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Tue, 28 Jun 2016 11:41:28 +0900 (KST) From: Andi Shyti To: Kukjin Kim , Krzysztof Kozlowski , Mark Brown Cc: Jaehoon Chung , linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, Andi Shyti , Andi Shyti Subject: [PATCH v2 2/5] spi: s3c64xx: consider the case when the CS line is not connected Date: Tue, 28 Jun 2016 11:41:12 +0900 Message-id: <1467081676-8442-3-git-send-email-andi.shyti@samsung.com> X-Mailer: git-send-email 2.8.1 In-reply-to: <1467081676-8442-1-git-send-email-andi.shyti@samsung.com> References: <1467081676-8442-1-git-send-email-andi.shyti@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrBLMWRmVeSWpSXmKPExsWyRsSkUPfm48Jwg+tNohbbjzxjtVj84zmT xdSHT9gsbvxqY7V4/cLQov/xa2aLTY+vsVpc3jWHzWLG+X1MFo0fb7I7cHlcX/KJ2WPTqk42 j81L6j36tqxi9Pi8SS6ANYrLJiU1J7MstUjfLoEr49+Gm+wFbeIV945MYW5gnCfcxcjBISFg IrFyqUwXIyeQKSZx4d56ti5GLg4hgRWMEifvzGWBSJhIvGq6yQKRmMUo8WDnZmYI5yOjROPn C2BVbAKaEk23f7CB2CICxRJPrv5nBSliFvjGKLHg5ERGkISwQLTEvI/tzCA2i4CqxKvb/9lA zuAVcJWY8lwEYpucxOXpD8DmcAq4SezYd4oVxBYCKlk/axnYTAmBbewSHfuPsEPMEZD4NvkQ C8Q7shKbDjBDzJGUOLjiBssERuEFjAyrGEVTC5ILipPSiwz1ihNzi0vz0vWS83M3MQIj4PS/ Z707GG8fsD7EKMDBqMTDe2FyYbgQa2JZcWXuIUZToA0TmaVEk/OBcZZXEm9obGZkYWpiamxk bmmmJM6rKPUzWEggPbEkNTs1tSC1KL6oNCe1+BAjEwenVAPj3TnGTo7yB7afDJ/l+Eve+hqT Def6WZdeyT94bKbzpiDue2eL63eJq3H6yr+ltu788E5xndnzEz+kr6bfZH8pwr+gkSEjXt1E +/XsNOMFUxLsH7w9JsKkkcO8dHNzyofkabe9JZ+z576ZevXwXKnpXHaTDh9Tjpq7fZrG8z1O 38V0HDbodU4SV2Ipzkg01GIuKk4EAIet90N7AgAA X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrGIsWRmVeSWpSXmKPExsVy+t9jQd0bjwvDDU5+1rTYfuQZq8XiH8+Z LKY+fMJmceNXG6vF6xeGFv2PXzNbbHp8jdXi8q45bBYzzu9jsmj8eJPdgcvj+pJPzB6bVnWy eWxeUu/Rt2UVo8fnTXIBrFENjDYZqYkpqUUKqXnJ+SmZeem2St7B8c7xpmYGhrqGlhbmSgp5 ibmptkouPgG6bpk5QEcpKZQl5pQChQISi4uV9O0wTQgNcdO1gGmM0PUNCYLrMTJAAwlrGDP+ bbjJXtAmXnHvyBTmBsZ5wl2MnBwSAiYSr5puskDYYhIX7q1n62Lk4hASmMUo8WDnZmYI5yOj ROPnC2BVbAKaEk23f7CB2CICxRJPrv5nBSliFvjGKLHg5ERGkISwQLTEvI/tzCA2i4CqxKvb /4EaODh4BVwlpjwXgdgmJ3F5+gOwOZwCbhI79p1iBbGFgErWz1rGOoGRdwEjwypGidSC5ILi pPRco7zUcr3ixNzi0rx0veT83E2M4Dh7Jr2D8fAu90OMAhyMSjy8FyYXhguxJpYVV+YeYpTg YFYS4c16BBTiTUmsrEotyo8vKs1JLT7EaAp010RmKdHkfGAKyCuJNzQ2MTOyNDI3tDAyNlcS 5338f12YkEB6YklqdmpqQWoRTB8TB6dUA2Pguv63Ct4nfy3u0zrWHfMgNDj8vbdVwfoFRnl8 kvJxvMWzpPScrtU+ue65+Nc+wbfTVmsk3FjKdc7965mMOelefC77nV7r1ig2b5h4b9r8+08u mZouFC98zmN6KOORTf0qjWsySqz7A8rOzWksPvz9mfS9i87iT34+3/7dVYGHQXDPtfP3WE2V WIozEg21mIuKEwEZn4kgyQIAAA== DLP-Filter: Pass X-MTR: 20000000000000000@CPGS X-CFilter-Loop: Reflected Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When the CS line is not connected, it is not needed to enable or disable the chip selection functionality from the s3c64xx devices in order to perform a transfer. Set the CS controller logically always enabled already during initialization (by writing '0' in the S3C64XX_SPI_SLAVE_SEL register) and never disable it. Signed-off-by: Andi Shyti --- Documentation/devicetree/bindings/spi/spi-samsung.txt | 3 +++ drivers/spi/spi-s3c64xx.c | 9 ++++++++- include/linux/platform_data/spi-s3c64xx.h | 1 + 3 files changed, 12 insertions(+), 1 deletion(-) diff --git a/Documentation/devicetree/bindings/spi/spi-samsung.txt b/Documentation/devicetree/bindings/spi/spi-samsung.txt index 6dbdeb3..930bc73 100644 --- a/Documentation/devicetree/bindings/spi/spi-samsung.txt +++ b/Documentation/devicetree/bindings/spi/spi-samsung.txt @@ -40,6 +40,9 @@ Optional Board Specific Properties: - cs-gpios: should specify GPIOs used for chipselects (see spi-bus.txt) +- no-cs-readback: the CS line is disconnected, therefore the device should not + operate based on CS signalling. + SPI Controller specific data in SPI slave nodes: - The spi slave nodes should provide the following information which is required diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c index 972367d..14269b0 100644 --- a/drivers/spi/spi-s3c64xx.c +++ b/drivers/spi/spi-s3c64xx.c @@ -315,6 +315,9 @@ static void s3c64xx_spi_set_cs(struct spi_device *spi, bool enable) struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(spi->master); + if (sdd->cntrlr_info->no_cs) + return; + if (enable) { if (!(sdd->port_conf->quirks & S3C64XX_SPI_QUIRK_CS_AUTO)) { writel(0, sdd->regs + S3C64XX_SPI_SLAVE_SEL); @@ -960,7 +963,9 @@ static void s3c64xx_spi_hwinit(struct s3c64xx_spi_driver_data *sdd, int channel) sdd->cur_speed = 0; - if (!(sdd->port_conf->quirks & S3C64XX_SPI_QUIRK_CS_AUTO)) + if (sci->no_cs) + writel(0, sdd->regs + S3C64XX_SPI_SLAVE_SEL); + else if (!(sdd->port_conf->quirks & S3C64XX_SPI_QUIRK_CS_AUTO)) writel(S3C64XX_SPI_SLAVE_SIG_INACT, sdd->regs + S3C64XX_SPI_SLAVE_SEL); /* Disable Interrupts - we use Polling if not DMA mode */ @@ -1015,6 +1020,8 @@ static struct s3c64xx_spi_info *s3c64xx_spi_parse_dt(struct device *dev) sci->num_cs = temp; } + sci->no_cs = of_property_read_bool(dev->of_node, "broken-cs"); + return sci; } #else diff --git a/include/linux/platform_data/spi-s3c64xx.h b/include/linux/platform_data/spi-s3c64xx.h index fb5625b..5c1e21c 100644 --- a/include/linux/platform_data/spi-s3c64xx.h +++ b/include/linux/platform_data/spi-s3c64xx.h @@ -38,6 +38,7 @@ struct s3c64xx_spi_csinfo { struct s3c64xx_spi_info { int src_clk_nr; int num_cs; + bool no_cs; int (*cfg_gpio)(void); dma_filter_fn filter; void *dma_tx;