From c4841ae4059f5eb46af38f53793f772e3dac140b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micha=C5=82=20Barna=C5=9B?= Date: Mon, 19 Feb 2024 16:32:02 +0000 Subject: [PATCH 1/3] misc: atsha204a: remove broken for loop MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Some previous commit changed the continue statement to return, making the for loop used to retry waking up the chip to always return after one iteration. This commit removes the loop, cleaning the code a little. Signed-off-by: Michał Barnaś --- drivers/misc/atsha204a-i2c.c | 47 +++++++++++++++--------------------- 1 file changed, 20 insertions(+), 27 deletions(-) diff --git a/drivers/misc/atsha204a-i2c.c b/drivers/misc/atsha204a-i2c.c index d3c515828ff..ab83bbc3e95 100644 --- a/drivers/misc/atsha204a-i2c.c +++ b/drivers/misc/atsha204a-i2c.c @@ -96,40 +96,33 @@ int atsha204a_wakeup(struct udevice *dev) { u8 req[4]; struct atsha204a_resp resp; - int try, res; + int res; debug("Waking up ATSHA204A\n"); - for (try = 1; try <= 10; ++try) { - debug("Try %i... ", try); + /* + * The device ignores any levels or transitions on the SCL pin + * when the device is idle, asleep or during waking up. + * Don't check for error when waking up the device. + */ + memset(req, 0, 4); + atsha204a_send(dev, req, 4); - /* - * The device ignores any levels or transitions on the SCL pin - * when the device is idle, asleep or during waking up. - * Don't check for error when waking up the device. - */ - memset(req, 0, 4); - atsha204a_send(dev, req, 4); + udelay(ATSHA204A_TWLO_US + ATSHA204A_TWHI_US); - udelay(ATSHA204A_TWLO_US + ATSHA204A_TWHI_US); - - res = atsha204a_recv_resp(dev, &resp); - if (res) { - debug("failed on receiving response, ending\n"); - return res; - } - - if (resp.code != ATSHA204A_STATUS_AFTER_WAKE) { - debug ("failed (responce code = %02x), ending\n", - resp.code); - return -EBADMSG; - } - - debug("success\n"); - return 0; + res = atsha204a_recv_resp(dev, &resp); + if (res) { + debug("failed on receiving response, ending\n"); + return res; } - return -ETIMEDOUT; + if (resp.code != ATSHA204A_STATUS_AFTER_WAKE) { + debug("failed (response code = %02x), ending\n", resp.code); + return -EBADMSG; + } + + debug("success\n"); + return 0; } int atsha204a_idle(struct udevice *dev) From 6e0d4a7e02fa6d82f70fa74b9be564301111c462 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micha=C5=82=20Barna=C5=9B?= Date: Mon, 19 Feb 2024 16:32:03 +0000 Subject: [PATCH 2/3] misc: atsha204a: fix sleep function MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fix the sleep function to issue the sleep command instead of idle one. Signed-off-by: Michał Barnaś --- drivers/misc/atsha204a-i2c.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/misc/atsha204a-i2c.c b/drivers/misc/atsha204a-i2c.c index ab83bbc3e95..29daefb2a52 100644 --- a/drivers/misc/atsha204a-i2c.c +++ b/drivers/misc/atsha204a-i2c.c @@ -139,7 +139,7 @@ int atsha204a_idle(struct udevice *dev) int atsha204a_sleep(struct udevice *dev) { int res; - u8 req = ATSHA204A_FUNC_IDLE; + u8 req = ATSHA204A_FUNC_SLEEP; res = atsha204a_send(dev, &req, 1); if (res) From 2a31d71d830fa4269208c846256a5a274b0d70fb Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micha=C5=82=20Barna=C5=9B?= Date: Mon, 19 Feb 2024 16:32:04 +0000 Subject: [PATCH 3/3] misc: atsha204a: fix wakeup function MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The ATSHA204A chip requires SDA line to go low for at least 60us to wake up the chip. Previous implementation did not meet this requirement due to the NAK received on bus and not sending the zeroes. The function to ignore the NAK and send bytes regardless is not supported in the u-boot making it impossible to wake up the chip this way. Instead, the bus speed, if needed, is set to lowest value and the message is sent to the address 0x0. This way, the address of zero makes the SDA line go low for about 80us, meeting the required time to wake up the chip. The zero length packet is not sent by the i2c, so the one byte is sent to the transfer function, but only the address is sent anyway. After sending the zero address, the bus speed is restored to the previous value if it was slowed down to wake up the chip. Signed-off-by: Michał Barnaś --- drivers/misc/atsha204a-i2c.c | 49 ++++++++++++++++++++++++++++++++---- 1 file changed, 44 insertions(+), 5 deletions(-) diff --git a/drivers/misc/atsha204a-i2c.c b/drivers/misc/atsha204a-i2c.c index 29daefb2a52..707daa90bdb 100644 --- a/drivers/misc/atsha204a-i2c.c +++ b/drivers/misc/atsha204a-i2c.c @@ -21,7 +21,6 @@ #include #include -#define ATSHA204A_TWLO_US 60 #define ATSHA204A_TWHI_US 2500 #define ATSHA204A_TRANSACTION_TIMEOUT 100000 #define ATSHA204A_TRANSACTION_RETRY 5 @@ -34,6 +33,48 @@ static inline u16 atsha204a_crc16(const u8 *buffer, size_t len) return bitrev16(crc16(0, buffer, len)); } +static int atsha204a_ping_bus(struct udevice *dev) +{ + struct udevice *bus = dev_get_parent(dev); + struct i2c_msg msg; + int speed; + int res; + u8 val = 0; + + speed = dm_i2c_get_bus_speed(bus); + if (speed != I2C_SPEED_STANDARD_RATE) { + int rv; + + rv = dm_i2c_set_bus_speed(bus, I2C_SPEED_STANDARD_RATE); + if (rv) + debug("Couldn't change the I2C bus speed\n"); + } + + /* + * The I2C drivers don't support sending messages when NAK is received. + * This chip requires wake up low signal on SDA for >= 60us. + * To achieve this, we slow the bus to 100kHz and send an empty + * message to address 0. This will hold the SDA line low for the + * required time to wake up the chip. + */ + msg.addr = 0; + msg.flags = I2C_M_STOP; + msg.len = sizeof(val); + msg.buf = &val; + + res = dm_i2c_xfer(dev, &msg, 1); + + if (speed != I2C_SPEED_STANDARD_RATE) { + int rv; + + rv = dm_i2c_set_bus_speed(bus, speed); + if (rv) + debug("Couldn't restore the I2C bus speed\n"); + } + + return res; +} + static int atsha204a_send(struct udevice *dev, const u8 *buf, u8 len) { fdt_addr_t *priv = dev_get_priv(dev); @@ -94,7 +135,6 @@ static int atsha204a_recv_resp(struct udevice *dev, int atsha204a_wakeup(struct udevice *dev) { - u8 req[4]; struct atsha204a_resp resp; int res; @@ -105,10 +145,9 @@ int atsha204a_wakeup(struct udevice *dev) * when the device is idle, asleep or during waking up. * Don't check for error when waking up the device. */ - memset(req, 0, 4); - atsha204a_send(dev, req, 4); + atsha204a_ping_bus(dev); - udelay(ATSHA204A_TWLO_US + ATSHA204A_TWHI_US); + udelay(ATSHA204A_TWHI_US); res = atsha204a_recv_resp(dev, &resp); if (res) {