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mmc: core: Add helper for parsing clock phase properties

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Drivers for MMC hosts that accept phase corrections can take advantage
of the helper by embedding an instance of struct mmc_clk_phase_map in
their private data and invoking mmc_of_parse_clk_phase() to extract
phase parameters. It is the responsibility of the host driver to
translate and apply the extracted values to hardware as required.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Link: https://lore.kernel.org/r/20210114031433.2388532-2-andrew@aj.id.au
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Andrew Jeffery 2021-01-14 13:44:28 +10:30 committed by Ulf Hansson
parent 7c7905df68
commit 3561afa026
2 changed files with 57 additions and 0 deletions
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44
drivers/mmc/core/host.c
View file

@ -163,6 +163,50 @@ static void mmc_retune_timer(struct timer_list *t)
mmc_retune_needed(host);
}
static void mmc_of_parse_timing_phase(struct device *dev, const char *prop,
struct mmc_clk_phase *phase)
{
int degrees[2] = {0};
int rc;
rc = device_property_read_u32_array(dev, prop, degrees, 2);
phase->valid = !rc;
if (phase->valid) {
phase->in_deg = degrees[0];
phase->out_deg = degrees[1];
}
}
void
mmc_of_parse_clk_phase(struct mmc_host *host, struct mmc_clk_phase_map *map)
{
struct device *dev = host->parent;
mmc_of_parse_timing_phase(dev, "clk-phase-legacy",
&map->phase[MMC_TIMING_LEGACY]);
mmc_of_parse_timing_phase(dev, "clk-phase-mmc-hs",
&map->phase[MMC_TIMING_MMC_HS]);
mmc_of_parse_timing_phase(dev, "clk-phase-sd-hs",
&map->phase[MMC_TIMING_SD_HS]);
mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr12",
&map->phase[MMC_TIMING_UHS_SDR12]);
mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr25",
&map->phase[MMC_TIMING_UHS_SDR25]);
mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr50",
&map->phase[MMC_TIMING_UHS_SDR50]);
mmc_of_parse_timing_phase(dev, "clk-phase-uhs-sdr104",
&map->phase[MMC_TIMING_UHS_SDR104]);
mmc_of_parse_timing_phase(dev, "clk-phase-uhs-ddr50",
&map->phase[MMC_TIMING_UHS_DDR50]);
mmc_of_parse_timing_phase(dev, "clk-phase-mmc-ddr52",
&map->phase[MMC_TIMING_MMC_DDR52]);
mmc_of_parse_timing_phase(dev, "clk-phase-mmc-hs200",
&map->phase[MMC_TIMING_MMC_HS200]);
mmc_of_parse_timing_phase(dev, "clk-phase-mmc-hs400",
&map->phase[MMC_TIMING_MMC_HS400]);
}
EXPORT_SYMBOL(mmc_of_parse_clk_phase);
/**
* mmc_of_parse() - parse host's device-tree node
* @host: host whose node should be parsed.

13
include/linux/mmc/host.h
View file

@ -79,6 +79,17 @@ struct mmc_ios {
bool enhanced_strobe; /* hs400es selection */
};
struct mmc_clk_phase {
bool valid;
u16 in_deg;
u16 out_deg;
};
#define MMC_NUM_CLK_PHASES (MMC_TIMING_MMC_HS400 + 1)
struct mmc_clk_phase_map {
struct mmc_clk_phase phase[MMC_NUM_CLK_PHASES];
};
struct mmc_host;
struct mmc_host_ops {
@ -490,6 +501,8 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *);
int mmc_add_host(struct mmc_host *);
void mmc_remove_host(struct mmc_host *);
void mmc_free_host(struct mmc_host *);
void mmc_of_parse_clk_phase(struct mmc_host *host,
struct mmc_clk_phase_map *map);
int mmc_of_parse(struct mmc_host *host);
int mmc_of_parse_voltage(struct device_node *np, u32 *mask);