer, but for the last transfer it remains asserted. In this driver, all the SPI messages contain exactly one transfer, which means that each transfer is the last of its message, and as a consequence the chip select is never toggled. Actually, there was a second bug hidding the first one, hence the problem was not seen until v4.6. This problem was fixed by commit a52db659c79c ("spi: pxa2xx: Fix cs_change management") for PXA based boards. This fix makes the TD035S work again on a cm-x300 board. The same applies to other PXA boards, ie. corgi and tosa. Fixes: a52db659c79c ("spi: pxa2xx: Fix cs_change management") Reported-by: Andrea Adami Signed-off-by: Robert Jarzmik Acked-by: Daniel Thompson Signed-off-by: Lee Jones Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/video/backlight/corgi_lcd.c | 2 +- drivers/video/backlight/tdo24m.c | 2 +- drivers/video/backlight/tosa_lcd.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) --- a/drivers/video/backlight/corgi_lcd.c +++ b/drivers/video/backlight/corgi_lcd.c @@ -177,7 +177,7 @@ static int corgi_ssp_lcdtg_send(struct c struct spi_message msg; struct spi_transfer xfer = { .len = 1, - .cs_change = 1, + .cs_change = 0, .tx_buf = lcd->buf, }; --- a/drivers/video/backlight/tdo24m.c +++ b/drivers/video/backlight/tdo24m.c @@ -369,7 +369,7 @@ static int tdo24m_probe(struct spi_devic spi_message_init(m); - x->cs_change = 1; + x->cs_change = 0; x->tx_buf = &lcd->buf[0]; spi_message_add_tail(x, m); --- a/drivers/video/backlight/tosa_lcd.c +++ b/drivers/video/backlight/tosa_lcd.c @@ -49,7 +49,7 @@ static int tosa_tg_send(struct spi_devic struct spi_message msg; struct spi_transfer xfer = { .len = 1, - .cs_change = 1, + .cs_change = 0, .tx_buf = buf, };