lkml.org 
[lkml]   [2021]   [Jun]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 02/10] i2c: xiic: Add standard mode support for > 255 byte read transfers
From
Date
On 5/31/21 3:19 PM, Raviteja Narayanam wrote:

[...]

> + if (i2c->dynamic) {
> + u8 bytes;
> + u16 val;
> +
> + /* Clear and enable Rx full interrupt. */
> + xiic_irq_clr_en(i2c, XIIC_INTR_RX_FULL_MASK |
> + XIIC_INTR_TX_ERROR_MASK);
> +
> + /*
> + * We want to get all but last byte, because the TX_ERROR IRQ
> + * is used to indicate error ACK on the address, and
> + * negative ack on the last received byte, so to not mix
> + * them receive all but last.
> + * In the case where there is only one byte to receive
> + * we can check if ERROR and RX full is set at the same time
> + */
> + rx_watermark = msg->len;
> + bytes = min_t(u8, rx_watermark, IIC_RX_FIFO_DEPTH);
> + bytes--;
> +
> + xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, bytes);
> +
> + local_irq_save(flags);
> + if (!(msg->flags & I2C_M_NOSTART))
> + /* write the address */
> + xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET,
> + i2c_8bit_addr_from_msg(msg) |
> + XIIC_TX_DYN_START_MASK);
> +
> + xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK);
> +
> + /* If last message, include dynamic stop bit with length */
> + val = (i2c->nmsgs == 1) ? XIIC_TX_DYN_STOP_MASK : 0;
> + val |= msg->len;
> +
> + xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, val);
> + local_irq_restore(flags);

Is local_irq_save()/local_irq_restore() used here to prevent concurrent
access to the XIIC ?

[...]

\
 
 \ /
  Last update: 2021-06-02 13:17    [W:0.093 / U:0.184 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site