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(dynamic-2a01-0c22-6e61-8c00-154f-326e-8d45-8ce7.c22.pool.telefonica.de. [2a01:c22:6e61:8c00:154f:326e:8d45:8ce7]) by smtp.googlemail.com with ESMTPSA id l4-20020a05600012c400b002bbb2d43f65sm20419613wrx.14.2023.01.15.02.18.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 15 Jan 2023 02:18:27 -0800 (PST) Message-ID: Date: Sun, 15 Jan 2023 11:15:48 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: [PATCH v3 2/3] i2c: algo: bit: allow getsda to be NULL Content-Language: en-US From: Heiner Kallweit To: Rob Herring , Krzysztof Kozlowski , Wolfram Sang Cc: "linux-i2c@vger.kernel.org" , "devicetree@vger.kernel.org" References: <3a5545f3-f858-2c80-8bd4-2e0d401a1dc0@gmail.com> In-Reply-To: <3a5545f3-f858-2c80-8bd4-2e0d401a1dc0@gmail.com> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org This is in preparation of supporting write-only SDA in i2c-gpio. Signed-off-by: Heiner Kallweit --- v3: - check for adap->getsda in readbytes() - align warning message level for info on missing getscl/getsda --- drivers/i2c/algos/i2c-algo-bit.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c index fc90293af..a1b822723 100644 --- a/drivers/i2c/algos/i2c-algo-bit.c +++ b/drivers/i2c/algos/i2c-algo-bit.c @@ -184,8 +184,9 @@ static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c) /* read ack: SDA should be pulled down by slave, or it may * NAK (usually to report problems with the data we wrote). + * Always report ACK if SDA is write-only. */ - ack = !getsda(adap); /* ack: sda is pulled low -> success */ + ack = !adap->getsda || !getsda(adap); /* ack: sda is pulled low -> success */ bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c, ack ? "A" : "NA"); @@ -232,6 +233,10 @@ static int test_bus(struct i2c_adapter *i2c_adap) const char *name = i2c_adap->name; int scl, sda, ret; + /* Testing not possible if both pins are write-only. */ + if (adap->getscl == NULL && adap->getsda == NULL) + return 0; + if (adap->pre_xfer) { ret = adap->pre_xfer(i2c_adap); if (ret < 0) @@ -420,6 +425,10 @@ static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) unsigned char *temp = msg->buf; int count = msg->len; const unsigned flags = msg->flags; + struct i2c_algo_bit_data *adap = i2c_adap->algo_data; + + if (!adap->getsda) + return -EOPNOTSUPP; while (count > 0) { inval = i2c_inb(i2c_adap); @@ -670,8 +679,11 @@ static int __i2c_bit_add_bus(struct i2c_adapter *adap, if (ret < 0) return ret; - /* Complain if SCL can't be read */ + if (bit_adap->getsda == NULL) + dev_warn(&adap->dev, "Not I2C compliant: can't read SDA\n"); + if (bit_adap->getscl == NULL) { + /* Complain if SCL can't be read */ dev_warn(&adap->dev, "Not I2C compliant: can't read SCL\n"); dev_warn(&adap->dev, "Bus may be unreliable\n"); }