rsb.c
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/*
* (C) Copyright 2014 Hans de Goede <hdegoede@redhat.com>
*
* Based on allwinner u-boot sources rsb code which is:
* (C) Copyright 2007-2013
* Allwinner Technology Co., Ltd. <www.allwinnertech.com>
* lixiang <lixiang@allwinnertech.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <errno.h>
#include <asm/arch/cpu.h>
#include <asm/arch/gpio.h>
#include <asm/arch/prcm.h>
#include <asm/arch/rsb.h>
static int rsb_set_device_mode(void);
static void rsb_cfg_io(void)
{
#ifdef CONFIG_MACH_SUN8I
sunxi_gpio_set_cfgpin(SUNXI_GPL(0), SUN8I_GPL_R_RSB);
sunxi_gpio_set_cfgpin(SUNXI_GPL(1), SUN8I_GPL_R_RSB);
sunxi_gpio_set_pull(SUNXI_GPL(0), 1);
sunxi_gpio_set_pull(SUNXI_GPL(1), 1);
sunxi_gpio_set_drv(SUNXI_GPL(0), 2);
sunxi_gpio_set_drv(SUNXI_GPL(1), 2);
#elif defined CONFIG_MACH_SUN9I
sunxi_gpio_set_cfgpin(SUNXI_GPN(0), SUN9I_GPN_R_RSB);
sunxi_gpio_set_cfgpin(SUNXI_GPN(1), SUN9I_GPN_R_RSB);
sunxi_gpio_set_pull(SUNXI_GPN(0), 1);
sunxi_gpio_set_pull(SUNXI_GPN(1), 1);
sunxi_gpio_set_drv(SUNXI_GPN(0), 2);
sunxi_gpio_set_drv(SUNXI_GPN(1), 2);
#else
#error unsupported MACH_SUNXI
#endif
}
static void rsb_set_clk(void)
{
struct sunxi_rsb_reg * const rsb =
(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
u32 div = 0;
u32 cd_odly = 0;
/* Source is Hosc24M, set RSB clk to 3Mhz */
div = 24000000 / 3000000 / 2 - 1;
cd_odly = div >> 1;
if (!cd_odly)
cd_odly = 1;
writel((cd_odly << 8) | div, &rsb->ccr);
}
int rsb_init(void)
{
struct sunxi_rsb_reg * const rsb =
(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
/* Enable RSB and PIO clk, and de-assert their resets */
prcm_apb0_enable(PRCM_APB0_GATE_PIO | PRCM_APB0_GATE_RSB);
/* Setup external pins */
rsb_cfg_io();
writel(RSB_CTRL_SOFT_RST, &rsb->ctrl);
rsb_set_clk();
return rsb_set_device_mode();
}
static int rsb_await_trans(void)
{
struct sunxi_rsb_reg * const rsb =
(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
unsigned long tmo = timer_get_us() + 1000000;
u32 stat;
int ret;
while (1) {
stat = readl(&rsb->stat);
if (stat & RSB_STAT_LBSY_INT) {
ret = -EBUSY;
break;
}
if (stat & RSB_STAT_TERR_INT) {
ret = -EIO;
break;
}
if (stat & RSB_STAT_TOVER_INT) {
ret = 0;
break;
}
if (timer_get_us() > tmo) {
ret = -ETIME;
break;
}
}
writel(stat, &rsb->stat); /* Clear status bits */
return ret;
}
static int rsb_set_device_mode(void)
{
struct sunxi_rsb_reg * const rsb =
(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
unsigned long tmo = timer_get_us() + 1000000;
writel(RSB_DMCR_DEVICE_MODE_START | RSB_DMCR_DEVICE_MODE_DATA,
&rsb->dmcr);
while (readl(&rsb->dmcr) & RSB_DMCR_DEVICE_MODE_START) {
if (timer_get_us() > tmo)
return -ETIME;
}
return rsb_await_trans();
}
static int rsb_do_trans(void)
{
struct sunxi_rsb_reg * const rsb =
(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
setbits_le32(&rsb->ctrl, RSB_CTRL_START_TRANS);
return rsb_await_trans();
}
int rsb_set_device_address(u16 device_addr, u16 runtime_addr)
{
struct sunxi_rsb_reg * const rsb =
(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
writel(RSB_DEVADDR_RUNTIME_ADDR(runtime_addr) |
RSB_DEVADDR_DEVICE_ADDR(device_addr), &rsb->devaddr);
writel(RSB_CMD_SET_RTSADDR, &rsb->cmd);
return rsb_do_trans();
}
int rsb_write(const u16 runtime_device_addr, const u8 reg_addr, u8 data)
{
struct sunxi_rsb_reg * const rsb =
(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
writel(RSB_DEVADDR_RUNTIME_ADDR(runtime_device_addr), &rsb->devaddr);
writel(reg_addr, &rsb->addr);
writel(data, &rsb->data);
writel(RSB_CMD_BYTE_WRITE, &rsb->cmd);
return rsb_do_trans();
}
int rsb_read(const u16 runtime_device_addr, const u8 reg_addr, u8 *data)
{
struct sunxi_rsb_reg * const rsb =
(struct sunxi_rsb_reg *)SUNXI_RSB_BASE;
int ret;
writel(RSB_DEVADDR_RUNTIME_ADDR(runtime_device_addr), &rsb->devaddr);
writel(reg_addr, &rsb->addr);
writel(RSB_CMD_BYTE_READ, &rsb->cmd);
ret = rsb_do_trans();
if (ret)
return ret;
*data = readl(&rsb->data) & 0xff;
return 0;
}