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3b10e6eb68
The A31 uses a new push-pull two wire interface, which features higher transfer speeds (upto 6 MHz) in theory. While the hardware can burst 8 bytes each time, this driver will only see very little use and thus is limited to single byte transmission only. Signed-off-by: Oliver Schinagl <oliver@schinagl.nl> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Acked-by: Ian Campbell <ijc@hellion.org.uk>
118 lines
2.9 KiB
C
118 lines
2.9 KiB
C
/*
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* Sunxi A31 Power Management Unit
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*
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* (C) Copyright 2013 Oliver Schinagl <oliver@schinagl.nl>
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* http://linux-sunxi.org
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*
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* Based on sun6i sources and earlier U-Boot Allwiner A10 SPL work
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*
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* (C) Copyright 2006-2013
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* Allwinner Technology Co., Ltd. <www.allwinnertech.com>
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* Berg Xing <bergxing@allwinnertech.com>
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* Tom Cubie <tangliang@allwinnertech.com>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <errno.h>
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#include <asm/io.h>
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#include <asm/arch/cpu.h>
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#include <asm/arch/gpio.h>
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#include <asm/arch/p2wi.h>
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#include <asm/arch/prcm.h>
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#include <asm/arch/clock.h>
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#include <asm/arch/sys_proto.h>
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void p2wi_init(void)
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{
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struct sunxi_p2wi_reg *p2wi = (struct sunxi_p2wi_reg *)SUNXI_P2WI_BASE;
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/* Enable p2wi and PIO clk, and de-assert their resets */
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prcm_apb0_enable(PRCM_APB0_GATE_PIO | PRCM_APB0_GATE_P2WI);
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sunxi_gpio_set_cfgpin(SUNXI_GPL(0), SUNXI_GPL0_R_P2WI_SCK);
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sunxi_gpio_set_cfgpin(SUNXI_GPL(1), SUNXI_GPL1_R_P2WI_SDA);
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/* Reset p2wi controller and set clock to CLKIN(12)/8 = 1.5 MHz */
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writel(P2WI_CTRL_RESET, &p2wi->ctrl);
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sdelay(0x100);
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writel(P2WI_CC_SDA_OUT_DELAY(1) | P2WI_CC_CLK_DIV(8),
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&p2wi->cc);
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}
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int p2wi_change_to_p2wi_mode(u8 slave_addr, u8 ctrl_reg, u8 init_data)
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{
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struct sunxi_p2wi_reg *p2wi = (struct sunxi_p2wi_reg *)SUNXI_P2WI_BASE;
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unsigned long tmo = timer_get_us() + 1000000;
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writel(P2WI_PM_DEV_ADDR(slave_addr) |
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P2WI_PM_CTRL_ADDR(ctrl_reg) |
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P2WI_PM_INIT_DATA(init_data) |
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P2WI_PM_INIT_SEND,
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&p2wi->pm);
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while ((readl(&p2wi->pm) & P2WI_PM_INIT_SEND)) {
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if (timer_get_us() > tmo)
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return -ETIME;
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}
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return 0;
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}
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static int p2wi_await_trans(void)
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{
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struct sunxi_p2wi_reg *p2wi = (struct sunxi_p2wi_reg *)SUNXI_P2WI_BASE;
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unsigned long tmo = timer_get_us() + 1000000;
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int ret;
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u8 reg;
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while (1) {
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reg = readl(&p2wi->status);
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if (reg & P2WI_STAT_TRANS_ERR) {
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ret = -EIO;
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break;
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}
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if (reg & P2WI_STAT_TRANS_DONE) {
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ret = 0;
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break;
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}
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if (timer_get_us() > tmo) {
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ret = -ETIME;
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break;
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}
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}
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writel(reg, &p2wi->status); /* Clear status bits */
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return ret;
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}
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int p2wi_read(const u8 addr, u8 *data)
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{
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struct sunxi_p2wi_reg *p2wi = (struct sunxi_p2wi_reg *)SUNXI_P2WI_BASE;
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int ret;
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writel(P2WI_DATADDR_BYTE_1(addr), &p2wi->dataddr0);
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writel(P2WI_DATA_NUM_BYTES(1) |
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P2WI_DATA_NUM_BYTES_READ, &p2wi->numbytes);
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writel(P2WI_STAT_TRANS_DONE, &p2wi->status);
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writel(P2WI_CTRL_TRANS_START, &p2wi->ctrl);
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ret = p2wi_await_trans();
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*data = readl(&p2wi->data0) & P2WI_DATA_BYTE_1_MASK;
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return ret;
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}
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int p2wi_write(const u8 addr, u8 data)
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{
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struct sunxi_p2wi_reg *p2wi = (struct sunxi_p2wi_reg *)SUNXI_P2WI_BASE;
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writel(P2WI_DATADDR_BYTE_1(addr), &p2wi->dataddr0);
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writel(P2WI_DATA_BYTE_1(data), &p2wi->data0);
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writel(P2WI_DATA_NUM_BYTES(1), &p2wi->numbytes);
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writel(P2WI_STAT_TRANS_DONE, &p2wi->status);
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writel(P2WI_CTRL_TRANS_START, &p2wi->ctrl);
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return p2wi_await_trans();
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}
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