linux/drivers/mmc/host/dw_mmc-rockchip.c
Doug Anderson e7791079ae mmc: dw_mmc: rockchip: Don't recalc the clock when it goes off
The "set_ios" function is called with a clock of 0 when the clock is
turning off.  There's no reason to go through all the extra Rockchip
logic (whose goal is to make sure DIV is 0 or 1) in that case.  The
Rockchip logic happened to work because the CCF will pick the lowest
possible rate when you ask it for a clock of 0, but it's silly to go
through all the remuxing and adjusting for no reason.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
2014-11-10 12:40:36 +01:00

140 lines
3.5 KiB
C

/*
* Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/mmc/host.h>
#include <linux/mmc/dw_mmc.h>
#include <linux/of_address.h>
#include "dw_mmc.h"
#include "dw_mmc-pltfm.h"
#define RK3288_CLKGEN_DIV 2
static void dw_mci_rockchip_prepare_command(struct dw_mci *host, u32 *cmdr)
{
*cmdr |= SDMMC_CMD_USE_HOLD_REG;
}
static int dw_mci_rk3288_setup_clock(struct dw_mci *host)
{
host->bus_hz /= RK3288_CLKGEN_DIV;
return 0;
}
static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
{
int ret;
unsigned int cclkin;
u32 bus_hz;
if (ios->clock == 0)
return;
/*
* cclkin: source clock of mmc controller
* bus_hz: card interface clock generated by CLKGEN
* bus_hz = cclkin / RK3288_CLKGEN_DIV
* ios->clock = (div == 0) ? bus_hz : (bus_hz / (2 * div))
*
* Note: div can only be 0 or 1
* if DDR50 8bit mode(only emmc work in 8bit mode),
* div must be set 1
*/
if (ios->bus_width == MMC_BUS_WIDTH_8 &&
ios->timing == MMC_TIMING_MMC_DDR52)
cclkin = 2 * ios->clock * RK3288_CLKGEN_DIV;
else
cclkin = ios->clock * RK3288_CLKGEN_DIV;
ret = clk_set_rate(host->ciu_clk, cclkin);
if (ret)
dev_warn(host->dev, "failed to set rate %uHz\n", ios->clock);
bus_hz = clk_get_rate(host->ciu_clk) / RK3288_CLKGEN_DIV;
if (bus_hz != host->bus_hz) {
host->bus_hz = bus_hz;
/* force dw_mci_setup_bus() */
host->current_speed = 0;
}
}
static const struct dw_mci_drv_data rk2928_drv_data = {
.prepare_command = dw_mci_rockchip_prepare_command,
};
static const struct dw_mci_drv_data rk3288_drv_data = {
.prepare_command = dw_mci_rockchip_prepare_command,
.set_ios = dw_mci_rk3288_set_ios,
.setup_clock = dw_mci_rk3288_setup_clock,
};
static const struct of_device_id dw_mci_rockchip_match[] = {
{ .compatible = "rockchip,rk2928-dw-mshc",
.data = &rk2928_drv_data },
{ .compatible = "rockchip,rk3288-dw-mshc",
.data = &rk3288_drv_data },
{},
};
MODULE_DEVICE_TABLE(of, dw_mci_rockchip_match);
static int dw_mci_rockchip_probe(struct platform_device *pdev)
{
const struct dw_mci_drv_data *drv_data;
const struct of_device_id *match;
if (!pdev->dev.of_node)
return -ENODEV;
match = of_match_node(dw_mci_rockchip_match, pdev->dev.of_node);
drv_data = match->data;
return dw_mci_pltfm_register(pdev, drv_data);
}
#ifdef CONFIG_PM_SLEEP
static int dw_mci_rockchip_suspend(struct device *dev)
{
struct dw_mci *host = dev_get_drvdata(dev);
return dw_mci_suspend(host);
}
static int dw_mci_rockchip_resume(struct device *dev)
{
struct dw_mci *host = dev_get_drvdata(dev);
return dw_mci_resume(host);
}
#endif /* CONFIG_PM_SLEEP */
static SIMPLE_DEV_PM_OPS(dw_mci_rockchip_pmops,
dw_mci_rockchip_suspend,
dw_mci_rockchip_resume);
static struct platform_driver dw_mci_rockchip_pltfm_driver = {
.probe = dw_mci_rockchip_probe,
.remove = __exit_p(dw_mci_pltfm_remove),
.driver = {
.name = "dwmmc_rockchip",
.of_match_table = dw_mci_rockchip_match,
.pm = &dw_mci_rockchip_pmops,
},
};
module_platform_driver(dw_mci_rockchip_pltfm_driver);
MODULE_AUTHOR("Addy Ke <addy.ke@rock-chips.com>");
MODULE_DESCRIPTION("Rockchip Specific DW-MSHC Driver Extension");
MODULE_ALIAS("platform:dwmmc-rockchip");
MODULE_LICENSE("GPL v2");